Three new rice varieties designed to help Filipino farmers grow more rice in difficult conditions have been officially recommended for approval for release in the Philippines. Developed by the International Rice Research Institute (IRRI), one variety is flood-tolerant variety, one is drought-tolerant, and one is salt-tolerant.
Three new rice varieties designed to help Filipino farmers grow more rice in difficult conditions have been officially recommended for approval for release in the Philippines. Developed by the International Rice Research Institute (IRRI), one variety is flood-tolerant variety, one is drought-tolerant, and one is salt-tolerant.
The Philippine Rice Research Institute (PhilRice) has already started distributing small amounts of seed of the new varieties to farmers for further adaptation tests. Seed increase of breeder and foundation seeds is now being done by IRRI and PhilRice. When officially approved, basic seed will be available to seed growers and selected farmers that can cater to other farmers. It is also expected that seed exchange among farmers in the target areas will be active with the new technologies.
Each variety has been tested in field conditions and evaluated through the National Cooperative Testing program of PhilRice. The Rice Technical Working Group will now recommend the varieties for official release to the Technical Secretariat and then the Council Secretariat of the National Seed Industry Council will officially approve the varieties, which is expected to occur sometime in late 2009.
Salt-tolerant rice
In the Philippines, around 400,000 hectares of coastal rice-growing land is affected by salinity from sea water. Farmers often don’t plant this region because of the risk of crop failure, but, with the new salt-tolerant variety IR63307-4B-4-3, they can now use this land to grow rice.
Under high salt stress, high-yielding Philippine rice varieties typically produce less than a ton of rice per hectare. Under the same conditions, IR63307-4B-4-3 can produce 2.5 to 3.5 tons of rice per hectare. However, in the absence of salinity, this salt-tolerant variety can yield 6.5 to 7.0 tons per hectare.
In addition to the salt-tolerance trait built into IR63307-4B-4-3, proper crop management is essential to achieving high grain yield in salt-affected soils. This includes water management through strong and effective levies to check sea-water ingression, planting of older seedlings (to avoid salt damage when the plants are young and at a sensitive stage), and suitable nutrient management. The extra costs of these practices are readily offset by the value of the overall increase in productivity.
The total potential of increased rice production from salt-affected areas in the Philippines could be 0.8 to 1.0 million tons per annum and the new rice variety, IR63307-4B-4-3, could contribute substantially if grown across all of the Philippines’ salt-prone lands. In Bangladesh, the same variety was released in 2007 as BRRI dhan 47 and it has been widely adopted by farmers, who are undertaking large-scale seed production to fulfill demand as word spreads about its yield advantages.
IRRI’s rice research on salt-tolerance is financially supported by the Federal Government of Germany and the CGIAR Generation Challenge Programme. It is done in collaboration with national partners especially from South and Southeast Asia.
Rice is one of the few crops that thrive in wet agricultural environments. Rice seed can even germinate in saturated soil, but most rice plants will be seriously damaged or die if they remain totally under-water for more than a week.
Around 370,000 hectares of rice-growing land in the Philippines experiences flooding, causing average crop losses of about 250,000 tons every year. Severe typhoon activity in 2006 increased flooding of rice crops in the Philippines and an estimated 228,350 tons of rice was lost due to flooding that year. Flooding most commonly occurs in poorer areas that lack proper flood control infrastructure.
The length of time rice is totally submerged during flooding largely determines the amount of crop loss. IRRI’s new flood-tolerant rice for the Philippines, currently called IR64-Sub1, can tolerate more than two weeks under water. The same conditions would typically reduce yields of IR64-Sub1’s counterpart rice variety without submergence tolerance, IR64, to less than 1 ton per hectare, yet IR64-Sub1 can yield nearly 5 tons per hectare.
IR64 is a popular variety of rice that is widely grown across the Philippines. IR64-Sub1 is exactly the same as IR64 except it also has the SUB1 gene that confers its tolerance of flooding. The SUB1 gene was discovered by researchers at IRRI and the University of California, Davis, and it has since been bred into many rice varieties.
In early 2009, the first rice varieties with the SUB1 gene were approved forrelease in the Indian state of Uttar Pradesh.
IRRI’s rice research on flood-tolerance is financially supported by the Ministry of Foreign Affairs of Japan and the Federal Government of Germany.
Around 1,180,000 hectares of cultivated area in the Philippines is under an upland rice ecosystem in which farmers follow a direct-seeding method of rice cultivation and the rice survives solely on rainfall for its water requirement. All of this upland area is prone to drought.
Even a week without rain in upland areas of the Philippines may be enough time for rice plants to start suffering stress from a lack of water. As a result, the rice plants will be less productive.
IRRI’s new drought-tolerant rice variety for the Philippines, IR74371-54-1-1, can yield up to 10% more than standard varieties in seasons with good rainfall and it provides 0.5 to 0.8 tons per hectare yield advantage when an area is exposed to drought.
Farmers in drought-prone areas typically don’t choose to add costly inputs, such as fertilizer, because, if drought occurs, they risk losing their crop and the cost of the fertilizer. A drought-tolerant rice variety will give them added security to invest in their rice crops to get higher yields.
Farmers who have tested IR74371-54-1-1 have been impressed with the variety and its versatility to be transplanted, dry seeded, or wet seeded. It also has good grain and eating quality.
In 2009, another IRRI line, IR74371-70-1-1, has been recommended for release in two highly drought prone provinces of eastern India.
This research is financially supported by the Rockefeller Foundation and the CGIAR Generation Challenge Programme.
