水稻收获指数遗传及其与主要农艺性状的相关研究

应用完全双列杂交的遗传设计，以5个各具特性的水稻品种为材料，对收获指数的遗传进行研究。结果表明，收获指数的一般配合力（GCA）效应、特殊配合力（SCA）效应和反交（R）效应均达极显著水平，其方差比为2.595∶1.232∶1；F₂群体收获指数从低到高呈连续的近正态分布，表现数量性状的遗传特点；在加性显性模型中加性效应和显性效应达极显著值，狭义遗传力和广义遗传力分别为40.17%、67.94%。遗传相关分析表明，收获指数与结实率显著正相关，与穗长、千粒重和生物量显著负相关，由于穗长、千粒重有较高的遗传力，因此在早代对穗长、千粒重进行选择能间接改良收获指数。初步明确水稻收获指数是一个由多基因控制的数量性状，符合加性显性模型，遗传以加性效应为主，显性效应和其它效应（如反交效应）也起一定的作用，遗传力较高，可在早期分离世代进行选择。上述的结果将为水稻新品种选育提供理论依据。

Heredity of Rice Harvest Index and Correlations between HI and Main Agronomic Characters

Improvement of harvest index(HI) has become one of the main objectives in rice breeding.It is very important to know the genetic regularity of rice HI for yield improvement.The experiment was conducted with complete diallel crossing design,using five rice cultivars with different characteristics.The results indicated that general combining ability(GCA),special combining ability(SCA) and reverse crossing effect of the HI were significant at 0.01 probability level,and their variance ratio was 2.595:1.232:1;HI from low to high in F_2 populations was distributed serially and normally,showing the heredity of quantitative character;additive effect and dominance effect were significant at 0.01 probability level in additive-dominance model;Narrow-sense heritability and broad-sense heritability were 40.17% and 67.94%,respectively.The genetic correlation analysis showed that HI was significantly correlated positively with grain filling rate,and negatively with ear length,1000-grain weight,and biomass.The improvement of HI would be effective by selecting ear length and 1000-grain weight during early generation, which had higher heritability.It was preliminarily revealed that: rice HI is a quantitative character and fit into additive-dominance model with mainly additive effects,simultaneously dominant effect and somewhat other effects(e.g.reverse crossing effect).HI has a higher heritability and can be selected in early segregating generation,which is useful for rice breeding.