Correlation Between Incomplete Leaf Length And Plant Height And Its Genetic Basis In Rice (Oryza Sativa L.)

The area of hybrid rice planted occupied more than 50 percent of total rice area. Quality of hybrid rice seeds affect realization of heterosis. There were three levels for identification of hybrid rice seed genetic purity: seedling level, protein level and DNA molecular level. Identification by seedling traits has the advantage of low cost in time and money. Incomplete leaf length(ILL) is the unique character of seedling trait in rice. Study on the genetic model of ILL , its correlation with plant height(PH) and genetic basis for the correlation may benefit identification of hybrid rice seeds at seedling level. The main results were as follows:1. Genetic variation of coleoptile length(CL), Incomplete leaf length(ILL) and seedling height(SH) of 7d after germinated and their correlation with PH were studied by using 95 varieties of japonica rice in 6 different ecotypes under natural and controlled(30 ℃ 12 h light) conditions. Results showed that true genetic variation for the 3 seedling traits were existed among the 95 varieties. Obvious relationship between average values of the 3 traits and the growth duration was not found. The ILL in controlled condition was shorter than that in natural condition. Highly significant differences(a=0.01) among different ecotypes were found in the trait of incomplete leaf length, and correlation between ILL and PH was significant(a=0.05) or highly significant(α=0.01) under both natural and controlled conditions. The trait of ILL can be used at seedling stage to test seed purity of F₁ hybrids made by parents with wide difference in plant height.2. Genetic segregation analyses of incomplete leaf length(ILL) were carried out by using the major gene-polygene mixed inheritance model, based on data of P₁ P₂ F₁ B₁ B₂ and F₂ populations in the cross Ochikara /02428, and P₁ P₂ F₁ F₂ and F_2:3 populations in indica hybrid rice shanyou-63 and japonica hybrid rice 3-you-18 which were widely used in production. The results showed that, in the cross of Ochikara/02428, the trait of ILL was controlled by two major genes with additive-dominance-epistatic effects plus polygenes with additive-dominance effects. Long ILL was partial dominant to short one. Heritability of major gene was larger than that of polygene. In the crosses of shanyou-63 and 3-you-18, the trait ILL was controlled by one major gene with additive-dominance effects plus...