Tepary Beans Offer Farmers a Low-Input, Climate-Resilient Alternative to Legumes

Tepary beans are one of the most drought-tolerant legume crops in the world, but they were once considered an endangered species in the United States. Waltram Ravelombola, an organic and specialty crop breeder at Texas A&M AgriLife Research in Vernon and in the Texas A&M Department of Soil and Crop Sciences, is one of a few scientists who have introduced tepary beans into modern cropping systems and diets.

This legume is an ancient crop native to northern Mexico and the southwestern United States. The beans can come in a variety of sizes and colours, such as pinto or black beans, but they offer drought tolerance that other legumes do not, according to Ravelombola.

Teparys can be consumed as beans by humans or as forage by livestock, and they have a higher nutritional value than cowpeas and guar. Tepary, like cowpeas and guar, can fix nitrogen in the soil. However, Ravelombola stated that there are currently insufficient supplies of seeds to be planted.

For his "Developing High-Throughput Phenotyping and Genomic Resources for Adaptation to Dryland Conditions in the USDA Tepary Bean Germplasm" project, he is using 265 tepary bean plant transfers obtained from the USDA Germplasm Resources Information Network.

"Our goal is to start with these seeds and develop tepary bean cultivars that are better suited to dryland regions of the United States," he explained. "We want to investigate the adaptations of existing germplasm to dryland conditions, build a high-throughput phenotyping platform for drought stress, biomass, and yield prediction, and develop genomic resources for dryland adaptations."

Ravelombola stated that he will conduct field phenotyping using drone technology, whole-genome resequencing to identify important genes and genetic markers, and then pursue genomic selection in tepary beans. Currently, little is known about the crop's genome.

Breeders can select highly drought-tolerant and high-yielding tepary bean genotypes using genetic markers to accelerate development, breeding, and cultivar release. When the project is completed, tepary bean cultivars adapted to various areas will be of interest to pulse growers, seed industries, and food companies across the United States, according to Ravelombola.

Ravelombola explained that his research began with a discussion with a colleague at Vernon about tepary bean adaptations to the region. The USDA-ARS grant enabled him to use field phenotyping, genomics, and high-throughput phenotyping to gain a better understanding of the crop's adaptations to the dryland farming system. Tepary bean research is still limited.

According to Ravelombola, it will take at least eight growing seasons; depending on climate, there may be more than one growing season per year. The first two seasons will be devoted to identifying adapted germplasm, while the third season will be devoted to population development. The following seasons will be dedicated to population and selection advancement, with the final two years dedicated to yield trials.

This lengthy process began last year, when Ravelombola planted a small plot of beans and hand-harvested them. He's dedicating three-quarters of an acre to tepary beans this year, which he planted on June 8 at the Texas A&M AgriLife research farm in Chillicothe. Those beans will be harvested in September and used to grow the research for the following year.

Ravelombola stated that the beans will not be irrigated. He will monitor the amount of moisture they receive from rain to determine how well they will produce in different regions with varying moisture levels. He eventually stated that because of their legume properties, he would like to try them as a cover crop as well. However, that will have to wait until seed availability improves over time.