Genetic Variation among Sorghum (<i>Sorghum bicolor</i> L. Moench) Landraces from Eritrea under Post-Flowering Drought Stress Conditions

Abstract

Sorghum ( Sorghum bicolour (L.) Moench) grown under rain-fed conditions is usually affected by drought stress at different stages, resulting in reduced yield. The assessment of variation in morpho-physiological traits contributing towards drought tolerance at these stages is of vital importance. This study was conducted using a split plot design with three replications to evaluate 25 sorghum accessions at post flowering stage under well watered and drought stress conditions at Hamelmalo Agricultural College. The data of 14 different morpho-physiological traits were subjected to analysis of variance, estimation of genetic variability and heritability and principal component analysis. We analyzed variance for seedling vigor, number of leaves, leaf area, stay-green, peduncle exsertion, panicle length and width, plant height, days to flowering and maturity, grain yield, biomass and harvest index under drought stress and irrigated conditions. The results showed that genotypic differences were significant at P < 0.05 - < 0.001. High magnitude of phenotypic and genotypic coefficient of variations for plant height, harvest index and biomass as well as high heritability for days to flowering, panicle length, days to maturity and over all agronomic score were recorded. Principal component (PC) analysis showed that the first 4 PCs had Eigen value >1 explaining 74.6% of the total variation with grain yield, biomass, stay-green, leaf area, peduncle exsertion and days to flowering and maturity being the most important characters in PC1 and PC2. This research demonstrated high diversity for the characters studied. Moreover, the result showed that drought stress reduced the yield of some genotypes, though others were tolerant to drought. Accessions EG 885, EG 469, EG 481, EG 849, Hamelmalo, EG 836 and EG 711 were identified as superior for post-flowering drought tolerance and could be used by breeders in improvement programs.