Location: Vegetable Crops Research2018 Annual Report
1a. Objectives (from AD-416):
Objective 1: Identify and maintain a set of wild potato plants, determine the DNA sequence of each, evaluate the distribution of genetic diversity among these wild potatoes, and use this information to guide breeders in developing improved potato germplasm. Objective 2: Characterize the set of wild potato plants from Objective 1 for resistance to major potato diseases and pests, including late blight, early blight, Verticillium wilt, and Colorado potato beetle, and map these resistance traits to identify the genetic regions responsible for these traits. Objective 3: Create hybrids between diploid cultivated potato and the set of wild potato plants from Objective 1, characterize these hybrids for plant and tuber traits, and provide the data to the breeding community to use in developing improved potato germplasm.
1b. Approach (from AD-416):
Objective 1: We have identified 10 wild diploid Solanum species with demonstrated utility in potato breeding. Within each species, we will choose 10 accessions for this project based on published resistance data, personal experience, and genebank passport data. Multiple individuals from each wild species will have their S-locus RNase alleles sequenced. Fertility of individuals will be assessed by assaying for pollen viability and production of berries with viable seeds. Disease and pest resistance screens will be carried out on multiple plants in each accession for which a specific resistance trait has been reported previously. Based on these data, twenty individuals from each species will be selected for SNP genotyping, detailed phenotyping and clonal maintenance. Objective 2: Individual clones identified in Objective 1 will be characterized for resistance to major potato diseases and pests, including late blight, early blight, Verticillium wilt, and Colorado potato beetle. For each disease or pest, we will perform disease inoculations or beetle challenges that generate quantitative resistance scores using previously published methods. R-genes within each individual will be sequenced using RenSeq and the position of R-genes will be mapped to the potato genome. Objective 3: We will create hybrids by crossing flowers of diploid cultivated potato with pollen from the 200 wild potato plants identified in Objective 1. Resulting hybrids will be characterized for plant growth and tuber traits including size, shape, color and yield. These phenotypic data will be shared with the potato breeding community to use in developing improved potato germplasm. Phenotypic data and genotypic data will be deposited into GRIN and the clones used for this research will be donated to the NRSP-6 potato genebank for use by others.
3. Progress Report:
We have identified accessions to evaluate and are establishing them in tissue culture. When they are large enough to be subcultured, transplants will be planted in a greenhouse and screening assays will begin. We have identified a protocol for evaluating RNase sequence diversity and are currently testing primers for amplifying the S-RNase gene.