南方籼稻抗旱性状的遗传分析

Genetic Analysis of the Drought-resistant Indices in Indica Rice

在旱地条件下 ,对籼稻 9个抗旱性状进行了遗传分析。结果表明 :( 1 )各抗旱指标都存在遗传变异 ,其中穗茎粗、单株有效穗数、每穗实粒数、剑叶长、叶绿素a/b、脯氨酸含量和自由水含量的遗传变异主要受加性效应的影响 ,倒二节间长和谷粒宽的遗传变异主要受显性效应的影响 ;所有抗旱指标都存在显性×环境的互作效应 ,每穗实粒数、叶绿素a/b和自由水含量还存在加性×环境的互作效应。 ( 2 )各抗旱指标都存在普通狭义遗传率 ;每穗实粒数、叶绿素a/b和自由水含量还存在互作狭义遗传率 ,且后两者的互作狭义遗传率大于普通狭义遗传率 ,受环境的影响较大。 ( 3 )单株有效穗数、穗茎粗和倒二节间长既存在普通杂种优势 ,又存在互作杂种优势 ,且环境不改变这三项指标显性基因作用的方向 ,其中倒二节间长为负向杂种优势 ;叶绿素a/b和脯氨酸含量只存在负向互作杂种优势 ,其余各指标杂种优势不明显。 ( 4)每穗实粒数、叶绿素a/b和自由水含量的加性×环境互作效应较大 ,另外 6个指标的加性×环境互作效应都为 0。

Nine drought-resistant indices were determined under non-irrigated condition. Then genetic analysis of these indices were conducted. The results showed: (1)Genetic variations existed in all drought-resistant indices. Those of ear stem width, effective panicle number per plant, filled grain number per panicle, flag leaf length, chlorophyll a/b, proline content and free water content were affected chiefly by additive gene action. Those of last but one internode length and grain width were affected chiefly by dominant gene action; All drought-resistant indices had interaction effects of dominance×environment, and filled grain number per panicle, chlorophyll a/b and free water content also had interaction effects of additive×environment. (2) All drought-resistant indices had the general narrow sense heritabilities (h 2 G). Filled grain number per panicle, chlorophyll a/b and free water content also had the interactive narrow sense heritabilities (h 2 GE ), and the interactive narrow sense heritabilities of the last two were bigger than the general narrow sense heritabilities. (3) Effective panicle number per plant, ear stem width and last but one internode length had both heterosis (Δ D) and interaction heterosis (Δ DE ), and also genotype×environment interactions could not change their direction of dominant gene effects. Last but one internode length had negative heterosis, chlorophyll a/b and proline content only had negative interaction heterosis, while the rest had no obvious heterosis. (4) The interaction effects of additive×environment of filled grain number per panicle, chlorophyll a/b and free water content were larger, but those of the others equaled to zero.