Effects of Temperature and Age on the Germination of Naked Caryopses of Indigenous Grasses of Western New South Wales.

Abstract

The effects of temperature and age on the germination of naked caryopses of nine native grasses from western New South Wales were studied in the laboratory. Maximum germination percentages varied from >90% for Astrebla lappacea to <<1% for Eragrostis setifolia. Optimum temperatures for germination of A. lappacea, Bothriochloa macra, Dichanthium sericeum, Enneapogon avenaceus, Monachather paradoxa, Paspalidium constrictum and Thyridolepis mitchelliana were 20-30°C. Highest germination of Danthonia caespitosa was at 15°C. At temperatures close to their respective optima, most seeds germinated within seven days of imbibition, although rates of germination varied with temperature. In three species (A. lappacea, D, caespitosa, P. constrictum), germination percentages were similar or higher for two-year-old seed compared with 6-month-old seed. At its optimum temperature, two-year-old seed of T. mitchelliana had > 10% germination. In the other five species, germination was <10% for seed stored for more than 12 months. These results have implications for the agronomic use of these species.