Advanced back-cross QTL analysis of tomato. II. Evaluation of near-isogenic lines carrying single-donor introgressions for desirable wild QTL-allelesderived from Lycopersicon hirsutum and L-pimpinellifolium (vol 97, pg 170,1998)

Improved-processing tomato lines were produced by the molecular breeding st rategy of advanced backcross QTL (AB-QTL) analysis. These near-isogenic lin es (NILs) contained unique introgressions of wild alleles originating from two donor wild species, Lycopersicon hirsutum (LA1777) and L. pimpinellifol ium (LA1589). Wild alleles targeted for trait improvement were selected on the basis of previously published replicated QTL data obtained from advance d backcross populations for a battery of important agronomic traits. Twenty three NILs were developed for 15 genomic regions which were predicted to c ontain 25 quantitative trait factors for the improvement of seven agronomic traits: total yield, red yield, soluble solids, brix x red yield, viscosit y, fruit color, and fruit firmness. An evaluation of the agronomic performa nce of the NILs in five locations worldwide revealed that 22 out of the 25 (88%) quantitative factors showed the phenotypic improvement predicted by Q TL analysis of the BC3 populations, as NILs in at least one location. Per-l ocation gains over the elite control ranged from 9% to 59% for brix x red y ield; 14% to 33% for fruit color; 17% to 34% for fruit firmness; 6% to 22% for soluble-solids content; 7% to 22% for viscosity; 15% to 48% for red yie ld, and 20% to 28% for total yield. The inheritance of QTLs, the implementa tion of the AB-QTL methodology for characterizing unadapted germplasm and t he applicability of this method to other crops are discussed.