Tuesday, January 26, 2010

Indica rice in the African uplands


Asian rice (Oryza sativa) includes tropical japonica and indica. For years, farmers and scientists alike have not grown indica varieties on the dryer uplands of West Africa, assuming that indica varieties were poorly suited there. AfricaRice scientist Dr. Kazuki Saito spent five years in Laos doing his PhD research. As in Africa, most of the farmers in Laos did not apply fertilizer, and they grew indica varieties in the lowlands, but low-yielding, traditional tropical japonicas in the uplands. In Laos, Dr. Saito tried testing improved indica varieties from the other Southeast Asian countries for the uplands and they performed well.

He thought, if indica varieties could perform well in the uplands of Southeast Asia, they might also do well in the African uplands. So, Dr. Saito brought seeds from Asia, from IRRI (the International Rice Research Institute in the Philippines) and started to test them in Benin. Although Africa has its own species of rice (Oryza glaberrima), Asian rice is widely grown in Africa. Except for the African rice, all of the upland varieties in West Africa were tropicaljaponica.

1080191 irrigated on the left, unirrigated on the right.JPG
AfricaRice is now testing 30 varieties, mostly indicas, to compare their performance with irrigation (on the left) and un-irrigated (on the right)
For two years, AfricaRice scientists planted rice at their experimental farm in southern Benin, comparing Nerica1(high-yielding hybrids bred from African and Asian rice) and two traditional varieties Morobérékan (tropicaljaponica) and CG 14 (O. glaberrima) with three indicavarieties.

The results were encouraging. The indica varieties are bushy, which helps them to compete with weeds. Experiments showed that the indica varieties performed well in low and high soil fertility conditions.

As the following table shows, an indica variety from Indonesia outperformed the others where the soil was fertile and also where it was not. This means that this variety holds promise for breeding improved rice in African uplands.
Table: Yield of indica and other rice varieties
Rice variety
Yield in low soil fertility
(t/ha)
Yield in fertile soil
(t/ha)
B 6144 (indica from Indonesia)
2.2
4.4
IR 78875 (indica from IRRI)
1.7
3.5
CG 14 (O. glaberrima)
1.7
1.3
IR 55423 (indica from IRRI)
1.7
4.4
Morobérékan (Africanjaponica)
1.1
2.4
Nerica1
1.1
4.3
As a next step, in the 2009 wet season, AfricaRice scientists planted rice in collaboration with 20 smallholder farmers at their fields in Central Benin to compare farmers’ varieties with three indica varieties and to see how the farmers judge their performance.
AfricaRice is also evaluating indica varieties for the drought-prone upland environment, and is now testing 30 rice varieties (including 25 indicas) in irrigated and dry conditions.
When these experiments are completed, the results will suggest which varieties may be interesting for the smallholder farmers in drought-prone environments.
Further reading
Saito, Kazuki and Koichi Futakuchi. 2009. “Performance of diverse upland rice cultivars in low and high soil fertility conditions in West Africa.” Field Crops Research 111:243-250.