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LOGO: Journal of Cotton Science


CO2 Exchange Rate in Cotton Does Not Explain Negative Associations Between Lint Yield and Fiber Quality

Authors: Jenny D. Clement, Greg A. Constable, and Warren C. Conaty
Pages: 270-278
Breeding and Genetics

An experiment was conducted to determine if negative associations between yield and fiber quality in cotton (Gossypium hirsutum L.) were due to leaf CO2 exchange rate (CER). A 3-year study evaluated six high-quality genotypes, with two high-yielding commercial control cultivars and a G. barbadense L.cultivar, for CER and stomatal conductance to water vapor (g) across contrasting seasons. Yield, fiber quality, and harvest index (HI) were compared with CER and g measured on the uppermost fully expanded leaf on two occasions between mid-flower and cutout. The results show no significant associations between CER and fiber-quality parameters (p<0.05). There was no association between CER and yield, HI, or stem weight. It was concluded that high-quality lines did not photosynthesize less than the high-yielding commercial check. There was a positive association between HI and yield (p<0.01). An inefficient growth habit as measured by a low HI in at least one high-fiber quality genotype was a possible reason for lower lint yield.