Assessment of Genetic Diversity among the Maize (Zea mays L.) Genotypes Based on SSR Markers Linked to Drought Tolerance

Abstract

Genetic diversity within maize germplasm is essential for the development of improved maize hybrids through breeding programs. This study was conducted to assess the genetic diversity among the twelve maize genotypes sourced from different origins, using 25 drought associated SSR markers and to identify potential parental lines for future breeding programs. The results revealed that majority of the SSR markers were polymorphic and effective in estimating the genetic variation among the selected maize genotypes. Twenty-five SSR markers amplified a total of 124 alleles and the number of alleles per locus ranged from 4 to 7 and an average of 5 alleles. Markers bnlg 1179, umc 1542, bnlg 1866 and bnlg 2190 produced the highest number of alleles (7). The amplified PCR products with 25 SSRs were ranged from 100 bp to 298 bp. The largest PCR fragment (298 bp) was generated by primer umc 1596, while the smallest fragment (100 bp) generated by bnlg 490. Polymorphism Information Content (PIC) valued varied from 0.70 to 0.84 with a mean of 0.75. While heterozygosity (H) ranged from 0.75 to 0.86, averaging 0.79. Cluster analysis based on the dendrogram grouped the 12 genotypes in to 4 major clusters, with the highest number of genotypes observed in cluster IV. These results clearly indicating that the selected genotypes possessed high level of genetic diversity as they showed high level of polymorphism of drought linked SSR markers. The identified genetic resource may be useful in future quantitative trait loci (QTL) mapping for different traits. These resources are particularly valuable for the development of abiotic stress tolerant maize varieties including drought.