Current Research Projects
Allen D. Knapp
Our research program seeks improve plant performance with fewer off-farm inputs. The hypothesis is that reducing the susceptibility of crop plants to stress without reducing yield would stabilize agricultural production and reduce the risk of crop failure for producers. We are also involved in studies on seed dormancy in eastern gamagrass (Tripsacum dactyloides L.).
We are investigating germination and early seedling development of several maize inbred lines. Currently, these inbreds include corn-belt dents such as B73, MO17, A632 and A619. These inbreds were chosen because of their putative differential susceptibility to low temperature stress. The corn-belt dents inbreds are being compared to inbreds developed by Agriculture Canada and New Zealand via selection for improved tolerance to low temperature stress. At this point we are hoping to improve our knowledge about the possible relationships between adaptation to stress and seed/seedling vigor and gain insight regarding the potential physiological mechanisms of adaptation and acclimation in maize. We have recently received a series of inbred lines developed by the highlands maize program at CIMMYT which we hope will provide some idea of the range of low temperature adaptational mechanisms in maize.
Our soybean research is sponsored by a grant from the Iowa Soybean Promotion Board. The focus of this grant is to study, in the laboratory and in the field, the factors limiting soybean emergence with early planting in no-till environments. Soybean seedlots of various vigor levels will be characterized via classical seed quality tests as well as new techniques. We are studying the changes in free polyamine levels to determine if differences in the levels of these compounds are indicative of the potential field performance of a seed lot. We are also obtaining further information regarding the passive trapping system for volatile aldehyde assays developed at Ohio State University. Additionally, Dr. Raymond Arritt, a mesoscale climatologist, is studying the field environments, and Dr. X.B. Yang a plant pathologist is investigating the role of pathogens in the emergence of soybean seedlings. We hope that the data generated from these efforts can be used to develop better seedling emergence predictive schemes and, in the long run, be used to develop emergence parameters relative to given field stresses.
Eastern Gamagrass Seed Dormancy
Eastern gamagrass (Tripsacum dactyloides) is a native warm-season perennial grass with excellent production potential. Interest in eastern gamagrass has increased in the late 1980's and early 1990's. Its potential uses include;
- forage production - Eastern gamagrass is a native, perennial, tall, warm-season bunch grass with high nutrition and palatability. These reasons, along with its ability to produce large quantities of high quality forage during the summer months, form the primary basis for increased interests in this species over the past 10-15 years.
- biomass production - dry matter yields, depending on site, management, have ranged from approximately 3 to 10 tons of dry matter per acre.
- environmental uses (wildlife habitat, reclamation, wetland plantings, forage production on marginal and slopping cropland) -Eastern gamagrass, while most productive in fertile lowlands, is adapted to a wide range of soil types and production environments. This would seem to make this species suitable for a wide array of environmentally friendly uses while providing the option of agronomic return from acres so reclaimed.
The major problem with eastern gamagrass lies in its establishment. As is common with warm-season grasses, eastern gamagrass seed is often dormant. Thus, seedling establishment is a difficult task. Two methods of establishment are often proposed, dormant fall planting or spring planting with prechilled seed. Successful establishment from fall plantings depends on the winter conditions experienced and are therefore highly variable. The use of prechilled seed has met with success however this can result in difficulties in handling the seed and in managing inventories. Therefore, if Eastern gamagrass is to reach it potential in Iowa, the seed dormancy must be studied such that establishment of this species is less costly and more uniformly successful.