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Responses of Field-Grown Cotton to Shade: an Overview

Duli Zhao and Derrick Oosterhuis


A 3-year field study was conducted to determine the effects of an 8-day period of shade (63% light reduction) at four growth stages; pinhead square (PHS), first flower(FF), peak flower (PF) and boll development (BD) on cotton (Gossypium hirsutum L.) carbohydrate composition, mineral nutrient status, lint yield, yield components and fiber quality. Shading for 8 days at the early square stage did not significantly affect cotton growth and yield. Shade during flowering and fruiting significantly increased fruit abscission, and decreased lint yield and fiber quality. The detrimental effect of shade on yield increased with later growth stages. At all four stages, shade significantly decreased leaf photosynthetic rate (43-55%) and nonstructural carbohydrate concentration (47-71%), and increased concentrations of chlorophyll and mineral nutrients. Effects of shade on carbohydrates and mineral nutrients of bracts and floral buds were also determined in this study. Shade during plant reproductive growth significantly reduced leaf photosynthesis and total nonstructural carbohydrate (TNC) concentrations, and affected mineral nutrient status and C/N ratio of cotton, resulting in increased fruit abscission and decreased lint yield and fiber quality.

Reprinted from Proceedings of the 1998 Beltwide Cotton Conferences pp. 1503 - 1507
©National Cotton Council, Memphis TN

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Document last modified Sunday, Dec 6 1998