Screening, compiling and validation of informative microsatellite sets for marker-assisted breeding of key Ethiopian sorghum cultivars

Abstract

Sorghum is among the most important cereal crops produced globally due to its drought tolerance nature and multiple uses. Ethiopia is endowed with high genetic diversity for sorghum and the main sources of several genes that are responsible for biotic and abiotic stress tolerance. Despite this potential, sorghum productivity in the country remains very low. The study was designed to screen and compile the best simple sequence repeats (SSRs) that can be used for marker-assisted breeding of sorghum. Out of a total 304 SSRs markers screened used across eleven farmers preferred sorghum genotypes, nearly half of the markers 139 (45.7%) detected 543 alleles and a high degree of polymorphic information content (PIC) averaging 0.53. The overall observed heterozygosity (Ho) across all loci varied from 0.00 to 1.00 with an average of 0.16. Nearly 60 % (83 markers) showed no Ho. The gene diversity index (expected heterozygosity, He) ranged from 0.17 to 0.91 with a mean of 0.58. The weighted neighbor-joining cluster analysis grouped the genotypes into three distinct groups. All genotypes with stay-green features (B 35, Sorcoll 163/07, E 36-1 and Sorcoll 141/07) were clustered together. Genotypes such as Gambella, Macia, 76T#23 and Meko were clustered in the second group. The third group consists of Teshale and Sorcoll 146/07. Most of the used SSR markers were linked with stay-green traits and successfully discriminated genotypes with stay green (cluster I) from those genotypes with non-stay green features (cluster II and III). The result reveals the potential application of microsatellites in Ethiopian marker-assisted breeding program for further characterization and/or mapping of targeted traits in sorghum.