Carbohydrate Status of Narrow Row Cotton as Related to Vegetative and Fruit Development1

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Abstract
Narrow row, high population culture is a promising system for cotton (Gossypium hirsutum L.) production; but with improper management the dynamic balance between vegetative and fruit development can be upset, resulting in low lint yields. This study was conducted to investigate the relationship of plant carbohydrate status to vegetative and fruit development. Plant dry weights and total available carbohydrates (TAG) were compared during two seasons in narrow row cotton planted at population densities of 7.4, 14.8, and 22.2 plants/m3. Although large differences occurred in plant size, TAG levels among the three populations were similar during the various sampling dates. TAG had a cyclic pattern with low levels during mid‐season. This depression coincided with a rapid increase in fruiting form weight when lint yields were high and with a rapid increase in vegetative weight when lint yields were low. This excessive vegetative growth can effectively compete with fruiting forms for TAG. In a related experiment, TAG levels along plant axes were lowest near the central part of the plant where developing bolls were located. This shows that the TAG depression can be relatively localized within plants suggesting that photosynthates are not effectively translocated from the top to the central part of the plant. Restructuring of the plant canopy to allow more solar radiation penetration to leaves near developing bolls and/or selecting for more efficient translocation from upper leaves to developing bolls should help increase yields.