SEED GERMINATION AND SEEDLING GROWTH CHARACTERISTICS OF ATRAZINE-SUSCEPTIBLE AND RESISTANT BIOTYPES OF Brassica campestris

Seed germination and seedling characteristics of atrazine-susceptible and resistant wild turnip rape biotypes (Brassica campestris L.) were examined. Seeds of the susceptible biotype germinated earlier, and the germinated seeds grew faster and emerged earlier than seeds of the resistant biotype. Seedlings of the susceptible biotype emerged from greater planting depths than the resistant seedlings. Emerged susceptible seedlings were larger, with longer hypocotyls and greater cotyledon area, and produced more dry matter than the resistant biotype seedlings. Differences in water content of germinated seeds of the two biotypes were noted, with the susceptible biotypes consistently showing a higher water content. There was no significant difference in the respiration rate of the two biotypes at the early stage of seedling growth.