Genetic Diversity of Potato (Solanum tuberosum L.) Cultivars Grown in Lesotho as Determined by Morphological Markers

Abstract— Irish potato is the only tuber crop grown by farmers in Lesotho, particularly in the foothills where environment is conducive for its growth and high yield. Potato seeds are imported from South Africa without verifying for authenticity, fraudulence and intellectual property rights. The objectives of the study were to: (i) estimate genetic distance among potato cultivars using morphological markers, (ii) determine discriminatory power of morphological markers in distinguishing potato cultivars. The study was conducted at National University of Lesotho experimental farm, Roma. Experiment was laid out using Randomized Complete Block Design with eight treatments and three replications. Treatments were cultivars; Mondial, Panamera, Taurus, Tyger, Tyson, Valor, Avalanche and Innovator. Data on 21 markers were collected using potato descriptor, thereafter analyzed using Genstat (Version 17) to perform cluster analysis and principal component analysis. Results of cluster analysis revealed variability among potato cultivars. Cultivars constituted 1 major group, which in turn divided into two sub-group. Two sub-groups further sub-divided three times forming sub-subgroups and outliers. First six principal components contributed 97% of variation among cultivars. Characters with high discriminatory power were marketable tubers, root fresh weight, tuber fresh weight, number of main stems, leaf dry weight, leaf fresh weight and total yield. In conclusion, cluster analysis has group cultivars according to their similarities and principal component analysis revealed characters with high discriminatory power.