Climbing Bean Variety Developed for Rwanda

LONDON - Feb 9/10 - SNS -- Researchers have developed climbing beans varieties which are better suited to rainy high-altitude areas and which are being distributed in Rwanda, according to a recent article at the Science and Development Network website.

The Rwandan Agricultural Research Institute (ISAR) and the International Center for Tropical Agriculture (CIAT) worked together to develop 15 varieties of climbing bean, targeting smallholder farmers in similar areas across Central and East Africa.

Because climbing beans are off the ground, they are resistant to anthracnose, root rot and ascochyta. Those diseases do well in damp, higher altitude areas, resulting in significant yield losses in the more commonly grown 'bush type' beans.

Test plots have also had dramatic yield improvements over bush type beans, sometimes producing three or four times as many beans. Climbing beans are also well suited to small farms because they can be grown on two meter tall stakes. Augustine Musoni, bean breeder and coordinator of bean research at ISAR, reckons this will also help reduce soil erosion in sloping areas that experience heavy rain.

"The climbing bean varieties do well in nutrient-poor soils and take about four months to mature, thus offering farmers the possibility for four planting seasons annually with a hectare yielding 3–4,000 kilogram each harvesting season," said Robin Buruchara, regional coordinator for CIAT in Africa told SciDev.net. Following is text from that article:

Climbing beans are more often grown in Central American countries but are becoming more popular in Africa, said Musoni.

He added the new varieties, which ISAR began formally distributing to farmers last month (15 January), are good at nitrogen fixing, a process in which soil bacteria in the bean plant's roots absorb nitrogen, which is then released into the soil and acts as a fertilizer.

The varieties are already proving popular. Rwandan farmer Alphonsin Nyirambranjinka said the new variety gives her yields almost three times that of the bush beans she used to grow. "The new variety gives good yields for us to eat at home and I sell the rest the local market. The beans also taste sweet."

Paul Kimani, a bean breeder and professor of plant breeding and genetics at the University of Nairobi, Kenya — where the new varieties have tripled yields — said the new varieties "fix between 5-40 kilograms of nitrogen per year per hectare, compared with maize, which fixes no nitrogen".

He added that the need to grow the beans up stakes could add to costs but higher yields would cover the extra expenditure. Kimani said the biggest barrier was getting the seeds to farmers.

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