Effect of Morphological Plant Characters Towards Resistance Against Aphids on Wheat

EFFECT OF MORPHOLOGICAL PLANT CHARACTERS TOWARDS RESISTANCE AGAINST APHIDS ON WHEAT

By

Rizwan Rasool Roll. No. 665

Thesis submitted in partial fulfillment of the requirements for the degree of

MASTER OF SCIENCE IN

ZOOLOGY

DEPARTMENT OF ZOOLOGY GC UNIVERSITY, FAISALABAD.

JANUARY 2010

Declaration

The work reported in this thesis was carried out by me under the supervision of Dr.

Muhammad Hassan Department of Zoology GC University, Faisalabad, Pakistan.

I hereby declare that the “Effect of Morphological Plant Characters towards Resistance

against Aphids on Wheat” and the contents of thesis are the product of my own research and no

part has been copied from any published source (except the references, standard mathematical

or genetic models /equations /formulas /protocols etc). I further declare that this work has not

been submitted for award of any other degree /diploma. The University may take action if the

information provided is found inaccurate at any stage.

Signature of the Student

Registration No: Regd.No.2007-GCUF-2325-324

CERTIFICATE BY THE RESEARCH SUPERVISOR

I certify that the contents and form of thesis submitted by Mr. Rizwan

Rasool, Roll No.665, and Regd.No.2007-GCUF-2325-324 has been found

satisfactory and according to the prescribed format. I recommend it be

processed for evaluation by the External Examiner for the award of degree.

Supervisor Dr. Muhammad Hassan Chairperson, Department of Zoology, GC University, Faisalabad.

Co-Supervisor

Dr. Muhammad Mushtaq-ul Hassan Associate Professor, Department of Zoology, GC University, Faisalabad.

Co-Supervisor Dr. Amjad Ali Entomologist, Department of Entomology, Ayub Agriculture Research Institute, Faisalabad.

Chairperson

Dr. Muhammad Hassan Department of Zoology, GC University, Faisalabad. .

To

My Loving Father

SUB/MAJ. (R) Muhammad Aslam

Ghazi-e-Pakistan

Tamgha-e-Khidmat I

Whose love is more precious,

Than pearls and diamonds,

By virtue of whose prays I have been able to reach at this position.

My Worthy Mother

Muniran Beghum

Who is heaven for me,

Whose hands are always,

Raised for my well being even at this moment of time.

My Sweet and Cute Nephews and Nieces

Tayyab Ali Faiz, Sarmad Ali Faiz

Rida Fatima, Atroba Fatima, Saddos Fatima

CONTENTS

Chapter No. Title Page No.

List of Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i

List of Appendices. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii

List of Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii

Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix

INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

REVIEW OF LITERATURE . . . . . . . . . . . . . . . . . . . . . . . . . . 9

MATERIALS AND METHODS . . . . . . . . . . . . . . . . . . . . . . . . 17

RESULTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

DISCUSSION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

APPENDICES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

LIST OF TABLES

Description PAGE NO

Table 1. Analysis of Variance and Means Comparison of the Data Regarding Population of the Aphids in Various Genotypes of Wheat During 2009.

25

Table 2. Analysis of Variance and Means Comparison of the Data Regarding Leaf Size (cm2) in Various Genotypes of Wheat During 2009.

29

Table 3. Analysis of Variance and Means Comparison of the Data Regarding Chlorophyll Contents (%) in Various Genotypes of Wheat During 2009.

31

Table 4. Analysis of Variance and Means Comparison of the Data Regarding Number of Nodes in Various Genotypes of Wheat During 2009.

32

Table 5. Analysis of Variance and Means Comparison of the Data Regarding Internodal Distance (cm) in Various Genotypes of Wheat During 2009.

34

Table 6. Analysis of Variance and Means Comparison of the Data Regarding Plant Height (cm) in Various Genotypes of Wheat During 2009.

36

Table 7. Analysis of Variance and Means Comparison of the Data Regarding Number of Grains per Tiller in Various Genotypes of Wheat During 2009.

37

Table 8. Analysis of Variance and Means Comparison of the Data Regarding Number of Spikelets in Various Genotypes of Wheat During 2009.

38

Table 9. Analysis of Variance and Means Comparison of the Data Regarding Spike Length (cm) in Various Genotypes of Wheat During 2009.

40

LIST OF TABLES

Description PAGE NO

Table 10. Analysis of Variance and Means Comparison of the Data Regarding Number of Hair on Midrib in Various Genotypes of Wheat During 2009.

41

Table 11. Analysis of Variance and Means Comparison of the Data Regarding Number of Hair on Lamina ( per cm2) in Various Genotypes of Wheat During 2009.

42

Table 12. Analysis of Variance and Means Comparison of the Data Regarding Hair Length (µm) on Midrib in Various Genotypes of Wheat During 2009.

43

Table 13. Analysis of Variance and Means Comparison of the Data Regarding Hair Length (µm) on Lamina in Various Genotypes of Wheat During 2009.

44

Table 14. Correlation Coefficient Values between Aphids Population Per Tiller and Various Physico-Morphological Characters of Various Genotypes of Wheat During 2009.

46

Table 15. Multiple Regression Analysis along with Coefficient of Determination Values Among Aphids Density and Various Physico-Morphological Characters of Various Genotypes of Wheat During 2009.

47

LIST OF APPENDICES

Description PAGE NO

Appendix 1. Wheat aphids 62

Appendix 2. Data regarding aphids population per tiller in different genotypes of wheat on 14-02-2009.

63


64


65


66


67


68


69


70


71


72

LIST OF APPENDICES

Description PAGE NO


73


74


75


76

Appendix 16. Data regarding leaf area (cm2) in different genotypes of wheat.

77

Appendix 17. Data regarding chlorophyll contents (%) in different genotypes of wheat .

78

Appendix 18. Data regarding number of nodes (per tiller) in different genotypes of wheat.

79

Appendix 19. Data regarding inter-nodal distance (cm) in different genotypes of wheat..

80

Appendix 20. Data regarding plant height (cm) indifferent genotypes of wheat.

81

Appendix 21. Data regarding number of grains per tiller on different genotypes of wheat.

82

LIST OF APPENDICES

Description PAGE NO

Appendix 22. Data regarding number of spikelets per tiller in different genotypes/advanced lines of wheat.

83

Appendix 23. Data regarding spike length (cm) in different genotypes/advanced lines of wheat .

84

Appendix 24. Data regarding hair density on midrib (per cm) in different genotypes/advanced lines of wheat.

85

Appendix 25. Data regarding hair density on lamina (per cm2) in different genotypes/advanced lines of wheat.

86

Appendix 26. Data regarding hair length on midrib (µm)in different genotypes/advanced lines of wheat.

87

Appendix 27. Data regarding hair length on lamina (µm) in different genotypes/advanced lines of wheat.

88

LIST OF FIGURES

Description PAGE NO

Figure 1. Showing aphids population at different dates of observation.

26

Figure 2. Showing means comparison of aphids population in different genotypes of wheat.

27

SUMMARY

The study was conducted to determine the impact of various physico-

morphological plant characters viz., leaf area (cm2), chlorophyll contents (%), number

of nodes per tiller, inter-nodal distance (cm), plant height (cm), number of grains per

tiller, number of spikelets, spike length (cm), number of hair on midrib (per cm) and

lamina (per cm2) and length of hair(µm) on midrib and lamina on the population

fluctuation of aphids in different genotypes of wheat during 2009. The study was

carried out in the field area of Entomological Research Institute, Faisalabad, during

2009 following RCBD replicated thrice. The data regarding aphids‟ population were

recorded at 3 ± 2 days interval. The data were processed for simple correlation and

multiple linear regression analysis. The results are summarized as under:

- Significant differences were found among genotypes and dates of

observation regarding aphids‟ population.

- The genotype V-05066 was found comparatively susceptible with maximum

aphids‟ population i.e., 18.69 per tiller, whereas V-04178 was found

comparatively resistant with minimum population of aphids i.e., 5.73 per

tiller.

- February 24, 2009 showed maximum population of aphids (46.07/tiller) and

this population of aphids decreased on the subsequent dates of

observation.

- Variations were found to be significant among genotypes regarding leaf

area, chlorophyll contents, number of nodes per tiller and inter-nodal

distance.

- The genotypes under study did not differ significantly in their plant height,

number of grain per tiller, number of spikelets, spike length, number of hair

and length of hair.

- All the physico-morphological plant characters under study showed non

significant correlation with the population of aphids on wheat crop.

- Number of spikelets per plant was the most important factors which

contributed maximum i.e., (7.3%) in population fluctuation of the pest

followed by hair density on lamina (5.9%), leaf area (3.6%), plant height

(3.5%), hair density on midrib (3.0%), number of grains per tiller (2.2%) and

inter-nodal distance (2.0%). The other physico-morphological plant

characters showed negligible contribution ranged from (0.1 to 0.9%).

ACKNOWLEDGEMENTS

All praises and thanks to Almighty Allah, the compassionate, omnipotent ,whose

blessings and exaltations flourished my thoughts and thrive my ambitions and gave me

talented teachers, helping friends and honour me to be among those who make contributions to

sacred wealth for His humanity. Special praises and humblest thanks to the greatest social

reformer Holy Prophet Hazrat Muhammad (SAW), the most perfect of even born on the

surface of earth, who is a forever torch of guidance and knowledge for humanity.

With the profound, I acknowledge that this manuscript has found its way to significant

under the kind supervision of Dr. Muhammad Hassan Chairperson department of zoology,

GC University, Faisalabad, who is an ocean of love and affection to the students. I am very

thankful for his useful suggestions, inspiring guidance and consistence encouragement without

which this work would have never been materialized. It would be honorable for me to extend

the deepest sense of appreciation and gratitude for my worthy, learned and elite Dr.Amjad Ali,

Entomologist, Entomological Research Institute, Faisalabad and Dr. Muhammad Mushtaq-ul

Hassan, Associate Professor, Department of Zoology, G.C. University, Faisalabad for their

cordial cooperation, keen interest and, kind behavior.

I find no words to express my heartiest thanks to my nice fellows Sumaira, Naila,

Rashad, Hanif, Shahbaz, Naseer and Huda Zaidi and to my closest friend and research

fellow Sher Afghan who helped me during the course of my work. I am extremely grateful to

all my sweet and affectionate class fellows especially Faheem, Madeeha, Nida, Tatheer,

Amna, Arooj, Anisa, Fakhar Saqlain, Asma, Kiran, Saira, and Misbah who not only

supported me and boost me up during my research work, but also raised their hands for me in

prayers whenever I needed. Without these prayers and encouragement neither this work nor

anything else that I have been able to achieve could have seen the light of day.

I feel grateful to acknowledge the help and cooperation extended by all the professors

and non teacher staff of GC University Faisalabad and Entomology department, Ayub

Agriculture Research Institute, Faisalabad, for their direct and indirect guidance.

I owe my heartiest thanks and immense feelings of love for my sweet and beloved

brother Faiz Rasool, Aamir Rasool,Anayat Rasool and my sisters . Last but not the least, I

feel pleasure by extending my whole hearted thanks to my most loving and caring parents.

Rizwan Rasool

INTRODUCTION

Wheat, Triticum aestivum (L.), is a vital food crop, occupies the largest

cultivated area during Rabi season. The importance of wheat is increasing day by day

due to increased human population pressure in the country. Hence, it is need of the

day to boost per acre yield which is subjected to continuous genetic improvement of

wheat plant (Fida et al., 2003-2004). Average wheat yield in Pakistan has been

stagnant for the last seven years, widening the demand between demand and basic

staple food.

Wheat, as a human food is prized for its taste and as a source of calories,

protein, and certain vitamins and minerals, is the world, most important crop. Its

importance is derived from the properties of its gluten, a cohesive network of tough

endosperm, proteins that stretch with the expansion of the fermented dough, yet hold

together to produce a “risen” loaf of bread. Only the grain of wheat and to lesser

extent the grain of rye has this property. In addition to utilization of bread such as

“chapatti” in Pakistan and India, it is also used for pastry products. These uses

combined with its nutritive value and storage quality, have made wheat a staple food

for more than one third of the population. Out of the total food grain consumption, the

share of the wheat is more than 70 percent.

It is cultivated over 8.459 (m.ha) with the annual production of 23.031

(m.tones). The average global world wheat production from 1995-1999 was 584

million tons per annum (Marathia and Gomez-MacPherson, 2000) and world

production is expected to reach 860 million tons per annum by 2030 (Tolmay, 2006).

The average yield in the year 2007 was 2723 kg/ha (source: Ministry of Food,

Agriculture and Livestock, Federal Bureau Statistics).

