Identification and characterization of a novel locus controlling early fruit development in tomato

Cultivated tomatoes (Lycopersicon esculentum) encompass a wide range of fru it size and shape variants. This variation provides the basis for dissectin g the genetic and molecular pathways of ovary and fruit development. One fr uit shape variant is displayed by the cultivar Sun 1642 (TA491). TA491 has an elongated fruit phenotype, while the wild relative L. pimpinellifolium L A1589 produces fruit that are nearly perfect spheres, a shape typical of wi ld tomatoes. Developmental studies indicated that the differences in fruit shape between TA491 and LA1589 are determined by events occurring immediate ly after pollination and extending to 14 days post-pollination. Quantitativ e trait mapping revealed a single major locus on chromosome 7 (named sun) t o be responsible for the differential development of TA491 and LA1589 fruit . Other fruit shape loci characterized in tomato (e.g. fs8.1 and ovate) exe rt their effects before anthesis and early in ovary development. sun is the first major locus identified in tomato controlling fruit shape through pos t-pollination events.