| Abstract Detail
Conference Wide Ashrafi, Hamid [1], Lin, Guoyang [2], Foolad, Majid [1]. Comparative mapping of early blight resistant QTLs and candidate resistance genes in early filial and a RIL population of tomato. MOST cultivars of tomato, Lycoperscion escoulentum Mill., are susceptible to early blight (EB), a devastating fungal (Alternaria solani Soruer) disease of tomato in the northern and eastern part of the U.S. and elsewhere. Current measures of the disease control include sanitation, crop rotation and heavy use of fungicides. Genetic resistance, however, is the most economic and environmentally-sound measure of disease control. Resistance to EB is known to be complex and polygenic, and does not follow the gene-for-gene model of resistance. Although there has not been any report of genetic resistance within the cultivated species of tomato, sources of EB resistance have been identified within the wild relatives of tomato, including L. hirsutum and L. pimpinellifolium. Mapping QTLs conferring horizontal resistance is a promising approach for studying and improving EB resistance in tomato. We have developed F2, F3, F4 and an F2:8-derived RIL population of a L. esculentum × L. pimpinellifolium cross and evaluated them for EB resistance under field conditions. Genetic maps were constructed based on the F2 (including 256 RFLP, EST and RGA markers) and the RIL population (including 264 RFLP, CAPS and EST markers). In each of the F2, F3 and F4 population, an average of ~10 QTLs were identified for resistance, which were highly consistent across populations. QTL mapping in the RIL population detected several QTLs in F7 (evaluated in 2004) and F8 (evaluated in 2005) generations. QTLs were contributed by both L. pimpinellifolium and L. esculentum parents and were rather consistent across generations. Co-localizations of QTLs with several ESTs were observed, suggesting potential involvement of ESTs with EB resistance. Candidate-gene approach as used in this study may lead to the identification and mapping of new R genes underlying EB resistance in tomato.
Log in to add this item to your schedule
1 - The Pennsylvania State University, Department of Horticulture and The Inter-college Graduate Degree Program in Genetics, 103 Tyson Building, University Park, PA, 16802-4200, USA
2 - The Pennsylvania State University, Department of Horticulture, 103 Tyson Building, University Park, PA, 16802-4200, USA
Keywords:
Early Blight
QTL mapping
EST
Candidate Gene
Alternaria solani.
Session: Poster-161
Location: Ballroom CD/Monona Terrace
Date: Tuesday, July 25th, 2006
Time: 8:00 AM
Abstract ID:442 |