Pakistan is one of the top producers of wheat in the world accounting for about

2% of the global wheat supply. Among the major producers, it has the third highest

growth rate in yield and production over the past twenty years. A more than three fold

increase in wheat production from 4.3 million tones in 1966-67 to 1990-91 represented

a nearly 6% rate of gain per year, considerably ahead of the population growth rate of

3.3% per year during the same period (PARC, 1986). There is an ample scope for

increasing wheat productivity. A continuing challenge to wheat production in Pakistan

is to exploit the potential of drier rain-fed areas where the pace of change has been

stagnant (NARC, 1996).

The per hectare yield of our country is lower as compared to other wheat

growing countries of the world. Various factors contribute to the low yield of Pakistan

such as lack of advanced methods of cultivation, use of low yielding varieties,

improper irrigation facilities, low level of soil fertility in some areas, insect pest attack.

The major cause for decline in the net yield.

Various species of insect pest attack on wheat however, aphids commonly

known as greenflies or plant lice belong to order Homoptera and family Aphididae

have great importance (Iqbal, 2003-2004). Wheat aphids, attack wheat, barley, oats,

etc, and are widely distributed in India. Like other aphids, the nymphs and adults suck

the cell sap from plants, particularly from their ears.

The insects are green, inert, louse like and appear on young leaves or ears in

large numbers during the cold and cloudy weathers. The nymphs and the females look

alike, except that the later are larger. The winged forms appear only in the early

summer. Due to the introduction of new varieties and use of insecticides, especially in

cotton growing areas, several species of aphids have become serious pests in some

areas. Among these, Wheat aphid, (Macrosiphum miscanthi), bud cheery aphids

(Rhopalosiphum padi) and English grain aphid (Sitobion avenae) are more common.

The aphid initiates feeding at the base of the leaves near the top of the plant. As the

colony develops, the leaf edges begin to roll inward, enclosing the aphids in tubular,

protective structure. This protection makes the aphid un-accessible to natural enemies

and insecticidal spray. As a result of salivary toxins injection by the aphid, plants

become purplish and develop longitudinal and whitish streaks on leaves. The damage

is particularly severe in cold and cloudy weather during winter. They mostly appear

from December to January.

Trdan and Milevoj (1999) reported that aphid caused 10 to 50%reduction in

crop yield directly and 20 - 80% indirectly. Dahams et al. (1985) tested Denton,

Wichita, Chinese and Russian wheat aphid. Like other winter aphids wheat aphid

breeds at a fast rate during the cold weather and reaches the height of its population

in February-March when the ears are ripening. The female give birth to the young

ones and are capable of reproducing without mating. During the active breeding

season, there are no males and the rate of reproduction is very high. When the wheat

crop is ripening and the summer is approaching, the winged forms of both males and

females appear on wheat. The plant lice suck sap from the ears and tender leaves,

and decrease yield of the crop. The damage is particularly severe in years of cold and

cloudy weather.

Aheer et al. (1993b) reported 36.7% loss in grain production due to

Macrosiphum granarium (k.) Hashmi et al. 1983 reported four aphid species on wheat,

these include, Sitobion avenae (F.), Schizaphis granarium (Rond), Rhopalosiphum

rufiabdominalis (Sastor) and Rhopalosiphum maidis (Fitch.) Popev et al. (1988)

surveyed aphid pests of wheat in 1983-85 and recorded 14 species attacking wheat

cultivars out of which S.avenae and R.maidis were not important. Geza (2000) found

29 aphid species among flying insects on winter wheat.

In Pakistan, wheat is severely attacked by wheat aphid (Mohyuddin,1981)

which adversely affects the yield (Emden, 1979; Abdulkhairova , 1979; Grima et

al.,1993). Cell sap sucking by aphids causes reduction in plant‟s vitality. The leaves

which are infested by aphid turn pale soon, wilt and wear a silky appearance. The

honeydew exuded by this insect encourages the snappy growth of sooty fungus on the

foliage, which eventually affects the rate of photosynthesis in plants. Kindler et al.

(1995) concluded that leaf curling is also caused by aphid feeding. Aheer et al.

(1993b) reported 7.19 aphids per tiller reduced 16.38 yields and as reported by

Kieckheter and Gallner (1992) 15 aphids per tiller caused 30 to 40 percent loss in

grain yield.

The aphid problem can be tackled with application of commonly used

insecticides, but the drawback lies with their indiscriminate use resulting in problems

of health hazards, environmental pollution and development of resistance in insects

against insecticides. World-wide use of insect resistant cultivars is seen as one of the

most desirable alternatives to insecticides because of their low cost and

environmentally friendly action (Burton et al., 1994). Therefore it is advised that such

varieties should be screened out which are resistant against aphid attack. Furthermore

wheat is a major food staple and use of any chemical insecticide will lead to the health

hazards and entry of various chemicals into food chain. By using chemical insecticides

natural balance also become disturbed, especially between predators and parasites.

Therefore it is advised that biological control should be practiced to avoid all these

problems. Biological control or biocontrol constitutes a deliberate attempt to use

natural enemies either by introducing new species into the environment of the pest or

by increasing the effectiveness of those already present. Traditionally, this method

employed to control insect pests by parasitoids, predators and pathogens and among

these we rely mostly on the predators. The most common predators of aphid in

Pakistan are Coccinellid beetles, Chrysoperla carnea and Syrphid fly.

Recently an attempt of biological control by intercropping of brassica lines in

Entomological Ayub Agriculture Research Institutes Fiasalabad has resulted in 79%

control of aphid. Beside the above mentioned cultural practice varietal resistance is an

important phenomenon in insect pest management. The factors involved in resistance

may be physical or chemical. The breeders in Pakistan focused their attention to

increase the yield potential and evolved a number of varieties of different crops with

higher yields. Unfortunately a little attention has been paid to factors responsible for

insect pest resistance. Initially much attention was devoted to the mechanical barriers

possessed by the plants (Grime, 1979) which prevented insects from feeding, or

ovipositing on them. With the recent advances in the knowledge in the physiology and

biochemistry of plant (Miller, 1973) and insects, it has become possible to determine

the physiological and biochemical nature of the plant immunity/resistance (Grime,

1979). The research for pest resistance in different plants by transferring genes into

the commercial cultivars has also attained a great momentum for the past few years

(Amir, 1977).

Painter (1951) described plant resistance as the “relative amount of the

heritable qualities that influence the ultimate degree of damage done by the insects”.

Maxwell et al. (1972) extended the definition of Painter (1951) by considering the level

of infestation and environmental conditions. According to them, resistance is “those

heritable characteristics possessed by the plant which influence the ultimate degree of

damage done by the insect. From a practical point of view, resistance is the ability of

certain varieties to produce larger yield of good quality than other varieties at the same

initial level of infestation and under similar environmental conditions.” According to

Starks et al. (1977) resistance to insects is the “inheritable property that enables a

plant to inhibit the growth of the insect population or to recover from injury caused by

populations that were not inhibited to grow”. Inhibition of population growth generally

derives from the biochemical or morphological characteristics of a plant which affect

the behavior or the metabolism of insects so as to reduce the relative degree of

damage these insects can partially cause. Painter (1951) grouped mechanism of

resistance into three main categories, viz., nonpreference, antibiosis, and tolerance.

Nonpreference refers to plant characteristics that lead insects away from a

particular host. Recently, the term antixenosis, has been suggested as a more

appropriate term for nonpreference. Xenosis in Greek means "Guest", and antixenosis

means against or expelling guests. Antibiosis refers to all adverse effects on the insect

life history which result when a resistant host plant variety or species is used for food.

Some effects of antibiosis mode of resistance are, reduced survival, reduced growth

rate, insects take longer time to complete the life cycle, reduced weight and size,

shortened adult life-span, reduced fecundity and morphological abnormalities.

Tolerance includes all plant responses resulting in the ability to withstand insect

infestations and yield satisfactorily in spite of injury levels that would debilitate

nonresistant plants. Unlike nonpreference and antibiosis, only plant response is

involved in tolerance.

Apparent resistance also referred as ecological resistance or pseudo

resistance. Apparent resistance is not heritable and is dependent heavily on

environment. The characteristics of this resistance are temporary and cultivars

involved are potentially susceptible. Resistant varieties are first line of defense in

cases where pesticides can not be used or other alternative controls are not available.

Resistant cultivars are compatible with chemical control, cultural control, behavioral

control, and in most cases are also compatible with biological control strategies.

Although the above widely recognized classification of mechanism appears to

provide a generally acceptable breakdown of the phenomenon of the host plant

resistance, however, some overlap may occur between antixenosis and antibiosis,

and a problem may arise in the separation of these two mechanisms. Antixenosis

refers to undesirability, i.e., avoidance of insects whereas antibiosis refers to

unsuitability, i.e., adverse effects on the insect after feeding on the host plant.

However, sometimes it becomes difficult to separate the two mechanisms unless the

insect-plant relationship is fully examined. Information in the number of the genes

involved in the resistance of plant to a particular insect pest has great practical

significance in identifying diverse sources of resistance and using these for breeding

broad-based resistant plants.

However the continuous growing of insect resistant varieties. The term biotype

is generally used to describe a population capable of damaging and surviving on

plants previously known to resistant to other populations of the same species. More

specifically, biotype refers to ten populations of the same species. More specifically,

biotype refers to the populations within species which can survive on and destroy

varieties that have genes for resistance (Heinrichs et al., 1985).

Development and standardization of screening techniques is pre-requisite to

any effective resistance breeding programme. Information about the periods of the

greatest insect activity and hot spots is the first step to initiate work on resistance

screening. Other effective means of augmenting insect populations, viz., delayed

plantings and use of infester rows of a susceptible cultivar may also be employed.

Screening of insect resistance under natural multi-choice field conditions. In order to

overcome these problems, it is essential to develop and standardize multi or no-choice

screening techniques where test cultivars can be subjected to uniform insect pressure

at the most susceptible stage of the crop. There are several examples which reveal

distinct advantages to farmers by growing insect-resistant varieties. The Hessian fly,

Mayetiola destructor (say), used to be a serious pest of wheat in USA, but its

incidence was reduced from nearly 100 percent to below 1 percent in certain areas by

cultivation of resistant varieties.

Several resistant lines of wheat, Triticum aestivum (L.), have been developed to

control populations of the Russian wheat aphid, Diuraphis noxia (Mayoral et al., 1996).

The yield losses from wheat stem sawfly alone could exceed 75 percent when

resistant varieties are not used. The resistance of wheat cultivars to natural infestation

by aphids was evaluated by adult weight, number of the pigmented eyes embryos

inside the adult and the portion of the flag leaves colonized. The main resistance

mechanism was thought to be antibiosis though non-preference may also have

occurred.

The international trend for reducing the impact of D. noxia on small grains is the

use of Russian wheat aphid resistant cultivars (Webster et al., 1987; Du Toit, 1989b;

Robinson et al., 1992). To date resistant cultivars have been developed and released

not only in South Africa (Tolmay and Van Deventer, 2005) but in the USA in Colorado

(Randolph et al., 2005) and Kansas (Qureshi et al., 2005). This proved to be a

worthwhile investment with researchers in the USA estimating the return on

investment in developing the resistant cultivar Halt to be 13:1 (Webster and Kenkel.,

1999) while Marasas et al. (1997) reported a rate of return benefit to society from the

yield gains of resistant cultivars in South Africa at 34%.

Using host plant resistance instead of chemical control or as a component of

IPM (Integrated Pest Management) certainly has an edge over the later as being an

economical, effective through growing season and environmentally safe. It has,

therefore, been proposed to investigate the various varieties of wheat for their

resistance/ susceptibility to various species of aphids under fields as well as under

laboratory conditions. Efforts are also being made to investigate the factors

(morphological, chemical etc.) responsible for inducing resistance to different varieties

of wheat in the province of Sindh, Pakistan.

Mechanism of resistance involves two types of factors, chemical factors or the

physical plant factors. In all thermo-production processes including bread baking,

besides chemical characteristics, physical especially thermo-physical properties are

important factors in the control of the quality (Golmohammadi et al., 2005). Plant

resistance has many advantages as a primary tactic in insect pest management.

Important advantages are specificity, persistence, compatibility, and safety to humans

and environment, ease of adoption and cumulative effectiveness.

Keeping in view all these facts, the study was conducted with the objectives to

determine various physico-morphological plant characters, such as leaf area(cm2),

chlorophyll contents (%), number of nodes per tiller and inter-nodal distance (cm),

plant height (cm), number of grains per tiller, spike length (cm), number of spikelets,

hair density (per cm and per cm2 ) and length of hair on midrib and lamina (µm) in

various genotypes of wheat and their correlation with population of aphids.

