With the decline of available irrigation water from the Ogallala Aquifer and the rising costs of pumping irrigation water, farmers in the Southern Great Plains are planting more dryland cotton.

The purpose of this program is to evaluate the World Collection of Cotton for germplasm with enhanced water use efficiency. We are presently screening the photoperiodic race stocks of Gossypium hirsutum L. for improved water use efficiency. We are using the nonflowering, photoperiodic material to minimize the variability in growth associated with boll loads. Hopefully, traits uniquely associated with drought resistance or enhanced water use efficiency can be identified through this approach.