Torrid Panicgrass Dormancy Relief Through Exogenous Chemical Treatments and Seed Storage Optimization of Temperature and Relative Humidity Parameters

Abstract

Seed dormancy is an evolutionary adaptation for increasing seedling survival by delaying germination and is found in many families of seed plants. Although dormancy is ecologically important, it becomes problematic during agronomic production and restoration. Torrid panicgrass (Panicum torridum) is a native Hawaiian annual grass that has been identified as a re-vegetation candidate for seasonally dry areas. Torrid panicgrass seed appears to possess a nondeep to intermediate physiological dormancy. This research aimed to characterize dormancy relief parameters by 1) evaluating exogenous hormonal, reactive oxygen intermediates, and simulated combustion product treatments; and 2) determining optimized storage conditions of relative humidity (RH) and temperature over a 10-month duration. Results indicate that all exogenous chemical treatments tested were not effective at relieving the dormancy present in torrid panicgrass. Optimal storage conditions to relieve dormancy were found with seeds equilibrated to 12% RH, stored at 30 °C for a period of 8 months resulting in 55% germination. Maintenance of viability for long-term storage up to 10 months was best achieved with seeds stored at 12% RH at 10, 20, or 30 °C.