Location: Rangeland and Pasture Research2013 Annual Report
1a. Objectives (from AD-416):
The vision of this research is to increase the ecological and economic sustainability of forage-based livestock production systems associated with the Southern Plains mixed-grass prairie. Our strategy is to minimize environmental impacts and increase the efficiency of plant and animal resources while addressing the production and conservation goals of the Southern Plains mixed-grass prairie. Over the next five years, we will focus on these following objectives: Objective 1: Develop enhanced germplasm of eastern gamagrass, sand bluestem, little bluestem, and Texas bluegrass for improved forage yield, forage quality, seed yield, and stand persistence. Objective 1A: Breed eastern gamagrass cultivars with improved biomass yield and other performance traits. Objective 1B: Continue to develop a diallel population of sand bluestem from 15 diverse accessions. Objective 1C: Breed little bluestem cultivars with improved forage and seed production. Objective 1D: Breed and evaluate pure Texas bluegrass and interspecific hybrids with improved performance traits. Objective 2: Develop perennial sorghum-based, interspecific, and wide hybrids with high sugar content for livestock and biofuel production on the Southern Plains. Objective 3: Evaluate the potential for using patch-burning and supplementation strategies on rangelands to improve the productivity of stocker cattle and beef cows while enhancing other ecological services. Objective 4: Evaluate alternative grass, forb, and shrub establishment practices on degraded rangelands to restore livestock productivity and ecological services. Objective 5: Evaluate and improve native and introduced warm-season grasses for use in forage-based livestock production, and determine the environmental benefits of these grasses relative to other forages, and/or cropping options.
1b. Approach (from AD-416):
To identify germplasm with superior traits, expand the limits of germplasm variation by wide hybridization using interspecific and intergeneric introgression and genetic manipulation, evaluate and improve native and introduced warm-season grasses for use in forage-based livestock production, and then release superior germplasm and improved cultivars. Broad-based germplasm collections of eastern gamagrass, Texas bluegrass, little and sand bluestems are maintained at the Southern Plains Range Research Station in Woodward, OK. Further, a major resource problem is over-used rangeland, making it susceptible to erosion and weeds, also compromising other ecological services. The challenge is to develop economic, energy-efficient forage grazing systems for the Southern Plains while maintaining or improving ecological service to wildlife and society. This research will employ basic agronomic, animal performance, plant and animal physiology, genetics, cytogenetic, and molecular biology experiments.
3. Progress Report:
Progress was made on all four objectives, all of which fall under National Program 215, Pastures, Forages, and Rangelands. Objective 1 in our project is to develop enhanced germplasm of native grasses for improved forage yield, forage quality, seed yield, and stand persistence. In the first subobjective for eastern gamagrass, in July of 2013, open pollinated seeds were harvested for the first time from the isolated, diploid (syn-1 seed increase) population. These seeds will be included in future forage and seed yield trials. The experiment to test germplasm and available cultivars for their tolerance of grazing was planted in spring of 2012. However, grazing was delayed due to lack of full stand establishment as a result of drought. The missing plants were re-established in spring of 2013 and grazing is rescheduled to begin in 2014. In the second subobjective to develop a diallel population of sand bluestem, we have continued to make progress in completing the crosses. Once the crossing is complete, the seeds will be germinated and plants will be grown in a greenhouse until transplanted into field plots. In the fourth subobjective to improve little bluestem, we have completed cycle-2 selection for increased seed set. Selected plants are in the greenhouse and will be transplanted into field plots in the spring of 2014. In the fifth subobjective for Texas bluegrass, two new isolated pure Texas bluegrass seed increase nurseries were planted in spring of 2013. The first isolate nursery was "D-4" and the second isolate nursery was "Wide-Leaf". Also, seed-producing hybrids derived from “"exas X Kentucky" and "(Texas X Kentucky) X Kentucky" crosses produced in the greenhouse were identified and are undergoing further screening. Objective 2 in our project is to develop perennial, sorghum-based, interspecific and wide hybrids with high soluble sugar content. In the fall of 2012, we received two sorghum PIs (641849, 651495) which were used as pollen donors in a cross with a local Ravennagrass selection. Twenty-eight putative hybrid seeds germinated and were transplanted to the field. Field evaluation (phenotype) and DNA analysis are in progress to determine if any of the seedlings are true hybrids. Objective 3 in our project is to evaluate the potential for using patch-burning and supplementation to improve the productivity of cattle and enhance ecological services. The experimental plots have been established on the rangeland. But as a result of drought, this project has been delayed because of insufficient fuel on the site to carry a fire; hence, this experiment has been delayed until 2014. Objective 4 in our project is to evaluate alternative grass, forb, and shrub establishment practices on degraded rangelands to restore livestock productivity and ecological services. The experimental plots have been laid out, but we did not plant in 2013 because of drought conditions leading up to April 20 and the predicted drought conditions based on the Palmer drought index. Since this spring, the planting site has received rainfall and, if it continues, we will be able to plant this experiment in April 2014.
Gunter, S.A., Whitworth, W., Mongomery, G., Beck, P. 2012. Cool-season annual pastures with clovers to supplement wintering beef cows nursing calves. Journal of Animal Science and Biotechnology. 3:25.