REVIEW OF LITERATURE

Pubescent wheat varieties are resistant to grain aphid (Sitobion avenae) and

R.padi (Foster and Rochow 1983). Host plant resistance has been used as a control

measure for various agricultural pests for many years (Smith, 1989). The aphid

population affects the produce adversely (Wratten and Redhead, 1976; Girma et al.,

1993) by causing 35-40% yield losses directly (Kiechefer and Gellner, 1992) and 20-

80% yield losses indirectly by transmitting viral and fungal diseases (Marzochi and

Nicoli, 1991; Rossing et al., 1994; Trdan and Mileroj, 1999). The incidence of aphids

has been reported to be significantly different on different cultivars of wheat (Hinzand

Daeber, 1976; Castro, 1980; Aheer et al., 1993; Ciepiela, 1993; Parvez and Ali, 1999;

Ahmad and Nasir, 2001). It also depends on the crop stages (Dyadechko and Ruban,

1975; Rios and Conde, 1986; Kieckhefer and Gellner, 1988; Kieckhefer and Kantack,

1988; Robe et al., 1989; Rustamani et al., 1999) because their pre-reproductive,

reproductive and post-reproductive periods and fecundity are significantly affected by

crop varieties (Saikia et al., 1989).

Wheat aphids severely damage the wheat crop in Pakistan (Mohyuddin, 1981;

Hamid, 1983).Varieties that are moderately resistant to grain aphid have been

recognized recently (Lowe, 1981, 1982, 185a) and such resistance has proved easy to

locate among breeding lines and varieties of wheat (Lowe, 1984). Yield losses due to

D. noxia are severe with individual plant losses as high as 90% possible (Du Toit and

Walters, 1984). Volkmar and Wetzel (1991) carried out study on the occurrence and

control of insect pests. They reported that the optimum dates for the control of S.

avenae were at the beginning of ear emergence.

Aphids are often the most significant factor limiting profitable winter wheat

production (Burton et al., 1985, Kieckhefer and Kantack 1988, Webster 1995, Ricdell

et al., Kindler et al., 2002). To combat the increasing resistance in aphids to pesticides

and to reduce its hazardous effects on environment, adoption of Integrated Pest

Management (IPM) strategies are needed (Hatchett et al., 1987). Leszczynski (1987)

studied six cultivars of winter wheat to determine the degree of resistance against

Sitobion avenae (F.). Pons et al. (1989) found that S. avenae was more abundant on

the ears than on the leaves. Yang and Lin (1990) reported that feeding by aphids after

the milk stage of wheat could reduce yield more than feeding before the milk stage.

Xiong (1991) studied the occurrence of the aphid R. padi during 1980-84 in relation to

the growing period of wheat. Robinson (1992) recorded crop losses of 68% in Ethiopia

and 35-60% in South Africa for wheat. Kindler et al. (1992) stated that Russian wheat

aphid Diuraphis noxia poses a serious threat to the yield and quality of wheat and

barley production in United States.

Aheer et al. (1993 a) studied the effect of aphid infestation on twelve advanced

lines of wheat (PR-31, PH-32, V-5002, V-5004, V-6236, V-6550, V-6632, V-84133-6,

V-85110, V-85195, V-85276 and V-96299) and were compared with the late sown two

commercial varieties (Bahawalpur-79 and Faiasalabad-83). Similarly, other 12

advanced lines (M-143, M-179, NR-7, PR-28, PR-30, V-1697, V-5003, V-6751, V-

8512, V-84021, V-85054 and V-86369) were compared with normal sown two

commercial varieties (Pak-81 and Sutlej-96). Aheer et al. (1993 b) tested 13 wheat

varieties/advanced lines i.e., Kohinoor-83, Pak-81, Punjab-81, Sutlej-86, V-6236, V-

6300, V-6521, V-6550, V-6566, V-6632, V-6751, V-6916 and V-7061 for resistance

against S. avenae and Rhopalosiphum rufiabdominalis and reported significant

difference among varieties/advanced lines to aphid population. They further reported

that Kohinoor-83 was relatively susceptible with 22.53 percent grain yield loss,

whereas V-7061 was resistant with 10.76 percent yield loss. Correlation between yield

loss and number of aphids was significant and negative.

Five wheat cultivars viz. Inqlab-91, Pasban, Pak-81, Uqab-2000 and Iqbal-2000

were screened for resistance/susceptibility against aphids during 2000-2001 in the

farmers field at Chak 26, district Mandi Bahauddin. The population of aphids was

recorded from 15 tillers of five plants selected randomly. Mean densities of the wheat

aphids were 2.29, 2.07, 2.41, 2.23 and 2.22 per tiller on Inqlab-91, Pasban, Pak-81,

Uqab-2000 and Iqbal-2000, respectively. Peak level of aphids‟ population occurred

during third week of March. Non-significant variation was noted among mean densities

of aphids‟ population on various cultivars during different months. The month of April

had lower level of occurrence of aphids, while March had higher incidence followed by

February (Aheer et al., 1993b).

Aheer et al. (1997) screened sixteen advanced lines of wheat against aphid

attack under field conditions at Faisalabad, during 1993. Significant differences exist

among wheat lines regarding pest population ranging from 0.48-2.61 per tiller and

grain yield (2400-3113 kg/ha).

Zwer and Elsiding (1993) pointed out that Russian wheat aphid is a major

economic pest of wheat and barley. World-wide the use of insect-resistant cultivars is

seen as one of the most desirable alternatives to insecticides because of their low cost

and environmentally friendly action (Quisenberry et al., 1994). Formusoh et al. (1994)

studied the lowest aphid infestation and comparatively higher seed yield for varieties

resistant to aphid‟s attack than susceptible lines. Anonymous (1994-95) studied 10

advanced lines of wheat for resistance against aphids and reported negligible

population ranged from 1.25 to 4.22/tiller. Similarly in another experiment conducted

by the same organization in the same year for resistance against aphids in wheat

varieties revealed non-significant results regarding aphids population.

Rajesh et al. (1995) reported that wheat varieties GW-173 and CPAM 2004

were susceptible based on aphids‟ population, while J-405, J-486 and Swati were the

least susceptible varieties. Voss et al. 1997 observed that population of Sitobion

avenae and Rhopalosiphum padi develop on maturing wheat (Triticum aestivum) in

the Dakots and western Minnesota (U.S.A). Farid et al. (1998 a) studied the impact of

wheat resistance (resistant Pl 137739 and Pl 262660 and susceptible‟ Stephens‟) on

Russian wheat aphid (D. noxia) by using varying densities (0, 20 or 40 aphids per

plant). Resistant lines were less damaged by aphids than susceptible with leaf area,

grain weight and reduction in height.

Abou-Elhagag and Abdel-Hafez (1998) reported the peak of these natural

enemies occurred in the beginning of April and late in March during the 1995/96 and

1996/97 seasons, respectively. Farid et al. (1998 b) studied the impact of wheat

resistance on D. noxia and observed that resistant lines were less damage by aphids

than susceptible lines.

Varietal resistance studies on 22 cultivars and 6 allied cultivars of wheat

indicated that among allied cultivars Triticum monococcum had maximum infestation

of 2.569 aphids per tiller. Triticum durum was highly protected cultivar against aphids

attack. The F statistic for black aphid was 110.44 and at 0.05 levels 7 groups of

susceptibility resistance were obtained through LSD (Sattar 1996).

Rana and Ombir (1999) observed that Sixty-three varieties of wheat, when

grown under field conditions, showed a varied reaction against cereal aphids‟

infestation. Out of 63 varieties, 30 varieties were tolerant falling in grade I (0-5

aphids/shoot). Twenty varieties were susceptible and were grouped in grade II (6-10

aphids/shoot), while seven varieties were susceptible with 11-20 aphids/shoot and

were grouped in grade III.

Anonymous (1999-2000) studied comparative resistant of normal sown

advanced lines/varieties of wheat to the attack of aphids in micro wheat yield trial and

reported non-significant difference among varieties. Schotzko and Bosque-Perez

(2000) conducted field experiment to evaluate the impact of resistance to Russian

wheat aphid, D. noxia, in wheat. Two advanced lines were planted the centennial

(susceptible) and the IDO-488 (resistant). Resistance/susceptibility of 10 wheat

varieties (Pictic-62, Pak-81, Barani-83, Kohinoor-83, FSD-85, Punjab-85, Rawal-87,

Chakwal-86, Pasban-90 and FDS-83) to S. avenae was observed by Ahmad and

Nasir (2001).

Geza (2000) reported that flight of aphids on wheat was continuous from late

April to harvest. In the average of 17 years flight data the peak was observed in June.

Establishment of the first allotted individuals of aphids with holocyclic development

can be expected from the second decade of April. As a result of the continuous

reproduction, the peak in number of individuals was observed in the second decade of

June. During the 6 years between 1993 and 1998 this value was 17.18 aphids per

plant. Every year there were deviations from the average data e.g., in 1994 aphids

number per plant was 33.61. These pests appeared on the ears in the first decade of

June, their number was continuously increasing due to drying of leaves. Singh et al.

(2001) reported that root aphid infestation started from 3rd week of December, 1998.

Thereafter, it gradually increased reaching to its peak during 2nd week of January and

continued until 1st week of February 1999. Hassan et al. (2004) recorded maximum

mean population of aphids per tiller (1.17) on February 28, 2004.

Agrawal (1999) describe five primary factors involved in increased plant

tolerance. Host plant resistance to insect pests of crop plants is generally seen as an

effective, environmentally responsible, economically and socially acceptable method

of pest control which plays an integral role in sustainable agricultural systems

(Wiseman, 1999).These include increased net photosynthetic rate, high relative

growth rate, increased branching or tillering after apical dominance release, pre-

existing high levels of carbon stored in roots, and the ability to shunt stored carbon

from roots to shoots.

The most susceptible cultivar was found to be CAR 422/ANA (16.17 aphid),

comparatively resistant (less susceptible/palatable) cultivars were TANIEUClPVN

(4.49), IL-75-2·264(4.88), PATlO/ALO (4.00), BAUIPRLIVEE#5 (3.68) and CHILIEUC

(1.87). The cultivars TURACC/CHIL (8.41), PRINA (8.36), CHILIPRL (8.30),

SERIICEPEO 120 (8.19), and BJY/CCC (7.59), CHILlCHUM 18 (7.32), and PSN/6CW

(7.27), lRENA (6.81), CHILIWUH-3 (6.58), TANIPEW/SARA (6.41), ATIILA (6.40) and

control Inq-91 (5.14) displayed moderate resistance to aphids. Only two cultivars such

as GAAlPRL and MCNIIMU were found to be moderately susceptible to aphids

(Parvez et al., 1999).

Singh et al. (2001) conducted a screening trial of 38 wheat strains and reported

the mean number of fruit aphids per plant in different strains varied from 1.0 to 26.33,

showing statistically significant difference. Anonymous (2001-2002) reported non-

significant difference among wheat genotypes (MH-97, Iqbal-2000, Inqlab-91, V-

99166, Punjab-96, V-97046, Uqab-2000, V-98617, V-98059 and V-97052) regarding

the population of aphids. The population however ranged from 1.39 to 2.33 per tiller.

Burio et al. (2001) carried out fixed studies of aphid population on nine wheat

genotypes in Peshawar. The population reached a peak of 4.545 aphids/leaf during

the second weak of March on all genotypes. With the maturity of the leaves, the

aphids shifted to the ears were almost dry. Mean varietal response was variable, with

IBW-96369 infested by the highest (2.45 aphids/leaf) and IBW-96351 by the lowest

average population of 1.30 aphids/leaf during the cropping season.

In South Africa damage to wheat crops can be limited by the use of systemic

insecticides, but the large-scale use of insecticides has been discontinued as farmers

are now planting resistant cultivars to control this pest (Tolmay et al., 2005) as a key

component of an integrated control strategy against D. noxia in both commercial and

small-scale production situations. Resistance breeding against D. noxia takes place in

South Africa (Tolmay et al., 2005; Van Niekerk, 2001), the USA (Quick et al., 1996), at

CIMMYT in Mexico and ICARDA in Syria (Robinson, 1992) and pre-emptively in

Australia (Botha and Hardie, 2000).

