Evaluation of General and Specific Combining Ability and Genetic Parameters for Morphological Traits in Open-Field Tomato (Solanum lycopersicum L.)

The tomato (Solanum lycopersicum L.), a globally recognized fruit, stands as a pivotal industrial crop, underpinning a vast processing industry. The genetics and inheritance knowledge about target traits are required for improving tomato hybrids. Therefore, the present study was conducted to evaluate gene actions and the combining ability of tomato parental lines. ۲۰ hybrids derived from diallel crossing between ۵ parents and ۴ commercial hybrids were evaluated. Analysis of variance revealed the presence of a significant general combining ability (GCA) effect for all traits and a significant specific combining ability (SCA) effect for fruit dry weight and fruit average weight. Despite the nuclear genome effects, maternal effects, including maternal nuclear and cytoplasmic effects, played a significant role in controlling fruit dry weight, fruit volume, fruit average weight, fruit diameter, and fruit length-to-diameter ratio traits. The maternal effect was high and significant for fruit volume (p<۰.۰۰۱), fruit diameter, and fruit average weight. The GCA/SCA ratio ranged from ۰.۶۵ to ۱, indicating the greater effect of additive gene actions in controlling traits. P۱ and P۵ parents exhibited the highest GCA for fruit number average fruit weight, and fruit volume traits, respectively. Furthermore, the R۱×۳ hybrid was identified as the superior combiner for fruit number per plant and average fruit weight traits. Overall, additive gene action effects had a significant proportion in the inheritance of the traits, and maternal genetic effects showed a great impact on the regulation of tomato fruit size-related traits. Consequently, the female parent fruit shape and size should be considered in tomato breeding programs.

کلیدواژه ها:

Combining Ability ، Gene Operation ، Heritability ، Hybrid ، Tomato