Amod K. Thakur, Sreelata Rath, Ashwani Kumar Influence of System of Rice Intensification (SRI) practices on grain yield and associated physiological changes in rice plants compared to conventional flooded rice Directorate of Water Management (ICAR) Bhubaneswar, Orissa -751023, India
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1043 Influence of System of Rice Intensification (SRI) practices on grain yield and associated physiological changes in rice plants compared to conventional flooded rice
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Amod K. Thakur, Sreelata Rath, Ashwani Kumar
Influence of System of Rice Intensification (SRI) practices on grain yield and associated
physiological changes in rice plants compared to conventional flooded rice
Directorate of Water Management (ICAR)Bhubaneswar, Orissa -751023, India
ObjectiveTo examine the extent to which making certain changes in crop management practices can alter phenotypical characteristics and induce physiological changes in rice plants.
How SRI practices affect rice plants’ morphology, their physiology, and their implications on crop performance?
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Methodology
Location: Deras Research Farm, Orissa, India
Season: Dry (January-May) 2007 & 2008
Soil: Aeric Haplaquepts, sandy clay-loam in texture, pH 5.5.
Design: RCBD - five replicates
Plot sizes: 20 × 10 m2
Variety: Surendra
Crop management systems: System of Rice Intensification (SRI) and Traditional flooding (TF) with standard management practices
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Management practices SRI TFSeedling age, days
12 21
Plant spacing and density
20 x 20 cm One seedling /hill
20 x10 cmThree seedlings /hill
Weed control Three, Cono-weeder; 10, 20 and 30 DAT
Manual, 10, 20 and 30 DAT
Water management
AWD after 3 DAD during vegetative stage
Flooding with 5-6 cm depth of water during the vegetative stage.
Nutrient management
Organic manure @ 5 t ha-1
Chemical fertilizers: 80 kg N ha-1, 40 kg P2O5 ha-1, 40 kg K2O ha-1
Comparison between numbers of phyllochrons completed under SRI and TF
Management practice
12 DAG 30 DAG 40 DAG 50 DAG 60 DAG 70 DAG
SRI Transplanted< 4th
phyllochron
6th Phyllochron
7– 8th phyllochron
8-9th phyllochron
9th phyllochron 10th Phyllochron
TF In Nursery
Transplanting shock
6th Phyllochron
7th phyllochron
8th phyllochron 8th Phyllochron
DAG: Days after germination
Cro
p G
row
th R
ate
The increase in CGR in SRI crops was mainly due to maintenance of leaf area (lower leaf senescence) - Lower rate of leaf senescence might be due to larger amounts of CYTOKININS (xylem exudates) are transported from roots.
0
10
20
30
40
50
60
30-40 40-50 50-60 60-70
CGR (g m-2
day-1
)
Period (Days after germination)
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Lea
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evel
op
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Management practice
Leaf number (hill-1)
Leaf number
(m-2)
Ave. leaf length (cm)
Ave. leaf width (cm)
LAI
SRI 79.8 1997.6 65.25 1.82 3.95
TF 35.6 1766.5 48.14 1.34 2.60
LSD.05 15.8 229.4 6.09 0.21 0.28
SRI hills - more than twice the number of leaves compared to TF hills
SRI leaves- longer as well as wider than TF leaves
SRI - Longer panicles, more number of grains in spike (40%), higher 1000-grain weight and more grain ripening percent than the TF crop, responsible for higher grain yield (42%).
Parameters SRI TF LSD0.50
Panicles / m2 439.5 355.2 61.6
Ave. Panicle length, cm 22.5 18.7 2.3
Spikelet / panicle 151.6 107.9 12.9
Filled spikelet, % 89.6 79.3 5.1
1000-grain weight, g 24.7 24.0 0.2
Grain yield, t/ha 6.41 4.50 0.23
HI 0.47 0.32 0.04
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0
50
100
150
200
250
300
350
Short Medium Long Extra long
Panicle number/m2
Category of panicles
SRI TP
Short: >10 cm - 17 cm Medium: 17.1 cm - 20 cm Long: 20.1 cm - 24 cm Extra-long: 24.1 cm - <26 cm
Distribution of panicles according to its length under SRI and TF
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Salient findings
Significant changes were observed in the morphological and physiological characteristics of SRI plants• Greater root growth & activity• Improved shoot growth• Greater LAI• Favourable canopy structure • Higher levels of leaf chlorophyll• Increasing fluorescence efficiency • photosynthetic rate• Delayed senescence
Improvement in grain yield under SRI is attributable to improved morphology and physiological features of the rice plant below and above ground (Better Root-shoot interaction).
SRI methods narrow the gap between genetic potential and in-field yield achievements through management practices.