Submitted to: Journal of Cotton Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 11, 2012
Publication Date: August 17, 2012
Citation: Pettigrew, W.T., Meredith Jr, W.R. 2012. Genotypic variation in physiological strategies for attaining cotton lint yield production. Journal of Cotton Science. 16:179-189. Interpretive Summary: Continued improvements in cotton yield and fiber quality are essential to the economic survival of both the US cotton industry and individual cotton producers. However, yield and fiber quality are complex traits that are controlled by numerous physiological and biochemical processes. This study investigated various physiological strategies that diverse cotton varieties used to achieve their yield and fiber quality production. Ten cotton lines were grown over a four year period (2005-2008) at Stoneville, MS and evaluated for yield, fiber quality, and various physiological traits. Some of the yield differences could be explained by differences in the manner in which these lines photosynthetically converted sunlight into the chemical energy plants utilize for growth. One of the high yielding cotton lines had leaves that were photosynthetically more efficient in converting the sunlight into chemical energy, while another high yielding line was able to prolong the duration of sunlight intercepting leaf area. Fiber quality differences were not as easily explained by the physiological processes monitored. Geneticists and breeders can utilize this type of information to develop improved genotypes to address yield and fiber quality objectives. Crop physiologist and agronomists should be able to take these results and match cotton varieties with appropriate environments and production practices to generate cropping system packages that optimize both the amount and quality of lint produced.
Technical Abstract: The quality and quantity of cotton (Gossypium hirsutum L.) lint produced are complex traits controlled by multiple processes. The physiology behind yield and quality variations is not completely understood. Objectives for this research were to document the physiological strategies diverse cotton genotypes take to achieve their varied yield and fiber quality. The genotypes ‘DPL 444BR’, ‘DPL 555BR’, ‘FM 800BR’, ‘MD 9’, ‘MD 15-OP’, ‘MD 29’, ‘MD 51 normal’, ‘MD 51 okra’, ‘PM 1218BR’, and ‘ST 4892BR’ were grown in the field from 2005-2008. Dry matter partitioning, leaf photosynthesis, chlorophyll concentration, root hydraulic conductance, lint yield, yield components, and fiber quality data were collected. Lint yields ranged from 1675 to 1119 kg ha-1 among the genotypes. The size of the available carbon assimilate pool generated by a genotype appeared to be related to lint yield production. Genotypes used different strategies to generate this carbon assimilate pool, i.e. through improved photosynthetic rates and/or solar radiation interception, and then convert that carbon into lint production. Fiber quality variations, however, could not easily be explained by just variations in the plants ability to produce carbon assimilates. Beyond just the quantity of carbon assimilates, it’s the manner the plant assembles these carbon skeletons into the cellular matrix that determines the quality of the fiber produced. This type of information can be utilized to meet the challenge of future yield and fiber quality improvements.