Morpho-physiological performance and multivariate analysis of stay green introgression sorghum (sorghum bicolor (l) moench) genotypes under drought stress, Ethiopia

Drought is the most important environmental factor which brings huge impact on crop growth, development, grain yield, and biomass productivity. Sorghum production is highly constrained by post flowering drought stress affecting the final yield production. Improving the drought tolerance/resistance sorghum is one of the most important objectives of plant breeders. The field experiment was executed under post flowering water deficit and well-watered sets at Efratana Gidim District using irrigation scheme. The experiment was laid out using alpha lattice design with the objective of evaluating performance and determining genetic variations among yield and related traits in stay green introgression near isogenic sorghum lines. The analysis of variance displayed highly significant (p ≤ 0.001) and significant (p ≤ 0.05) differences for most traits. Heritability estimates ranged from 46.6% (chlorophyll at flowering (CHlF)) to 98.5% (plant height (PHT)) and from 67.2% (CHlF) to 99.6% (PHT) for water deficit and well-watered sets, respectively. Genetic advance as percentage of mean ranged from 5.49% (CHlF) to 80.68% (photosynthesis rate at hard dough stage (AG)) and from 4.85% (days to maturity (DTM) to 58.33% (peduncle exertion (PedEx)) for water deficit and well-watered sets, respectively. Four and five clusters obtained from water deficit and well-watered sets, respectively. Principal components with eigen values > 1 explained 78.05% and 74.03% of variations for water deficit and well-watered sets, respectively. The investigated morpho-physiological traits showed substantial diversity among evaluated sorghum genotypes. In line with the objective of the experiment, outstanding stay green expression results has been obtained. From the tested genotypes, thirteen stay green gene introgression lines showed consistence above mean grain yield performance under both experimental conditions. And these materials can be further evaluated in sorghum improvement program of the country to address the drought stress problem.