Potato variety improvement through gene transfer and virological methods
Potato (Solanum tuberosum) is the fourth most important crop in the United States. Nearly half of the national production takes place in the Pacific Northwest with Idaho and Washington first and second in total production. Potato is an expensive crop, requiring numerous specialized inputs. Pesticides are required to control numerous pests and diseases. In addition the vegetative propagation of tuber seed adds additional cost to maintain a seed supply relatively free of systemically transmitted pathogens and pests. Since a large part of the production is processed quality factors are also important. The potato is potentially a source of antioxidants of anthocyanins and carotenoids in the diet if varieties with high levels of these can be commercialized. Disease and pest resistance, quality factors and nutritional enhancements are traits available through manipulation of Germplasm resources.
To address these problems we are conducting the following research projects:
- Resistance to viruses has been identified and is being incorporated into the mainstream breeding populations. Mapping studies will located the resistance factors on chromosomes and provide labor saving tools to accelerate breeding.
- Resistance to Columbia root-knot nematode has been indentified and is being incorporated into mainstream breeding populations. A gene mapping and isolation project is underway to map the genomic location of the resistance gene(s) and to isolate the gene from Bacterial Artificial Chromosome (BAC) Libraries. This work is being carried out in the context of a National Science Foundation Grant “Development of Tools for Potato Functional Genomics: Application to Disease Resistance and Development." Resistance genes from three different wild species will be compared for phenotypes and gene structure differences.
- Resistance to potato late blight derived from Mexican wild species has been identified and is being incorporated in to the breeding program. Annually screening of breeding populations from various programs in the United States including those of the Northwest is being conducted in the Toluca Valley of Mexico, the birthplace of potato late blight and the region of greatest genetic diversity of the pathogen. Screening at Toluca is designed to ensure selection of durable resistance, i.e., resistance that will be effective against highly genetically diverse late blight and last a long time.
- Potatoes with high levels of the pigments classes anthocyanins and carotenoids have been selected. Measurement of the antioxidant potential has been performed and potatoes that can contribute a substantial level of antioxidant potential to the human diet have been identified. Yield trials are being conducted, seed of promising clones multiplied and contacts with processors pursued to maximize the potential of commercialization within various markets.
- Breeding Potato with high carotenoid content