EFFECT OF INJECTING COLCHICINE IN THE GREEN BOLLS ON COTTON FIBER PHYSICAL PROPERTIES AND STRUCTURAL DEFORMITIES

Seeds of the two Egyptian cotton cultivars; Giza 77 (extra-long staple ) and Giza 75 (long-staple), Gossypium barbadense L, and Upland cotton cultivar McNaire 220, G. hirsutum L., were sown in the two suc­cessive growing seasons of 1990 and 1991. The first season was as­signed to determine the suitable colchicine concentration and the toler­ance of locuius to colchicine injection. On the basis of study of 1990, colchicine concentrations of 0.00% (distilled water as a control) and 0.01% were used for injecting green bolls of 25,30 and 35 days past anthesis(DPA), to study the direct effect of colchicine on the cotton fi­ber physical and stuctdural properties, and the possibility of inducing fi­ber structural deformities. It was found that colchicine caused an increase in maturity ratio and degree of wall thickening of Giza 75, but reduced fiber sugar con­tent of Giza 77 and McNaire 220 in all boll ages. It also decreased fiber strength, elongation percentage and reduced sugar content of Giza 75 in all boll ages, fiber strength of Giza 77 of bolls aged 25 and 30 ❑PA, degree of wall thickening of Giza 77 and McNaire 220 in all boll ages . However, it did not affect fiber strengh of Giza 77 of boll aged 35 DPA and (T1) of McNaire 220 of bolls at all ages and strength uniformity per­cent of the three cultivars and elongation percent of Giza 77 and McNaire 220. Whereas, the older fiber-aged, water or colchicine treated bolls, had the higher values of strength, maturity and degree of wall thickening of the higher values of strength, maturity and degree of wall thickening of the three cultivars, but they had the lower values of reduc­ing sugar content in the three cultivars. With repect to fiber deformities structures, their total major and minor attained their maximum at 30