8 April 2024

6 minute read

By: Emma Lande

North America

Editor's note: Image above shows Melinda Yerka with one of her malting and brewing sorghum varieties. Photo courtesy of Melinda Yerka.

A University of Nevada, Reno researcher is aiming to make a major discovery in global sorghum cultivation. Her preliminary research suggests that she has developed sorghum varieties having big enough seeds that they are efficiently broken up during the harvest, making their nutrients more bioavailable to dairy cows than existing sorghums. Even better, these unique sorghums are well-adapted to production in Nevada and California.

Melinda Yerka, an associate professor in the Department of Agriculture, Veterinary & Rangeland Sciences, and her team have been adapting sorghum to have desirable grain qualities when grown in the Western U.S., outside of the traditional “Sorghum Belt” in the Great Plains. Some of these new varieties have very large seeds, in addition to very high levels of protein and starch. Much of this work has been conducted at the Experiment Station, a unit of the University's College of Agriculture, Biotechnology & Natural Resources, since 2017 when the new sorghum breeding program was established.

Yerka and her team used a relatively new approach to plant breeding research, called a Multiparent Advanced Generation InterCross (MAGIC) population design to develop these new varieties. The MAGIC population design involved breeding together (intermating) eight different parental varieties into a single pool of new varieties, or “progeny.” Each parental variety contributed specific traits relative to grain chemistry, which means that the progeny (the new varieties) have many unique combinations of traits that are desirable for human foods, craft malting and brewing, animal feeds, and ethanol production. MAGIC populations have been used in all major cereal species to identify DNA fingerprints for various traits in plants to help scientists create improved varieties.

Yerka collaborated closely with the U.S. Department of Agriculture’s Grain Quality and Structure Research Unit in Manhattan, Kansas, which specializes in sorghum grain quality assessments, to analyze the starch, protein and lysine content of the grain of her sorghum varieties. Other key collaborators for the project include researchers from Texas Tech University; University of Nebraska, Lincoln; and University of California Agriculture and Natural Resources.

Yerka’s research was designed to develop sustainable and resilient alternatives in dairy cow nutrition to address the shortcomings of current dairy feeds that struggle with hot, arid conditions and need more water in the West.

“Corn and alfalfa were once dependable dairy cow feed, but they are no longer viable in the long run, due to their substantial water needs in changing climates, particularly in California and Nevada,” said Yerka. “The water crisis in the Western states is a wake-up call for farmers to seek alternative crops like sorghum that require less water to grow. Making sorghum more competitive with corn and alfalfa in dairy nutrition by improving the bioavailability of starch and protein could very well be a means for farmers in rural communities to maintain profitability and preserve generations of family farms.”

According to the California Department of Food and Agriculture, dairy farming was the highest-earning agricultural commodity in 2022, contributing over 30% of the state's total agricultural revenue. Yerka hopes that using California and Nevada for breeding her sorghums will also decrease producers’ need to rely on feed imports from other states, which can be costly and unstable when other regions also deal with increasing climate variability.

Traditionally, sorghum has been overshadowed by its more popular fodder counterparts, corn and alfalfa, due to its seeds’ diminutive size that renders it indigestible for livestock. However, the successful testing and future commercialization of these new varieties that combine large, soft seeds with either high protein or high starch contents could rewrite the rules of how the nutrition profile of sorghum compares with corn and alfalfa.

The large seeds break up during harvest using existing sorghum forage choppers, so no special equipment is needed to process them, which should increase the bioavailability of their exceptional nutritional composition. If so, their multi-use potential in foods, feeds and biofuels and their natural adaptation to hot and dry climates could catapult these new varieties to the top of super grains for commercial processors, livestock fodder and health-conscious consumers who are interested in making local food systems more sustainable.

Other benefits emerging from Yerka’s field trials indicate that the seeds of the new hybrids remain soft and pliable for up to a month post-maturity, allowing for a more adaptable harvest schedule. This was a major focus of the project, as the seeds of existing sorghums bred in other states, when grown in California, dry quickly after maturity and are too hard to break up during harvest or while being chewed by cattle.

Yerka Seeds: A collaboration with the University’s College of Business

This September, Yerka founded Yerka Seeds to create and market commercial sorghum hybrids to producers. It functions by taking publicly available varieties developed by her academic lab and finishing their development into commercially competitive hybrids. Yerka has been working with the University’s Nevada Small Business Development Center, part of the College of Business, to devise strategies for the company’s success.

The Center, which provides free entrepreneurship training, advising and specialty services for startups and small businesses in Nevada, has helped Yerka explore financing strategies and possible business models for the seed company. The Center also helped her think through her intellectual property risks and strategies.

“Melinda has been the driving force behind the formation of the Yerka Seed Company, and our advisors have been collaborating with her to explore commercialization options that will help her mitigate potential business risks,” said Jake Carrico, the director of advising for the Center.

Next summer, Yerka Seeds will collaborate with a limited number of dairy farms across the West to grow the new sorghums and feed them to cattle as both a grain and a silage to assess the environmental stability and bioavailability of these desirable traits. The hope is to demonstrate and prove that the large seeds do indeed break up using commercial harvest equipment and/or feeding to release their nutrients at a level that is more comparable to corn and alfalfa than current sorghum seeds. This will be the first step to commercialization in subsequent years.

If next summer’s trials are successful, additional plant breeding and multi-environment testing will be conducted to identify the best commercial hybrids for wholesale distribution through Yerka Seeds, which acts as the commercialization arm for sorghum and corn varieties preliminarily developed and tested by the Yerka Lab.

Yerka Seeds’ food, feed, and craft malting and brewing hybrids will be developed in a manner consistent with the farm-to-table movement. The seeds will be grown on individual farms and sold directly to end users (consumers, maltsters and breweries). This personalized approach, connecting consumers to a specific farm, aligns with a growing consumer desire for local food and transparency in food sourcing.

Working with international partners to help address global food challenges

Yerka and her partners have recently begun collaborating with sorghum breeders at the International Maize and Wheat Improvement Center to expand her sorghums to less developed nations. Her team is currently applying the MAGIC population design to develop high protein and starch grain sorghum varieties that are adapted to various climates in Africa, particularly in Kenya, Senegal, Ethiopia and Tanzania.

“Should the newly developed sorghums prove competitive with established feed crops in California and Nevada, they will serve as a compelling showcase of sorghum's genetic potential in aiding global food and feed systems to adapt effectively to the challenges posed by climate change,” Yerka said.

Support and funding for her team’s research has largely come from the University of Nevada, Reno’s Experiment Station, the U.S. Department of Agriculture’s Agriculture and Food Research Initiative, the U.S. Department of Agriculture’s Agriculture Research Service, and Texas Tech University.