Genetic Variability for Bioenergy and Agronomic Traits in Sorghum Mini Core Collection.

Sweet sorghum is smart food-feed-bioenergy crop. Brix, biomass and juice yields are the major bioenergy traits. Brix indicate total sugar content in the stalk juice. Sorghum mini core collection was evaluated for bioenergy and agronomic traits for two postrainy seasons under irrigated and drought stressed conditions, Patancheru, India. Main and interaction effects were significant for most traits. Drought stress significantly increased Brix (up to 26.8%), while it reduced biomass (up to 31.6%) and juice (up to 55.5%) yields. IS# 13294, 13549, 23216, 23684, 24139, 24939, and 24953 across environments recorded significantly greater Brix (14.0-15.2%) than IS 33844 (Brix, 12.4%); however, were low yielders (seed yield, 6.8-17.0 g plant-1) and had lower 100-seed weight (1.6-2.6 g). IS# 1004, 4698, 23891, and 28141 were comparable for Brix (11.7-12.8%) but produced significantly greater seed yield (11.7-22.7%) than IS 33844 (seed yield, 33.5-36.0 g plant-1). For biomass, grain yield and 100-seed weight, IS# 23891 and 28141 were significantly superior (biomass, 279-285 g plant-1; seed yield, 40 g plant-1; 100-seed weight, 5 g) over IS 33844 (biomass, 162-206 g plant-1; seed yield, 33-36 g plant-1; 100-seed weight, 3.5 g). Accessions with greater biomass (18.4-53.6%) and juice (27.9-53.5%) yields, in comparison to IS 33844 (biomass, 182.3-273.7 g plant-1; juice, 53.2-94.7 g plant-1), were IS# 4698, 1004, 27034, 27887, 29772 and 31651; the latter four were low yielders. Multiple trait accessions include IS# 4698 and 1004 for biomass, juice, and grain yields, and IS# 28887 and 29772 for Brix, biomass and juice yields. Neighbor-joining tree based on 41 SSRs grouped these accessions into three clusters: high brix accessions mostly from Africa in cluster 3 and from America in cluster 1, while accessions with greater biomass, juice and grain yields in cluster 2. The identified accessions are ideal resources for the development of cultivars with bioenergy traits.