The hormonal control of sex differentiation in dioecious plants of hemp (Cannabis sativa): The influence of plant growth regulators on sex expression in male and female plants

Abstract

The influence of GA;t, IAA, ethrel, ABA and kinetin on sex expression in male and female plants of hemp (Cannabis sativa cultivar LKC SD) was investigated. The growth regulators were applied separately and in combinations on stem apices of plant determined sexually and having the first flower primordia. Gibberellic acid promoted masculinization, whereas IAA, ethylene and ki-netin had a feminization effect on sex of hemp. Abseisic acid did not exert any direct effect on sex determination, it however acted antagoni- sticaly in relation to the effect exerted by GA3 and IAA. The results of combined application of IAA and ethrel with other growth regulators suggest, that the mechanism of action of auxin and ethylene in the control of sex expression in hemp is different. Auxins in this process cannot be regarded only as causing agents of ethylene production increase.