M. E. Morojele*¹, D. N. M. Mbewe²

¹Small Grain Institute, Private Bag X29. Bethlehem. 9700. South Africa.

²The University of Zambia, Lusaka. Zambia

ABSTRACT

Different cultivars of common bean are grown in Lesotho for home consumption originating from Zambia, South Africa and America. These have created a wide genetic diversity and duplication such that it is not easy to distinguish them. The study was conducted in Lusaka to distinguish the same common bean cultivars using morphological markers and to estimate their degree of similarity. A collection of 42 cultivars were included in the study. Seventeen morphological characters were used following International Plant Genetic Resource Unit descriptor (1982). Data collected were analysed using principal component and cluster analysis. Principal component analysis was used to identify the characters which caused major variation among cultivars. Out of 10 principal components generated from 17 characters, only the first three components which constituted 54.57% of the total variation were considered for analysis. The first, second and third components accounted for 23.23%, 16.80% and 14.54%, respectively. The characters responsible for separation along the first principal component and loadings (parenthesis) were plant height (0.57), growth habit (0.55) and seed pattern (-0.27).The characters influencing separation along the second principal component include number of flowers per node (0.50), number of locules per pod (0.44), seed colour (0.44) and leaflet length (0.30). Along the third principal component, cultivars were separated according to the pod colour (0.64) and flower colour (0.14).Thirty-five individual cultivars and two groups of cultivars were distinguished by cluster analysis.  One group consisted of three cultivars from Zambia, while the other group consisted of two cultivars from Zambia and two from Lesotho.

Keywords: Common bean, morphological markers, principal component analysis, cluster analysis