Parent-offspring correlation estimate of heritability for late blight resistance conferred by an accession of the tomato wild species Solanum pimpinellifolium.

摘要

Late blight (LB), caused by Phytophthora infestans, is a destructive disease of tomato (Solanum lycopersicum). To gain adequate control of LB in tomato, new sources of resistance are being identified and characterized with the aim of introducing resistance genes to elite tomato germplasm. In this study, heritability (h2) of LB resistance conferred by a S. pimpinellifolium resistant accession (PI 270443) was estimated using populations developed from crosses with a LB-susceptible tomato breeding line. In the F₂ population, 986 seedlings were evaluated for LB, and 50 resistant and 40 susceptible individuals were selected and self-pollinated to generate F₃ progeny. Seedlings of the F₃ progeny were evaluated for LB in two separate experiments. Using parent-offspring correlation analysis, h2 of LB resistance was estimated to be 0.86, indicating that this resistance was highly heritable and could be transferred to the cultivated tomato via phenotypic selection. The number of resistance genes involved was estimated to be two. Breeding efforts to transfer this resistance to elite tomato lines and genetic mapping to identify the underlying resistance genes are underway