Abstract:

【Objective】 Oil content is an important quantitative trait of peanut. High oil content has became a major target of genetic improvement on peanut cultivar. Heterosis and genetic analysis of oil content will provide a very important guidance for breeding of high oil peanut cultivar. 【Method】 The method of joint segregation analysis of multiple generations with P1, P2, F1 and F2 of major gene plus polygene mixed inheritance model was used to analyze the inheritance of oil content in peanut cultivars. Four basic populations (P1, P2, F1 and F2) from four peanut crosses respectively were made for analysis of the genetic model. The female parent in each cross was progeny of distant hybridization with a high oil gene pool of peanut wild species. The male parents were peanut cultivars with low oil content. 【Result】 The results indicated that the heterosis of oil content was showed in F1 with significant different degree among four crosses, and the mid-parents heterosis were from 1.4% to 9.4% respectively. The differences of oil content genetic characteristcs among four crosses were obvious. The frequency distributions of oil content in F2 populations derived from two crosses SW9721-3×Te21 and SW9721-12×Puhua22 showed the characteristics of mixture normal distribution, which indicated that inheritance of oil content followed the major gene plus polygene model. Results showed that genetic model D-0 was the most fitted genetic model for the trait. In other words, oil content was controlled by one major gene with additive-dominant effects plus polygenes with additive-dominant-epistasis effects. The major gene heritabilities in F2 were 47.51% and 45.00%, respectively, and polygene heritabilities were 22.75% and 18.72%, respectively. The frequency distributions of oil content in F2 populations derived from SW9721-23×95-3 and SW9721-38×Luhua11 showed the characteristics of normal distribution, which indicated that inheritance of oil content followed the polygene model. Results showed that genetic model C-0 was the most fitted genetic model for the trait. In other words, oil content was controlled by polygenes with additive-dominant-epistasis effects. The polygene heritabilities in F2 were 66.51% and 66.09%, respectively. 【Conclusion】 The heterosis and transgressive segregation of oil content commonly existed in hybrid progenies of peanut. The genetic effects of genes for oil content traits were significantly different in magintude, some with major gene character. Oil content in peanut was controlled by additive gene effects. And therefore, in high oil peanut breeding for cultivars improvement, some strains with high oil content may be selected through single directional selection.

Key words: peanut (Arachis hypogaea L.)')">peanut (Arachis hypogaea L.), oil content, heterosis, genetic model of major gene plus poly gene, genetic effects