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
40 days before heading
326 252 77.3
25 days before heading
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
50 days before heading
236 83.3 83.3
40 days before heading
252 89.6 82.4
25 days before heading
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