The genetic potential for growth, development and yield of many cotton cultivars used on the High Plains of Texas is often not attained due to environmental constraints imposed by an inadequate water supply. In order to make significant progress in developing cottons that are more productive under these conditions, it is important to understand how water stress affects the developmental and physiological processes that contribute to yield. Furthermore, it is advantageous to distinguish direct from indirect effects of water stress on these processes.

A field study was conducted during the 1980 and 1981 growing seasons with the basic purpose of identifying cause and effect relationships of the water stress response. Three commercial cultivars differing, in degree of indeterminacy were planted at three different dates beginning in early May and continuing through mid-June. Water supplies were modified utilizing irrigated and nonirrigated plots. Growth and development of plants in each treatment were monitored through periodic growth analysis. Photosynthetic characteristics were evaluated at both the single leaf and whole canopy levels throughout the growing season.