Pest resistant crops offer a solution that can be tailored to meet the specific

need of producers while usually offering more benefits than drawbacks for the

environment. The most important benefit of a pest resistant crop is the fact that the

pest control occurs independently of the managerial ability, skill and resource level of

the producer (Tolmay, 2001). On the past 50 years‟ trends, the average yield per

hectare indicated a nominal increasing trend. From 2001-2002 to 2010-11 average

yields per hectare would increase from 2445.79 kg to 2560.56 kg, in 2005-06 and

2751.94 kg in 2010-11. Thus no significant break-through has been projected in

average yield per hectare. The diminishing trend of minimum average per hectare

yield of wheat would probably due to the expected drought situation in the decade to

come and lack of high yielding varieties if not the traditional farm practices (PARC,

2000, Saboor et al.,2003)

The genotypes in descending order towards susceptibility are: Iqbal-2000 > D-

88627 > Pasban > V-02166 > V-98044 > V 99099 > Inqlab-91 > V-00146 (Iqbal et al.,

2003). Anonymous (2003-2004) studied Iqbal-2000, MH- 97, Uqab-2000, V-99022, V-

970046, V 97603, Inqlab-91, V-00183, V-98059, V-98627 and V- 00146 to aphid

attack and reported that Iqbal-2000 was susceptible with maximum number of aphids

per tiller 2.23, whereas all other genotypes were at par with a range of 0.341 to 0.635

and 1.17 to 1.98 in normal and late sown season, respectively.

The genotypes differed significantly in response to the population of aphids per

tiller and these genotypes categorized in order of susceptibility are Iqbal-2000 (8.06),

D-98627 (7.21), AS-2002 (6.65), V-99074 (6.62), 97B2210 (6.60), V-99176 (6.50),

Parwaz (6.41), V-99119 (6.19), V-00183 (5.95), V-99022 (5.80), V-99160 (5.60), V-

99068 (5.48), MH-97 (5.26), Pasban (5.17), V-02166 (5.01), V-98044 (5.00), Uqab-

2000 (4.93), Pak-81 (4.87), V-99161 (4.81), V-99044 (4.73), V-98059 (4.55), Chenab-

2000 (4.55), V-99134 (4.53), Punjab-96 (4.47), V-02156 (4.08), Rohtas (4.02), V-

99099 (3.02) and V-00146 (2.91). The peak population of aphids was observed during

third week of March 2003. (Iqbal et al., 2003).

Migui and Lamb (2003) tested 41 accessions of wild and cultivated wheat

belonging to 19 Triticum species in the field for resistance to three species of aphids

R. padi, S. avenae and Schizaphis graminum Rondani. They reported that all three

species of aphids survived and reproduced on all wheat varieties, and reduced spike

biomass compared to uninfected controls. Overall resistance to the three aphid

species was observed in five to seven accessions per aphid species.

On 19th and 23rd February, the population was non significantly different on all

varieties/lines. On 2nd March, the maximum population was recorded on Iqbal-2000

followed by 2445, 2486 and 2210 in descending order having significant difference

among them in aphid population. The minimum population was recorded on BWP-97.

On 9th March, PND-1 had maximum population followed by 2445 and 2486, which had

non-significant difference between each other in population. The population on

Punjab-96 was higher than that on Inqlab-91, which has minimum population. The

minimum population was recorded on Inqlab-91. On 30th March, the aphid population

declined to a very low level. The maximum population was recorded on 2460. The

minimum population was recorded on PND-1, 2333, 2210, Inqlab-91, 2049, 2486, MH-

97, 2045, BWP- 97, Iqbal-2000 and Punjab-96, which had non-significant difference in

population among them. After 30th March, the aphids population almost diminished on

all the wheat varieties/lines (Aslam et al., 2004).

During Rabi 2002-03, average yield obtained by the sample farmers in the

study area was 28.6 maunds per acre as compared to last year (33.4 maunds/acre).

Overall wheat yield decreased by about 17 percent during rabi 2002-03 as compared

to rabi 2001-02. The inter district comparison shows that percent decrease in wheat

yield was relatively higher in Multan district as compared to Sheikhupura and

Bahawalpur districts. The t-test results show that the difference in average wheat yield

during rabi 2001-02 and 2002-03 is highly significant in the area (Bashir et al., 2006).

Wheat yield is positively related to quantity of seed rate, DAP and Nitrogen but

negatively related to the number of irrigations. The negative sign indicates that on

average, the farmers provided, at least one extra irrigation (Hussain et al., 2005).

Six wheat varieties/advanced lines viz. Inqlab-91, AS-02, V-0055, V-00125,

Manthar and Bhakkar 2002 were examined on six sowing dates viz. 25th October, 10th

November, 25th November, 10th December, 25th December 2004 and 10th January

2005 against wheat aphid. The data revealed no significant difference among varieties

on all sowing dates. However earlier sown crop showed less aphids population per

tiller. Minimum aphids per tiller (0.083) were recorded on Bhakkar-2002 followed by

AS-02 (0.458 aphid/tiller) sown on 25th October. The data revealed that varieties

showed non-significant difference among each other. However, line V-00125 showed

less aphids population per tiller (13.29) followed by varieties Bhakkar-2002 (16.09).

Maximum aphids population per tiller (22.46) was recorded on V-0055 followed by

Inqlab-91 (20.07). In case of sowing dates the results were highly significant. Minimum

aphids population per tiller (1.49) was recorded when the crop was sown on early date

i.e. 25th October followed by 10th November (6.79) and both dates were statistically

similar but differed from remaining sowing dates. Sowing 25th November, 10th

December, 25th December 2004 and 10th January, 2005 were statistically at par and

showed maximum aphids population (10.40-45.63 aphids/tiller) (Ahmad et al., 2006).

Materials and Methods

3.1 Screening of Wheat Genotypes

The study was conducted to determine the impact of physico-

morphological plant characters towards resistance /susceptibility against aphid in

different genotypes of wheat during 2008-2009. Eleven (11) genotypes (V-05066, V-

5BT-006, V-04178, V-04022, V-05603, V-05082, Saher, Inqlab-91, Chakwal-5C-011,

V-033010, and V-032862) were sown following Randomized Complete Block Design

with three replications in the research area of Entomological Research institute,

Faisalabad. The plot size was kept as 8.25m X 1.83m.

3.2 Population Density Counts

The data regarding count of aphid population were recorded at the

interval of 3 ± 2 days from 14-02-2009 to 01-04-2009 by randomly selecting 10 tillers

from each plot. The average population per tiller was then calculated by the formula

T1+T2+T3+T4+T5+T6+T7+T8+T9+T10

Population Density (P) = -----------------------------------------------------------

10

Where P = Average population per tiller

T1, T2, T3------------ and T10= Aphids population density on randomly selected tillers.

3.3 Methodology to Test Mechanism of Resistance

3.3.1 Physical Plant Characters

The following physical plant characters were studied at regular intervals on nine

different dates from 28-02-2009 to 03-04-2009.

a) Chlorophyll

b) Leaf area

c) Inter-nodal distance

d) Number of nodes

3.3.1. a) Chlorophyll

On every date fifteen leaves of five tillers from each plot were selected at

random and the chlorophyll contents were measured by using chlorophyll meter of

SPAD-502, Konica Minolita Sensing, INC (Made in Japan). The average chlorophyll

contents per tiller were calculated.

3.3.1.b) Leaf area

Five leaves from each plot were selected at random at every observation

and the leaf length and width of each leaf were measured in centimeters with the help

of common scale. Length and width of the leaf was multiplied to get the leaf area in

Cm2. The average leaf area was calculated by using the following formula

L1+L2+L3+L4+L5

Leaf Area (L) = ------------------------------- cm2

5

3.3.1.c) Inter-nodal Distance

On every date, five tillers from each plot were selected at random and

the inter-nodal distance was measured in centimeters. The average distance of nodes

per tiller was calculated by using the following formula

N1+ N2+ N3+ N4

Distance between Nodes (D) = ------------------------------- cm

4

Where :

N1= Distance between the first two nodes

N2= Distance between the second and third node

N3= Distance between the third and fourth node and so on

Then the further average was calculated to determine the average inter-nodal

distance in a plot by using the following formula.

D1+ D2+ D3+ D4 +D5

Average Distance (A) = --------------------------- cm

5

Where :

(D1) = Average inter-nodal distance between the nodes of the first tiller

(D2) = Average inter-nodal distance between the nodes of the second tiller

(D3) = Average inter-nodal distance between the nodes of the third tiller

3.3.1. d) Number of Nodes

Five tillers from each plot were selected at random and the number of

the nodes was counted. The average distance of nodes per tiller were calculated by

using the following formula

T1+T2+T3+T4+T5

Number of nodes (B) = -------------------------------

5

Where :

T1, T2, T3, T4 and T5= Number of nodes per tiller

3.3.2 Characters Studied at Maturity

Following plant characters were taken at the maturity.

a) Plant height (cm)

b) Number of grains per tiller

c) Number of spikelets

d) Spike length (cm)

e) Hair density on midrib (per cm)

f) Hair density on lamina (per cm)

g) Length of hair on midrib (µm)

h) Length of hair on lamina (µm)

3.3.2 a) Plant Height (Cm)

The data of plant height was taken at maturity on 25-03-2009. Five

plants were selected from each plot at random. The average plant height was

calculated by using the following formula.

T1+T2+T3+T4+T5

Plant Height (H) = -------------------------------

5

Where :

T1, T2, T3, T4 and T5= Number of plants selected from a plot

3.3.2 b) Number Of Grains Per Tiller

The data regarding number of grains per tiller were recorded on

25-03-2009. Five tillers from each plot were selected at random and number of grains

was counted. Then the average is calculated by using the following formula.

T1+T2+T3+T4+T5

Number of grains (G) = -------------------------------

5

Where:

T1, T2, T3, T4 and T5= Number of tillers selected from each plot

3.3.2 c) Number of Spikelets

Five ears from each plot were taken randomly and the number of

spikelets at each of the spike was counted on 31-03-2009. Then the average number

of spikelets was calculated by using the following formula

S1+S2+S3+S4+S5

Number of Spikelets (S) = -------------------------------

5

Where:

S1, S2, S3, S4and S5 = Number of spikes taken from a plot

3.3.2 d) Spike Length(cm)

Spike length of five spikes was measured from each plot at random on

31-3-03-2009. The average length was calculated by using the following formula.

S1+S2+S3+S4+S5

Spike length (SL) = -------------------------------

5

Where:

S1, S2, S3, S4and S5 = Number of spikes taken from a plot

3.3.2 e) Hair density on midrib (per cm)

Data regarding Hair density on midrib (per cm) was taken by choosing

three green leaves at random from each plot. First of all the leaves were cut in a size

of 1-Cm2 by using an iron dye. For counting hair density on the midrib the leaves were

cut from the area of the leaf containing midrib in centre of the leaf. Then it was

observed under the stereo-binocular. Three leaves from each plot were selected at

random and three sections from each leaf were taken. The average number of hair

was calculated by using the following formula

H1+H2+H3+H4+H5+H6+H7+H8+H9

Hair density on midrib (per cm) (HM) = ------------------------------------------------------

9

Where (HM) = Average number of hair on midrib

H1, H2, H3, H4 to--------= Leaf sections taken from a plot

3.3.2 f) Hair density on lamina (per cm)

Data regarding Hair density on lamina (per cm) was taken by choosing

three green leaves at random from each plot. First of all the leaves were cut in a size

of 1-Cm2 by using an iron dye. For counting hair density on the lamina, the leaves

were cut from the area of the leaf containing lamina portion. Then it was observed

under the stereo-binocular microscope. Three leaves from each plot were selected at

random and three sections from each leaf were taken. The average number of hair on

lamina was calculated by using the following formula.

H1+H2+H3+H4+H5+H6+H7+H8+H9

Hair density on lamina (per cm) (HL) = ------------------------------------------------------

9

Where (HL) = Average number of hair on lamina

H1, H2, H3, H4 to--------= Leaf sections taken from a plot

3.3.2 g)Length of Hair on Midrib(µm)

Data regarding length of hair on midrib was taken by choosing three

green leaves at random from each plot. First of all the leaves were cut in a size of 1-

Cm2 by using an iron dye. For measuring hair length on the midrib, the leaves were cut

from the area of the leaf containing midrib in centre of the leaf. Then it was observed

under the stereo-binocular microscope and the length of the hair was measured in by

using ocular micrometer. Three leaves from each plot were selected at random and

three sections from each leaf were taken. The average length was calculated by using

the following formula.

L1+L2+L3+ L 4+ L 5+ L 6+ L 7+ L 8+ L9

Hair length on midrib (LM) = ------------------------------------------------------

9

Where (LM) = Average length of hair on midrib

L1, L2, L3, L 4 to--------= Leaf sections taken from a plot

3.3.2 h)Length of Hair on Lamina(µm)

Data regarding length of hair on lamina was taken by choosing three

green leaves at random from each plot and three sections from each leaf were cut in

size of 1-Cm2. First of all the leaves were cut in a size of 1-Cm2 by using an iron dye.

