Location: Rangeland and Pasture Research2008 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. Controlled crosses 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 being made in the greenhouse to develop a complete diallel. It will take about five years to complete this objective. Data is being collected from a population of 4,000 little bluestem plants. These data will be used to select 3 to 5 populations of little bluestem with improved forage and seed production. A study has been initiated to evaluate six management strategies to minimize the effects of the southern cornstalk borer on eastern gamagrass seed production. The treatments consist of single or dual application of two insecticides used to control stalk borers in corn fields. A manuscript on the life cycle of the southern cornstalk borer in eastern gamagrass has been prepared for journal submission. (NP 215, Components 1 and 2).
1. Identification of Texas X Kentucky Bluegrass Hybrids using ISSR Markers: Hybrids of Texas and Kentucky bluegrass can be created by controlled movement of pollen from stamens of Kentucky bluegrass flowers onto the stigmas of Texas bluegrass flowers. Hybrid plants are generally identified visually, on the basis of inherited morphological traits from both parents, after seeds are planted and grown in a greenhouse and subsequently transplanted into field plots. A scientist at the Southern Plains Range Research Station in Woodward, Oklahoma, tested and identified ISSR primers that would confirm Texas by Kentucky bluegrass hybrids from their DNA. Nine of the 17 primers tested consistently produced robust DNA fingerprints. Combined with a rapid DNA extraction protocol, the ISSR technique enabled a fast and practical way to detect hybrids early in the breeding program. (NP 215, Component 2)
2. Intermediate Wheatgrass Confirmed as a New Host Plant of the Wheat Stem Maggot in Oklahoma A scientist at the Southern Plains Range Research Station in Woodward, Oklahoma, observed damage consistent with that of the wheat stem maggot in a field plot of intermediate wheatgrass. Adult wheat stem maggot flies were reared from aborted reproductive culms of intermediate wheatgrass collected in Woodward County, Oklahoma. Percentage of aborted inflorescences, determined by randomly sampling ranged from 10 to 28%. Intermediate wheatgrass was confirmed as a new host record for this species of stem maggot in Oklahoma. (NP 215, Component 2)
5. Significant Activities that Support Special Target Populations