Herbicide Susceptibility of Ultra Low Gossypol Cotton Seed

Cotton (Gossypium hirsutum) is primarily used for its qualities as a fiber crop with the seed as a byproduct.  The protein profile of cottonseed makes it a desirable food source, but it is limited in its uses due to gossypol, a toxic compound produced by the plant.  Glandless cotton lacks gossypol, but is more susceptible to pests and sensitive to some commonly used pre-emergence herbicides, such as Prometryn.  Researchers at Texas A&M University have recently developed cotton plants that contain ultra-low gossypol cotton seed (ULGCS) levels in the seed, but contain normal gossypol glands in the rest of the plant.  To test the sensitivity of the ULGCS plants to pre-emergence herbicides, a greenhouse study was conducted.  The seeds of two ULGCS lines, the non-transgenic parent line, the glandless Acala cotton variety, and DP1133B2RF variety were planted into pots containing a Weswood silty clay loam soil with a pH of 7.8.  Four types of pre-emergence herbicides, including prometryn, fluometuron, pyrithiobac-sodium, and s-metolachlor, were applied to the soil surface and the pots were watered following planting. The pots were transferred to a greenhouse after herbicide application and grown for 28 days past emergence. Percent emergence, vigor, and phytotoxicity were rated weekly, and biomass was quantified at 28 DAP.  A summary of the results will be presented as a poster at the meeting.