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2019 ASHS Annual Conference

Interactive Effects of Carbon Dioxide, Drought, and Temperature on Sweetpotato Cultivar Growth and Yield

Thursday, July 25, 2019
Cohiba 5-11 (Tropicana Las Vegas)
K.Raja Reddy, Mississippi State University, Mississippi State, MS
Shasthree Taduri, Mississippi State University, Mississippi State, MS
Chathurika Wijewardana, Mississippi State University, Mississippi State, MS
Ajaz Lone, Mississippi State University, Mississippi State, MS
Stephen Meyers, Mississippi State University, Pontotoc, MS
Mark Shankle, Mississippi State University, Pontotoc, MS
Projected changes in climate warrant developing climate-ready agronomic crops. Among the abiotic stress factors, temperature and drought either alone or in combination impact crop growth yield. The objective of this study was to test the hypothesis that sweetpotato cultivars (Beauregard, Hatteras, and Louisiana 1188) differ in their responses to carbon dioxide concentrations (410 and 760 µmol mol-1), temperature (30/22 and 38/30oC), and drought stress (well-watered, 100% evapotranspiration, ET and 50% ET) and their interactions. The control treatment consisted of 30/22oC temperature, 410 µmol mol-1 [CO2], and well-watered plants (100% evapotranspiration). All other treatments were imposed at planting except irrigation treatments, which were imposed at 36 days after transplanting (DAP) and continued to 83 DAP. Plant growth and developmental parameters and plant-component dry weights were measured at the end of the experiment. Gas exchange, pigments, and cell membrane stability were measured several times during the experiment. Treatment variables significantly affected all the measured parameters in all cultivars. Cultivars differed significantly for many of the measured parameters. Well-watered conditions favored stem and leaf growth more than storage root growth. Elevated carbon dioxide ameliorated some of the damaging effects of drought and high temperature in all the cultivars. Elevated temperature either alone or in combination depressed storage root yield in all cultivars. Cultivars were classified based on total stress response index, developed from the cumulative sum of response indices of vegetative, physiological, and parameters. Among the three cultivars tested, Hatteras (+23.92) was classified as drought and temperature tolerant, and Beauregard (-12.61) and Louisiana 1188 (-12.67) were identified as drought and high temperature-sensitive. This analysis on limited number of cultivars suggests that large scale screening of sweetpotato germplasm for abiotic stresses are needed to develop climate-ready germplasm.
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