Seed quality and the possible contributions to seedling disease and yield potential has been investigated by numerous researchers. Tom Kerby, vice president of technical services for Delta and Pine Land Co., has compiled a review of the previous studies while the company adds to the body of work with a new study conducted in 2004.
A paper summarizing the results of that latest study and the thorough literature review was presented at the Cotton Disease Council's meeting during the recent Beltwide Cotton Conferences.
“There has been a long-standing belief that there is a connection between seed quality and yield potential,” Kerby says. “As the value of seed increased, the implications of this assumption have become more important.
“Growers want to know what impact initial seed quality has on seedling disease and yield potential.”
Kerby points to the use of a vigor index in determining the emergence potential for seed.
He says a number of researchers have demonstrated a relationship between vigor index (the sum of the four-day warm germination test and the seven-day cool test germination percentage) and the percentage of seeds that emerge under adverse to average field conditions.
“Low-quality planting seed has been shown to require more DD-60s to emerge under adverse conditions than high-quality seed,” Kerby says.
“High-quality seed may still be exposed to pathogens during emergence, but the exposure time may be decreased compared to poor quality seed.
“Several studies, where detailed development data were taken, indicated growth, development and yield were not affected by seed quality. However, plant stand was affected except under ideal planting conditions,” he adds.
D&PL conducted both field and laboratory trials measuring emergence in the field and seedling dry weight in the lab. Emerged seedlings were randomly selected in the field to reach dry weight readings.
“In our trials, we found that the vigor index was an indicator of emergence and was reflected in dry weight measurements taken in the field and lab. The data indicate that once an adequate stand was realized, there was no impact on yield,” Kerby said.