Theses and Dissertations

Issuing Body

Mississippi State University


Macoon, Bisoondat

Committee Member

Reddy, K, Raja

Committee Member

Evans, B. Bill

Committee Member

Baldwin, S. Brian

Date of Degree


Document Type

Graduate Thesis - Open Access

Degree Name

Master of Science


College of Agriculture and Life Sciences


Department of Plant and Soil Sciences


An experiment was conducted to determine temperature effects on switchgrass seed germination, a native species with feedstock potential for the biofuel industry. Stratified seeds were germinated at constant temperatures, 15 to 45°C with 5°C interval. Maximum seed germination (MSG) and germination rate (GR), estimated by fitting sigmoid function to germination-time series data, varied among genotypes. Quadratic and bilinear models best described the MSG and GR responses to temperature, respectively. The mean cardinal temperatures, minimum, optimum and maximum, were 8.1, 26.6 and 45.1ºC for MSG and 11.1, 33.1 and 46.0ºC for GR, respectively, varied among genotypes. Genotypes were classified for temperature tolerance based on cumulative temperature response index: ‘Summer’ and ‘Expresso’ were identified as the most heat- and cold-tolerant genotypes, respectively. The functional algorithms and identified tolerant genotypes may be used to improve switchgrass models for field applications and breeding programs to develop new genotypes with enhanced tolerance for niche environments.



switchgrass||cardinal temperatures||Panicum virgatum||seed germination||cumulative temperature response index||tolerance||screening tool