USDA Economic Research Service release:

The five primary feed grain crops grown in the United States are barley, corn, oats, sorghum, and soybeans. In the Southern Great Plains, a substantial amount of sorghum production is used as an alternative crop to corn for livestock feed because of its similar nutrition content and its reputation of being better able to withstand hot and arid weather conditions. Researchers at USDA, Economic Research Service and Kansas State University matched historic farm-level data drawn from the Kansas Farm Management Association to growing season weather data to estimate the effects of temperature on sorghum yields.

 

The researchers estimated a statistical model that linked yields to low (0–10 degrees centigrade (⁰C)), moderate (10–33 ⁰C), and severe heat (+33 ⁰C) levels and precipitation, and found that sorghum is highly sensitive to temperatures beyond 33 ⁰C. They then simulated different warming scenarios by increasing historic temperatures by 1–5 ⁰C increments and recalculating yields using the previously estimated effects. Under the most moderate warming scenario (+1 ⁰C), average sorghum yields decline by 11 percent; under the most severe warming scenario (+5 ⁰C), average sorghum yields decline by 67 percent. When accounting for different precipitation outcomes, researchers found that when warming is accompanied by lower-than-average precipitation, yield losses do not substantially increase. Yield loss is partially abated when warming is accompanied by higher-than-average precipitation. These two findings suggest that severe heat drives yield loss in sorghum rather than drought, and heat-induced yield losses can be partially offset by irrigation. Notably, these results hold even when additional weather, such as vapor pressure deficit, and economic variables, such as input/output price ratios, were included in the model.

 

Shifting planting and harvesting dates have the potential to mitigate the effects of rising temperatures brought on by climate change. To test this, the researchers simulated adjustments to sorghum’s growing season and found that earlier planting and harvesting dates diminish yield loss but only marginally: Under +2 ⁰C warming and an unaltered growing season, acreage-weighted average yield losses are estimated at 24 percent; under +2 ⁰C warming and a shifted growing season, acreage-weighted average yield losses are estimated at 22 percent. The researchers considered additional alterations of the growing season, including shortening and extending the growing season, but found that no alteration of the growing season provided substantial reductions in yield losses. The results of this research indicate that sorghum, like other row crops, will face major yield losses under projected warming, and that these losses cannot be easily offset by farmers’ adjustment of planting and harvesting dates.

Texas AgfriLife release:

 

Protecting seed health is essential for reducing plant disease threats that can endanger the food and fiber system on a global scale.

The World Seed Federation reports that global seed exports netted $14.4 billion in 2019 and imports, $13.8 billion. Seeds contaminated at their origin or during transport can introduce invasive pathogens or pests, disrupt production, increase supply chain issues and cause devastating international economic impacts.

Texas A&M AgriLife offers state-of-the-art diagnostic services, research and educational outreach to protect from plant health risks associated with transporting seeds.

 

Providing premier diagnostic laboratories

 

Two nationally acclaimed laboratories provide accurate and timely plant diagnostic services for Texas A&M AgriLife personnel, farmers, the agriculture and green industries, and Texas residents. The Texas Plant Disease Diagnostic Laboratory in College Station and the Texas High Plains Plant Disease Diagnostic Laboratory in Amarillo are part of the National Plant Diagnostic Network and managed by the Texas A&M University Department of Plant Pathology and Microbiology.

 

The College Station facility handles about 3,000 samples and processes more than 5,000 disease-monitoring survey samples each year.

 

The diagnostic laboratory in Amarillo at the Texas A&M AgriLife Research and Extension Center specializes in disease diagnostics of small grains and row crops such as wheat, corn, sorghum and cotton. In addition, following the legalization of hemp production in Texas, the laboratory offers hemp plant disease diagnostic services.

 

“Seed safety is a phytosanitary, or plant health, issue,” said Kevin Ong, Ph.D., AgriLife Extension plant pathologist and director of the College Station laboratory. “Because some plant disease pathogens can be transmitted in seeds, phytosanitary rules and requirements regulate moving or importing certain types of seeds in agriculture.”

 

Both laboratories help the U.S. Department of Agriculture – Animal and Plant Health Inspection Service, USDA-APHIS, the Texas Department of Agriculture, TDA, and seed industries by providing seed health testing services to address pathogens of high consequence, Ong said.

 

“Reliable testing is crucial,” said Ken Obasa, Ph.D., AgriLife Extension plant pathologist and leader of the Amarillo laboratory. “It ensures a healthy seed supply, prevents or controls the spread of disease, and increases crop yield, profitability and trade.”

 

One example of how the laboratories help support seed health is testing for the tomato brown rugose fruit virus, ToBRFV, in pepper and tomato seeds. To prevent the introduction of ToBRFV into the U.S., a federal order regulates the transport of tomatoes and peppers, and tomato and pepper seeds must be tested for the virus.

The Texas Plant Disease Diagnostic Laboratory Applied Research Unit, in collaboration with seed health industry partners, helped validate a detection test for this pathogen. The test was approved by the National Seed Health System. The laboratory also offers ToBRFV seed testing services to the seed health testing industry.

 

Making research-based information available to growers and the seed industry

In addition to testing seeds for pathogens, another important way to protect seed health is by communicating timely information to growers.

For example, in 2017, fusarium wilt of cotton race 4, FOV4, was confirmed in cotton fields in El Paso and Hudspeth counties. The seedborne fungal disease creates substantial yield loss by causing large areas of seedlings in a field to die. Older plants develop wilt and root rot. The disease can also spread to other cotton fields if contaminated soil is transferred by farm equipment.

