Abstract
Common bean anthracnose caused by Colletotrichum lindemuthianum is one of the major biotic constraints to production of French beans (Phaseolus vulgaris L.) in Kenya. This study aimed at screening French bean genotypes in relation to their response to common bean anthracnose in order to identify potential sources of germplasm for breeding. The genotypes were tested in three sites (Kakamega, Mwea and Kutus) where results revealed a significant genotype by environment interaction effect (p ≤ 0.05) which emphasizes the strong influence of the growing conditions on the expression of host resistance. Physiological characterization identified a total of 14 distinct races out of 16 successfully plated isolates, revealing a very high diversity of C. lindemuthianum in Kenya. Six races have not been reported in previous studies in the country and are considered as new races, that is, races 84, 141, 246, 515, 576 and 768. Andean race 401 was the most virulent race with a virulence index of 67% among the genotypes. Molecular analysis using six sequence characterized amplified region (SCAR) markers revealed polymorphism among the genotypes. The SCAR markers SBB-14, SH-18 and SAB-03 have shown to be useful for marker assisted selection (MAS) of the target resistance genes. This study has also identified locally improved breeding lines as potential donors for resistance breeding to C. lindemuthianum in Kenya. Key words: Anthracnose, sequence characterized amplified region (SCAR), marker assisted selection (MAS).
Highlights
French bean is valued for its production of tender, thin pods containing small seeds (Singh et al, 2015)
The germplasm panel was made up of 33 entries comprising 16 commercial French bean genotypes commonly grown in Kenya, 3 local breeding lines, 2 landraces and the 12 standard differential cultivars for C. lindemuthianum
Reaction of French beans and differential cultivars to anthracnose under field conditions According to the analysis of variance (ANOVA), there were significant differences (p≤0.05) in the severity of anthracnose infection both among the genotypes and environments
Summary
French bean ( referred to as the snap or green bean) is valued for its production of tender, thin pods containing small seeds (Singh et al, 2015). It is a type of common bean (Phaseolus vulgaris L.), a crop grown widely as a source of protein (Broughton et al, 2003; Blair et al, 2007). French bean is valued for its protein (23%); the pods are rich in calcium (Ca), phosphorous (P) and iron (Fe) They are packed with dietary fiber which contains high levels of vitamin A, a strong antioxidant that fights against high cholesterol, heart disease and cancer. In Kenya the green leaves are used as vegetables (Mwaninki, 2017)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
