Effects of stratification, germination temperature, and pretreatment with gibberellic acid and hydrogen peroxide on germination of 'Fry' muscadine (Vitis rotundifolia) seed

Germination of muscadine seed has frequently been low and irregular in the University of Georgia breeding program. A systematic study was undertaken to determine the best seed treatments and germination conditions for muscadine seed. Open-pollinated seeds of 'Fry' muscadine were used for all treatments. Stratification of seeds was performed by placing dry seed in damp vermiculite at 4 degrees C for periods of 0, 30, 60, and 90 d. The 90-d stratification period gave the highest germination percentage, with successively lower germination in the shorter stratification treatments. Pretreatment of seeds before stratification with three rates (0.5, 1.0, and 2.0 M) of hydrogen peroxide (H2O2) and four rates (1, 2, 4, and 8 g.L-1) of gibberellic acid (GA(3)) were used in an attempt to promote germination. Low rates of H2O2 (0.5 M) and GA(3) (1 g.L-1) were beneficial in some instances, whereas high rates of GA(3) were detrimental. Nicking the seedcoats before stratification and soaking seeds in running water after stratification were ineffective in promoting germination. Germination temperatures of 32/22 degrees C (8 h/16 h) were superior to 22/22, 27/22, and 37/22 degrees C.