Evaluation and genome wide association mapping of ethiopian sorghum landraces (Sorghum Bicolor (L.) Moench) under moisture stress condition at sheraro, north ethiopia

Abstract

Drought is one of the most important environmental challenges farmers face around the globe including in Ethiopia and it is the main cause of yield reduction. Improvement of the crop for drought tolerance related traits requires studying the genetics of the traits. Therefore, the present study was initiated to evaluate the performance of sorghum genotypes and to identify chromosomal regions associated with drought tolerance and other agronomic traits using genome wide association studies (GWAS). The field experiment was conducted at Sheraro, Northern Ethiopia, in 2018/19 growing season. The experimental materials consisted of 945 genotypes and the experiment was laid out in an alpha lattice design replicated twice. The experimental materials were genotyped with a total of 25,634 SNPs markers (minor allele frequency > 0.01) to perform GWAS. Analysis of variance revealed that there was highly significant difference (p<0.01) among the genotypes for all the traits. Genotypic coefficient of variation (GCV) ranged from 2.75 % (days to maturity) to 29 % (leaf angle), whereas phenotypic coefficient of variation (PCV) ranged from 3.81 % (days to maturity) to 31.53 % (leaf angle). Heritability ranged from 47.78 % (number of tillers) to 92.55 % (number of leaves) and genetic advance as percentage of mean (GAM) ranged from 4.09 % (days to maturity) to 57.38 % (leaf angle). Traits like panicle length, leaf angle and chlorophyll content at maturity had high GCV and PCV. High heritability coupled high GAM was observed for leaf area, leaf angle, panicle length, chlorophyll content at maturity, plant height and number of leaves. The studied genotypes were grouped into five subgroups with 73.62% of individuals had ancestry membership coefficient greater than 60% and the remaining 26.38% of the individuals were admixed. A total of 98 different SNPs having significant associations with 15 traits were detected. The identified marker-trait associations could be useful in marker-assisted selection. In General, this study had contributed to the characterization of genes and alleles controlling drought related traits, and will serve as a source of markers for molecular breeding