VIEW ARTICLE

Ecology and Epidemiology

Influence of Moisture Content, Temperature, and Length of Storage on Seed Germination and Survival of Endophytic Fungi in Seeds of Tall Fescue and Perennial Ryegrass. R. E. Welty, Research plant pathologist, U.S. Department of Agriculture, Agricultural Research Service, Departments of Botany and Plant Pathology and Agricultural Engineering, Oregon State University, Corvallis 97331; M. D. Azevedo, and T. M. Cooper. Research assistants, U.S. Department of Agriculture, Agricultural Research Service, Departments of Botany and Plant Pathology and Agricultural Engineering, Oregon State University, Corvallis 97331. Phytopathology 77:893-900. Accepted for publication 21 November 1986. Copyright 1987 The American Phytopathological Society. DOI: 10.1094/Phyto-77-893.

Seeds of tall fescue and perennial ryegrass were stored 18 mo at 10–30 C and 11.5–95% relative humidity to evaluate the effect of these conditions on germination and viable endophyte. It was found that temperature, moisture content of seed, and time interact to influence germination and endophyte survival in both grass species. Moisture contents of tall fescue seed that resulted in the most rapid decrease in endophyte viability, while maintaining the highest level of germination, were 19.4, 9.6, and 8.2% at 10, 20, and 30 C, respectively. Moisture contents that resulted in decreases in viable endophyte and germination at 10, 20, and 30 C were 24, 15.2, and 14.1%, respectively. The results for endophyte survival and germination in seeds of perennial ryegrass were generally similar to those for seeds of tall fescue; however, in moisture contents that maintained germination, endophyte viability decreased more slowly in ryegrass than in tall fescue. Conditions that favored rapid decreases in endophyte viability in ryegrass seeds also resulted in loss of germination. When seeds of either species are stored at or above 15% moisture content and 20 or 30 C, loss of germination is likely to occur after 2 or 3 mo of storage. Field emergence of stored seed was lower than expected by blotter germination.