1027 Current State of Rice Production and Research in DPR Korea

Current State of Rice Production

and Research in DPR Korea

Academy of Agricultural Sciences

1. General Information

1.1 Geography

Location: Northeast of Asian Continent

(between latitudes 43° to 38° north, and longitudes

124°10′47″ to 131°52′40″ east)

Borders: Shared with PR of China and the Russian

Federation, and surrounded by seas

80% of the territory : covered with mountains

1.1 Geography

Plains: mainly in the west and south

Mountains: mainly in the north and east

East seacoast: deep, not many indentations

West seacoast: not deep, but big differences

in tides (between high tide and ebb tide)

1.2. Climate

DPR Korea: typical temperate zone, with distinct changes of 4 seasons

Annual average temperature: 8-12 ℃

Annual precipitation: 600-1400 ㎜

Hottest season : August with ave. temp. 23℃

Coldest season: January with ave. temp. -5 ～ -7℃

Rainy season: July and August

1.3 Rice-Based Cropping System

Main cropping season: May to September

Prevailing system: rice mono-cropping

For double cropping: wheat-rice, barley-rice

and potato-rice systems

● Rice is the main staple food.

● Decline in rice yield is largely due to unavailability of

high yielding, and disease- and pest-resistant rice

varieties, also low inputs such as fertilizers and chemicals

and frequent natural calamities, including severe high and

low temperatures, and flooding and drought.

● There are options to increase rice production such as

integrated crop management, higher inputs, post-harvest

technology, and sustainable farming methods, but the

most urgent need is for availability of high-yielding rice

varieties with resistance and tolerance to biotic and

abiotic stresses that are able to increase rice yield per

unit area.

2. Progress of Rice Research in

DPR Korea

2.1. Outline of Rice Research Institute

Mission: With the mandate of breeding high-and-stable yielding rice

varieties by means of “green revolution” to meet the demands of the

advancing agriculture, especially rice production.

Being the primary rice breeding institution in the country, RRI is

responsible for development and release of new rice varieties suitable

to all rice-growing areas in the country.

Structure: Research units and laboratories; namely plant breeding

units (mainly for conventional rice breeding ), hybrid rice breeding unit,

elite lines’ performance screening unit, unit for basic research, and

biotechnology laboratory, and so on.

△ Major goals:- To develop hybrid rice with high yielding potential

( BT-type japonica intersubspeicfic hybrid rice with yield

advantage of more than 30% over inbred rice, stable sterility, and

good grain quality)

- To develop a rice variety with long growth duration and high-yielding

potential (by utilization of induced mutation, distant crossing and

intersubspecific crossing, and wide hybridization with wild species

such as Oryza rufipogon)

- To develop early rice varieties suitable to second cropping

- To develop a new rice variety suitable to organic farming with no or

low input of chemical fertilizers.

- Develop rice varieties with high grain quality (good appearance, eating

quality, nutrition value and so on)

- Develop new rice varieties with resistance or tolerance to stresses by

combining conventional breeding method with biotechnology (cell and

tissue culture, MAS – marker assisted selection)

- Studying phyto-physiology and phytopathology, and screening elite

lines for tolerance and resistance to biotic and abiotic stresses

• Also, development of germplasm resistant to rice blast, bacterial leaf

blight, and brown spot by way of utilization of resistant resources

collected from internal and external sources, including IRRI

1.3. Progress in Rice Research

RRI has released over 150 rice varieties

Years Variety Breeding method1960s Rs No. 25 Introduction1970s Py No. 15 Wide crossing

1980sPy No. 21 Japonica-indica crossingPy No. 33 Japonica-indica crossingOC No. 13 Anther culture

1990s

Py No. 44, 45 CrossingShc No. 9 MutationPd No. 9 Protoplast culturePd No. 3 Anther culture

2000sNo.11, 15 BackcrossingNo. 7, 18, 19, 20 Japonica crossing

List of typical rice varieties released

• Developed several early rice varieties suitable for second cropping with

high and stable yield in double cropping system.

• Developed rice varieties suitable for rice cropping system without

film-covered seedling stage, and high-yielding in relatively low N input

condition

• Recently, a study has been launched to breed rice varieties resistant to

major diseases as well as tolerant to submergence. Several varieties with

good grain quality popular with consumers have been planted for quite long

time.

• Recently, much progress was made in hybrid rice research using 3-line

system. Pioneer first groups of hybrid parental lines were selected and are

now being tested in experimental plots (with small area).

Priorities in rice breeding research:

• Development of super hybrid rice with multiple

resistance.

• Development of rice varieties with high-yielding

potential as well as good grain quality

•Development of rice germplasm resistant and

tolerant to biotic and abiotic stresses such as rice

blast, bacterial leaf blight, and submergence. .

