Genetic potential of wild tomato relatives for resistance breeding in Solanum lycopersicum

Abstract

The tomato Solanum lycopersicum ranks among the top three most produced vegetables worldwide, yet it remains vulnerable to various diseases, pests and abiotic stresses. Climate change exacerbates disease severity and abiotic impacts, increasing the demand for adaptive varieties and hybrids. Interspecific hybridization expands genetic diversity via introgression of target trait genes, potentially reducing reliance on chemical protectants, enhancing plant adaptive potential and improving abiotic stress tolerance. Recent studies focus on wild Solanum species as a source of valuable traits for tomato breeding. This review addresses the reproductive barriers between cultivated and wild species, which are of critical significance for plant breeding and examines the methodologies developed to overcome these barriers. Currently, wild species are most actively involved in breeding programs and in the introgression of traits into the cultivated tomato include S. cheesmaniae, S. habrochaites, S. pennellii, S. pimpinellifolium. Species S. peruvianum, S. chmielewskii, S. corneliomulleri, S. sitiens, S. ochranthum, S. lycopersicoides, S. sisybrifolium are difficult to hybridize with cultivated tomato, and have not yet contributed substantially to the introgression of valuable traits. The success of interspecific hybridization with wild relatives largely depends on the choice of compatible tomato genotypes, the utilization of cultivated tomato as the maternal parent, and the application of embryo culture techniques to rescue hybrids in cases of embryo abortion. Somatic hybridization offers an alternative approach for overcoming interspecific crossing barriers. However, its effectiveness in facilitating the introgression of desirable traits into tomato remains insufficiently evaluated.