For measuring hair length on the lamina, the leaves were cut from the area of the leaf

on the sides of the midrib. Then it was observed under the microscope and the length

of the hair was measured by using ocular micrometer. Three leaves from each plot

were selected at random and three sections from each leaf were taken. The average

length was calculated by using the following formula.

L1+L2+L3+ L 4+ L 5+ L 6+ L 7+ L 8+ L9

Hair length on lamina (LL) = ------------------------------------------------------

9

Where (LL) = Average length of hair on lamina

L1, L2, L3, L 4 to--------= Leaf sections taken from a plot

3.4 Statistical Analysis

The data were analyzed on an IBM-PC computer using MSTAT

package. Means were separated by Least Significant Difference test (LSD) (Steel and

Torrie, 1980) or by Duncan‟s New Multiple Range Test (DMRT) (Duncan, 1955).

3.4.1 Statistical Correlations

Simple correlation was worked out between population density of insect

pest (aphids) and the physico-morphic plant characters. Multiple linear regression

models were also developed along with coefficient of determination values with the

objective to find out the actual contribution of each factor as well as in different

combinations in population fluctuation of the pest. In this analysis the population of the

pest was taken as response variable (y) and the following, predictive, variables were

used to represent the equation.

X1= Leaf area (cm2)

X2= Chlorophyll (%)

X3= Number of nodes

X4= Inter-nodal distance (cm)

X5= Plant height (cm)

X6= Grains per tiller

X7= Number of spikelets

X8= Spike length (cm)

X9= Hair density on midrib (per cm)

X10= Hair density on lamina (per cm)

X11= Length of hair (µm) on lamina

X12 = Length of hair on midrib

For the analysis an IBM compatible computer was used with the help of

MSTAT software.

RESULTS

The study was conducted to determine the resistance/susceptibility against

aphids in different genotypes of wheat based on population density count under field

conditions during 2009. Various physico-morphological plant characters were also

studied to find the impact of these factors in population fluctuation of the pest. The

experiment was conducted in the area of Entomological Research Institute,

Faisalabad. The results are described under the following subsections.

4.1. Population of Aphids

4.1.1 Resistance/susceptibility Based on Population Density Count

The data regarding aphid density per tiller observed on various dates of

observation in different genotypes of wheat are given in appendices 2 to15. The

analysis of variance of the same reveals significant difference (P 0.01) among dates

of observation and various genotypes of wheat (Table 1 and Fig.1). The interactional

response among dates of observation and genotypes did not show significant

difference. The means were compared by DMR Test P=0.05. The means comparison

of the data shows that V-05066 possessed maximum population of aphids i.e., 18.69

per tiller and was at par statistically with those of recorded on V-05603 and Inqlab-91

with 17.74 and 15.45 per tiller population of aphids, respectively. The minimum aphid

density 5.73/tiller was recorded on V-04178 and did not show significant difference

with those observed on V-5BT-006, V-04022, V-05082, Saher, Chakwal-5C-011, V-

033010 and V-032862 with 8.87, 10.74, 6.99, 7.27, 11.54, 7.32 and 11.46/tiller aphid

density, respectively. From these results it was concluded that V-04178 found

comparatively resistant genotype, whereas V-05603, the susceptible showing

minimum and maximum aphid population/tiller, respectively.

4.1.2 Period of Abundance

The means comparison of the data (Table 1 and Fig.2) reveals that the last

week of February resulted in maximum aphid population per tiller (46.07) and proved

to be the most favourable period for the development of the pest. Furthermore, aphids

appeared at the end of second week of February i.e. 6.13/tiller and an

Table 1. Analysis of Variance and Means Comparison of the Data Regarding Population of the Aphids in Various Genotypes of Wheat During 2009 Analysis of Variance

C.V=124.20% ** = Significant at P≤0.01 NS= Non- Significant

Means Comparison

Date Mean Variety Mean

14-02-2009 6.133 e V-05066 18.694 a

17-02-2009 19.601 d V-5BT-006 8.868 c

21-02-2009 26.861 c V-04178 5.730 c

24-02-2009 46.072 a V-04022 10.744 bc

28-02-2009 39.042 b V-05603 17.737 a

04-03-2009 19.879 d V-05082 6.997 c

07-03-2009 4.764 e Saher 7.271 c

10-03-2009 2.527 e Inqlab-91 15.450 ab

14-03-2009 0.433 e Chakwal-5C-011 11.540 bc

17-03-2009 0.379 e V-033010 7.325 c

21-03-2009 0.261 e V-032862 11.467 bc

24-03-2009 0.127 e LSD at 5% 5.705

28-03-2009 0.036 e

01-04-2009 0.006 e

LSD at 5% 6.66

Means sharing similar letters are not significantly different by DMR Test.

LSD= Least Significant Difference

Source of

Variance

(S.O.V.)

Degree of

Freedom

(D.F.)

Sum of

Squares

(S.S.)

Mean Squares

(M.S.) F.Ratio

Replication 2 28.34 14.171 0.07NS

Dates of

Observation(D) 14 11380.81 7955.772 42.05**

Genotype(G) 10 9029.73 902.973 4.77**

D×G 140 29567.18 211.194 1.12 NS

Error 328 62059.54 189.206

Figure 1.

6.133

19.601

26.861

46.072

39.042

19.897

4.764

2.527

0.433

0.379

0.261

0.127

0.036

0.006

0 10 20 30 40 50

14/02/09

17/02/09

21/02/09

24/02/09

28/02/09

4/3/2009

7/3/2009

10/3/2009

14/03/09

17/03/09

21/03/09

24/03/09

28/03/09

1/4/2009

Aphid Population/ per tiller

Date

s

Showing Aphids Population at Different Dates of Observations

increasing trend was observed continuously on the subsequent dates of observation

till February 24, 2009 which showed the highest peak. A continuous decreasing trend

was observed thereafter throughout the study period and this population reached on to

0.006/tiller on April 01, 2009.

4.2 Physico-morphological Plant Characters

4.2.1 Leaf Area (cm2)

The data regarding leaf area in various genotypes of wheat at different dates of

observation is given in Appendix 16. The analysis of variance of the same reveals

highly significant difference among dates of observation and genotypes (Table 2). The

interactional trend between dates of observation and genotypes was non significant.

The means were compared by DMR Test at P=0.05.

4.2.1.1 Variation in Genotypes

The means comparison of the data (Table 2) reveals that Chakwal-5C-011

showed maximum leaf area i.e., 54.54-cm2 and did not differ significantly with those of

observed in V-05066 showing 51.52-cm2. The minimum leaf area was recorded to be

31.07-cm2 in genotypes V-033010 and differed significantly from those of observed in

all other genotypes. The genotype V-05603 had 39.35-cm2 leaf areas and did not

differ statistically with 42.86, 39.61, 44.72 and 43.49-cm2 leaf area in V-5BT-006, V-

04178, V-04022 and V-05082, respectively. The Inqlab-91 showed 46.68-cm2 leaf

area which categorized as intermediate and did not differ with those of Saher (45.02-

cm2), V-05082 (43.49-cm2), V-04022 (44.72-cm2) and V-5BT-006 (42.86-cm2). From

these results it was concluded that the genotype V-033010 showed minimum leaf area

whereas Chakwal-5C-011, the maximum leaf area.

4.2.1.2 Variation in Dates of Observation

The results (Table 2) reveal that the observation recorded on March 21, 2009

showed maximum leaf area i.e., 48.72-cm2 and did not differ significantly with those of

41.22, 45.89, 45.43, 44.92 and 44.49-cm2 at observations recorded on March

17,March 19, March 07 and February 28,2009, respectively. The minimum leaf area

was observed to be 33.34-cm2 on April 03, 2009 and differed significantly from those

of observed at all other dates of observation. Non significant difference was found to

Table 2. Analysis of Variance and Means Comparison of the Data Regarding Leaf Size (cm2) in Various Genotypes of Wheat During 2009 Analysis of Variance


Means Comparison


28-02-2009 44.490 abc V-05066 51.523 ab

07-03-2009 44.925 abc V-5BT-006 42.863 cde

14-03-2009 48.216 a V-04178 39.607 de

17-03-2009 45.889 ab V-04022 44.719 cde

19-03-2009 45.425 ab V-05603 39.352 e

21-03-2009 48.721 a V-05082 43.487 cde

26-03-2009 41.589 bc Saher 45.022 cd

30-03-2009 40.507 c Inqlab-91 46.676 bc

03-04-2009 33.335 d Chakwal-5C-011 54.539 a

LSD at 5% 4.409 V-033010 31.072 f

V-032862 41.592 cde

LSD at 5% 4.875

Means sharing similar letters are not significantly different by DMR Test. LSD= Least Significant Difference.

Source of

Variance

(S.O.V.)

Degree of

Freedom

(D.F.)

Sum of

Squares

(S.S.)

Mean Squares

(M.S.) F.Ratio

Replication 2 57.75 28.874 0.35NS

Dates of

Observation(D) 8 5860.33 732.541 8.88**

Genotypes(G) 10 10547.03 1054.703 12.79**

D×G 80 6415.78 80.197 0.97NS

Error 196 16165.57 82.477

exist among those observations recorded on March 30, March 26, March 19, March

17, March 07 and April 28, 2009. From these results it was concluded that the

observation recorded on March 21, showed maximum leaf area whereas the minimum

leaf area was observed near crop termination.

4.2.2 Chlorophyll Contents

The data regarding chlorophyll contents in different genotypes of wheat at

various dates of observation are given in Appendix 16. The analysis of variance (Table

3) reveals highly significant difference among dates of observation, genotypes and in

their interactions. The means were compared by DMR Test at P=0.05.

4.2.2.1 Variation in Genotypes

The results (Table 3) show that the maximum chlorophyll contents were

recorded to be 48.635 in the leaves of V-033010 and did not show significant

difference with 48.26% in the leaves of V-032862. The minimum contents of

chlorophyll were found to be 30.59% in the leaves of V-04178 and did not show

significant difference with 32.58% and 33.17% in the leaves of V-05082 and Inqlab-91,

respectively. All the other genotypes showed intermediate response regarding the

chlorophyll contents with a range of 38.64% to 33.84% in the leaves of V-05603 and

V-04022, respectively.

4.2.2.2 Variations in Dates of Observation

The results (Table 3) show that the observation recorded on March 07, 2009

resulted in maximum chlorophyll contents in the leaves of various genotypes of wheat

i.e., 48.23% and did not differ significantly with 47.46%, 45.77% and 44.16% at March

14, February 28 and March 17, respectively. The minimum contents of chlorophyll

were recorded to be 15.69% in those observations recorded on April 03. From these

results, it was observed that the chlorophyll contents continuously decreased on the

subsequent dates of observation after March 07, 2009 and reached to a minimum

level on April 03, 2009.

4.2.3 Number of Nodes

The data relating to the number of nodes per tiller at different dates of

observation on various genotypes of wheat is presented in Appendix 17. The

Table 3. Analysis of Variance and Means Comparison of the Data Regarding Chlorophyll Contents in Various Genotypes of Wheat During 2009 Analysis of Variance


Means Comparison


28-02-2009 45.769 ab V-05066 36.404 bcd

07-03-2009 48.226 a V-5BT-006 34.379 cde

14-03-2009 47.456 a V-04178 30.594 f

17-03-2009 44.162 a V-04022 33.837 cde

19-03-2009 42.536 c V-05603 38.641 b

21-03-2009 39.014 d V-05082 32.582 ef

26-03-2009 26.785 e Saher 36.048 bcd

30-03-2009 25.235 e Inqlab-91 33.176 def

03-04-2009 15.690 f Chakwal-5C-011 36.735 bc

LSD at 5% 2.675 V-033010 48.631 a

V-032862 48.260 a

LSD at 5% 2.957

Means sharing similar letters are not significantly different by DMR Tests. LSD = Least Significant Difference.

Source of

Variance

(S.O.V.)

Degree of

Freedom

(D.F.)

Sum of

Squares

(S.S.)