3. Progress in Rice Cultivation

Constraints

• Short growing season for rice cultivation

• Cold temperatures in spring, and high temperatures and humidity in summer

• Disease, insect and weed problems

• Poor soil fertility

• Shortage of materials for rice cultivation

Options to overcome these constraints are:

• Variety selection,• Improvement of seedling raising,• Reasonable planting density and pattern,• Proper fertilizer application and water

management

Varieties suitable for high yielding

• Tillering: over 10 panicles /hill• Large panicles: more than 150 grains/panicle • Grain weight; 30-34g/1000grains• Height: 90-100cm• Erect upper leaves

Improvement of raising of rice seedlings

Current conventional method:- Making seedbed- Sowing (seeding rate; 90-100g/m²)

- Cover with vinyl sheets, keep temperature at 20-30ºC

- Nursery period: 50-55 days

- Nursery area: 600-650m² /ha

- When transplanting, seedling height is 18-20 cm, and

number of leaves is 6 with 1-2 tillers

Dry weight: 80-100mg/plant

Washing roots of seedlings

Modified method being spread• Spread vinyl sheets on seedbed• Put soil layer on it (2 cm)• Sowing: seed rate of 200-700g/m², depending on

seedling age• Cover with vinyl sheets to keep temperature at 20-

30ºC • Nursery period: 30-40days• Nursery area: 100-300m² /ha• When transplanting, seedling height is14-18cm,

and number of leaves is 4-5

Dry weight: 30-60mg/plant

Planting seedling with roots in soil blocks

Transplanting: early planting and optimal density

• To increase tillers, panicles and grains per panicle

• To improve solar radiation in rice population• To prevent disease

Yield components according to planting density of rice

Planting density

(hills/m²)

No. of panicles/m²

Ripened grains/ panicle

Ripened grains/m²

24.2 363 74.8 27,154

30.3 366 75.9 27,839

36.4 395 69.8 27,571

Dry weight of rice plant according to width of row (g/m²)

Row width

(cm)Tillering stage

Heading stage

Ripening stage

20 179 669 1,349

25 208 697 1,429

30 205 705 1,389

Yield rate (%) according to planting

density (m²) of rice

80

85

90

95

100

105

110

12.1 hill 19.4 24.2 30.3 36.4

trial1trial2trial3trial4trial5trial6

Growth rate of rice plant according to width of row (g/m²/day)

Row width

(cm)

Tillering

stage

Heading stage

20 3.6 15.8

25 4.2 17.0

30 4.1 15.9

Rice yield components according to width of row

Row width

(cm)

No. of panicles/

m²

No. of ripened grains/

panicle

No. of ripened

grains/m²

20 260 97.9 25 420

25 275 93.9 25 850

30 276 92.7 25 610

Rice yield (m2) rate in % according to width of row

No. of tillers and panicles of rice plants according to N fertilization time

N fertilization time No. of tillers/m²

No. of panicles/m²

Rate of productive tillers (%)

At transplanting time

368 233 61.3

17 days after transplanting

363 225 61.8

50 days before heading

432 236 48.8


326 252 77.3


290 262 87.1

Chlorophyll content (mg/fresh weight g) of rice plant according to N fertilization time

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

8th Jun 26th Jun 7th July 20th July 10th Aug

Time 1Time 2Time 3Time 4Time 5

Yield components of rice plant according to N fertilizing time

N fertilization time

No of panicles/m²

Grains/ panicle

Ripening rate (%)

At transplanting time

233 83.5 84.4

17 days after transplanting

224 79.4 82.0


236 83.3 83.3


252 89.6 82.4


262 93.4 81.3

Yield rate (%) according to N fertilization time

Application of N nutrients at reproductive stage

• Problems

Disease occurrence

Bad ripening • To overcome these problems

Diagnosis of N nutrient status in rice plant according to use of leaf color chart (LCC)

Water management

• Tillering stage: shallow water

• Non-productive tillering stage: dry

• After that: shallow water again

Economics of improved rice cultivation

• Increase yield of rice

• Decrease need of labor and material inputs for rice culture

4. Production constraints

During recent years, rice production has declined because of a substantial decrease in rice yields. The main constraints to sustainable rice production in the country are:

● Limited arable land

● Changeable and adverse natural climate conditions

(critical high and low temperatures, drought and floods, etc.)

● Soils with low fertility

● Lack of production inputs

● Weeds, insects, and diseases, especially bacterial blight and

blast

● Lack of rice germplasm to develop better new rice varieties

● Insufficient instruments for monitoring and research

( experimental equipment and facilities, etc.)

4.3 Options to address constraints

● Make up for the limited arable land by increasing yield per unit

area or by multiple-cropping

● Fertilization of soils by putting more organic materials (barnyard manure

or compost, crop residues and green manure) into the soil

● Increasing inputs to agriculture (including fertilizer, herbicides,

insecticides, fuel and farm machines, etc.)

● Development new rice varieties with higher yield potential and resistance

or tolerance to stresses by combining conventional breeding with

advanced techniques, especially biotechnology

● Collection and application of new rice germplasm through exchange,

and acquisition of more knowledge and experience on rice breeding

and cultivation through frequent international workshops, seminars

and training courses, and so on

● Improvement of rice cultivation technique for achieving maximum yield