Effectiveness of Fruiting Sites in Cotton: Yield

The fruiting sites at which cotton, Gossypium hirsutum L., plants set bolls that are harvested influence how well the plants tolerate insects. The objective of this research was to determine the fruiting patterns of eight cultivars of cotton in terms of fruiting sites of harvestable bolls when planted in a conventional pattern of rows spaced 1-m apart with a plant population of approximately 95 000 plants ha⁻¹ for 2 yr in Mississippi. Descriptive terms are defined as follows: (i) sympodium—a fruiting branch; (ii) monopodium—a vegetative branch; (iii) node—the place on the main stem where sympodia monopodiarise, we numbered the nodes beginning with the cotyledeonary node as number one; (iv) position—refers to the order which buds (potential bolls) are produced on a sympodinm branch; and (v) fruiting site—any specific node-position combination. Cultivars compared and their release dates were: Stoneville 213, 1962; Stoneville 506, 1980; Stoneville 825, 1979; Tamcot CAMD-E, 1979; Deltapine 50, 1984; McNair 235, 1975; DES 119, 1986; and Deltapine 20, 1985. Bolls at position one on sympodial branches produced 66 to 75% of total yield; those at position two produced 18 to 21%; all other positions on sympodial branches produced from 2 to 4% of total yield. Monopodial branches produced from 3 to 9% of the total yield. Sympodial branches from Nodes 9 through 14 produced the bulk of the lint in all cultivars. Distribution of lint over sympodia among cultivars was significantly different for positions one and two, with the newer, early maturing cultivars producing significantly more lint from sympodial branches at Nodes 6 through 8 than the older cultivar Stoneville 213. Tamcot CAMD-E, McNair 235, and Deltapine 20 also produced less lint on monopodial branches than Stoneville 213. This research provides valuable information needed to more effectively manage the production of the newer, early maturing cuitivars of cotton presently being grown in the mid-South. Contribution of the USDA-ARS in cooperation with Mississippi Agric. and Forestry Exp. Stn.