Evaluation of Common Bean Cultivars Resistance to the Bean Common Mosaic Necrosis Virus in Western Kenya

Mukoye Benard,Were Hassan Karakacha,Mangeni Bonphace Collins,Ndong’a Millicent

doi:10.11648/j.ijgg.20190704.15

Abstract

The common bean (Phaseolus vulgaris), is a high protein crop and the main legume in the cropping system of western Kenya. Despite its importance, common bean yields are low (<1.0 t/ha) and declining. Bean Common mosaic virus (BCMV) and Bean common mosaic necrosis virus (BCMNV) are the most common and most destructive and can cause a yield loss as high as 100%. In Kenya, limited cultivars and exotic genotypes with resistance to BCMV and BCMNV strains have been reported. Reports indicate BCMNV being a widespread virus compared to BCMV in western Kenya. This study therefore, sought to screen popular cultivars for resistance to the virus. Sixteen popularly grown bean cultivars together with cowpea (Vigna unguiculata), soybean (Glycine max) and groundnut (Arachis hypogaea) were planted in a green house in a completely randomized block design with three replicates. The plants were inoculated with BCMNV Enzyme Linked Immunosorbent Assay (ELISA) positive isolate at 3-leaf stage. Data was taken weekly for 3 weeks on type of symptoms expressed and number of plants infected. Ten bean cultivars were susceptible, 4 tolerant and 2 resistant. For improved yields of common bean, farmers should be advised to plant certified seeds for all legumes in the cropping system.

Highlights

Western Kenya is one of the food baskets of the country, and a region with about 1/3 of the country’s population
Sixteen popularly grown common bean cultivars in western Kenya inoculated with bean common mosaic necrosis virus (BCMNV) isolate from western Kenya (Kakamega) in a greenhouse exhibited typical virus symptoms such as leaf mosaic, down ward leaf curl and yellowing as shown on popular variety GLP 2 (Figure 1)
Four bean varieties (Imbeko, KK/RIL5/Red 13, Okwoto, RIL05/CAL 194) were symptomless with BCMNV BG 12 isolate from western Kenya tested positive for BCMNV by DAS Enzyme Linked Immunosorbent Assay (ELISA)

Summary

Introduction

Western Kenya is one of the food baskets of the country, and a region with about 1/3 of the country’s population. The common bean (Phaseolus vulgaris L), is a high protein (22g/100g) crop and the main legume in the cropping system of the region. Common bean productivity is declining and yields obtained of less than 1.0 t ha-1 are low compared to a production potential of 1400 – 2000 kg ha-1 [1, 2]. This has happened at a time when a greater variety of high protein food sources are needed to ensure food security. Decreasing yields are attributed to poor access to improved seeds, declining soil fertility, drought, and high incidence of pests, diseases and unpredictable weather. The two viruses are closely related and belong to the Family Potyviridae, genus Potyvirus, which is the largest of the eight genera currently assigned to the family by the International Committee on Taxonomy of Viruses [4]

Methods

Results

Discussion

Conclusion