谷子产量和品质相关性状的杂种优势及遗传特性分析

Heterosis and Genetic Characteristics Analysis for Yield and Quality Related Characters in Setaria italica

摘要:

为了解谷子（Setaria italica）两系杂交后代的产量和品质相关性状的杂种优势，以3个高度雄性不育系为母本（A1、A2和A3），6个抗除草剂恢复系为父本（R1、R2、R3、R4、R5和R6），采用不完全双列杂交（NCⅡ）设计配制了18个组合，分析组合的株高、粒重和蛋白含量等11个性状的配合力和杂种优势特性。结果表明，不同亲本间及杂交组合间的性状均存在显著差异。其中，两系杂交组合的小区产量与千粒重、单穗粒重、株高、穗长显著相关，而与小米的品质（粗蛋白、粗脂肪、总淀粉）无显著相关。同一性状不同亲本的一般配合力（GCA）效应值不同，A1（不育系）和R1（恢复系）的产量和品质性状的GCA正效应值较大，是改良谷子高产优质的潜在优良亲本。而杂交组合的特定特殊配合力（SCA）效应值与亲本GCA效应值表现并不一致，其中A1×R5、A1×R6、A2×R1、A2×R4的SCA效应值较高，属于优异组合。此外，各性状的广义遗传力和狭义遗传力均大于65%，主要受加性效应和非加性效应共同控制。谷子杂交组合的株高、穗重、小区产量具有显著的中亲优势，部分杂交组合具有较强的超亲优势。株高、穗长、穗码、千粒重、脂肪的狭义遗传力较高，加性遗传作用较大，而穗重、茎节数、蛋白非加性遗传作用更为突出。虽然产量性状和品质性状的杂种优势特性不同，但均由加性效应与显性效应共同作用决定。

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.