XML Genetic Analysis of Traits Associated with Yield and Earliness in Nine Tomato (Lycopersicon esculentum Mill.) Lines Using Diallel Crossing Method

A study was conducted on a 9×9 full diallel set of tomato to find out the extent combining ability for yield and earliness characters by randomized complete block design with three replications and four plants for each replication. The analysis was done according to Hayman and Griffing methods using Diallel software. Significant differences among genotypes were found for all of traits. Highly significant variation due to general combining ability (GCA) as well as specific combining ability (SCA) indicated the importance of additive and non-additive types of gene action in inheritance of all characters except number of fruits per palnts. The heterosis showed a positive response to earliness in number of days to first flowering. The Prg genotype with the lowest GCA among all parents، had the most effect in earliness and the Mb3 genotype with the highest GCA had the most effect on yield components. Cross combinations Supc × Ptk، Pte × Ptk، Mb3 × Vfj، Supl44 × Csh74 and Sps × Csh74 were five best specific combiners for yield components and earliness.