Multi-environment QTL mapping reveals genetic architecture of fruit cracking in a tomato RIL Solanum lycopersicum×S. pimpinellifolium population.

Abstract

QTL and codominant genetic markers for fruit cracking have been identified in a tomato genetic map derived from a RIL population, providing molecular tools for marker-assisted breeding of this trait. In tomato, as well as in other fleshy fruits, one of the main disorders that widely limit quality and production is fruit cracking or splitting of the epidermis that is observed on the fruit skin and flesh at any stage of fruit growth and maturation. To elucidate the genetic basis of fruit cracking, a quantitative trait loci (QTL) analysis was conducted in a recombinant inbred line (RIL) population derived from a cross between tomato (Solanum lycopersicum) and the wild-relative species S. pimpinellifolium. The RIL population was evaluated for fruit cracking during three consecutive growing seasons. Construction of a high-density linkage map based on codominant markers, covering more than 1000cM of the whole genome, led to the identification of both main and epistatic QTL controlling fruit cracking on the basis of a single-environment as well as multiple-environment analysis. This information will enhance molecular breeding for novel cracking resistant varieties and simultaneously assist the identification of genes underlying these QTL, helping to reveal the genetic basis of fruit cracking in tomato.