Quantifying Management and Environment Effects On Cotton Micronaire

Cotton fibre micronaire is an indirect measure of fibre linear density and maturity. Factors affecting supply and partitioning of assimilates to fruit affect micronaire. High micronaire occurs when there is an excess of assimilates due to good growing conditions and/or fruit number is low. Conversely low micronaire occurs when growing conditions are poor and/or fruit number is high. Little research has established the degree of impact of factors influencing micronaire, so research was conducted to investigate impacts on micronaire from changes in: planting dates influencing temperature; cultivar; canopy manipulation; water stress, and fruit number. Results highlighted that understanding significant changes in micronaire resulting from these treatments need to account for cultivar effects, the influence of management modifying the period of fibre thickening, and direct influences on boll growth. Knowledge will be used in crop simulation helping to refine management improving quality of Australian cotton.