[Research updates] Physiological and molecular basis heat tolerance in bentgrass

The overall goal of this project is to improve heat tolerance of creeping bentgrass by identifying mechanisms of heat tolerance in Agrostis. Researchers are determining whether any specific gene can be identified and used for direct genetic manipulation, and if heat-stress proteins or other genetic components can be used as genetic markers for heat tolerance.

The study examined thermal Agrostis scabra, non-thermal Agrostis scabra, A. rossiae, and Agrostis palustris cv. L-93. Soil temperatures were 20 (control), 35 and 40 C, while air temperature was held at 20 C. Treatments were imposed for 70 days. After 10 days, all plants grown at 42 C had lower chlorophyll content than plants grown at 35 and 20 C. Differences in chlorophyll content between 35 and 20 C were not significant. Both ecotypes of thermal A. scabra had greater chlorophyll content than other Agrostis species at 35 C. Canopy temperature for all species at 35 and 42 C increased over time as much as 6 and 8 C respectively. These physiological measurements showed that thermal Agrostis scabra species had superior tolerance to elevated soil temperatures. These species had better cooling mechanisms and produced large numbers of roots at 5 cm at 35 C soil temperatures, while root growth declined for creeping bentgrass.