Mean Squares

(M.S.) F.Ratio

Replication 2 147.65 73.826 2.43NS

Dates of

Observation(D) 8 36127.29 4515.911 148.80**

Genotype(G) 10 9657.18 965.718 31.82**

D×G 80 8736.79 109.210 3.60**

Error 196 5984.30 30.348

Table 4. Analysis of Variance and Means Comparison of the Data Regarding No. of Nodes in Various Genotypes of Wheat During 2009

Analysis of Variance


Means Comparison


28-02-2009 3.952 V-05066 3.867 b

07-03-2009 4.018 V-5BT-006 4.052 a

14-03-2009 3.982 V-04178 3.993 ab

17-03-2009 3.848 V-04022 3.859 b

19-03-2009 4.003 V-05603 4.067 a

21-03-2009 3.995 V-05082 3.941 ab

26-03-2009 3.988 Saher 4.037 a

30-03-2009 3.970 Inqlab-91 3.852 b

03-04-2009 3.915 Chakwal-5C-011 4.104 a

NS Non -Significant V-033010 3.850 b

V-032862 3.978 ab

LSD at 5% 0.149

Means sharing similar letters are not significantly different by DMR Tests. LSD= Least Significant Difference

Source of

Variance

(S.O.V.)

Degree of

Freedom

(D.F.)

Sum of

Squares

(S.S.)

Mean Squares

(M.S.) F.Ratio

Replication 2 0.05 0.025 0.32NS

Dates of

Observation(D) 8 0.73 0.092 1.19NS

Genotype(G) 10 2.45 0.245 3.18**

D×G 80 5.85 0.073 0.95NS

Error 196 15.07 0.077

analysis of variance of the same showed significant difference (P ≤0.01) among

genotypes (Table 4). The variation among dates of observation and interactional

response between dates of observation and genotypes did not show significant

difference.

4.2.3.1 Variations in Genotypes

The results presented in (Table 4) reveal that genotype Chakwal-5C-011

showed maximum number of nodes i.e. 4.10 per plant and did not differ significantly

from 4.06, 4.05, 4.03 3.97and 3.99 number of nodes per tiller in genotypes V-05603,

V-5BT-006, Saher, V-032862 and V-04178, respectively. The genotype V-033010,

Inqlab-91 and V-04022 each showed 3.85 number of nodes per tiller and were at par

statistically with those of observed on V-05066, V-04178, V-05082 and V-032862 with

3.86, 3.99, 3.94 and 3.97 number of nodes per tiller, respectively. From these results

it was concluded that Chakwal-5C-011 possessed maximum number of nodes per

tiller.

4.2.3.2 Variations in Dates of Observation

Nothing could be drawn from these results as the data showed non significant

variation among dates of observation. However, number of nodes per tiller ranged

from minimum of 3.84 to maximum of 4.02 per tiller, respectively.

4.2.4 Inter-nodal Distance (cm)

The data relating to inter-nodal distance in plants of various genotypes of wheat

and at various dates of observations is given in Appendix 18. The analysis of variance

of the same showed highly significant variation among genotypes and dates of

observation (Table 5). The interactional response between dates of observation and

genotype showed non-significant difference.

4.2.4.1 Variation in Genotype

The means comparison of the data (Table 5) reveals that the genotype V-5BT-

006 had maximum internodal distance i.e., 12.62-cm and did not show significant

difference with 11.87-cm in genotype V-04022. The minimum internodal distance was

recorded to be 10.76-cm in genotype V-032862 and did not show significant difference

with 11.27, 11.55, 10.93, 11.44, 11.33, 10.79 and 11.24-cm in genotypes V-033010,

Chakwal-5C-011, Inqlab-91, Saher, V-05082, V-05603 and

Table 5. Analysis of Variance and Means Comparison of the Data Regarding Internodal Distance (cm) in Various Genotypes of Wheat During 2009 Analysis of Variance


Means Comparison


28-02-2009 12.856 a V-05066 11.248 bcd

07-03-2009 11.819 b V-5BT-006 12.626 a

14-03-2009 11.662 bc V-04178 11.711 bc

17-03-2009 11.312 bcd V-04022 11.879 ab

19-03-2009 11.057 bcd V-05603 10.790 d

21-03-2009 10.876 cd V-05082 11.334 bcd

26-03-2009 10.819 d Saher 11.442 bcd

30-03-2009 11.026 cd Inqlab-91 10.935 cd

03-04-2009 11.299 bcd Chakwal-5C-011 11.551 bcd

LSD at 5% 0.698 V-033010 11.273 bcd

V-032862 10.768 ds

LSD at 5% 0.772

Means sharing similar letters are not significantly different by DMR Test.

LSD= Least Significant Difference

Source of

Variance

(S.O.V.)

Degree of

Freedom

(D.F.)

Sum of

Squares

(S.S.)

Mean Squares

(M.S.) F.Ratio


Dates of

Observation(D) 8 107.23 13.404 6.49**

Genotype(G) 10 77.85 7.785 3.77**

D×G 80 210.32 2.629 1.27NS

Error 196 404.97 2.066

V-5066, respectively. The genotype V-04178 showed 11.71-cm inter-nodal distance

and did not show significant difference with V-04022 (11.87-cm) and with the most of

the other genotypes except V-05603, V-32862 and V-5BT-006.

4.2.4.2 Variation in Dates of Observation

The results (Table 5) show that maximum internodal distance was observed to

be 2.85-cm on April 28, 2009 and showed significant difference from those of

observed in all other dates of observation. The decreasing trend was observed in the

internodal distance on the subsequent dates of observation up to March 26, 2009 with

10.82-cm. an increasing trend was observed on the subsequent dates of observation

i.e. March 30 and April 03, 2009 with 11.03 and 11.29-cm inter-nodal distance,

respectively. The later mentioned figures did not show significant variation with those

of observed on all other dates of observation except February 28, 2009.

4.2.5 Plant Height

The data regarding plant height at maturity in different genotypes of wheat are

given in Appendix 19. The analysis of variance of the same reveals non-significant

difference among genotypes (Table 6). Nothing could be drawn from these results as

the data showed non-significant variation among genotypes. However, plant height

ranged from minimum of 77.73-cm to maximum of 106.80-cm on genotype V-033010

and V-5BT-006, respectively.

4.2.6 Number of Grains Per Tiller

The data pertaining to number of grains per tiller in different genotypes of wheat

are given in Appendix 20. The analysis of variance and means comparison of the

same are presented in (Table 7). The results showed non-significant difference among

genotypes therefore, no conclusion was drawn from these results, and however, the

minimum number of grains per tiller was recorded to be 61.00 in genotype V-050082

and maximum 78.80 per tiller on V-5BT-006.

4.2.7 Number of Spikelets Per Tiller

The data relating to number of spikelets per tiller in different genotypes of

wheat are depicted in Appendix 21. The analysis of variance and means comparison

of the same are given in (Table 8). The results showed non-significant difference

Table 6. Analysis of Variance and Means Comparison of the Data Regarding Plant Height (cm) in Various Genotypes of Wheat During 2009 Analysis of Variance

C.V=20.18% NS= Non-significant

Means Comparison

Variety Mean

V-05066 101.900

V-5BT-006 106.800

V-04178 102.907

V-04022 105.600

V-05603 93.567

V-05082 106.087

Saher 96.427

Inqlab-91 97.733

Chakwal-5C-011 103.667

V-033010 77.733

V-032862 120.567

Source of

Variance

(S.O.V.)

Degree of

Freedom

(D.F.)

Sum of

Squares

(S.S.)

Mean Squares

(M.S.) F.Ratio

Replication 2 634.38 317.189 0.76NS

Genotype(G) 10 3308.71 330.871 0.79NS

Error 20 8334.41 416.720

Table 7. Analysis of Variance and Means Comparison of the Data Regarding Grains per Tiller in Various Genotypes of Wheat During 2009 Analysis of Variance


Means Comparison

Variety Mean

V-05066 69.867

V-5BT-006 78.800

V-04178 70.000

V-04022 70.00

V-05603 64.267

V-05082 61.00

Saher 66.800

Inqlab-91 65.267

Chakwal-5C-011 69.000

V-033010 74.733

V-032862 64.800

Source of

Variance

(S.O.V.)

Degree of

Freedom

(D.F.)

Sum of

Squares

(S.S.)

Mean Squares

(M.S.) F.Ratio

Replication 2 81 40.499 1.18NS

Genotype(G) 10 758.01 75.801 2.21NS

Error 20 686.47 34.323

Table 8. Analysis of Variance and Means Comparison of the Data Regarding No. of Spikelets in Various Genotypes of Wheat During 2009 Analysis of Variance


Means Comparison

Variety Mean

V-05066 69.00

V-5BT-006 72.667

V-04178 60.273

V-04022 72.933

V-05603 64.400

V-05082 60.933

Saher 64.467

Inqlab-91 64.867

Chakwal-5C-011 68.933

V-033010 62.200

V-032862 75.200

Source of

Variance

(S.O.V.)

Degree of

Freedom

(D.F.)

Sum of

Squares

(S.S.)

Mean Squares

(M.S.) F.Ratio

Replication 2 24.51 12.255 0.26NS

Genotype(G) 10 795.00 79.500 1.71NS

Error 20 931.91 46.595

among genotypes. The number of spikelets, however, ranged from minimum of 60.27

to maximum of 72.67 per tiller on V-04178 and V-5BT-006, respectively.

4.2.8 Spike Length (cm)

Variations were found to be non-significant among genotypes regarding spike

length (Appendix 22, Table 9). The minimum spike length was recorded to be 9.08-cm

on genotype V-04178 while maximum spike length was observed to be 13.91 cm on

V-032862.

4.2.9 Hair Density

4.2.9.1 Hair density on midrib (per cm)

The data regarding hair density on midrib (per cm) in different genotypes of

wheat are given in Appendix 23. The analysis of variance and means comparison of

the same are depicted in (Table 10). The results reveal non-significant difference

among genotypes. Therefore nothing could be drawn from these results. It was,

however, the hair density on midrib (per cm) ranged from 0.00 to 0.11 per cm.

4.2.9.2 Hair density on lamina (per cm)

The data relating to hair density on leaf lamina in various genotypes of wheat

are given in Appendix 24. The analysis of variance and means comparison of the

same are presented in (Table 11). The results showed non-significant variation among

genotypes. The number of hair on leaf lamina ranged from minimum of 0.27 to

maximum of 0.94 per cm on V-033010 and Chakwal-5C-011, respectively.

4.2.10 Hair Length

4.2.10.1 Hair Length on Midrib

Non-significant differences were found to exist among genotypes of wheat

regarding hair length on midrib (Appendix 25, Table 12). Nothing could be concluded

from these results as non-significant differences among genotypes, however hair

length on midrib ranged from minimum of 0.00 to maximum of 0.80 per cm.

4.2.10.2 Hair Length on Lamina

The data pertaining to hair length on lamina on different genotypes of wheat are

presented in Appendix 26. The analysis of variance and means comparison of the

same are depicted in (Table 13). The results showed non-significant variations

Table 9. Analysis of Variance and Means Comparison of the Data Regarding Spike Length (cm) in Various Genotypes of Wheat During 2009 Analysis of Variance


Means Comparison

Variety Mean

V-05066 10.493

V-5BT-006 11.740

V-04178 9.087

V-04022 10.993

V-05603 11.073

V-05082 10.427

Saher 10.753

Inqlab-91 11.640

Chakwal-5C-011 11.113

V-033010 11.007

V-032862 13.913

Source of

Variance

(S.O.V.)

Degree of

Freedom

(D.F.)

Sum of

Squares

(S.S.)

Mean Squares

(M.S.) F.Ratio


Genotype(G) 10 40.89 4.089 2.92NS

Error 20 28.03 1.402

Table 10. Analysis of Variance and Means Comparison of the Data Regarding Number of Hair on Various Genotypes of Wheat During 2009 Analysis of Variance


Means Comparison

Variety Mean

V-05066 0.037

V-5BT-006 0.037

V-04178 0.037

V-04022 0.000

V-05603 0.000

V-05082 0.000

Saher 0.037

Inqlab-91 0.110

Chakwal-5C-011 0.000

V-033010 0.037

V-032862 0.000

Source of

Variance

(S.O.V.)

Degree of

Freedom

(D.F.)

Sum of

Squares

(S.S.)

Mean Squares

(M.S.) F.Ratio


Genotype(G) 10 0.03 0.003 1.20NS

Error 20 0.05 0.003

Table 11. Analysis of Variance and Means Comparison of the Data Regarding Number of Hair on Lamina on Various Genotypes of Wheat During 2009 Analysis of Variance


Means Comparison

Variety Mean

V-05066 0.700

V-5BT-006 0.437

V-04178 0.540

V-04022 0.383

V-05603 0.327

V-05082 0.347

Saher 0.590

Inqlab-91 0.493


V-033010 0.27

V-032862 0.533

Source of

Variance

(S.O.V.)

Degree of

Freedom

(D.F.)

Sum of

Squares

(S.S.)

