1a. Objectives (from AD-416):
The goal of this proposal is to characterize Rlretb, a gene for resistance to potato leafroll virus (PLRV) from the potato species Solanum etuberosum, and identify molecular markers tightly linked to Rlretb that would be useful for marker-assisted selection and for the eventual cloning of the gene.
1b. Approach (from AD-416):
The ARS potato breeding and pathology program at Aberdeen, Idaho will conduct field screening for resistance to PLRV and greenhouse grafting studies evaluations that will elucidate the mechanisms of resistance to potato leafroll virus conferred by Rlretb. Research responsibilities also will include hybridization to synthesize diploid populations segregating for Rlretb, which would be useful for the fine mapping of this gene.
3. Progress Report:
Ten, haploid clones derived from Potato Leafroll Virus (PLRV) resistant tetraploid clones were intercrossed in the greenhouse for the production of populations to aid in the further mapping and cloning of PLRV resistance gene, Rlretb. A combination of poor or no flowering was observed, with reproductive sterilities additionally contributing to no true potato seed production. Hybridizations for generating progenies will again be conducted in 2013, with a greater number of plants of each parental clone to be planted to facilitate success. Thirty-five breeding clones representing a family segregating for markers linked to the Rlretb gene are also being maintained by our project. Clone response to PLRV infection, important for mapping of the Rlretb gene, was previously conducted by our project. Tubers of these 35 clones were sent from our program for establishment in tissue culture to provide pathogen-free plantlets and to ensure their long-term maintenance. The research conducted contributes to Objectives 1, 2, and 3 of the in-house project.