Inheritance of Several Plant Type Characters in Truss Tomato

Plant type characters of truss tomato were studied for exploring the inheritance of leaf angle, and providing a theoretical basis for breeding truss tomato cultivars in compact plant type. Participant truss tomato inbred lines were involved in the cross and backcross for multi-generations, and the mixed major genes plus polygene inheritance model was employed to analyze the inheritance model of leaf angle, plant width, and leaf drooping value. The inheritance of leaf angle and plant width was controlled by one pair of additive major genes plus additive-dominant polygene (D-2). The additive effect of the major genes controlling leaf angle was 6.51, the additive effect of the polygene was 15.01, the potential ratio was 0.914,and the dominant degree was 0; the heritability of the major genes was 45.61% in B1 generation, 37.29% in B2 generation,and 47.71% in F2 generation. The additive effect of the major genes controlling plant width was 3.08, while the additive effect and dominant effect of the polygene were 3.58 and -1.59, respectively, with the potential ratio of -0.44 and 0 dominant degree; the heritability of the major genes was 23.30% in B1 generation, 20.73% in B2 generation, and 36.11% in F2 generation; leaf-drooping-value trait was controlled by one pair of negative complete dominant major genes plus additive-dominant polygene (D-4). The additive effect of the major genes was 8.18, the dominant effect was -8.18, the additive effect in the polygene was 3.12, the dominant effect was 19.07, the potential ratio was 6.09, and the dominant degree was -1; the heritability of the polygene was 69.15% in B1 generation, 68.5% in B2 generation, and 49.57% in F2 generation. The improvement on leaf angle and plant width of 173×101 should be focused on the major genes and the selection should be made in early generations, while the improvement on leaf-drooping-value of 173×101 should be made in late generations.