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ARS Home » Northeast Area » Washington, D.C. » National Arboretum » Floral and Nursery Plants Research » Research » Publications at this Location » Publication #310685
Title: Cultural treatments for accelerated growth and flowering of Panicum virgatum

Author
item Alexander, Lisa
item HAYNES, ELLEN - University Of Tennessee
item BURRIS, JASON - University Of Tennessee
item JACKSON, SAMUEL - Genera Energy, Llc
item STEWART, NEAL - University Of Tennessee

Submitted to: Biofuels
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/1/2015
Publication Date: 3/30/2015
Citation: Alexander, L.W., Haynes, E.R., Burris, J., Jackson, S., Stewart, N.C. 2015. Cultural treatments for accelerated growth and flowering of Panicum virgatum. Biofuels. 5(6):771-780.

Interpretive Summary: New switchgrass cultivars, especially hybrid cultivars, are expected to increase switchgrass biomass yield and quality for biofuel production. However, the time to evaluate parental genotypes and produce clones for field evaluation is a major limitation to the production of new switchgrass cultivars. We determined the optimal growth chamber treatment for accelerating the seed-to-seed breeding cycle of switchgrass. Under a treatment consisting of 18 hours of light and a day temperature of 25°C, 44% of treated seedlings flowered after 90 days and >15% of plants reached full anthesis or post-anthesis seed set after 90 days. Allowing 45 days for seed set and 30 days for cold stratification, the seed to seed generation time for the post-anthesis plants grown in 18 h/25°C conditions is approximately 165 days, allowing for the production of two generations of switchgrass per year. This represents a greater than 20% reduction in switchgrass generation time. These protocols will be used by switchgrass researchers and switchgrass production companies that develop and evaluate new hybrids and cultivars for biofuel production.

Technical Abstract: Background: Exploiting heterosis through hybrid breeding is essential to increase switchgrass (Panicum virgatum) biomass yields; however, the time to evaluate parental genotypes and produce clones for field evaluation is a major limitation to hybrid production. In order to reduce the seed-to-seed generation time of switchgrass, we investigated the effect of four variables on the vegetative and reproductive morphology of the P. virgatum cultivar ‘Alamo’: day length, temperature, container size, and application of plant growth regulators. Seedlings showed the most rapid growth and flowering under 18 hours of daylight with growth being severely and mildly inhibited at 8 h and 23 h, respectively. Under the optimum (18 h) photoperiod, a day temperature of 25°C led to the fastest growth and flowering while a 5°C increase or decrease inhibited growth and flowering. Within the 18 h/25°C treatment, 44% of plants flowered after 90 d and >15% of plants reached full anthesis or post-anthesis seed set. Allowing 45 d for seed set and 30 d for cold stratification, the seed to seed generation time for the post-anthesis plants grown in 18 h/25°C conditions is approximately 165 days, allowing for the production of two generations of switchgrass per year.