Fruiting Pattern in Narrow‐Row Cotton 1

Previous research with narrow‐row cotton ( Gossypium hirsutum L.) has concentrated on end‐of‐season effects on yield and fiber characteristics with little attention given to seasonal fruiting patterns. Our objective was to monitor the seasonal fruiting pattern of cotton planted at various combinations of row spacings and plant densities. ‘Deltapine 16’ was grown 3 years on one or two rows per beds that were either 76 or 102 cm from center to center with densities of 7.4, 14.8, and 22.2 plants/m 2 . The plots were divided into flower tagged (tagged plots) and yield portions (yield plots). In the tagged plots, flowers were tagged daily with the date of anthesis. Open bolls were harvested weekly and assigned to weekly flowering intervals before being analyzed for boll and fiber properties. Before harvesting the yield plots, we also took open boll samples to be analyzed for boll and fiber properties. At equivalent plant densities in the yield plots, two rows per bed resulted in up to 11% more seedcotton than one row per bed. Plant density had no significant effect on yield. In the tagged plots, seasonal flower and boll production was higher from two rows per bed than one row per bed with differences ranging from 8 to 22% more flowers and 2 to 12% more bolls, depending upon bed size and plant density. The seedcotton yield advantage of two rows per bed was near maximal from bolls that were set (flowered) by late July; thereafter the production rate on one and two rows per bed was similar. Boll period (time from flowering to open boll) was increased slightly by high plant density. Boll size, lint index, seed index, fiber strength, and fiber fineness from the yield plots were all significantly reduced by increases in plant density, although the average effects were less than 5%. While fruiting pattern and yield were primarily influenced by row spacing, plant density had the greatest influence on boll and fiber properties.