Phenotypic And Snps Based Screening Of Selected Tef (Eragrostis Tef) Accessions For Drought Tolerance At Vegetative Stage.

Abstract

Tef (Eragrostis tef (Zuccagni) Trotter) is a staple food supporting over 50 million people in Ethiopia. Ethiopia is the center of origin and diversity of tef. Tef production is low, specifically due to drought and lodging. Tef is more vulnerable to moisture stress during its early stages of development than it is at maturity. Moisture stress at pre-flowering stage can result in 69 - 77% grain yield reduction. Therefore, this study was aimed at morphological screening of 60 diverse tef accessions for moisture stress tolerance at their vegetative growth stage under water stress and non-stress greenhouse conditions and using SNPs marker. The experiment was laid out completely randomized design (CRD) with three replications. Phenotypic traits were recorded to evaluate the effect of water stress on tef. To complement the greenhouse experiment, 538,253 filtered SNPs generated from resequencing of the same accessions were used for Genome-wide association study (GWAS). GWAS based on mixed linear model (MLM) in TASSEL 5.2.9 identified SNPs with significant association (FDR ≤ 0.05) to the studied traits. The two way ANOVA revealed existence of highly Significant (P<0.001) differences among tef genotypes for root length, shoot length, root fresh weight, shoot fresh weight, root dry weight, and significant differences (p<0.05) for shoot dry weight at both stressed and non-stressed conditions. The water treatment effect was also highly significant (p<0.001) for all the studied traits except for root length. Accessions by Treatment interactions were highly significant (p<0.001) for root fresh weight, shoot fresh weight and root dry weight, significant (p<0.05) for shoot dry weight, and non-significant for rout length and shoot length, indicating that thus water stress has detrimental effect on the majority of the evaluated phenotypic traits. Tef accessions found as tolerant to moisture stress; 243501, 225760, 243489, 243495, 243531 and 55183. GWAS identified a total of 215 loci significantly (FDR < 0.05) associated with the considered traits (shoot length, root dry weight, shoot fresh weight and root fresh weight) under water stress condition. The detected significant SNPs were distribution over the 20 tef chromosomes. Overall, in response to water stress, considerable genetic variability were found across the studied tef accessions, indicating promising possibility to develop water stress tolerant genotypes through integrated application of phenotypic and markers assisted breeding. Moreover, the detected significant markers could be used to screen more accessions in the tef gene pool and also to begin genome-assisted breeding of tef for water-stress tolerance.