Researcher tries to get to heart of cotton seed
At the New Castle County Farm Bureau dinner in Townsend, Del., Oct. 10, Dr. Lori Unruh Snyder briefly described her unprecedented work examining damage in cotton seeds. She had driven eight hours from Raleigh, North Carolina, to attend the dinner with her mother, June Unruh of Townsend. Dr. Unruh Snyder is an associate professor in the Crop and Soil Science Department with her research focus as a Seed Physiologist at North Carolina State University.
In a telephone interview a few days later, Unruh Snyder described how she had come to examine cotton seeds so closely in research that is currently funded by Cotton Incorporated, a non-profit organization in Cary, N.C., which represents all cotton farmers in the United States. She is working closely with Dr. Gaylon Morgan there.
When farmers experienced a really bad year of cotton germination in 2019, it led to the entire Cotton Belt of 15 states looking at seed from a quality perspective.
The farmers took their concerns to Cotton Incorporated, which brought together Extension professors from across the Cotton Belt. Two of Unruh Snyder’s colleagues, Drs. Guy Collins and Keith Edmisten, N.C. State Extension cotton specialists, suggested that she be brought in to see what perspectives she could provide utilizing her seed lab at N.C. State. She was asked to create a system of identifying damaged seeds from a bag of cotton, a method that could be replicated and validated.
Unruh Snyder accepted the challenge, starting with a literature review to see who had identified mechanically damaged seeds or done testing to develop categories of damage.
Cotton seed goes through many mechanical processes as the seed is separated from the lint, she said. The cotton plant and the seeds it produces are subjected to biotic and abiotic stress during the crop cycle. These stresses can impact the quality of lint and seed that the plant produces. Following harvest, there is a ginning process in which sawmill blades remove lint before a final acid wash removes even more. The seed then goes through quality control, sorting, and packaging.
“I found articles from 1955 and ’65. That’s where it stopped,” Unruh Snyder said.
She started with three categories: very damaged, damaged, and pinhole, the latter caused potentially by boll weevils or other insects with piercing-sucking mouthparts.
The research required locating specifically where on the seed the damage occurred. She evaluated each seed through standard germination tests, noting the pattern of damage and severity.
Unruh Snyder and her graduate student, Marisa Crisp, who started as a freshman in her lab and now is working on her Master’s thesis directly related to this issue, conducted several thousand warm germination tests in which seeds were germinated under ideal conditions in growth chambers. “Any seed that germinates and is normal according to the AOSA seed testing standards has to have cotyledons that are at least 50% intact and healthy, and the hypocotyl to radical must be greater than 4 centimeters to be counted as germinated,” she said.
Putting together the cracks and damage levels, she saw an interesting pattern. By the time she had looked at all the varieties farmers choose in the United States, her research team saw the potential differences in varieties and locations (on the seed) of damage.
“I came up with a formula that includes germination. It helps give a percentage of survival based on damage location and severity, a potential way to predict what will happen to that variety in the field,” she said.
Having someone patient enough to look at each individual seed — thousands of seeds — is really unheard of, Unruh Snyder said. “It requires dedication to the details. There is no rapid way. I was so thankful for the team of undergraduate students, Mika’el Chabeda, Reagan Dunn, and Becca Karriker, who saw the vision of how we can make a difference and help the farmers this way.”
“It was painstakingly slow, but details matter. How else can you get to a new result?” she asked.
“My seed team photographed every seed we germinated,” she said. They cataloged the seed image, seedling image, vigor, and germination rate. Unruh Snyder then presented this information at the Plains Cotton Growers Association last November in Lubbock, Texas, where all cotton seed companies in the United States sat at the same table for the first time to talk about how we can work together on seed quality issues.
It was not enough for Unruh Snyder to be able to know the percentage of damaged seed in a bag. As the daughter of farmers, she wanted to try the best she could to examine seed damage from the farmer’s perspective. “If I were a farmer, what would this mean to me if I bought a bag of seed?” She wanted to move forward, to prove a hypothesis, to discover does damage matter and affect yield.
“Obviously, every seed company wants to give the best quality to farmers. I believe in that,” she said.
So this year, she has taken the research one step further, taking it to the field to see what happens to performance there. Last September, she planted seeds of each damage type in the field, and data was presented at the North Carolina Cotton field day in 2021 to show seedling emergence performance. “My prediction of what would come up was exactly right,” she said. “I validated myself in the field. Even if very damaged, despite the location (on the seed), there was a 30% chance the seedling would survive and produce a crop.”
She said, “My observation at this point: there is a potential impact to yield with those damage types and locations of where they are on the seed.”
Further testing is planned in three locations with a single variety to see if locale affects results.
Unruh Snyder’s team is working on proving the significance of seed damage location into different levels of severity of damage, including the normal most common cracks and pokes in the seed, and so forth.
She has also noted a potential difference in internode spacing on the stem of the cotton plants. This month she planned to collect plants in each category to validate the chance of morphology or phenology changes that may impact yield.
Unruh Snyder wants to take her research even farther into regenerative agriculture.
“What if we supplied seeds with the appropriate amino acid, like a vitamin, to give them a boost to benefit even more with the current agronomic planting recommendations during the times of abiotic and biotic stress?” she asked. Her other Master’s student, Matthew Starr, is working with farmers in Halifax County, N.C., to do field studies directly with cotton farmers, who have decided to see how the biostimulants aid their cotton yields. They plan to continue the study in the 2023 planting season. In a test in North Carolina during a severe drought, plants with a biostimulant survived because the biostimulant activates roots and helps the plant utilize the nutrients in the field, she explained.
“I am excited to see what Mathew’s research can do,” she said.
Unruh Snyder said she is working with the Cotton Beltwide Seed Quality Project, which includes working extensively with Dr. Murilo Maeda at Texas A&M AgriLife Extension in Lubbock, Texas.
What started as a single-research project in 2019 has now been conducted in 15 states. Unruh Snyder has also met with Australian cotton seed breeders and producers this past September, who already include the percentage of seed damage on the seed tag. She and the team would like to work towards having similar information available to growers in the United States.