Heterosis Analysis in Endogenous Substances in Root Bleeding Sap of Sorghum

Despite hybrid dominance contributing to the genetic improvement of crops,little is known about heterosis and inheritance patterns of endogenous substances in sorghum(Sorghum bicolor(L.)Moench)root bleeding sap.In this study,six sterile and six restorer lines of sorghum and 36 hybrid sorghum combinations formulated as incomplete double-row crosses were selected as test materials,and heterosis,combining ability,heritability,and their interrelationships of root bleeding sap endogenous substances in different hybrid sorghum combinations and their parents were investigated.The results showed that the root bleeding sap of the F1 generation of hybrid sorghum had a high heterosis in both soluble sugar content and amino acid content at the flowering stage,and the average high-parent heterosis was 129.34%and 74.57%,respectively.Indole-3-acetic acid(IAA),cytokinins(CTK),gibberellic acid(GA_(3)),abscisic acid(ABA),soluble sugar,amino acid,and root bleeding intensity were mainly affected by non-additive genetic effects of the genes.Soluble protein was affected by additive genetic effects of the genes and had a high narrow heritability(75.50%),which could be selected at low generations in breeding.The combining ability analyses showed that the sterile lines 521A and 170A,and the restorer lines Ji318R and 0–30 were promising parents with high general combining ability.Correlation analysis showed that all endogenous substances of root bleeding sap were positively correlated with the sum of parental general combining ability(GCA)at highly significant levels,and IAA,CTK,GA_(3),ABA,soluble sugar,amino acid,and root bleeding intensity were positively correlated with male GCA at significant or highly significant levels.Therefore,the GCA of the restorer lines root bleeding sap endogenous material or the sum of both parents’GCA can be used to predict the performance of wounding endogenous material in the F1 generation of hybrid sorghum.Overall,this study results can help elucidate heterosis mechanisms of root bleeding sap endogenous material and improve sorghum quality.