Abstract:In order to understand the heterosis of yield-related and quality characters in two-line hybrid progenies of Setaria italica, 18 hybrid combinations were designed with three male sterile lines (A1, A2, A3) and six herbicide resistant restorer lines (R1, R2, R3, R4, R5 and R6) by using incomplete diallel cross (NCⅡ), the eleven phenotypic characteristics of combining ability and the hereditability were analyzed, such as plant height, grain weight, protein content, and so on. The results showed that there were significant differences in quantitative traits among two parents and their combinations. Among all the traits, the plot yield of hybrid combination was significantly correlated with thousand-seed weight (TSW), ear weight (EW), plant height (PH), and ear length (EL), but not significantly related with quality traits, such as crude protein, crude fat and total starch. The general combining ability (GCA) effect values of different characters varied significantly in different parents. Meanwhile, A1 (male sterile line) and R1 (restorer line) had high positive effect values of GCA among most of yield and quality traits, which was potential parents for improving the high yield and quality of foxtail millet. However, it was noteworthy that the presentation of specific special combining ability (SCA) in combinations was not completely consistent with effect values of GCA in their parents. Among eighteen combinations, A1×R5, A1×R6, A2×R1, A2×R4 displayed high SCA effect, and showing excellent combinations. Furthermore, the broad-sense heritability and narrow-sense heritability of all quantitative traits were more than 65%, mainly co-controlled by additive effects and non-additive effects. PH, EW, and yield of S. italica hybrids had significant mid parent heterosis, and some combinations had strong super parent heterosis. In addition, the narrow-sense heritability value of PH, EL TSW, ear code, and crude fat content were higher than that of other traits, while the non-additive genetic effects of EW, stem node number and protein content were more prominent. Although the heterosis characteristics of yield and quality traits were different, they were determined by additive and dominance effect in the total genetic variation.