Mean Squares

(M.S.) F.Ratio


Genotype(G) 10 1.11 0.111 0.43NS

Error 20 5.11 0.256

Table 12. Analysis of Variance and Means Comparison of the Data Regarding Hair Length (µm) on Midrib at 10X Power of Microscope in Various Genotypes of Wheat During 2009 Analysis of Variance


Means Comparison

Variety Mean

V-05066 0.703

V-5BT-006 0.010

V-04178 0.023

V-04022 0.000

V-05603 0.000

V-05082 0.000

Saher 0.800

Inqlab-91 1.667


V-033010 0.147

V-032862 0.000

Source of

Variance

(S.O.V.)

Degree of

Freedom

(D.F.)

Sum of

Squares

(S.S.)

Mean Squares

(M.S.) F.Ratio


Genotype(G) 10 8.74 0.874 1.14NS

Error 20 15.39 0.769

Table 13. Analysis of Variance and Means Comparison of the Data Regarding Hair Length (µm) on Lamina at 10X Power of Microscope in Various Genotypes of Wheat During 2009 Analysis of Variance

C.V=58.79 %

NS= Non-significant

Means Comparison

Variety Mean

V-05066 12.500

V-5BT-006 8.017

V-04178 8.177

V-04022 9.633

V-05603 4.540

V-05082 12.360

Saher 11.490

Inqlab-91 10.850

Chakwal-5C-011 11.017

V-033010 3.327

V-032862 4.510

Source of

Variance

(S.O.V.)

Degree of

Freedom

(D.F.)

Sum of

Squares

(S.S.)

Mean Squares

(M.S.) F.Ratio

Replication 2 50.44 25.218 0.95NS

Genotype(G) 10 332.73 33.273 1.25NS

Error 20 531.03 26.552

among genotypes. However, the length of hair on lamina ranged from minimum of

3.32-cm to maximum of 12.50-cm.

4.3 Impact of Various Physico-Morphological Plant Factors on the

Population Fluctuation of Aphids:

The data regarding the population fluctuation of aphids and various physico-

morphological plant characters were processed to simple correlation and multiple

linear regression analysis through steps, with the objectives to find the effect of

physico-morphological plant characters on the aphids‟ population, to determine the

role of these plant characters on the population fluctuation of the pest quantities. The

results are described under the following subsections.

4.3.1 Simple Correlation (r-values)

The results regarding correlation coefficient values between aphids‟ population

per tiller and various physico-morphological plant characters in different genotypes of

wheat are given in (Table 14). The results reveal that all the physico-morphological

plant characters under study did not show significant correlation with the pest

population. However leaf area, chlorophyll, number of nodes, length of hair on lamina

and on midrib showed positive response with the aphids‟ density.

4.3.2 Impact of Morphological Plant Characters on Aphids’ Density

The results relating to multiple regression analysis along with coefficient of

determination values between aphids density and various physico-morphological plant

characters are given in table 15. It is evident from the results that none of the

regression equation showed significant impact on the population fluctuation of the

pest. However, the impact was found to be 29-60% in population fluctuation of the

pest when the effect of all the physico-morphological plant characters was computed

together. Furthermore number of spikelets showed minimum role i.e., 7.3% in

population fluctuation of the pest followed by hair density on lamina, leaf area, plant

height and hair density on midrib, which showed 5.9%, 3.6%, 3.5% and 3% role in the

population fluctuation of aphids. The other factors resulted in negligible contribution in

population fluctuation of pest, which ranged from minimum of 0.1% to 2.2%.

Table 14. Correlation Coefficient Values between Aphids Population per Tiller and Various Physico-Morphological Characters of Various Genotypes of Wheat During 2009

Physical Characters r-Values

Leaf area (cm2) +0.189

Chlorophyll (%) +0.043

Number of nodes per tiller -0.056

Inter-nodal distance (cm) -0.187

Plant height (cm) -0.129

Grains per tiller -0.214

Number of spikelets -0.178

Spike Length (cm) -0.021

Hair density on midrib (per cm) -0.157

Hair density on lamina (per cm2) -0.246

Length of hair (µm) on lamina +0.234

Length of hair (µm) on midrib +0.135

Table 15. Multiple Regression Analysis Along With Coefficient of Determination Values among Aphids Density and Various Physico- morphological Characters of Various Genotypes of Wheat During 2009.

Physical Characters R2 100R

2

%

Role

y = 1.9710 + 0.2019X1 0.036 3.6 3.6

y = 1.3429 + 0.2063X1 + 0.09906X2 0.39 3.9

0.3

y = 1.87308 + 0.2104X1 + 0.1073X2 – 0.2719X3 0.044 4.4 0.5

y = 6.9527 + 0.1747 X1 + 0.105X2 – 0.2204X3 –

1.4357X4 0.064 6.4 2.0

y = 9.5603 + 0.1945X1 + 0.05987X2 – 0.44705X3 –

1.6140X4 – 0.1336X5 0.099 9.9 3.5

y = 10.8380 + 0.1706X1 + 0.1246X2 – 0.3369X3 –

1.4803X4 – 0.14803X5 – 0.21978X6 0.121 12.1 2.2

y = 14.7534 + 0.2147X1 + 0.02003X2 – 0.4463X3 –

1.6252X4 – 0.1701X5 – 0.2954X6 – 0.26658X7 0.194 19.4 7.3

y = 14.60624 + 0.21368X1 + 0.021903X2 – 0.4504X3 –

1.6461X4 – 0.1697X5 – 0.29778 X6 – 0.2658X7 –

0.06871X8

0.195 19.5 0.1

y = 21.8329 + 0.1308X1 + 0.02958X2 – 0.1653X3 –

2.1594X4 – 0.18472X5 – 0.3058X6 – 0.2792X7 –

0.09076X8 – 7.4136X9

0.225 22.5 3.0

y = 16.4809 + 0.2021X1 + 0.08666X2 + 0.4537X3 –

3.0680X4 – 0.04091X5 – 0.3021X6 – 0.2475X7 –

0.2358X8 – 1.019X9 – 0.4927X10

0.284 28.4 5.9

y = 12.3214 + 0.2135X1 + 0.1466X2 + 0.2137X3 –

2.4030X4 – 0.0306X5 – 02069X6 – 0.2523X7 +

0.2258X8 + 0.1344X9 – 0.4817X10 + 0.1376X11

0.293 29.3 0.9

y = 11.769 + 0.2575X1 + 0.1567X2 + 0.1622 X3 –

2.5858X4 – 0.03466X5 – 0.1994X6 – 0.2599X7 –

0.1479X8 + 2.0301X9 – 0.5274X10 – 0.1448X11 –

0.2420X12

0.297 29.7 0.4

X1= Leaf area (cm2) X7= Number of spikelets

X2= Chlorophyll (%) X8= Spike length (cm)

X3= Number of nodes per tiller X9= Hair density on midrib (per cm)

X4= Inter-nodal distance (cm) X10= Hair density on lamina (per cm2)

X5= Plant height (cm) X11= Length of hair (µm) on lamina

X6= Grains per tiller X12 = Length of hair on midrib

Y= Aphids Population

R2

= Coefficient of Determination

DISCUSSION

The experiment was conducted to ascertain the role of various physico-

morphological plant characters contributing resistance/susceptibility against aphid in

different genotypes of wheat. The results are discussed as under:

The genotypes differed significantly and their response to aphids population. V-

05066 possessed maximum aphid density i.e., 18.69/tiller and found comparatively

susceptible, whereas V-04178 proved relatively resistant showing minimum aphids

population i.e., 5.73/tiller. The aphids‟ population recorded on V-050003 (17.73/tiller)

and Inqlab-91 (15.45/tiller) showed non-significant difference with those of found on V-

05066. The present findings are in conformity with those of Hinz and Daeber (1976),

Castro (1980), Aheer et al. (1993), Aheer et al. (1993 b), Aheer et al. (1997), Ciepiela

(1993), Parvez and Ali (1999), Ahmad and Nasir (2001) and Singh et al. (2001), who

also reported significant variations among different cultivars of wheat in response to

the population of aphids. The genotypes they studied were different as those of

studied in the present dissertation under variable weather conditions. The present

findings cannot be compared with those of Aheer et al. (1993), who studied the effect

of aphids‟ infestation on normal and late sown wheat cultivars. The present findings

are not in conformity with those of Anonymous (1994-95) and Aheer et al. (2006), who

found non-significant difference among 10 advanced lines of wheat studied for

resistance against aphid. Similarly the findings of Rajesh et al. (1995), Voss et al.

(1997), Farid et al. (1998 a), Abou-Elhagag and abdel-Hafez (1998), Farid et al. (1998

b), Sattar, (1966), Rana and Ombir (1999), Anonymous (1999-2000), Geza (2000),

Strauss and Agrawal (1999), Wiseman (1999), Parvez et al. (2000), Tolmay et al.

(2000). Quisenberry et al. (1994), Tolmay et al. (2005), Van Niekerk (2001), Quick et

al. (1996), Botha and Hardie (2000), PARC, (2000), Saboor et al. (2003), Iqbal et al.

(2003), anonymous (2003-2004), Migui and Lamb(2003), Aslam et al. (2004), Bashir

et al. (2006), Hussain et al. (2006) and Ahmad et al. (2006) cannot be compared with

the present findings as differences in their materials and methods.

In the present the population of aphid reached to a peak level i.e., 46.07/tiller

on February 24, 2009 and the decreasing trend in this population was observed on the

subsequent dates of observation till maturity. The present findings are not in

conformity with those of Mosaad et al. (1992) and Aheer et al. (2006) who reported

that peak population of aphid was recorded in the 3rd week of March. Similarly Sattar

et al. (2001) reported a peak of aphids per leaf during the 2nd week of March.

In the present study leaf area differed significantly in various genotypes of

wheat. The genotype Chakwal-5C-011 possessed maximum leaf area (54.53 cm2)

while the genotype V-033010 had minimum leaf area (31.07 cm2).

Chlorophyll contents differed significantly among genotypes. The genotype V-

033010 showed maximum chlorophyll contents i.e., 48.63% followed by V-032862

with 48.26% chlorophyll contents. The genotype V-04178 possessed minimum

chlorophyll contents i.e., 30.59 percent.

The number of nodes also differed significantly among genotypes of wheat.

Chakwal-5C-011 showed maximum number of nodes per tiller i.e., 4.10 and followed

by those of Saher (4.03/plant), V-05603 (4.06/plant), V-5BT-006 (4.05/plant) and V-

032862 (3.97/plant). The genotype V-033010 possessed minimum number of nodes

plant i.e., 3.85.

The differences were found to be significant among genotypes regarding

internodal distance per tiller. The maximum internodal distance was recorded to be

12.62 cm on V-5BT-006 and did not differ with 11.87-cm on V-04022. The minimum

internodal distance was observed to be 10.76-cm on genotype V-032862.

In the present study the results regarding plant height, number of grain per

tiller, number of spikelets, spike length, hair density on midrib (per cm) and lamina and

hair length on midrib and lamina showed non-significant difference among genotypes.

The present findings are not in conformity with those of Markkula and Rokka, (1972)

and Foster and Rochow (1983), who reported that pubescent wheat varieties were

resistant to grain aphids. But in the present study the varieties evolved by the

breeders were hairless and contributed minimum role in population fluctuation of the

pest.

In the present study all the physico-morphological plant characters showed

non-significant correlation with the aphid population. However, leaf area, chlorophyll

contents, length of hair on lamina and midrib had positive response whereas number

of nodes, internodal distance, plant height, grains per tiller, number of spikelets, spike

length, Hair density on midrib (per cm) and Hair density on lamina (per cm) exerted

negative response.

Multiple linear regression models revealed that number of spike lets were the

most important factors which contributed maximum i.e. 7.3% in population fluctuation

of the pest followed by hair density on lamina (per cm) (5.9%), leaf area (3.6%) and

plant height (3.5%). All other factors showed negligible contribution ranging from 0.1 to

3.00 percent.

No work on this aspect has been searched out from the various sources for

comparison.

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APPENDICES APPENDIX 1.Wheat Aphids

APPENDIX 2. DATA REGARDING APHIDS POPULATION PER TILLER ON DIFFERENT GENOTYPES OF WHEAT ON 14-02-2009.

