| Abstract: In order to explore the genetic law of fruit shape index of two eggplant combination cultivars, three high-generation inbred lines of eggplant (long tube, high round and short tube fruit shapes) with significant difference in fruit shape index were selected as materials to construct two hybrid combinations (combination I : long tube×high round, combination II : high round×short tube). The genetic law of fruit shape index was studied by six-generation joint analysis. The results showed that the inheritance of fruit shape index was a quantitative trait. The genetic models of fruit shape index of the two combinations were both suitable for the E-3 model, that was model of two pairs of additive major genes + additive-dominant polygene. Combination I showed a negative and a positive additive effect of major genes, and combination II showed two negative additive effects of major genes. The additive effects of polygenes in the two combinations were both greater than the dominant effects, indicating that the inheritance was dominated by additive effects. In combination I, the major gene heritability of B1 and B2 generations were greater than that of polygene heritability, and the major gene heritability was dominant. The polygene heritability of F2 generation was greater than that of the major gene heritability, and the polygene heritability was dominant. The environmental heritability of B2 generation was higher, which was 48.49%. In combination Ⅱ, The major gene heritability of B1 and B2 segregating generations was greater than the polygene heritability, and the major gene heritability was dominant. The polygene heritability of F2 was greater than the major gene heritability, and the polygene heritability was dominant. The inheritance of B1 and B2 generations were greatly influenced by environmental factors, with environmental heritability of higher than 40%. |