Advanced backcross QTL analysis of a Lycopersicon esculentum x Lycopersicon parviflorum cross

Lycopersicon parviflorum is a sexually compatible, wild tomato species whic h has been largely unutilized in tomato breeding. The Advanced Backcross QT L (AB-QTL) strategy was used to explore this genome for QTLs affecting trai ts of agronomic importance in an interspecific cross between a tomato elite processing inbred, Lycopersicon esculentum E6203, and the wild species L. parviflorum (LA2133). A total of 170 BC2 plants were genotyped by means of 133 genetic markers (131 RFLPs; one PCR-based marker. 1-2, and one morpholo gical marker, u, uniform ripening). Approximately 170 BC3 families were gro wn in replicated field trials, in California, Spain and Israel, and were sc ored for 30 horticultural traits. Significant putative QTLs were identified for all traits, for a total of 199 QTLs, ranging from 1 to 19 QTLs detecte d for each trait. For 19 (70%) traits (excluding traits for which effects o f either direction are not necessarily favourable or unfavourable) at least one QTL was identified for which the L. parviflorum allele was associated with an agronomically favourable effect, despite the overall inferior pheno type of the wild species.