SCREENING FOR HIGH-TEMPERATURE TOLERANT COTTON (GOSSYPIUM SPP.) BY USING SOME PHYSIO-MORPHOLOGICAL LEAF TRAITS

One hundred sixty cotton genotypes obtained from genetic stocks were evaluated for high temperature tolerance based on some physio-morphological leaf traits under field conditions and controlled condition. Genotypes showed differences for all investigated traits. In the study, stoma] density ranged from 83.49-128.35 stomata. (mm(2))(-1), stomata] conductance ranged from 140.77-394.90 mmol.m(-2).s(-1), stoma] width ranged from 92.39-154.01 mu m, stomatal rate of width/length ranged from 0.42-0.58, canopy temperature ranged from 20.24-52.00 degrees C, leaf area ranged from 67.50-173.05 cm(2), leaf SPAD value ranged from 31.80-63.73, and leaf photosynthesis yield ranged from 12.72-33.05 The results showed that high temperature stress did not influence stoma numbers, whereas it decreased stomatal conductance, stomatal width, stomatal width/length, leaf area, leaf SPAD and leaf photosynthesis yield; and that it increased canopy temperature values. The Fantom was determined to be tolerant with respect to stomata] conductance trait and the Tropikal-225 genotype with respect to stoma width and width/length traits.