The Challenge of Breeding New Crop Varieties in Louisiana

Richard Bogren  |  5/27/2019 2:35:03 PM

Rick Bogren

Louisiana’s subtropical environment poses challenges for the state’s agriculture industry. The state’s farmers grow sugarcane, which is pushing the northern edge of its subtropical range, along with rice and sweet potatoes, which are grown in only a few states. And other crops — the cereal grains wheat and oats — have particular challenges not found in northern areas where they’re grown extensively.

No commercial companies have made the investments necessary to breed and develop new varieties for these crops. For many years, the LSU AgCenter has developed and maintained research and development programs to meet the challenges of these “niche” crops and support farmers and processors who make their livelihoods from them.

Sugarcane

Sugar research at LSU began in 1887, when the federal Hatch Act established agricultural experiment stations in each land-grant college and university and LSU acquired the Louisiana Sugar Experiment Station that was started by the Louisiana Sugar Planters Association in 1885. Since then, the AgCenter has developed new, improved sugarcane varieties in association with the U.S. Department of Agriculture and Louisiana sugarcane producers and raw sugar processors.

Sugar development is the search for new plant varieties, says AgCenter sugarcane specialist Kenneth Gravois, who holds the Denver T. Loupe/American Society of Sugar Cane Technologists Sugar Heritage Professorship. “We want to create yield, biomass and sucrose content, then protect the yield from pests, insects and diseases through genetics or interventions of chemicals or cultural practices to create the most biomass and the highest sucrose content that we can fit in an acre,” he says.

Over the past 50 years, sugar researchers have doubled sugar yield per acre, mostly through incremental steps. Varieties have life spans — new varieties are sometimes better, but disease and insect complexes tend to adapt to new varieties, and something that wasn’t apparent before becomes a problem with a new variety. This phenomenon is often referred to as yield decline. To meet the challenge, researchers develop new crosses and plant new seedling crops every year to identify and propagate new varieties.

The sugar research program uses “recurrent selection”— old parents are used in in new combinations, and new parents with better genetic contributions are added. About 5% of the parents come from outside sources, other programs with a similar climate, such as Argentina, South Africa and Florida. “Managing parents is most important,” Gravois says. “The right cross leads to improvements.”

Each year the AgCenter program plants 90,000 seedlings from 200 crosses. Progeny from each cross are called a family, which shares the same genetic base but in different combinations. It takes breeders 12 years from initial seedling to a variety that’s good enough to be a commercial crop.

Rice

Widespread commercial rice farming in Louisiana began in the late 19th century. Louisiana farmers soon adopted wheat-growing practices and equipment from the Midwest, and farmers from there relocated to Louisiana to grow rice.The U.S. Department of Agriculture established the Louisiana Rice Experiment Station in spring 1909 to develop new varieties adapted for the Gulf Coast and soon phased out its role at the station that is now the LSU AgCenter H. Rouse Caffey Rice Research Station.

In 1949, the station established the Foundation Seed Program to ensure a pure source of seed for rice farmers. Since then, the program has sold more than 170,000 hundredweight of seed.

In 1972, Louisiana rice producers formed the Louisiana Rice Research Board and agreed to pay 5 cents of every 100 pounds of their rice crop sold to fund research. The resulting higher yields, however, were not just the result of new varieties. Work on production practices at the station also helped increase yields.

In the late 1990s, AgCenter researchers developed Clearfield varieties from a natural mutation. The lines are resistant to Clearfield herbicide, which allows growers to use the chemical to control red rice, a weed similar to commercial rice. Clearfield technology allowed farmers to drill seed rice into dry soil instead of water seeding from the air. Clearfield acreage exceeded 65 percent of rice grown in the South in some years. In total, a century of rice breeding at the station has resulted in more than 50 varieties.

Research at the station has changed dramatically through improvements in technology and knowledge. DNA markers used to determine if lines have desired characteristics have decreased the time required to develop a new variety, and the use of a winter nursery in Puerto Rico also enables new varieties to be available sooner.

Today, rice breeder Adam Famoso, the H. Rouse Caffey Endowed Professor of Biological and Agricultural Engineering, mostly concentrates on U.S. southern long-grain and medium-grain rice. A small percentage of his time also involves specialty rice, such as aromatic rice, as well as a long-grain rice that is less sticky for Latin American markets.

“The primary focus is on yield and quality,” Famoso says. He also considers other traits, such as disease resistance and production characteristics “because of their impacts on yield and quality.”

Although rice varieties, which are pure lines, are the primary source of seed for growers, researchers are also working to develop hybrids, which offer higher grain yields. Jim Oard, who holds the American Cyanamid Professorship for Excellence in Plant Biotechnology, Molecular Biology, and Crop Pest Management, leads the AgCenter hybrid rice effort.

Oard makes hundreds of crosses for the hybrid program each year. Last year he identified several new candidate hybrids for advancement that were comparable with top commercial varieties and hybrids grown in Louisiana.

Yield is the No. 1 criterion in rice research, and grain and milling quality and cooking quality are also high on consideration. Other parameters include grain size and shape and appearance, particularly for “chalk,” an undesirable opaque characteristic disliked in the high-quality market. A genetic marker for chalk under development could be used in both hybrid and conventional breeding programs. Researchers also look for early maturity to allow farmers to get their crop harvested before the peak of hurricane season and for shorter height with good straw strength to prevent rice from falling over, or lodging, in high winds.

Sweet Potatoes

Sweet potatoes are the fourth largest crop in the world; 90 percent is grown in China, where they raise sweet potatoes to feed livestock, primarily hogs. Because no commercial companies develop new sweet potato varieties in the United States, university programs are the source of new varieties — not just germplasm but finished products. Like sugarcane, sweet potatoes are clonally propagated and grown commercially from cuttings rather than seeds.

