Cotton grown in the U.S. comes from areas prone to periods of extremely high temperatures that can have a negative effect on cotton yield. Agricultural Research Service (ARS) scientists Michael E. Salvucci and Steven J. Crafts-Brandner are developing technology to improve cotton yields in Arizona's extremely hot and dry summer environment.

Plant physiologists Salvucci and Crafts-Brandner have found that high temperatures can adversely affect the function of a plant enzyme called Rubisco activase, resulting in impaired photosynthesis and reduced yields.

At the ARS Western Cotton Research Laboratory in Phoenix, the scientists observed how Rubisco activase adapted to various climates and how it functioned at high temperatures. They discovered that the enzyme from plants adapted to the hot Arizona desert worked better at high temperatures, compared to the enzyme from plants adapted to cold climates.

The research provides a scientific basis for improving the enzyme in crop plants such as cotton. The team is testing the hypothesis that plants engineered to contain Rubisco activase from a shrub adapted to the hot Arizona desert will perform more efficiently at high temperatures.

If successful, the research could improve the production of cotton in Arizona and across the U.S. Cotton Belt, and perhaps improve the performance of other crops that suffer from high temperatures.