Four different constant temperature regimes (25, 27.5. 30, or 32.5 C) concurrent with water deficit conditions have been investigated with respect to development of cotton fiber quality. Cotton (Gossypium hirsutum L., Texas Marker-1) was raised in an environmental growth chamber from germination to harvest under controlled constant temperature, relative humidity, and day/night light conditions of 16/8 hours. Texas Marker 1 (TM-1) has been employed as a genetically stable, nearly homozygous test stock which is in its 30th generation of inbreeding by controlled pollination. Reduced watering (ca. 50% of control treatment by weight) of the stressed plants began at flowering. Well-watered controls were maintained under identical environmental conditions. Flowers were tagged on day of anthesis. The first harvest date was at the time of first boll opening with the second harvest date 30 days later.

Plant productivity was monitored weekly by measurement by plant height, number of nodes, number of squares, number of flowers, and number of bolls. Assessment of the influence of temperature and water stress during growth was carries out by statistical analysis using analysis of variance, repeated measure, and slice-through-time treatments of the data. The biomass production of the plants was evaluated at harvest by boll weights (unopen and open), as well as by fresh and dried weights of branches leaves, and mainstems. Temperature provided the greatest influence on growth, but specifically water-stress had the most significant effect on height, nodes, squares, flowers, and bolls at the first harvest date and on fresh and dry weights of the plant. No effects of temperature or stress were observed by number of seeds seed weight, or boll weight but temperatures was significant with respect to fiber weight.