QTLs for organoleptic quality in fresh market tomato

Abstract

The organoleptic quality of tomato fruit is determined by many characters. Therefore, plant breeders often find difficulties to improve such a characteristic. A program of QTL detection for physical, chemical and sensorial traits has been achieved, in order to understand the genetic determinism of tomato organoleptic quality. One hundred and forty-four recombinant inbred lines (RILs), derived from an intraspecific cross, were analyzed with segregating molecular markers. An almost saturated map was constructed with RFLP, AFLP and RAPD marker. The RILs were also evaluated for fruit chemical (sugar, pigment and acid contents) and physical traits (color, firmness and fruit size). These analyses were combined with fruit evaluations by a panel of trained judges. A sensorial profile was thus defined for each RIL. Strong correlations have been detected between some chemical and sensorial traits. As an example, the fruit sweetness was positively correlated to the sugar content. Such a correlation is very useful since it allows tomato breeders to improve organoleptic quality indirectly. Significant quantitative trait locus (QTL) associations with marker loci were identified for each trait. Phenotypic variation explained by each QTL ranged from 7.9% to 45.6%. A few chromosomal regions appeared to explain a major part of the variation for many traits, one of the most important being on the long arm of chromosome 2. Some of these QTLs, with large identified effects, will be useful for marker aided selection.