Comparative Studies of Seed Germination of two Newly Isolated Lines of Grand Rapids Lettuce

Two lines of Grand Rapids lettuce were isolated by self-pollinationof single plants. Seeds of one line, designated ‘A’,germinate in the dark at 25 °C. Seeds of the second line,designated ‘B’ germinate in a manner typical oftheir variety. The lines differ in sensitivity to red (R) andfar-red (FR) light, in the ability of their seeds to overcomeresistance of an external osmotically active medium, in theresponse of mature seeds to abscisic acid, and in the responseof young seeds to gibberellin and benzyl adenine. ‘A’seeds germinate faster than ‘B’ seeds in the darkor after R or FR irradiation.