Fruits such as tomato are important source for nutrition and acts as essential component for balanced diet. Ripening of tomato involves in softening of cell wall structure and remodeling, which results in reduced firmness and shortening of shelf life. This is one of the main factors in post-harvest damage and leads to greater yield loss. Understanding the key molecular mechanisms underlying fruit ripening will be helpful to overcome this problem. It is also evident from the previous studies that, ripening process is the consequence of decrease in the fruit firmness. In our study we assessed significant variation for fruit firmness in a population derived by crossing firmness specific parent BML-3 and a normal parent BIL-29 along with some secondary traits. The observed phenotypic variation in fruit firmness, fruit breadth, fruit length and total soluble solid (TSS) indicated the potential use of these traits in selection indices. Genotyping of F2 mapping population was carried out using48 polymorphic SNPs with respective KAS Parassays. A genetic linkage map was constructed using 48 SNPs which consists of 6 linkage groups and covered the map distance of 817cM. Identification of QTLs for the adjusted means of each trait using the genetic linkage map resulted in identification of 2 QTLs for firmness on linkage group 5 (LG5),which together explained 62.2% phenotypic variation. A pair of flanking markers has been developed and validated to facilitate rapid selection fruit firmness in marker assisted introgression programs.
