Q&A with Potato Breeder Dr. Sagar Sathuvalli
By Sonia A. Hall, Center for Sustaining Agriculture and Natural Resources, Washington State University
This article is part of a series where we share insights from conversations that I had with public plant breeders across the Pacific Northwest about their breeding programs and how climate change considerations intersect with their work. Through these conversations, I wanted to better understand the complexities of the plant breeders’ world, where there are elements that already provide useful information about adapting to future climates, and where there are questions—about the climate in the future, or the plants’ responses, or production, market, or other factors affecting a particular crops’ future—that intersect or even overshadow questions about how to prepare for future climates.
Potato is a high-value, irrigated crop grown across Pacific Northwest states. It is affected by a range of pests and diseases, including many soil-borne pathogens. The need to break the cycle of some of these pathogens is a driver of crop rotation decisions. In my conversation with Dr. Sagar Sathuvalli, Associate Professor, Potato Breeding and Genetics at Oregon State University, it was clear that plant breeding had an important role to play in resistance to a wide range of pests and pathogens. He described a two-fold challenge to breeding for future climates. First, potato breeders don’t yet have good data on how climate change might change the dynamics of different pests and pathogens, and which might become greater threats in the future. And second, breeders must meet high expectations: neither yield nor quality can be compromised in pursuit of tolerance to climate-driven biotic or abiotic stresses. So here is how Dr. Sathuvalli is approaching these issues.
SAH: Please describe the focus of your breeding program.
SS: The Pacific Northwest produces more than half of all U.S. potatoes and provides the majority of potato exports. Farm gate value is roughly $1.7 billion and valued added during processing exceeds $3.0 billion and contributes about $1.0 billion to U.S. exports.
The Oregon Potato Breeding and Variety Development program is an integral part of the Pacific Northwest Tri-State (Oregon, Washington and Idaho) Potato Variety Development Program . Oregon breeding efforts focus on genetic improvement and cultivar development of potatoes in the four major market classes: 1) Russets for processing, 2) Fresh market russets, 3) Chipping and 4) Specialty. Traits of importance include yield potential, biotic stress resistance, abiotic stress resistance (drought and heat stress, cold sweetening), cooking quality, low acrylamide level, bruise resistance, storability, internal quality and appearance. Germplasm improvement focuses mainly on soil-borne pathogens (Columbia Root Knot Nematode, Verticillium wilt, Corky Ringspot, Potato Mop Top Virus, powdery scab) and Potato virus Y resistance. We also implemented induced mutations to generate new clonal variants to screen for drought tolerance.
SAH: Do you currently integrate climate change considerations into your breeding program? How? Are there conditions that make it hard, or unnecessary, to integrate climate change considerations into breeding?
SS: In order to address climate change impacts on potato production we integrate screening of early-generation clones at multiple locations across Oregon. Evaluating clones across Oregon helps us identify selections for heat stress (Ontario, OR), water or drought tolerance (Klamath Falls, OR) and high yield potential (Hermiston, OR). We have also implemented induced mutations (using gamma irradiation and chemical treatments) to generate new clonal variants of existing cultivars and in vitro techniques to screen for drought tolerance using polyethylene glycol (PEG) as a stressing agent. Early drought tolerant indicators, such as proline and abscisic acid levels and root vigor, are used for preliminary screening.
SAH: What traits or characteristics do you focus on in your current breeding program? Do those traits or characteristics confer the ability to adapt to future climates, that could be warmer in all seasons, with increasing variability and extremes? Or could they be affected by changing climates?
SS: The current breeding program focuses on developing new potato varieties with improved agronomic performance. We cannot compromise on yield and quality. If we released a variety that has lower yield but good pest and disease tolerance, it would likely not be adopted. Currently, we focus on developing pest and disease resistant varieties along with broader adaptation in the Pacific Northwest. If any selection performs well across the Northwest, there is a high probability that this selection can adapt to future climates. Yield potential is a good indicator – if a clone’s yield performance is consistent across different locations then there is a chance that this clone can adapt very well to future changing climates.
SAH: What trade-offs do you consider, or would you need to consider, in breeding for warmer conditions, longer frost-free periods, and likely wetter springs and winters, drier summers, and a shift in the availability of irrigation water to earlier in the year (as expected in much of the Pacific Northwest)?
SS: Breeding for warmer conditions can result in yield and quality issues. As quality is a prime factor for French Fry processing potatoes, we need to identify genotypes which can resist change in quality due to changes in the weather patterns. Irrigation is key for potato crops and it is essential to identify genotypes with an increased and effective root system for drought and heat stress tolerance.
SAH: Are there resources – online tools, Extension or other publications, events, etc. – that you know of that can help agricultural professionals integrate climate change into their work assisting producers with variety choice? Or any resources you wish existed?
SS: There are several scientific articles related with climate-smart breeding tools. We are currently working with data modeling scientists to understand historical changes in yield and quality of potatoes based on changing weather patterns during a growing season. We are also developing genomic tools and training populations to better understand the genetics behind response to abiotic stresses and implement genomic selection as a tool to tackle issue related to climate change.
Using trials in different locations to find varieties that perform well under a range of stressful conditions appears to be a common initial approach to integrating climate change considerations into breeding programs. But are conditions in these locations extreme enough to reflect what we can expect to see under future climates? And do particular locations have the right interactions among the different stresses? It will be really interesting to see if the work Dr. Sathuvalli is embarking on results in ways to better leverage information gained in particular years—with greater extremes or particular combinations of weather and disease scenarios—to select potato varieties that will continue to perform well under future climates.