Assessment of genetic diversity among sixty bread wheat (Triticum aestivum) cultivars using microsatellite markers
Assessment of genetic diversity among wheat cultivars is important to ensure that a continuous pool of cultivars with varying desirable traits is maintained. In view of this, a molecular study was conducted to assess the genetic diversity of sixty wheat cultivars using sixty microsatellite markers. Amplified alleles from each cultivar were scored after running in 6% poly acrylamide gel electrophoresis (PAGE). A dendrogram was constructed based on the genetic similarity coefficient of un-weighted pair-wise group method with arithmetic average (UPGMA). The results showed that 276 alleles were amplified by 48 polymorphic microsatellite markers averaging 5.7 alleles per locus. A total of 12 markers did not amplify any alleles from the 60 cultivars. Polymorphism of alleles and genetic diversity measured by polymorphic information content (PIC) and Shannon index (SI) respectively, found that genome A had the highest genetic diversity followed by genome B while genome D was the lowest diverse. Cluster analysis resulted in formation of four clusters comprising of 3, 7, 9 and 41 cultivars. Genetic distance between the clusters ranged from 0.56 to 0.87 and most cultivars showed high diversity between genetic distances of 0.65 and 0.75. The four clusters and their similarities will help breeders to breed new disease resistant cultivars and make rational deployment of cultivars in production based on the established relationships.
Key words: Genetic diversity, molecular marker, microsatellite (SSR marker), Triticum aestivum.