Organic naked barley research

by Sally Colby

Cereal grains such as barley are often viewed as somewhat average and uninteresting, but Karl Kunze is changing that. Kunze is a Ph.D. candidate in the small grains breeding program in Dr. Mark Sorrell’s Cornell University lab.

Kunze’s current work on organic naked barley is part of a USDA-NIFA-OREI funded research project. He’s concentrating on naked (hulless) organic barley with the goal of determining how to use technology in organic research; developing relationships between breeders, farmers, maltsters, chefs and consumers to breed crops that benefit all; and development of new crops for new markets.

Although Kunze’s research is headquartered in New York, other states participating in the research include Oregon, Wisconsin, Minnesota and California. Kunze explained that whether barley is naked or hulled is controlled by the nud gene, a trait that emerged as a single mutation 2,000 years after barley was domesticated. In dominant strains, the hull adheres to the kernel; in plants without the nud allele, the hull falls off at harvest.

Important traits in naked barley include threshability, germination, seedling vigor, test weight/yield and disease resistance. Beta-glucan, the soluble fiber shown to reduce LDL-cholesterol, is another desirable trait.

In New York, trials were conducted in winter and spring for three years. A major aspect of the barley breeding project includes diversity panels, or pre-breeding selection, which involves crossing parents from wild relatives to elite lines. The goal of the diversity panels is to maintain the adaptive traits that allow barley to grow well in the U.S. while maintaining genetic diversity. Both winter and spring varieties were tested in New York.

Naked barley is used in malting and distilling, so that aspect was considered. “Barley has been the ultimate grain for brewing and distilling,” said Kunze. “It has the right amount of carbohydrates and starches and also the right enzymes.” Naked barley also has potential for higher levels of malt extract, an important malting quality.

Kunze explained that winter barley requires a period of vernalization – cold temperatures before it can flower. Associated with this trait are genes that aid in some degree of winter tolerance. “In New York, compared to other grains such as wheat,” he said, “winter barley tends to be more sensitive than other cereal crops for winter survival.”

The northern range for winter barley is New York and Pennsylvania, where the crop is planted mid-September through October. If planted too early, potential issues include Hessian fly and early heading the following May. If planted too late, barley doesn’t have sufficient time to establish and has a greater chance of winter kill. Winter conditions in New England, with a combination of low temperatures and low snow cover, are too severe for a reliable winter barley crop.

For organic winter barley, the highest vigor occurs immediately after planting. “Depending on when the temperature is low, barley can be very well established by then,” said Kunze. “In New York, from November to April, barley is dormant. This is when we score for winter survival.” As temperatures rise in April, growth increases. Barley heads in late May to early June in New York, and is harvested in late June through early July.

Kunze said factors affecting winter survival include degree of establishment before freezing temperatures occur, severity of winter, snow cover and field defects. “Winter survival is a difficult trait to quantify accurately due to numerous environmental factors,” he said. “Survival pressure is variable, and we can only select for it every two to three years in New York when we have appropriate conditions.” Because numerous factors contribute to winter survival, it’s important to test various lines over a period of multiple years.

Spring barley is the predominant type grown in most regions of the U.S., including upper New England. Spring barley is planted in late March/early April for all regions. Tillering starts two to three weeks after planting, heading occurs in late June through early July and maturity and harvest is in late July.

Height and lodging are important traits for organic barley. Tall barley can be useful in managing weed competition, but if it’s too tall, chances of lodging increase. “Barley that’s too short is often less vigorous, and that’s a problem for organic conditions,” said Kunze. “Factors that contribute to lodging (falling over close to or at maturity) include height, weak stem length, over-fertilization and soil structure.”

Kunze looked at pre-harvest sprouting (PHS) – barley grain germinating in the field before it’s harvested. “It’s a particular problem in New York where rain events often occur during our harvest windows,” he said. “Selection for high germination has inadvertently resulted in making barley more susceptible.”

Yield is a critical factor for any agronomic crop, and Kunze found that depending on environment and location, yields of some naked barley lines in New York are comparable to traditional varieties. “One big factor is having well-managed organic land,” he said. “Cooler temperatures in April and May, when winter barley gets a head start, are ideal for development as barley is a cooler temperature cereal grain. Another interesting finding when we planted in organic conditions is that weed management for winter barley was minimal. One factor that may have helped is not much tilling in early months. However, yields are still lower, likely because conventional barley has been bred for conditions. Also, the lack of hull reduces yields by about 13% in naked barley compared to conventional.”

Spring barley yields aren’t especially high in New York, likely because germplasm is more adapted to Pacific Northwest conditions. Late-planted barley doesn’t endure high temperatures during development and weeds can be problematic.

If winter barley is planted early enough and winter isn’t too extreme, it performs well in organic conditions. Kunze reported that in three years of growing organic winter naked barley, weed pressure has been minimal. One of the negative aspects of organic winter barley is susceptibility to Fusarium head blight (FHB), so additional research will focus on resistance.

For spring barley in New York and areas with similar growing conditions, two of three years have been challenging with issues such as late planting dates, drought-like conditions during vegetative growth and poor organic land at some locations. Yields for those two years were low, required persistent weed management and barley diseases were a constant threat.

Barley is subject to several diseases including FHB, which produces deoxynivalenol (DON), a vomitoxin. Pesticides used in conventional barley production effectively reduce FHB at flowering but nothing is available for organic production. Smut is a seedborne fungus which can be managed with seed treatment, but organic solutions are limited. Rusts, especially leaf rust in the Northeast, can affect spring barley. Scald, a leaf fungus, is more prevalent in winter barley lines. Spot blotch is a fungus that overwinters in barley stubble and can also be seedborne.

Selection for resistance against various pathogens in both winter and spring organic barley will be key to managing disease. “We’re going to need much more breeding and evaluation to find lines that are more adapted to New York growing conditions,” said Kunze.

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