| Abstract Detail
Conference Wide Merk, Heather [1], Ashrafi, Hamid [1], Kinkade, Matthew [2], Foolad, Majid [1]. Identification and Molecular Mapping of A New Dominant Late Blight Resistance Gene (Ph-5) in A Lycopersicon pimpinellifolium Accession. LATE blight (LB), caused by Oomycete Phytophthora infestans, occurs throughout tomato and potato growing regions of N. America and elsewhere in the world. Recently, LB has become a major disease of both tomato and potato in the northeastern U.S. In 2004, LB totally destroyed some commercial organic plantings and many home garden tomatoes in 26 PA counties. Currently, no LB-resistant cultivar of tomato is available and the disease control measures include preventive cultural practices and heavy use of protective and systemic fungicides. Although fungicide applications can be effective in certain conditions, they have many drawbacks. Furthermore, both mating types (A1 and A2), which are necessary for sexual propagation, occur in the U.S. This is alarming as this can result in the production of oospores and the emergence of new races. Thus, there is an urgent need to develop tomato cultivars with durable LB resistance. In tomato, 3 major LB resistance genes have been identified and mapped, Ph-1 (chr. 7), Ph-2 (chr. 10) and Ph-3 (chr. 9). While new races have overcome Ph-1 and Ph-2 provides only partial resistance to several isolates, Ph-3 confers strong resistance. However, new P. infestans isolates have emerged which overcome Ph-3. It is imperative to explore new resistance genes or QTLs and pyramid them to attain durable resistance. Our extensive germplasm screening has resulted in identification of several new sources of LB resistance in tomato wild species Lycopersicon pimpinellifolium. Here we report the identification and mapping of a strong R gene (Ph-5) conferring resistance to at least 7 P. infestans isolates. A large (n=1008) L. esculentum × L. pimpinellifolium F2 population was screened and selectively genotyped to identify and map this gene to tomato chromosome 1. The detailed mapping procedure and characteristics of this new LB resistance gene will be presented.
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 Plant Biology, 103 Tyson Building, University Park, PA, 16802, USA
Keywords:
Late Blight
QTL
Phytophthora infestans
tomato
Lycopersicon
mapping.
Session: Poster-162
Location: Ballroom CD/Monona Terrace
Date: Tuesday, July 25th, 2006
Time: 8:00 AM
Abstract ID:443 |
