Link to home

Molecular markers linked to Verticillium wilt resistance in potato germplasm

Rawnaq Chowdhury: SDSU

<div>Verticillium wilt (VW) of potato (<em>Solanum tuberosum</em>), caused by two different soil-borne fungi <em>Verticillium albo-atrum</em> R & B or <em>V. dahliae</em> Kleb., is a major limiting factor in potato production throughout North America. Yield losses in potato associated with the disease can reach up to 50 % in severely infested fields. In tomato, resistance to race 1 of <em>Verticillium dahliae</em> is conferred by a dominant <em>Ve</em> gene that has been exploited in breeding programs from more than 50 years. However, previously developed markers within the <em>Ve</em> gene in potato are unreliable in predicting resistance. The goal of this project is to identify additional genomic regions that determine VW resistance in potato. An F2 mapping population was developed in our lab by selfing an F1 individual derived from two homozygous diploid parents, <em>S. tuberosum</em> DM1-3 (susceptible to VW) and <em>S. chacoense</em> M6 (resistant to VW). Using a rooted cutting protocol, the population was phenotyped and SNP genotyped. A major QTL in chromosome 1 was identified that explains 31% of the phenotypic variation. A total of 22 genes are located within the QTL region, and two genes have been selected for further functional validation studies. Using the sequence information of these two genes, are developing markers to distinguish between resistant and susceptible germplasm. The marker information will be a valuable tool for potato breeders interested in selecting for VW resistance.</div>