Breeding for Regional Organic Farms

red kuri field pumpkin

photo courtesy of Adrienne Shelton
Red kuri winter squash breeder Marcel van Diemen
evaluating breeding lines in the Netherlands.

I spent the last day of my graduate school career as most students do – my stomach locked into a tight ball of jittery nerves and my mind struggling to suppress the irrational fear that my research, which had consumed my life for five years, contained some critical flaw that I had overlooked. My thesis was unconventional. I had helped to breed an open-pollinated variety of sweet corn, developed by and for organic growers, using a method called participatory plant breeding. I had explored the history of organic farming in the United States, as well as the complicated evolution of intellectual property rights in relation to seeds. Drawing on both biological and social sciences, I argued that organic growers require unique variety traits adapted to organic production systems, and that involving growers in the breeding process is an effective way to accomplish this goal.

Looking back on that day, as I defended my PhD dissertation before a five-member committee who would ultimately determine whether I passed or failed, I can no longer remember most of the questions that they asked, nor how I responded. Yet one comment made by committee member Dr. Mike Casler has always stuck with me. Dr. Casler is a forage breeder at the University of Wisconsin-Madison, and an exceptional statistician. Statistics was a challenge for me in graduate school, and I had been particularly worried that Dr. Casler was going to find an error in my statistical model that I would be unable to explain or justify. To my surprise, he seemed quite satisfied with my work and told me (paraphrasing): “In the end, breeding is a pretty simple equation. A farmer’s job is never easy. Whether it is increased production costs, erratic weather, new pests or disease challenges, there are always multiple factors chipping away at the farmer’s bottom line. As a breeder, if I can develop a variety that gives a little of that bottom line back to the farmer, through increased yields, better disease resistance, or improved nutrition, then I have done my job and I can sleep well at night.”

photo courtesy of Adrienne Shelton
One of the experimental lines of the improved Buffalo breeding project, grown in New Hampshire in 2018. Seedlings of the experimental lines of the improved Buffalo were delivered to trial farms in April 2019.

Ultimately, the committee did grant me my degree, and the feeling of relief and accomplishment is just about the only other thing I remember from that day. Since graduate school, I have worked as a post-doctoral researcher, a product development manager for High Mowing Organic Seeds, and now as an organic product specialist for Vitalis Organic Seeds. I am often asked if I would rather be working as a breeder, given my Masters and PhD training. In those moments I always think of Dr. Casler and the wisdom he shared with me. As an organic product specialist, my role is to trial experimental varieties, developed by dozens of breeders, on organic farms in the Northeast and Midwest. Through these trials I am able to influence breeding objectives to ensure that the varieties being developed meet the regional needs of organic growers, and are appropriate for agronomic and market trends. Rather than just focusing on one or a few crops (as I would likely have to do as a breeder), I have the opportunity to identify new varieties that are best suited for organic production in a wide diversity of crops, and which can help improve a farmer’s bottom line, however he or she chooses to define it. Dr. Casler’s philosophy is the foundation of the work that I do, and indeed, I do sleep very well at night!

Vitalis Organic Seeds, a division of Enza Zaden, was founded in 1994 in The Netherlands, and is a global leader in organic breeding and seed production. We are an independent, family-owned company that focuses exclusively on breeding and seed production. We produce nearly 500 certified organic varieties distributed in over 35 countries, ensuring regional adaptation of premium genetics through 12 research stations around the world. Since entering the United States and Canadian markets in 2007, we have become a trusted supplier of organic vegetable and culinary herb seed in North America. While many organic growers are unfamiliar with Vitalis Organic Seeds as a company, they usually are much more familiar with our varieties, such as Dunja green zucchini, Sakura cherry tomato, Olympus bell pepper, and Corinto cucumber (to name just a few).

As a breeding company, we work with farmers of all scales, from large wholesale producers to small direct market gardeners, and everything in between. All of these growers expect and deserve the highest quality organic seed, free from pathogens and weed seeds, and with excellent germination. We strive to meet these standards with every bag of seed that we deliver. The variety traits required by different types of growers, however, is more variable. The critical traits that will make the difference between whether or not a lettuce variety will improve the bottom line of an organic lettuce grower in California is likely very different from the critical traits needed by an organic lettuce grower in Massachusetts. Factors such as climate, disease pressures, production methods, post-harvest shelf-life requirements, and consumer preferences all influence the focus of the breeding program. Plant breeding does not work well in a one-size-fits-all model. Instead, plant breeding needs to be approached on a more regional scale, working in collaboration with the farmers, to fully understand the traits that are required to develop a successful variety.

