Fiber yield and quality of cotton grown at two divergent population densities

Poor seed germination and early seedling damage often reduce plant populations in the north-eastern cotton (Gossypium hirsutum L.) producing region of the USA. A field study was conducted at Clayton, NC, on a Dothan sandy loam (fine-loamy, siliceous, thermic Plinthic Kandiudult) to investigate responses of cotton reproductive development to reduced plant population, All flowers on plants grown at 2 and 12 plants m(-2) were tagged so that associations among boil and lint quantity and quality, flowering date, and fruiting position could be determined, On plants grown at 2 plants m(-2), 33 and 65% of their fiber came from flowers initiated before 88 days after planting (DAP) in 1992 and 1993, respectively, Plants grown at 12 plants m(-2) produced 63 and 88% of their fiber from flowers initiated before 88 DAP in 1992 and 1993, respectively. Plant population did not affect total lint yield, however, Because of favorable late-season weather, plants grown at 2 plants m(-2) produced more bells on vegetative branches and at more distal sympodial positions than did plants grown at 12 plants m-2, Bell weight and micronaire were generally higher for earlier bells at all positions for the lower population density, Later bells exhibited poorer bell and fiber properties, indicating negative effects of reduced heat unit accumulation by later bells. Our findings indicate that replanting, which might delay stand establishment by 3 to 4 wk, would be of little help toward improving fiber yield because it would rely more heavily on later produced bells.