Tomato Yield Effects of Reciprocal Hybridization of Solanum lycopersicum Cultivars M82 and Micro-Tom

Plant breeders have accumulated hybrid effects to increase food production in order to counteract the loss of arable land. Hybrids may possess novel genetic potential to increase agricultural productivity; however, the relationships between genetic resources for optimizing crop productivity remain mostly unclear. In this study, we recorded heterosis effects of genetically inherited traits by reciprocal hybridization of the Solanum lycopersicum cultivar Micro-Tom and the commercial cultivar M82, which are currently available as in silico mutant populations, to identify mutant genes which can induce heterosis. The genetic variations between M82 and Micro-Tom caused intermediate phenotypic effects with regard to flowering time, plant height, and fruit size, indicating additive interactions among variations with a hybrid background. The total yield of F1 hybrid was similar to that of cultivar M82, regardless of reduced vegetative biomass, and it revealed an overdominance effect regarding number of harvested fruits. The inheritance of the phenotypes was similar among reciprocal F1 hybrids with different paternal and maternal materials. Based on the consistency of hybrids and wild types, Micro-Tom mutants showing floral homeotic defects and large plant size can be efficiently screened for overdominant yield mutants in F1 hybrids. Therefore, we suggest that identical traits in reciprocal hybrids between Micro-Tom and M82 varieties are useful as control F1 hybrids to improve field tomato productivity by screening mutant hybrids of Micro-Tom mutants and commercial variety M82.