Seed harvested from a herbicide susceptible genotype open pollinated with a transgenic herbicide resistant strain can be planted and sprayed with the herbicide to kill all non-hybrids. A 3:1 ratio of rows of resistant to susceptible strains was used to increase the percentage of open pollinated hybrids obtained from the female parent. Roundup was sprayed during the flowering period on RR cultivars which caused a high level of male sterility along with slight female sterility when the plants were under drought stressed conditions.