Marker-assisted introgression of blackmold resistance QTL alleles from wild Lycopersicon cheesmanii to cultivated tomato ( L. esculentum ) and evaluation of QTL phenotypic effects

摘要: Blackmold, caused by the fungus Alternaria alternata, is a major ripe fruit disease of processing tomatoes. Previously, we found blackmold resistance in wild tomato (Lycopersicon cheesmanii) and quantitative trait loci (QTL) for were mapped an interspecific population. Five QTLs selected introgression from L. cheesmanii into cultivated using marker-assisted selection (MAS). Restriction fragment length polymorphism PCR-based markers flanking, within, chromosomal regions containing used MAS during backcross selfing generations. BC1 plants heterozygous at QTLs, subsequent BC1S1 BC1S2 lines possessing different homozygous combinations alleles target identified DNA markers. Field experiments conducted 1998 (with 80 marker-selected lines) 1999 151 BC1S3 three California locations. Blackmold was assessed both years, horticultural traits evaluated 1999. The associated with large genetic variance to moderate heritability, suggesting that significant gain may be achieved this material. five introgressed showed significant, positive effect on resistance. A QTL chromosome 2 had largest resistance, alone combination other also earliness, trait. four primarily negative traits. Fine mapping near isogenic could help determine if such associations are due linkage drag or pleiotropy.