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ARS Home » Southeast Area » Florence, South Carolina » Coastal Plain Soil, Water and Plant Conservation Research » Research » Publications at this Location » Publication #397055

Research Project: Effective Cotton Genetics and Management Practices for Improved Cotton Quality and Production

Location: Coastal Plain Soil, Water and Plant Conservation Research

Title: Improving heat tolerance of cool-season forage grasses with HTP recurrent phenotypic selection

item Billman, Eric
item MORRISON, JESSE - Mississippi State University
item BALDWIN, BRIAN - Mississippi State University

Submitted to: Grassland International Congress
Publication Type: Abstract Only
Publication Acceptance Date: 10/5/2022
Publication Date: N/A
Citation: N/A

Interpretive Summary: Abstract only

Technical Abstract: Cool-season forage production is severely limited by adverse environmental stress conditions worldwide. In areas prone to heat stress conditions, i.e., > 180 days of daily highs exceeding 30°C, annual cool-season forage grasses must either be planted in late fall or early spring to avoid heat stress, while perennial cool-season grasses often do not survive intense summer heat from June – August. Breeding cool-season forage grasses for improved heat tolerance can allow for a wider range of species to suit producer needs while adapting to climate change threats. This research used high throughput recurrent phenotypic selection to improve the heat stress tolerance of annual ryegrass (Lolium multiflorum Lam.) and orchardgrass (Dactylis glomerata L.). Seeds were mass-screened in stable-environment growth chambers for the ability to germinate and survive for 7-days at 40°C day, 30°C night temperatures. Seed that germinated and survived were advanced to the next cycle of selection, with 3 cycles of selection conducted on the base germplasm for each species over a 3-year period. Polycross nurseries were established in Starkville, Mississippi for outcrossing and seed production, with seed harvest occurring May – June . Seed was then conditioned with a belt thresher, sequential sieving, and fractional aspirator. Germination tests were conducted each summer to verify gains from selection, with six replications of 100-seed on 10% water agar. From cycle 0 – 3, annual ryegrass germination increased from < 5% to 45%, and orchardgrass germination increased from 10% to 80%. Additionally, orchardgrass summer persistence improved from 20% - 55%. Velocity of germination was also increased, with annual ryegrass selections germinating within 2 – 4 days, and orchardgrass germinating within 4 – 7 days. These results indicated that controlling environmental conditions can allow for the selection of quantitative traits using recurrent selection methods, and may allow for further adaptation of forage species to climate change.