Fecha de publicación: 29/07/2022 Fuente: WIPO "hemp" An industrial hemp breeding method belongs to the technical field of hemp breeding. In order to improve the proportion of male plants in unit area and solve the problem that female plants in a male parent and male plants in a female parent need to be pulled out manually in the crossbreeding process, the method comprises the steps that in the later stage of the rapid growth period of industrial hemp, a mixed solution of ethylene and urea is sprayed, the ethylene concentration is 50 mg/L-250 mg/L, the urea concentration is 200 mg/L-500 mg/L, and the mixed solution is mixed with water to obtain a mixed solution; the method comprises the following steps: by taking the condition that the surfaces of leaves are wet but no liquid drips as a standard, shading treatment is carried out for 10-12 hours during spraying, treatment is carried out again after 7-10 days, within 20-25 days after treatment, all female plants are manually removed, female flower stigmas are induced on male plants, free pollination can be carried out after the male flowers are pollinated, and urea and potassium dihydrogen phosphate fertilizer are dressed 1-2 times during the period to promote seed maturation. According to the method for inducing the pure male industrial cannabis sativa, more than 95% of bred offspring is male plants.