Estimating Maternal Effects on Yield Traits in F 1 Hybrids of Tomato (Solanum lycopersicum) Using a Modified Diallel Cross Model

Abstract This study aimed to compare the effects of General Combining Ability (GCA) and Specific Combining Ability (SCA) before and after partitioning, and to assess each parent's contribution to its cross combination while detecting the significance of maternal effects on tomato fruit traits. Three tomato lines were crossbred in a 3 x 3 diallel cross design to produce F1 hybrids, which were evaluated alongside their respective parents using a Randomized Complete Block Design with four replications. Findings revealed that GCA effects estimated through Griffing’s method were consistent with the average GCA effects of each parent after partitioning in the proposed model. Additionally, the difference between female and male GCA effects provided a reliable estimation of maternal effects, particularly for additive alleles, as corroborated by Hayman analysis for traits such as seed number, weight, and yield. SCA effects calculated through Griffing’s method mirrored the average SCA effects of each cross and its reciprocal, while the proposed model showed that the difference between SCA effects of each cross and its reciprocal equaled reciprocal effects, demonstrating the precise estimation of reciprocal effects in capturing the interaction between nuclear and cytoplasmic genes in the cross and its reciprocal hybrid.