Effects of Water Availability on Two Cytotypes of Switchgrass (Panicum virgatum), a Potential Biofuel Crop
MetadataShow full item record
Switchgrass (Panicum virgatum) is a perennial grass that has a wide distribution across many regions and ecosystems in North America; it has great potential as a biofuel crop because of its genetic variation and potential to grow well on marginal land. Varied populations, or cultivars, of switchgrass have been developed across the eastern United States; these cultivars differ in potential as biofuel crops. Two ecotypes of switchgrass - upland, which grows in drier areas, and lowland, which grows in wetter areas correspond to the two cytotypes - octoploid, (8N, upland) and tetraploid (4N, lowland) - used in this study. In this study we examined effects of simulated drought and different degrees of water availability on cultivars yarying in ploidy-level (or ecotype) and site of origin to find a cultivar suitable for growth on marginal land. We simulated a drought to which we subjected seedlings from each cultivar for 58 days and periodically evaluated individual plant vitality using a qualitative scale of wilt progression. In a parallel experiment, we planted seeds from each cultivar in a field setting and subjected them to three treatments: ambient conditions, water addition throughout the summer, and water addition for two weeks followed by ambient conditions. The simulated drought resulted in all plants wilting after 58 days, which did not indicate which cultivar was most drought-tolerant. The Alamo cultivar performed best under high water availability and no other cultivars were noticeably affected by different treatment conditions. All of the cultivars exhibited drought tolerance meaning they can potentially produce well in marginal conditions, but none of them did conspicuously better than the others.