Improved cowpea varieties for Nigeria’s savannas

Nigeria has released two new cowpea varieties to raise production and improve farmers’ incomes.

Harvesting cowpea. Photo by IITA
Harvesting cowpea. Photo by IITA

The varieties—IT89KD-288 and IT89KD-391—were developed by scientists working at IITA, Ibadan, in collaboration with the Institute for Agricultural Research of the Ahmadu Bello University, Zaria; University of Maiduguri, Borno; and the Agricultural Development Programs of Borno, Kaduna, Kano, and Katsina States.

Both varieties have proven to be superior over the current improved lines being cultivated. They could be used to overcome the challenges faced by cowpea farmers in the country.

For instance, IT89KD-288 (now SAMPEA-11) is a dual-purpose cowpea variety with large white seeds and a rough seed coat. It has combined resistance to major diseases including septoria leaf spot, scab, and bacterial blight, as well as to nematodes, and tolerance for Nigeria’s strain of Striga gesnerioides (a parasitic weed that severely lowers yield).

“It also has a yield advantage of at least 80% over the local varieties,” said Alpha Kamara, IITA Agronomist, who is leading efforts to rapidly disseminate the varieties to farmers.

The nematode-resistant variety is an equally good candidate for sowing with cereals or as a relay crop with maize in the moist and dry savanna zones, and for high grain production in the dry season.

Scientists recommend that the variety be planted in mid-July in the Sudan savanna, early to mid-August in the northern Guinea savanna, and by the end of August in the southern Guinea savanna. However, if there is certainty of rains up till the end of October, IT89KD-288 can be planted in September.

Cowpea farmers in Kano, Nigeria. Photo by IITA.
Cowpea farmers in Kano, Nigeria. Photo by IITA.

IT89KD-391 (now SAMPEA-12) is also a dual-purpose cowpea variety but it has medium-to-large brown seeds with a rough seed coat. These are preferred seed characteristics for commercial production in northeast Nigeria.

“IT89KD-391 is a welcome improvement over SAMPEA 7, Ife brown, IT90K-76, and IT90K-82-2 which are the main improved brown-seeded varieties available. It has been tested extensively in this area and is well accepted by the farmers,” said Hakeem Ajeigbe, IITA Extension/Dissemination Specialist.

“The variety performs well as a sole crop and an intercrop. It could also be planted as a relay crop with maize in the Guinea savannas,” he added.
Several on-station and on-farm trials have shown that IT89KD-391 (SAMPEA 12) produces double the yields of local cultivars.

In 2008, Nigeria released a Striga-resistant improved cowpea variety (IT97K-499-35).

“The demand for these improved varieties is high because of their superior yields and their acceptability by consumers,” Kamara said.

Enriching livestock diets with cowpea

Loaded on camel-back, covering roofs, stored in tree tops, and traded in the market, cowpea haulms can be seen throughout the semiarid tropical regions being stored, marketed, and used as livestock feed. Expanding the intensification of crop−livestock systems encourages the use of dual-purpose cowpea varieties that produce high yields of both grain and fodder.

Farmer feeding sheep with cowpea haulms. Photo by ILRI.
Farmer feeding sheep with cowpea haulms. Photo by ILRI.

Research on yield and quality of cowpea haulms by centers belonging to the Consultative Group on International Agricultural Research is leading to improvements in livestock production and the associated incomes of crop−livestock farmers.

Cowpea is an important component in mixed crop−livestock systems in the semi-arid regions of the tropics. It is being grown more and more to provide high levels of fodder for livestock in addition to producing grain for people. Since the late 1980s, cowpea breeding programs have worked toward producing dual-purpose varieties that emphasize the production of grain and fodder resulting in varieties that can yield over 1 t/ha of grain and 2 t/ha of fodder.

Crop residues—the stalks, stems, and leaves remaining after seed harvest—make up a major component of livestock diets in mixed crop−livestock systems. Improving the nutritional quality of crop residues is thus important to enhance the productivity and profitability of these farming systems. Demand for livestock products through much of the semi-arid tropics will be likely to continue to increase along with the use of purchased feedstuffs. For this reason, sales of cowpea fodder have been expanding, providing cowpea farmers with additional opportunities for marketing their surplus crop.

Late-maturing varieties of cowpea are often used for fodder because they can take advantage of a longer growing season to amass more biomass. Where the longer growing period can make the crop susceptible to late drought, varieties may be preferred with a high fodder yield produced within a more moderate growing period. A collaborative program between IITA and the International Livestock Research Institute (ILRI), which was started in the 1980s to evaluate and develop dual-purpose varieties, has produced several that have become well accepted when tested on-farm.

Woman farmer tending to her goat. Photo by ILRI.
Woman farmer tending to her goat. Photo by ILRI.

It is useful to know the differences in performance of livestock fed on different varieties of cowpea. Some varieties have been tested for their ability to increase the weight of small ruminants or improve the milk yield of cows. However, only a few varieties can be compared at one time in live animal trials. This makes the systematic screening of cowpea genetic resources important for advancing the development of dual-purpose varieties.

Screening tools that can rapidly assess the nutritional quality of different varieties greatly aid the evaluation process. Near-infrared reflectance spectroscopy (NIRS) is one such tool, allowing the fast and inexpensive analysis of small quantities of plant biomass. This technique uses near-infrared light to measure nutritive quality, such as the amounts of nitrogen and fiber, or the digestibility of the fodder, all of which are related directly to animal performance. The technique takes only a few minutes, replacing the hours of chemical analysis that were once needed to evaluate ground samples of fodder. Once screened, selected varieties could be tested further to verify their performance potential.

The greater nutritional quality of legume residues allows them to be used as a supplement to livestock diets based on cereal stovers and other low-quality forages. Optimizing the amount of cowpea haulms in livestock diets was one focus of a research project sponsored by the CGIAR Systemwide Livestock Program on the use of cowpea fodder. As smallholder livestock systems evolve and become more market-oriented, the type of diets fed to livestock often changes. Legume fodders remain an important part of these changing diets. The development of cowpea varieties that feed both people and their farm animals better will give farmers new and wider choices.

There is still much to be done. With significant variation existing within cowpea germplasm collections, we can continue to improve dual-purpose varieties. Modern technologies are available to allow the rapid screening of important quality traits. Techniques such as NIRS for quality analysis and marker-assisted selection for desirable traits promise to speed the future development of new varieties of dual-purpose cowpea.