A line × tester analysis was conducted to evaluate yield and yield contributing traits in Bangladeshi summer tomato, with the aim to assess the general and specific combining abilities (GCA and SCA) of different genotypes to identify high-performing cross combinations for improving yield and related traits. Significant variances were observed for both GCA and SCA, indicating the involvement of both additive and non-additive gene actions in the inheritance of the studied traits. The study revealed that variances due to SCA exceeded GCA variances for all characters, highlighting the predominance of non-additive gene action (e.g., dominance and epistasis). Among the parental lines, tester T4 exhibited the highest GCA effects for the number of flowers per plant and average fruit weight, while line P17 was identified as the best general combiner for fruit yield per plant, showing significant positive GCA effects. However, all parental lines except P17 showed significant GCA effects for the number of locules per fruit. Several cross combinations, including P16 × T4, P17 × T4, P4 × T4, P16 × T6, P17 × T6, and P4 × T6, displayed significantly positive SCA effects for the number of fruits per cluster. Similarly, crosses such as P17 × T4, P4 × T4, P17 × T6, and P4 × T6 showed significant positive SCA effects for the number of fruits per plant. These promising cross combinations with significant positive SCA values are valuable genetic resources that will be exploited in future breeding programs to develop resilient and high-yielding tomato varieties. A line × tester analysis of Bangladeshi summer tomato revealed that non-additive gene action (specific combining ability, SCA) predominantly influences economically important traits like yield and fruit weight. Promising crosses, notably P17 × T4, P4 × T4, P17 × T6, and P4 × T6, exhibited significantly high SCA effects and strong performance, marking them as elite candidates for future hybrid breeding programs aimed at developing high-yielding summer varieties.
Masud et al. (Sun,) studied this question.