Molecular Characterization of Sorghum Germplasm for Drought Tolerance Exhibiting Stay-green Trait

Abstract

The best characterized form of drought tolerance in sorghum during crop growth is the non-senescence or “staygreen”
trait. To assess the genetic diversity available in sorghum germplasm for drought tolerance, 16 stay-green
specific simple sequence repeat markers (SSR) were used of which 10 were polymorphic. A total of 47 scorable
alleles were generated by these 10 primers of which 44 were polymorphic (93.6%). The number of alleles
produced by different primers ranged from three to seven with an average of 4.7 alleles per primer. Similarity
coefficients based on 10 polymorphic SSR markers ranged from 0.205 to 0.864. The dendrogram grouped the
sorghum accessions into 11 major clusters and categorized the drought-resistant and drought-susceptible genotypes
into separate clusters. Most of the genotypes in the cluster I and IV had better stay-green score ranging between
1.80 to 2.5. The study revealed that the presence of genetic diversity is high among the accessions and the staygreen
specific primers sorted the genotypes based on their level of drought tolerance