Location: Rangeland and Pasture Research2010 Annual Report
1a. Objectives (from AD-416)
The objectives of the proposed research are: 1) to breed eastern gamagrass [Tripsacum dactyloides (L.) L.] cultivars improved for biomass yield and other performance traits, 2) to breed and evaluate Texas bluegrass (Poa arachnifera Torr.) cultivars and interspecific hybrid cultivars (P. arachnifera x Poa species) improved for selected performance traits, 3) to develop a diallel population of sand bluestem (Andropogon hallii Hack.) from 15 diverse accessions and to evaluate sand bluestem germplasm lines with improved establishment capabilities, 4) to breed little bluestem [Schizachyrium scoparium (Michx.) Nash] cultivars with improved forage and seed production, and 5) to determine the life history of the southern cornstalk borer (Diatraea crambidoides Grote) in eastern gamagrass. To meet objective 1 we will use conventional methods to breed eastern gamagrass with improved vigor, seed production and persistence in the Southern Plains region. In objective 2, conventional methods will be used to breed Texas bluegrass cultivars and interspecific hybrid cultivars for improved vigor, rust-resistance, and persistence. In addition low-input turf cultivars will be developed. In objective 3, an attempt will be made to create a diallel population of seeds from 15 sand bluestem lines collected from the Southern Plains. Also, an evaluation will be made of sand bluestem germplasm lines selected for improved seedling establishment. In objective 4, we will use phenotypic mass selection to improve little bluestem for forage and seed production traits. Three to five diverse populations will be created on the basis of visual ratings for plant color, growth, disease incidence, leafiness, plant height at anthesis, and on determination of percentage seed set. For objective 5, the life cycle of the southern cornstalk borer will be examined in eastern gamagrass. Understanding the life cycle of this insect is a key to developing management strategies to avoid peak damage of this insect.
1b. Approach (from AD-416)
The overall approach is to identify germplasm with desirable traits, to expand the limits of germplasm variation by wide hybridization utilizing interspecific and intergeneric introgression and genetic manipulation, to evaluate and select superior genotypes, and then release superior germplasm and improved cultivars. A broad-base germplasm collection of eastern gamagrass is maintained at the Southern Plains Range Research Station at Woodward, OK. Facilities include 10,000 sq. feet of glass house space, a cytological-molecular laboratory equipped with light and fluorescent microscopes, karyotyping work station, RAPD-PCR accessories, sterile laminar flow hood, four growth chambers, -80 C freezer, and ample acreage for field trials and nurseries. This research will involve basic agronomic, physiology, genetics, cytogenetics and molecular biology studies.
3. Progress Report
Considerable progress has been made for the ongoing breeding and evaluation projects for eastern gamagrass and Texas bluegrass (Objectives 1 and 2). Controlled crosses of plant materials have been made in the greenhouses, seeds from hybrid lines have been germinated and transplanted into field plots, and breeding lines have been evaluated under field conditions. Controlled crosses of 15 sand bluestem germplasm lines are continuing to be made in the greenhouse to develop a complete diallel mating system, whereby all parents are crossed to make hybrids in all possible combinations (Objective 3). Plant material for Cycle 2 selections of seven little bluestem populations were planted into field plots and will be evaluated during their next growing season (Objective 4). A study continues to evaluate six management strategies to minimize the effects of the Southern Cornstalk Borer on eastern gamagrass seed production (Objective 5). The treatments consist of single or dual application of two insecticides used to control stalk borers in corn fields.