Phenotypic variability, heritability and GGE biplot analysis for agronomic traits in Ethiopian sorghum [Sorghum bicolor (L.) Moench] genotypes

Sorghum [Sorghum bicolor (L.) Moench] is a crucial crop for food and nutritional security in the semi-arid and tropical parts of African countries. Understanding the genetic variability of the crop is vital for development of improved and high yielding varieties. The extent and distribution of phenotypic variation was assessed in 324 sorghum genotypes using six agro-morphological traits including dry biomass (DB), plant height (PH), number of effective tillers (NET), leaf numbers (LN), internode length (IL) and stalk diameter (SD) measured at three environments (Mehoni, Melkassa and Mieso). The experiment was laid at alpha lattice design in two replications. The results revealed that the variance due to genotype (G), environment (E) and their interaction (GxE) were highly significant for the studied quantitative traits, confirming the importance of multi-location testing to take care of G × E interaction effect to identify supper and stable sorghum genotypes. Higher range of phenotypic and genotypic coefficient of variations (PCV, GCV) were observed. The highest estimate of genetic advance as percent of the mean (GAM) was observed for PH followed by biomass yield. Cluster analysis based on the agro-morphological traits grouped the genotypes into six clusters. The analysis revealed that the mean performance of NET, SD, LN and IL were the highest at Melkassa site, while PH and DB showed higher performances at Miesso site implying that these locations could be better for the crop to perform well. The “which-won-where” biplot analysis grouped the test environments into two mega environments (MEs) with different high performing genotypes for PH, NET, LN and SD. Ranking genotypes for DB identified four supper performing and stable genotypes (241237, 239113, 241187 and SB106) accros the tested environments. These genotypes are valuable genetic resources to be used in further sorghum breeding program. Overall, the study had generated valuable information for sorghum improvement, its conservation and wise utilization.