Common Bean Germplasm Diversity Study for Cold Tolerance in Ethiopia

Abstract

Limited tolerance of common beans ( Phaseolus vulgaris L.) to cold temperatures hinders an additional harvest during the small rainy season crop cycle (February to May) in the Ethiopian highlands that comprise two-thirds of the country. Therefore, identification of cold tolerant common bean genotypes is of paramount importance for the region. Field screening of 99 common bean genotypes originally procured from CIAT (International Center for Tropical Agriculture) was carried out for nine different plant traits associated with crop growth and yield at two locations differing in climates: Dire Dawa-higher daily maximum and minimum temperatures and absence of near zero chilling temperatures from February to May; Haramaya-lower daily maximum and minimum temperatures and occasionally near zero chilling temperatures during this period. The analysis of variance (ANOVA) showed the existence of significant variation among genotypes for the parameters measured. Principal component analysis (PCA) was carried out to assess the variation and correlation among genotypes for the traits and group them based on their performance at the two locations. The combination of first three principal components explained more than 50% of the genotypic variations. Principal component analysis was also able to discriminate the performance of genotypes between the two locations. It was grouped into at least 17 genotypes that were specific to Haramaya highland location. The results also revealed significant variation in performance among the 17 genotypes. These genotypes are specific to Ethiopian highlands and prominent resources for in-situ conservation of germplasms.