Abstract

This study aimed at determining inheritance of agronomic traits viz. plant height, days to 50% flowering, inter truss spacing and number of trusses per plant in local and introduced tomato lines. Six generations; P₁, P₂, F₁, F₂, BC₁P₁ and BC₁P₂ were developed for each of four bi-parental crosses between five genetically diverse parental lines; AVTO1429, Roma VF, AVTO1424, AVTO1314 and Valoria. A split-plot design, crosses as main plots and generations as subplot with three replicates was used in two sites during 2019, long rain season. Cross Roma VF x AVTO1424 and Roma VF x AVTO1314 were the earliest to 50% flowering in 33 days while Roma VF x Valoria select was the latest in 35 days. F1 hybrid of Roma VF x AVTO1314 showed flowering within 32 days whereas 35 days in P1 (Roma VF). Mwea Station had the tallest mean plant heights of 62cm (at 50% flowering) compared to Kabete Station with 48cm in all crosses and generations. A significant increase (>10%) in plant height at 50% flowering in comparison to parental genotypes was registered in F1 generations. Final plant height across the environments ranged from 82cm for shorter parent (Roma VF) of Roma VF x AVTO1429 to 120 cm for taller offspring, BC₁P₁. Notably, both inter truss spacing and number of trusses per plant were not significantly different (P≤0.05) for crosses evaluated in both sites. Agronomic traits which showed significant genotype x environment interaction in Roma VF x AVTO1314 were days to 50% flowering, final plant height, and number of trusses per plant whereas, in Roma VF x AVTO1429 it was plant height at 50% flowering and number of trusses per plant. The importance of gene effects for agronomic trait inheritance was in additive and dominance-additive portions which implied that the traits were inherited.