The LSU AgCenter sweet potato breeding and development program is under the direction of Don R. La Bonte, Lucien and Peggy Laborde Professor and director of the School of Plant, Environmental and Soil Sciences.

LSU began the first program in the U.S. to develop sweet potato varieties under the direction of J.C. Miller in the 1920s. Much of the early work was simply collecting plants from all over the world and growing flowers to cross. Over the years, LSU maintained the development program while others were dropping out. Today, the LSU AgCenter, the USDA U.S. Vegetable Laboratory and North Carolina State University are the only sweet potato breeding programs still around.

The North Carolina program primarily serves that state while the AgCenter develops new varieties not only for Louisiana but for other parts of the country. Louisiana growers contribute checkoff funds to support the research program, and growers from other states pay royalties for using Louisiana varieties. AgCenter plant breeder Larry Ralston developed the Beauregard variety that was released in 1987, and it has enjoyed market leadership for more than 30 years. A newer variety, Orleans, has been eating away at Beauregard’s dominance.

To create new varieties, breeders plant nurseries with elite parent plants. Sweet potato plants are bred by open pollination, so bees and other pollinators move among the various vines, distributing pollen to each plant. Breeders grow nursery plants on fences to induce flowering and make seed harvest easy. Seeds mature in late fall when days are short and nights are cool.

The AgCenter has seven nurseries with 15 to 30 parents in each. The nurseries are kept far enough apart so pollinators don’t carry pollen from one nursery to another. AgCenter breeders plant about 35,000 seeds in greenhouses each year and look for the characteristics they believe will lead to a new and improved variety. They produce “baby roots” about the size of a radish. If a plant looks good and the root looks good, the tops are snipped and planted for evaluation.

Breeders seek to identify commercial potential early. They look for shape and yield followed by such things as disease resistance and sprouting ability. The fresh market is the primary market for Louisiana sweet potato growers, so breeders are looking for roots that appeal to shoppers. Generally, developing a new variety takes about seven years.

One line from 2016, however, may be ready in five years because it shows such good potential.

Sweet potato growers don’t plant seeds but rather “slips,” or sprouts, that are snipped off of seed potatoes and then planted to produce a crop. Although growers retain a portion of the previous year’s harvest for seed potatoes, over time succeeding generations accumulate viruses, and disease develops in the seed stock. Mutations may also occur. So farmers regularly purchase clean seed from the AgCenter research station to replenish their stock. Most add some fresh seed each year rather than clean it all out at once.

In addition to sweet potatoes, the experiment station conducted potato breeding in the middle of the 20th century. One of the most nationally popular varieties, Red LaSoda, released in 1953, originated from this program. Red LaSoda was a red-skinned version of LaSoda, also developed by Louisiana scientists and is still widely planted today.

Cereal Grains

The AgCenter small grains breeding program in started in 1984 under the direction of Steve Harrison, who holds the Walker T. Nolin Professorship in the School of Plant, Environmental and Soil Sciences. Since then, the program has developed and released several oat and wheat varieties, which have all been exclusively licensed to various seed companies for distribution to growers. The program gets funding from federal grants, the Louisiana Soybean and Grain Research and Promotion Board and royalties from varieties that have come out of the program.

Wheat is important in Louisiana because it provides farmers cash flow in spring and early summer. It also contributes to conservation tillage and provides a winter cover crop. But because Louisiana wheat faces high disease pressures because of climate, researchers develop wheat varieties resistant to diseases Louisiana farmers encounter.

A wheat variety goes through eight to 10 years of research and development, followed by about two years of seed increase, before it reaches a grower’s field. During the final stages of seed purification, the breeding line is licensed as a variety to a commercial entity that has the infrastructure capable of producing, processing and distributing seed to growers. The primary concern when awarding a variety license is ensuring that the variety is produced and made available in a manner that serves growers, Harrison says. Also important is the economic return to the AgCenter to support continued research and variety development.

Like rice and sugarcane, wheat growers largely depend on university breeding programs, Harrison says. AgriPro/Coker is the only private wheat breeding program left in the South. Most growers grow wheat that came from a university breeding program even though that variety may be named and marketed by a seed company.

No commercial oat breeding programs exist in the United States. All oats in the Gulf Coast – for pastures, horses, deer plots – are from LSU AgCenter or University of Florida breeding programs, which work together, exchanging germplasm, testing and increasing lines for each other and sharing a summer nursery in Idaho. “It’s almost one program because we cooperate so closely,” Harrison says. “It’s a truly shared, two-university oat breeding program.”

To help continue the supply of new small-grain varieties, several universities established a regional cooperative in 2005. Called Sungrains, the cooperative’s mission is to more efficiently develop wheat, oat, rye and barley varieties for growers and seed producers across the region. The AgCenter small-grain program took the lead role in developing the Sungrains agreement, which currently includes the small-grain breeding programs of the LSU AgCenter, the University of Florida, the University of Georgia, North Carolina State University, the University of Arkansas and Texas A&M AgriLife.

Rick Bogren is a professor in LSU AgCenter Communications and associate editor of Louisiana Agriculture. (This article appears in the spring 2019 issue of Louisiana Agriculture.)

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An aerial view of test plots at the H. Rouse Caffey Rice Research Station. Photo by Bruce Schultz

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Eric Webster, LSU AgCenter weed scientist, talks about weed control among rice test plots during a field day at the H. Rouse Caffey Rice Research Station. Photo by Bruce Schultz

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Rick Zaunbrecher, research associate at the H. Rouse Caffey Rice Research Station, working in a rice field at the station. Photo by Bruce Schultz

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