Planting of cowpea, commonly called beans, a major export crop in some agro-ecological zones of Nigeria, has begun.
The global production of cowpea is estimated at 7.1 million metric tonnes with 6.7 million tonnes coming from Africa on an estimated 12 million hectares.
Nigeria produces about three million metric tonnes of cowpea on an estimated 3.6 million hectares, making it the world’s largest producer.
However, despite being the world’s largest producer, yields of varieties range between 350 and 400kg per hectare “due to so many constraints”, said Prof. Mohammed Ishiyaku, a cowpea farmer and the Executive Director of the Institute of Agricultural Research (IAR), Ahmadu Bello University (ABU), Zaria.
Prof. Ishiyaku is the principal farmer of the two new cowpea varieties which were released to farmers in 2019.
On the basis of earliness, relatively high yield (2.5-2.9t/ha) potential even under intense maruca infestations due to its resistance to the insect, the variety SAMPEA 20T was registered and released to farmers in Nigeria on December 12, 2019.
Trials in agro-ecological zones: Sudan Savanna (Kano, Danbatta, Bunkure, Minjibir and Dutse); Northern Guinea Savanna (Samaru, Mando and Nabordo); Southern Guinea Savanna (Makurdi, NABDA, Mokwa) and Forest Savanna Transition (Ile-Ife) have indicated good results compared to other seeds.
Bt. Cowpea requires very minimal (one to two) chemical sprays to control non-maruca insects.
In 2010, the International Institute of Tropical Agriculture (IITA), Ibadan, in collaboration with the IAR, the University of Maiduguri and other partners released two improved cowpea varieties: IT89KD-288 and IT89KD-391. The varieties are also good for farmers who may not want to grow the Bt. cowpea varieties.
According to IITA, the 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 to Nigeria’s strain of Strigagesnerioides also known as cowpea witchweed (a parasitic weed that severely lowers yield).
Scientists have recommended 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, where there is a certainty of rains up till the end of October, IT89KD-288 can be planted in September.
The 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 the North East of Nigeria.
The IT89KD-391 is a welcome improvement over SAMPEA 7, Ife Brown, IT90K-76 and IT90K-82-2 which are the main improved brown-seed varieties available.
Other available varieties are SAMPEA 18 (IT07K-293-13) – it matures early, is tolerant to striga, drought and alectra and SAMPEA 18 (IT07K-293-13) – early maturity, resistant to alectra and bacterial blight and tolerant to striga and drought, released in 2018.
SAMPEA 17 (IT07K-318-33) and SAMPEA 15 (IT99K-573-2-1) were released in 2016.
Other varieties from the Federal University of Agriculture (FUA), Makurdi, are FUAMPEA 2 (UAM09 1051-1) and FUAMPEA 1 (UAM09 1055-6) which are resistant to striga and alectra.
In terms of soil requirement, cowpea grows better in sandy soil, which scientists say “tends to be less restrictive on root growth. It is more tolerant to infertile and acid soils than many other crops. Beans, therefore, flourish in well-drained soils and less on heavy soils with pH of between 5,6 and 6,0.