Resistance of nutrient-rich bean varieties to major biotic constraints in Kenya

Abstract

Common bean, Phaseolus vulgaris L., is valued as a major source of affordable protein and minerals, and a source of income and employment for rural communities. It is an important staple in the diet of people of all income categories, with consumption levels in eastern and southern Africa exceeding 50kg per person per year, reaching 66 kg per person in parts of Kisii. Productivity of common bean in Kenya is severely constrained by abiotic and biotic stresses, especially diseases such as angular leaf spot, anthracnose, rust, common bacterial blight, bean common mosaic virus (BCMV), Fusarium wilt and root rots. This study was undertaken to evaluate 27 newly identified bean varieties with high iron and zinc concentration for resistance to the major diseases under field conditions. Eight varieties (RWR 10, K 132, MCM 2001, G5686, PVA 8, Soya Fupi, Nguaku Nguaku and Nain De Kyondo) showed high (grade 1 to 3) to moderate (grade 5) levels of resistance to anthracnose, bean rust, common bacterial blight, bean common mosaic virus and root rot. Variety Kiangara had good levels of resistance to all the diseases. These results indicate that some of the newly identified nutrient-rich bean varieties possess good levels of resistance to diseases and their adoption would, therefore, increase bean production and improve human health.