- Agronomic: potatoes
- Education and Training: farmer to farmer, on-farm/ranch research, participatory research
- Pest Management: genetic resistance
- Production Systems: transitioning to organic
The goal of our organic potato research program is an integrated, participatory potato breeding, variety evaluation and seed potato production system that serves the needs of the approximately 220 organic and low-input potato farmers in the Midwest. Modern potato varieties have been bred using conventional practices and may not be suited for organic and low input production systems. We evaluated heirloom potato varieties from the Seed Savers Exchange (SSE)potato collection for their immediate value in low-input and organic potato cropping systems in a participatory trial. The 12 participating farmers evaluated variety performance with guidance from researchers, focusing on traits such as plant vigor, pest and disease resistance, yield, taste and market appeal. Several heirloom potato varieties that exhibited higher yield or other attractive characteristics for marketing were identified. Additionally, we used single nucleotide polymorphism markers to characterize the diversity of a subset of the SSE potato collection and identify potential duplicate accessions.
Organic potato growers are in need of access to a greater diversity of varieties, and to varieties specifically adapted to organic production systems. Modern breeding programs serve high-input conventional farms, and produce varieties that are not well adapted to low input farming systems. In our conversations with Wisconsin organic growers, recurring themes have been their need for varieties suited to organic production with characteristics such as low nitrogen requirement, weed suppression, and resistance to insect pests and diseases. Heirloom varieties released before the advent of chemical fertilizers and pesticides are likely to be more suited to organic production. Characterization of heirloom varieties in organic growing environments is a necessary step to enable organic growers to make informed variety choices and to allow breeders to select suitable parents to breed cultivars suitable for organic farming systems. On-farm characterization by growers, in collaboration with UW researchers, will generate variety performance data that is directly relevant to grower needs.
Most potato breeding programs focus on traits important for the processing industry, since this is the largest market for conventional potatoes. Attributes that are important in low input systems such as organic farms, which are more likely to target local fresh markets, are rarely addressed. Increasing consumer interest in the flavor and nutritional qualities of specialty potatoes, especially pigmented cultivars, gives organic growers who specialize in these varieties a marketing edge. By evaluating potato varieties throughout the growing and storage season, and incorporating taste panels, nutritional analyses, and customer reaction into these evaluations, our farmer-researcher team will generate variety descriptions that are highly relevant to low input organic farms in the Midwest, and that include critical characteristics to assist organic growers in making variety choices and in marketing. An on-farm participatory approach to variety evaluation will generate information relevant to farmers, and is anticipated to increase the rate of adoption of better-performing varieties by farmers.
Germplasm collections are essential resources for continued crop improvement through breeding. Although the large Seed Savers Exchange (SSE) potato collection includes many rare heirloom varieties unavailable from any other source, this resource is underutilized by growers and breeders alike. This underuse is in large part due to the accumulation of yield-limiting levels of viral contamination during field-based vegetative propagation (tuber to tuber). A recent collaboration between SSE and the UW-Madison Charkowski laboratory has focused on eradicating pathogens from a subset of 100 potato varieties as tissue culture plantlets, and training SSE staff to continue pathogen eradication. Our proposal affords the first opportunity to characterize the true varietal potential of this germplasm in a pathogen-free state.
The single nucleotide polymorphism (SNP) marker platform recently developed as part of the Solanaceae Coordinated Agricultural Project (SolCAP) has massively expanded the capacity to evaluate the genetic diversity of variety collections, and to map variety traits such as disease resistance to genetic locations, an essential tool for directed plant breeding. Our genotypic characterization of SSE germplasm will utilize the SNP marker platform, allowing us to tap into the huge database and resources of this cross-disciplinary project. In particular, ongoing research to associate SNP markers with traits of importance in potato production will allow breeders to use the SNP data generated by our project to select for traits beneficial in low input production systems. Twenty varieties in the SSE collection that are suspected to be duplicates have been identified. These varieties will be evaluated with a dense array of SNP in order to confidently determine whether they are identical. This information will allow SSE to reduce redundancy in their potato collection, so that limited resources can be used more efficiently.
Our objectives were to (1) evaluate heirloom potato varieties for their immediate value in low-input potato cropping systems, and for the resilience of their performance across multiple environments; and (2) characterize the genetic diversity of heirloom potato varieties to determine the potential for crop improvement through a breeding program for low-input cropping systems.