With my focus on the Northeast and Midwest, I am particularly engaged with our breeding programs that are developing varieties best suited for the majority of organic farms in these regions – small-to-medium size diversified vegetable operations with a mix of direct and wholesale customers. For example, we are currently working on a project to develop an improved Buffalo tomato. The original Buffalo was a 200 gram, deep globe beefsteak with medium-early maturity developed by Enza Zaden in the 1980s. Buffalo eventually made its way to the United States, and was soon grown widely in high tunnels in the Northeast. The variety was especially appreciated for its outstanding flavor and thin skin. Its Achilles heal, however, was that the variety had very few disease resistances. As Enza Zaden began to release newer tomato varieties with improved resistances, Buffalo’s popularity declined and the variety was dropped from the portfolio. For Buffalo aficionados, however, this news was most unwelcome. There are still rumors of certain growers in Vermont who have a stockpile of the original Buffalo seed stored in their freezers. Another grower told me that he owes the success of his farm to the Buffalo tomato. He believes that he would not have the loyal customer base that he does now, if it were not for his introduction of the Buffalo tomato to his customers early in his farming career. The flavor and quality of that tomato got his customers hooked, and they have stuck with him ever since.

One organic grower in Rhode Island, Max Hence, was especially determined to bring the Buffalo back to the Northeast. About five years ago, he started making inquiries, and before long he was communicating with the Enza tomato breeding team in Spain. Based on Max’s description of the value of the variety to high tunnel tomato growers in New England, the breeders agreed to work on an improved Buffalo. It took a few years of backcrossing improved resistances into the original parent lines, such as Verticillium, Fusarium, and Cladosporium (leaf mold) resistances. We are now in our second year of trialing 16 new hybrids. All of the trials are being conducted on organic farms in RI, VT, NH, and CT, with input from the growers serving as the critical determining factor in choosing which line will become the next Buffalo tomato.

Developing an improved Buffalo is an example of a breeding project initiated by an organic farmer, with a focus on exceptional eating quality and specific disease resistances required by tunnel growers in New England. In other cases, the breeder might not have the specific needs of Northeast organic growers at the forefront of their mind, but nonetheless develop material that is particularly well-suited for our region.

An example of this is the development of the melon variety Divergent. Divergent is a specialty melon that is a cross between a Galia and a Cantaloupe, with orange flesh and a delightfully sweet flavor. This variety came out of our diverse melon breeding program, also based in Spain. While the product development team in Spain was really happy with the flavor and agronomic traits of the variety, they found that it did not have the extra long shelf-life required by the Spanish growers with whom they worked. Yet in our trials in the United States, it did not take long to realize that this variety was perfectly suited for organic growers in the Northern tier of the country. The variety is early maturing, which is a critical factor for the success of any heat-loving crop in the North. It has a strong disease resistance package, always important for organic production, and excellent flavor and texture.

Unlike the Spanish growers, many organic growers in the Northern United States are not looking for varieties with an extended shelf life. Their customers are regional retail stores, CSA members, local restaurant chefs, or shoppers at a farmers’ market. These direct market outlets do not require long shelf life, and in fact are preferred by customers because the produce is so fresh and ready-to-eat. In the Northeast, one of my trial partners exclaimed, “Divergent is the best news in cantaloupe in a long time.” I strongly agree, as the majority of cantaloupes are bred for the California and Arizona climate, with long shelf life as the top priority, usually at the expense of flavor and aroma.

A final example of a breeding program that I am working with is red kuri winter squash. While red kuri is a minor winter squash in the United States, it is very popular in countries such as France, Germany, and the Netherlands. In addition, red kuri is unique because there is significantly more organic production compared to conventional production in Europe. Red kuri squash has a rich, nutty flavor and the deep red flesh is a high source of beta-carotene, an antioxidant and precursor to Vitamin A. Unlike other hard squash, the skin of red kuris can be cooked and incorporated into purees or soups, making this squash easier to prepare than many other types.

Our red kuri breeding program is located at the original Vitalis research station in Voorst, NL. From the earliest stages of the breeding pipeline, experimental lines are grown and evaluated in organic systems. The varieties that are chosen out of this program are those that are high yielding, have excellent fruit quality and storability because of their high brix and dry matter content, and contain strong disease resistance packages. Because these varieties were bred in organic conditions, they are especially suited to maximize organic fertility sources and the complex soil biota in which they are grown. This year my colleagues and I are doing extensive trials of an experimental red kuri (still unnamed) with organic growers throughout the United States. In addition, we are working with distributors and retail grocery stores to analyze how this unique product can be effectively marketed in a produce segment that is dominated by butternut and acorn squash. The bright red skin color of red kuri adds a beautiful splash of color to the typical browns, yellows and greens of many winter squash displays. We believe that the rich flavor and high nutritional value of this squash will appeal to the more discerning organic consumers, and hope that someday red kuri may be as prevalent as butternut squash in US households.

These examples are just a small sampling of the many different types of breeding projects that are occurring at Vitalis Organic Seeds. We serve a very diverse group of organic growers, in the United States and around the world. In order to best meet the needs of our customers, and to ultimately help organic growers be more successful, we are committed to a multi-local approach that values farmer input and participation. Through this approach, we strive to get ever closer to achieving our mission of creating an organic world together.

Adrienne Shelton is an organic product specialist for Vitalis Organic Seeds. She lives in Vermont and has been working in organic agriculture for 20 years. She can be reached at More information about Vitalis Organic Seeds is available at