This blog post was written by guest contributor Travis Parker, who is a PhD candidate at UC Davis. Travis is leading dry bean breeding efforts focused on the needs of organic agriculture.
Legumes, including dry beans, have a central role in organic agriculture. Not only are legumes excellent at fixing nitrogen, but they break up pest cycles and improve soil structure. These advantages are compounded when farmers can sell the harvest from these crops at a premium.
Heirloom dry bean varieties are renowned by chefs for their excellent flavors and vibrant colors. Because of this, growers can typically sell them for prices three- to ten-fold higher than the better-known commercial types. Heirloom varieties typically arose in traditional farming systems, and are well adapted to the limited inputs of soil nutrients and pesticides often found in modern organic farms. They also have a long shelf life, affording farmers flexibility in their harvest and sale. Unfortunately, these varieties are often susceptible to bean common mosaic virus and lack the high yields of commercial types. Combining the high culinary quality of heirlooms with the strong disease resistance and field performance of commercial varieties would be a major asset to organic farmers.
Starting in 2013, the Gepts lab at UC Davis began a collaborative evaluation with Lundberg Family Farms to determine which heirloom bean varieties would perform best in organic systems. As expected, most of these were susceptible to bean common mosaic virus, but many were otherwise promising in culinary quality and yield. Beginning in 2015, we began making cross-pollinations to combine the best qualities of these heirloom and university-released types. In the same year, the project became incorporated as a component of the larger Student Collaborative Organic Plant-breeding and Education (“SCOPE”) project at UC Davis, funded by the USDA’s Organic Research and Extension Initiative (OREI) grant program. Organic Seed Alliance is an important collaborator in this project.
The SCOPE project also includes branches focusing on Lima bean, tomatoes, peppers, and small grains. This project has helped to provide a framework to recruit interns and other graduate students to participate in this breeding work. Through SCOPE, students can learn about the art and science of plant breeding, while contributing to a commercially relevant project.
The breeding program has developed new varieties through two methods. For varieties that suffer badly from bean common mosaic virus but are otherwise promising, we cross-pollinated the heirloom with a resistant variety and then cross-pollinated the progeny back to the heirloom parent. Any offspring that show virus susceptibility are removed from the breeding program. By repeating the cross-pollinations and selections several times, we can develop a new type that is extremely similar to the heirloom parent, but shows complete resistance to the virus. These varieties have shown major improvements in yield and reductions in maturity time, despite being nearly identical to the heirloom parent. Of course, these methods do not require genetic engineering or other methods excluded in organic agriculture.
A second branch of the breeding program seeks to improve more than virus resistance. In this branch, a single cross-pollination is made between the heirloom and commercial varieties. The progeny are strongly selected to remove any types with undesirable seed patterns and virus susceptibility. Of the rest, those that have the highest yields when grown in organic conditions are used to plant in future seasons. This has led to dramatic increases in yield and other characteristics, which would have been impossible through the repeated back cross-pollination method.
In 2018, the SCOPE breeding program evaluated its new varieties in a multi-location replicated trial. The results of this trial conclusively demonstrated that the new varieties were much higher yielding than their heirloom relatives. Of the ten new varieties entered into these trials, all had yield improvements of 39% or higher. In some, the improvement was as high as 424%. Drone-based imagery showed that the new varieties were more capable of taking advantage of available soil nutrition than heirloom types, which used the nutrients to produce more leaves and vines rather than harvestable yield.
In 2019, we expanded the multi-location trials to include farms as distant as San Diego and Maine. Preliminary taste tests have shown that the new varieties are of similar culinary quality as the heirlooms. The new varieties are scheduled for public release in the winter of 2019-2020.
More information about the project can be found here. We are always interested in new collaborations, so contact Travis Parker at trparker@ucdavis.edu if you are interested in growing the new varieties or would like more information!
Funding for this project has been provided by USDA/OREI, Clif Bar Family Foundation, Lundberg Family Farms, and USDA/WSARE.
