Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/28/1999
Publication Date: N/A
Interpretive Summary: A greater understanding of how cotton fiber quality is determined will help researchers develop improved cotton growing systems with lint that has higher value. This is especially important for systems where cotton is planted late and there is a shorter season for the crop. We studied how fiber properties of individual bolls are related to the amount of photosynthesis that is occurring during boll development. We found that bolls developed during the time that canopy photosynthesis was high had better quality in terms of factors that influence the ability of the fibers to take dye. As the amount canopy photosynthesis during the time that bolls were developing increased, fiber micronaire and cross-sectional area increased while immature content decreased. The rate of canopy photosynthesis during boll development had no effect on fiber length, fiber strength, or fiber color. This information will be useful to scientists developing cotton production systems with improved fiber quality.
Technical Abstract: Normal- and late-planted cotton (Gossypium hirsutum L.) often differ in fiber properties, especially those properties related to fiber secondary wall characteristics. This study was conducted to 1) determine the effect of planting date on fiber properties of bolls at two flowering times; and 2) determine the relationship between fiber properties and canopy photosynthesis during development of those bolls. Cotton ('Stoneville 453') was planted on 3 May and 3 June in 1995 and 3 May and 31 May in 1996. Canopy photosynthesis was measured ten to twelve times on sunny days from initial flowering through the end of the season. First sympodial position white flowers were tagged during the first and fourth week of flowering (WOF). Fiber properties were determined on tagged bolls that matured. Maximum canopy photosynthesis was 21% higher in 1996 than in 1995, and lint yield was 22% greater in 1996 than in 1995. Within each year, canopy photosynthesis was the same for the planting dates, although yield was approximately 30% lower for the late planting date each year. Bolls from the first WOF generally had lower lint percent, higher short fiber content, lower elongation, and lower whiteness index than bolls from the fourth WOF. For the bolls at these two flowering dates, there were few consistent differences between planting dates in fiber properties. Micronaire, immature fiber fraction, and fiber cross-sectional area were linearly related to the amount of canopy photosynthesis that occurred when bolls were 15 to 45 days old. The results of this study are consistent with the hypothesis that assimilate supply influences cotton fiber properties associated with secondary wall characteristics.