Evaluation of sorghum (Sorghum bicolor (L.) Moench) backcross nested association mapping populations under moisture stress at sheraro, northern ethiopia

Abstract

Sorghum is one of the most important cereal crops in Ethiopia. Production and productivity of Sorghum is constrained by frequent drought and prolonged dry spell especially over the last two decades in Ethiopia leading to food insecurity. The aim of the current study was to evaluate BCNAM populations for drought tolerance, analyze the genetics of traits and identify genotypes with desirable drought tolerance traits. The experiment was conducted at Sheraro, Northern Ethiopia. A total 1264 genotypes were evaluated using an alpha lattice design with two replications. Analyses of variance for quantitative characters showed highly significant difference among the progenies (P< 0.01) for all traits indicating possibility for selection. Similarly, parental lines also exhibited significant difference (p<0.05) for most of the traits except chlorophyll content at flowering, panicle width (cm), grain weight per panicle (g) and number of panicles per plant. Some progenies were early flowering including lines 32 (Teshale x IS14446) (61.525 days), 1226 (Teshale x IS32234) (62.9 days), 1099 (Teshale x IS16044) (64.53days), 749 (Teshale x IS14298 (66.04 days) and 305 Teshale x IS15428 (69.01 days). Whereas, lines 673 (Teshale x IS3583) (79.03 days), 903 (Teshale x IS16173)(77.68 days), 513 Teshale x IS22325 (75.2 days), 911 Teshale x IS16173 (73.73 days), and 37 Teshale x IS14446 (71.74 days) were late flowering. While the best performed progenies in grain yield per panicle were 747TeshalexIS14298 (67.47g), 2 TeshalexIS14446 (63.87g), 107 TeshalexIS14446 (61.03g), 767 TeshalexIS14298 (58.54g) and 1239 Teshalex IS32234 (55.89g) with the average yield of 38.21g per panicle. Traits with high GCV and PCV values such as chlorophyll content at maturity, number of panicle per plant, grain weight per plant and grain yield can be improved by simple selection. Chlorophyll content at maturity, date of 50% flowering, date of 95% maturity, panicle length, shows high heritability values indicate quick and visual selection is possible. Whereas chlorophyll content at maturity, grain filling period and thousand seed weight were exhibited high GAM shows additive gen action. Progenies 747, 479, 2, 702, and 914 were promising genotype for further evaluation. Principal component analysis shows 24.33%, 13.82%, 12.32%, 9.63% and 7.43% of the variation from PC1 to PC5 respectively with the cumulative variance of 67.53%.