Cotton Cultivar Response to Plant Populations in a Short-Season, Narrow-Row Cultural System
1982
Mohamad, Khalid Bin | Sappenfield, W. P. | Poehlman, J. M.
The need for reducing time of crop exposure to pests has given emphasis to cultural changes in row widths and plant densities for upland cotton, Gossypium hirsutum L., and this has challenged available cultivars to avoid losses in yield and fiber quality. Four genotypes, HYC72-234/320 (very early), ‘Auburn M’ (early), MO63-277 BR (medium early), and ‘Stoneville 213’ (medium early to full-season) were drilled and hill-drop seeded in rows 51 cm apart on beds 203 cm wide on Tiptonville silt loam (fine silty-mixed-thermic typic argiudolls). Four planting methods and rates were used to establish the average within-row plant populations of one, five, and nine plants per 31 cm of row. Eleven agronomic characteristics of upland cotton were measured in relation to the four within-row populations. Lint yields, combining genotypes, were significantly reduced by 90–131 kg/ha in stands of nine or more plants compared with stands of one and five plants in 31 cm of row. The percent of barren plants increased and the numbers of open bolls for four rows 1 m long prior to harvest decreased as number of plants per 31 cm of row increased. The lint yields of Auburn M and HYC72-234/320, early and determinate cultivars, were not influenced significantly by the within-row plant densities. Stoneville 213, a full-season indeterminate cultivar, produced significantly lower yields when within-row plant population was highest. Only minor differences were noted in lint fraction, seed size, boll size, and fiber properties due to the various within-row plant densities. Our findings suggest that cultivar fruiting efficiency potential and within-row plant population should be considered when planting dates are delayed or row-widths modified for cotton culture in the northern extremes of the Mississippi Delta.
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