 

Texas A&M AgriLife plant pathologists studied the biology of the pathogen and began field trials, identifying where the problem was and the resistance of different cotton varieties to FOV4. Their recommendations will help breeders develop new varieties.

 

Plant pathologists also developed methods and best management practices that cotton growers can use to prevent and mitigate the disease.

 

“On a statewide basis, Texas A&M AgriLife plant pathologists are educating cotton growers and the seed industry about the risk of this disease and the need to ensure that they are not planting seed produced in areas where this disease occurs,” said Thomas Isakeit, Ph.D., AgriLife Extension plant pathologist in the Department of Plant Pathology and Microbiology.

 

The situation is ongoing and being monitored to confirm that FOV4 is not spreading beyond the El Paso-Hudspeth counties area, Isakeit said. 

 

Informing Texans to safeguard Texas agriculture

 

Growers can do a great deal to contain the spread of plant pathogens, but the public must also be made aware of seed-related risks.

 

In summer 2020, thousands of people across the U.S. received packages of unidentified seeds in the mail. Assisting the outreach efforts of USDA-APHIS and TDA, Texas A&M AgriLife responded quickly to educate Texans of the serious threat the seeds could have on the state’s agriculture and environment.

 

News stories and media advisories explained why recipients should not open the packages, plant the seeds or even throw away the packages — the unrequested seeds from an unknown source could introduce pathogens or invasive weeds. The educational outreach also included instructions for reporting receipt of the seeds to USDA-APHIS.

 

Offering readily available resources

 

Disease pathogens can quietly and quickly move to new locations in contaminated seeds. Ong said the best preventive measure is to buy seeds from a reputable source or dealer, and if problems develop, local AgriLife Extension county offices and Texas A&M AgriLife diagnostic laboratories can help with disease diagnosis and testing.

 

For assistance with plant health issues, contact:

American Society of Agronomy release

 

After decades of being relegated and regulated, research on industrial hemp as a valuable crop is far behind. That’s because the United States banned the use of hemp in the 1930s. The result was all research about this crop stopped, too. Now that the Farm Bill allows for the growing and use of industrial hemp, researchers have a decades-long gap in knowledge.

 

At the forefront of those trying to enter back into the hemp market - seed companies and potential growers – is seed quality after harvest.

 

This is where Sabry Elias, professor of crop and soil science at Oregon State University, and his team come in. Elias recently presented his work at the 2021 ASA-CSSA-SSSA annual meeting, held in Salt Lake City.

 

“One of the challenges in growing industrial hemp is that the plants have an indeterminate flowering pattern,” Elias explains. “This results in seeds with different maturity levels and ages on the same plant at the time of harvest.”

 

This poses a series of questions that Elias and his team investigate. What is the difference in quality between a seed higher on the plant versus one lower on the plant? How can they test for these quality differences? After harvest, do seeds go dormant? If they do go dormant, for how long and how can dormancy be broken?

 

There are two fundamentals that impact seed quality that the researchers investigated: viability and vigor. Viability is the capability of seeds to germinate and produce normal seedlings. Vigor is the ability of seeds to germinate and grow under a wide range of field conditions. Elias explains that these qualities are controlled by genetic and environmental factors.

“Improved varieties possess good traits such as high yield, seed quality, and disease resistance,” he says. “Seeds that develop and mature under optimum conditions resulted in quality seeds. On the other hand, seeds developed under moisture stress, nutrient deficiency, extreme temperatures, etc. often result in light, shriveled seed or collectively called poor quality seeds.”  

 

The researchers performed four different tests on two varieties of hemp seeds. Two measured seed viability by trying to tell the difference between live and dead seeds. Two others measured seed vigor by looking at how fast they germinated and how well they grew under stress conditions.

 

“Two seed lots can have the same viability percentage (e.g., 85%), but one of them can be more vigorous than the other,” Elias explains. “It is like both a 90-year-old and 25-year-old are alive, but the person who is 25 is (usually) healthier than the one who is 90 years old.” 

 

One viability test used biochemical reactions and subsequent color changes of seeds to measure if a seed is viable. The other measured the capacity of seeds to germinate and produce normal seedlings. One of the vigor tests germinated the seeds to test how quickly they do so. The second placed the seeds in high-stress conditions and then germinated them.

 

Their findings showed that all four of these tests were useful in measuring the quality of hemp seeds. The team’s experiments also showed that harvesting the seeds lower on the hemp plant seven to eight days later than those higher on the plant improved the overall quality of the seeds.

 

“This makes the whole plant, upper and lower parts, available for harvest,” Elias says. “It increases the yield by one-third because the current practice of some hemp farming systems is to harvest only the upper two-thirds of the plants to avoid the underdeveloped seeds from the lower part.”

 

Lastly, the scientists looked at the dormancy of the seeds. Elias explains that dormant seeds are viable seeds but will not germinate even under favorable conditions, until dormancy is broken. Seeds are most dormant right after harvesting.

 

Dormancy slowly disappears over time or with treatments such as pre-chilling, dry heat, or hormonal treatments. Their research showed that a pre-chilling treatment at 10 degrees Celsius for five days was able to break dormancy.

 

“I believe that hemp has great potential as a cash crop for growers in the United States and around the world because of its multiple uses in food, pharmaceuticals, and industrial products,” Elias says. “In addition, I have passion for the areas of seed physiology, quality, and dormancy, particularly because research in hemp had been put off for decades.”