Figure 1. Two dryland fields in Cheyenne County during the drought of 2012 illustrate how proso millet thrives under low-moisture condition (left) compared to corn (right), which uses more water and did not survive that year.

Research milestones achieved by the nation’s only proso millet breeding program, based at the University of Nebraska Panhandle Research and Extension Center, will improve production opportunities for Nebraska growers. Dipak Santra, alternative crops breeding specialist at the Panhandle REC in Scottsbluff, is leading the effort to improve production and marketing aspects of proso millet, an important alternative crop where irrigation water is limited.

Recent completion of the first genetic map for proso millet (Figure 3) represented a major milestone to provide for future genetic improvements. Santra and several UNL colleagues have worked on the project for several years, identifying DNA markers that signal the locations of genes that control desirable agronomic traits, such as high yield, larger seed size, quicker maturation, and tolerance to lodging, seed shattering and drought.

Proso has 18 chromosomes, compared to 10 in corn, 12 in rice, 21 in wheat, 11 in dry beans, and seven in field pea.

The results of the genetic mapping project are published in the March issue of Molecular Breeding.

Santosh Rajput, a doctoral student and one of the paper’s co-authors, worked with Santra in the field and in the laboratory to identify traits in numerous varieties of proso millet. He received his doctorate in 2015 and now works as a plant breeder for Dryland Genetics, LLC in Ames, Iowa. The third co-author is James Schnable, assistant professor in the UNL Department of Agronomy and Horticulture.

Proso Well Adapted to Western Nebraska Climate

Among all of the cereal crops, proso millet uses the least amount of water to produce a bushel of grain, Santra said, and fits well in western Nebraska’s wheat-based dryland crop rotation because it is highly adapted to its growing conditions. It has a short growing season, requires less water, and can help improve yields in other crops in the rotation, such as wheat, corn and sunflower. Planted acreage, however, has been limited by the level of demand for bird seed (primarily domestic), resulting in extreme price volatility.

Genetic mapping of proso millet will allow for more efficient breeding of new millet varieties with traits desired by producers. These traits are controlled by genes. Santra describes the two plant breeding options: Traditionally, to find a line of proso millet that is less likely to lodge (lay down in the field), a plant breeder might need to screen 10,000 millet lines, Santra said. Each line would need to be grown in the field and selected by visual inspection, identifying which plants in which plots displayed the desired trait.

Genome mapping allows the plant breeder to locate markers associated with genes that control the trait. Thousands of millet lines could be screened in a greenhouse, and their genetic material screened in the laboratory. In one month, the plant breeder could narrow the choices of breeding lines to 100, compared to similar results after four months in the field using traditional methods. In addition, “You have a 95% probability that those plants will have the desired trait, based on marker location,” Santra said. The 100 lines with the desired trait can then be tested in the field, under replicated conditions.

In another example, typical of commercial variety development, breeders might want to select for several traits, such as shattering tolerance, high yield, and drought tolerance. Using DNA markers that have been identified and mapped might allow a plant breeder to narrow 48 potential lines to only two lines that contain all three markers, before testing in the field, compared to “shooting in the dark” and planting trial plots with all 48 lines.

Identifying New Food Uses for Proso Millet

The genetic mapping project comes on the heels of several other research projects that signal progress in improving proso millet and establishing it as a food crop for human consumption.

A new variety of waxy proso millet (amylose-free starch) was registered in late 2014. Plateau is a cross between Huntsman, a popular, high-yielding variety, and a Chinese line that is high in waxy starches but not well adapted to growing conditions in the High Plains.

Plateau, which was developed by Santra and others in IANR, was described in an article in the Journal of Plant Registrations. Faculty and staff from University of

Wyoming, Colorado State University, and USDA-ARS of Lincoln and Akron, Colo., assisted in trials and laboratory evaluations.

“Introduction of a proso millet variety with novel end-use characteristics such as waxy starch will open new opportunities for using proso millet in the food-and-beverage industry,” Santra said. “Plateau displayed grain yields competitive with those of currently grown proso varieties in the region.”

If Plateau and other millet varieties are to gain wider use in the food and beverage industry, manufacturers will need to know how these foods react to processing. That is the goal of another research project, which measured how millet reacted to extrusion. 

Researchers looked at the potential for proso millet being extruded for instant breakfast cereals, much as oat, barley and other grains. This research, conducted by the UNL Food Processing Center and Food Science and Technology

Department was described in a 2015 article in the International Journal of Food Science and Technology. It measured effects of feed moisture and extruder screw speed and temperature on physical characteristics and antioxidant activity of extruded proso millet flour.

Santra collaborated in the project conducted by Devin Rose (lead scientist), associate professor in the UNL Food Science and Technology, graduate student Paridhi Gulati, and Steven Weier of the Food Processing Center, as well as several others.

Various types of millets are consumed as porridges, soups, flat breads in Asia and Africa. Potential food uses in the United States include weaning mixes, pasta, breads and cookies in combination with wheat flower.