EFFECT OF INCREASING FOLIAGE REFLECTANCE ON YIELD, GROWTH, AND PHYSIOLOGICAL BEHAVIOR OF A DRYLAND COTTON CROP

The effect of kaolin reflectant sprays on the yield, physiological activity and growth of ''Acala SJ-2'' dryland cotton (G. hirsutum L.) was studied during 2 successive years in separate field experiments. In the 1st experiment the treatment increased yield by 12.6%. In the 2nd experiment a significant increase in the number of flowers resulted from the kaolin spray, but subsequent high rates of abscission prevented this spray from producing a significant increase in yield. The reflectant sprays decreased the rate of 14CO2 uptake due to a reduction in light absorption. A reduction in epidermal conductance due to partial physical blockage of the stomata was believed to cause the slower decrease in xylem leaf water potential which followed reflectant treatment. Plant growth, characterized by the stand''s height, leaf area index and dry weight, was not significantly affected.