Name of genotypes R1 R2 R3

V-05066 4.3 10.8 5.1

V-5BT-006 2.5 2.0 8.1

V-04178 4.0 1.8 1.7

V-04022 5.6 5.1 7.0

V-05603 5.6 14.0 12.2

V-05082 8.0 7.5 3.6

Saher 5.9 9.5 1.0

Inqlab-91 11.5 1.6 8.8

Chakwal-5C-011 4.8 3.5 8.4

V-033010 9.1 7.4 6.4

V-032862 4.2 9.9 2.1



V-05066 74.7 20.7 9.1

V-5BT-006 4.7 22.7 12.4

V-04178 13.2 7.1 4.8

V-04022 14.8 17.8 20.3

V-05603 19.0 22.4 55.1

05082 11.1 11.5 5.1

Saher 10.4 19.8 8.1

Inqlab-91 50.5 20.9 40.3

Chakwal-5C-011 16.1 15.6 21.5

V-033010 12.0 20.3 9.7

V-032862 21.5 21.9 11.3

APPENDIX 4. DATA REGARDING APHIDS POPULATION PER TILLER ON

DIFFERENT GENOTYPES OF WHEAT ON 21-02-2009.


V-05066 140.9 19.7 8.0

V-5BT-006 4.3 41.5 8.6

V-04178 18.5 10.6 6.2

V-04022 18.4 25.5 26.5

V-05603 26.8 16.8 85.7

V-05082 6.2 7.9 3.0

Saher 9.0 20.7 14.1

Inqlab-91 77.9 38.7 63.0

Chakwal-5C-011 22.5 24.1 26.1

V-033010 5.8 25.7 6.5

V-032862 34.5 24.1 18.5



V-05066 169.3 76.8 9.9

V-5BT-006 7.7 65.7 35.9

V-04178 26.1 22.5 22.1

V-04022 30.3 51.4 48.4

V-05603 75.1 35.8 110.3

V-05082 22.6 19.9 27.2

Saher 16.7 39.7 28.4

Inqlab-91 91.9 58.7 74.4

Chakwal-5C-011 34.0 32.5 79.1

V-033010 13.4 48.2 22.4

V-032862 52.4 37.6 30.9

APPENDIX 6. DATA REGARDING APHID POPULATION PER TILLER ON DIFFERENT GENOTYPES OF WHEAT CROP ON 28-02-2009.


V-05066 98.8 114.2 3.9

V-5BT-006 6.7 48.3 54.7

V-04178 15.2 23.7 31.6

V-04022 23.7 51.8 43.7

V-05603 96.6 38.0 49.2

V-05082 32.8 24.1 48.4

Saher 15.3 37.9 28.6

Inqlab-91 28.0 39.9 22.8

Chakwal-5C-011 22.9 16.8 106.0

V-033010 15.1 21.3 31.7

V-032862 35.8 27.0 24.9



V-05066 5.2 52.1 3.5

V-5BT-006 3.5 25.1 30.1

V-04178 7.7 16.5 16.6

V-04022 14.2 28.0 15.1

V-05603 50.1 28.0 31.0

V-05082 17.5 16.0 25.2

Saher 9.2 20.5 17.1

Inqlab-91 15.1 16.8 15.0

Chakwal-5C-011 12.5 9.5 53.5

V-033010 11.0 12.5 19.0

V-032862 22.5 18.4 18.0


Name pf genotypes R1 R2 R3

V-05066 2.3 2.0 4.9

V-5BT-006 0.8 4.5 4.6

V-04178 0.1 3.5 1.0

V-04022 4.7 5.3 13.0

V-05603 3.0 5.3 13.0

V-05082 4.2 7.6 2.0

Saher 1.9 .30 5.5

Inqlab-91 3.0 1.9 7.1

Chakwal-5C-011 2.6 2.3 1.1

V-033010 6.0 4.6 6.1

V-032862 9.1 10.4 10.8



V-05066 1.2 0.8 0.2

V-5BT-006 0.8 0.3 0.4

V-04178 0.9 0.1 0.1

V-04022 1.2 0.4 0.5

V-05603 0.5 0.9 0.4

V-05082 0.6 0.7 0.3

Saher 1.1 0.6 0.4

Inqlab-91 0.3 0.5 0.5

Chakwal-5C-011 0.8 0.4 0.4

V-033010 2.8 3.9 1.4

V-032862 25.0 0.9 34.1



V-05066 0.6 0.3 0.3

V-5BT-006 0.2 0.4 0.6

V-04178 0.1 0.1 0.6

V-04022 0.2 0.2 0.2

V-05603 0.5 0.4 0.1

V-05082 0.3 0.1 0.4

Saher 1.0 0.5 0.2

Inqlab-91 0.5 0.3 0.5

Chakwal-5C-011 0.4 0.1 0.4

V-033010 0.6 0.9 1.5

V-032862 0.8 1.5 0.4



V-05066 0.1 0.3 0.1

V-5BT-006 0.1 0.3 0.2

V-04178 0.4 0.3 0.1

V-04022 0.2 0.0 0.4

V-05603 0.3 0.4 0.2

V-05082 0.1 0.3 0.4

Saher 0.2 0.3 0.2

Inqlab-91 0.2 0.1 0.3

Chakwal-5C-011 0.2 0.1 0.2

V-033010 0.9 1.6 1.4

V-032862 1.2 0.3 1.2



V-05066 0.2 0.2 0.3

V-5BT-006 0.5 0.1 0.1

V-04178 0.0 0.2 0.1

V-04022 0.1 0.1 0.1

V-05603 0.2 0.2 0.1

V-05082 0.4 0.0 0.1

Saher 0.2 0.4 0.4

Inqlab-91 0.2 0.1 0.3

Chakwal-5C-011 0.4 0.2 0.1

V-033010 0.4 0.3 0.3

V-032862 0.6 1.0 0.7

APPENDIX 13. DATA REGARDING APHIDS POPULATION PER TILLER ON DIFFERENT GENOTYPES OF WHEAT CROP ON 24-03-2009.


V-05066 0.1 0.1 0.0

V-5BT-006 0.2 0.0 0.1

V-04178 0.0 0.1 0.1

V-04022 0.1 0.1 0.2

V-05603 0.1 0.0 0.1

V-05082 0.2 0.1 0.0

Saher 0.1 0.3 0.0

Inqlab-91 0.0 0.1 0.0

Chakwal-5C-011 0.2 0.1 0.1

V-033010 0.2 0.2 0.1

V-032862 0.3 0.5 0.4



V-05066 0.0 0.0 0.0

V-5BT-006 0.0 0.3 0.2

V-04178 0.0 0.0 0.0

V-04022 0.0 0.0 0.0

V-05603 0.1 0.0 0.0

V-05082 0.0 0.1 0.1

Saher 0.0 0.0 0.0

Inqlab-91 0.0 0.1 0.0

Chakwal-5C-011 0.0 0.0 0.0

V-033010 0.0 0.0 0.1

V-032862 0.1 0.0 0.1


Name of genotypes

R1

R2

R3

V-05066 0.0 0.0 0.0

V-5BT-006 0.0 0.0 0.0

V-04178 0.0 0.0 0.0

V-04022 0.0 0.0 0.0

V-05603 0.0 0.0 0.0

V-05082 0.0 0.0 0.0

Saher 0.0 0.0 0.0

Inqlab-91 0.0 0.0 0.0

Chakwal-5C-011 0.0 0.0 0.0

V-033010 0.0 0.0 0.0

V-032862 0.0 0.0 0.0

APPENDIX 20. DATA REGARDING PLANT HEIGHT (cm) INDIFFERENT GENOTYPES/ADVANCED LINES OF WHEAT.


V-05066 96.4 109.4 99.9

V-5BT-006 102.6 100.6 117.2

V-04178 95.3 118.2 95.2

V-04022 100.7 118.4 97.7

V-05603 100.7 89.6 90.4

V-05082 120.5 96.86 100.9

Saher 98.70 91.58 99.00

Inqlab-91 108.2 92.6 92.4

Chakwal-5C-011 125.9 100.7 84.4

V-033010 108.0 111.7 113.5

V-032862 113.2 122.6 125.9

APPENDIX 21. DATA REGARDING NUMBER OF GRAINS PER TILLER ON DIFFERENT GENOTYPES/ADVANCED LINES OF WHEAT.


V-05066 62.6 73.6 73.4

V-5BT-006 86.2 75.4 74.8

V-04178 69.4 70.0 70.6

V-04022 76.4 71.4 62.2

V-05603 62.0 65.4 65.4

V-05082 68.4 62.0 52.6

Saher 70.0 66.2 64.2

Inqlab-91 67.0 69.2 59.6

Chakwal-5C-011 77.8 66.8 62.4

V-033010 75.8 70.0 78.4

V-032862 55.6 71.6 67.2

APPENDIX 22. DATA REGARDING NUMBER OF SPIKELETS PER TILLER IN DIFFERENT GENOTYPES/ADVANCED LINES OF WHEAT.


V-05066 70.4

62.0 74.6

V-5BT-006 79.8 68.6 69.6

V-04178 68.6 60.2 52.02

V-04022 74.6 72.4 71.8

V-05603 63.8 57.0 72.4

V-05082 61.2 63.6 58.0

Saher 68.4 71.8 53.2

Inqlab-91 56.2 71.2 67.2

Chakwal-5C-011 72.6 68.2 66.0

V-033010 52.0 67.8 66.8

V-032862 78.8 75.0 71.8

APPENDIX 23. DATA REGARDING SPIKE LENGTH (cm) IN DIFFERENT GENOTYPES/ADVANCED LINES OF WHEAT .


V-05066 10.84 10.20 11.44

V-5BT-006 12.6 11.4 11.22

V-04178 9.48 8.74 9.04

V-04022 10.76 11.14 11.08

V-05603 11.42 10.24 11.56

V-05082 11.64 10.82 8.82

Saher 10.16 10.60 11.5

Inqlab-91 11.20 11.60 12.12

Chakwal-5C-011 11.7 10.4 11.24

V-033010 10.9 11.38 10.74

V-032862 17.9 13.4 12.44

APPENDIX 24. DATA REGARDING HAIR DENSITY ON MIDRIB (per cm) IN DIFFERENT GENOTYPES/ADVANCED LINES OF WHEAT.


V-05066 0.00 0.00 0.11

V-5BT-006 0.00 0.00 0.11

V-04178 0.00 0.00 0.11

V-04022 0.00 0.00 0.00

V-05603 0.00 0.00 0.00

V-05082 0.00 0.00 0.00

Saher 0.11 0.00 0.00

Inqlab-91 0.11 0.00 0.22

Chakwal-5C-011 0.00 0.00 0.00

V-033010 0.00 0.11 0.00

V-032862 0.00 0.00 0.00

APPENDIX 25. DATA REGARDING HAIR DENSITY ON LAMINA IN DIFFERENT GENOTYPES ADVANCED LINES OF WHEAT.


V-05066 0.94 0.93 0.23

V-5BT-006 0.11 0.42 0.78

V-04178 0.77 0.77 0.08

V-04022 0.00 0.57 0.58

V-05603 0.78 0.05 0.15

V-05082 0.89 0.07 0.08

Saher 0.89 0.82 0.06

Inqlab-91 0.55 0.67 0.26

Chakwal-5C-011 2.55 0.12 0.16

V-033010 0.55 0.17 0.11

V-032862 0.55 0.28 0.77

APPENDIX 26. DATA REGARDING HAIR LENGTH ON MIDRIB (µm) IN DIFFERENT GENOTYPES/ADVANCED LINES OF WHEAT.


V-05066 0.00 0.00 2.11

V-5BT-006 0.00 0.00 0.03

V-04178 0.00 0.00 0.07

V-04022 0.00 0.00 0.00

V-05603 0.00 0.00 0.00

V-05082 0.00 0.00 0.00

Saher 2.4 0.00 0.00

Inqlab-91 0.78 0.00 4.22

Chakwal-5C-011 0.00 0.00 0.00

V-033010 0.00 0.44 0.00

V-032862 0.00 0.00 0.00

APPENDIX 27. DATA REGARDING HAIR LENGTH ON LAMINA (µm) IN DIFFERENT GENOTYPES/ADVANCED LINES OF WHEAT.


V-05066 18.4 9.22 9.88

V-5BT-006 0.88 14.5 8.67

V-04178 14.1 7.11 3.32

V-04022 0.00 11.3 17.6

V-05603 5.69 4.43 3.50

V-05082 8.03 15.66 13.39

Saher 11.39 13.69 9.39

Inqlab-91 3.83 18.22 10.50

Chakwal-5C-011 5.24 13.7 14.11

V-033010 6.11 2.87 1.00

V-032862 6.16 2.44 4.93

Effect of Morphological Plant Characters Towards Resistance Against Aphids on Wheat

Documents

different genotypes

analysis of variance

wheat aphids appendix

aphids population

multiple regression

aphids density

number of hair

contents of thesis