The objective of this study was to develop a test to determine metabolic and imbibitional cold tolerance of cotton (Gossypium hirsutum) genotypes. Metabolic cold tolerance was determined by planting cotton seed in a sand media, exposing it to a constant temperature of 18 deg C for 21 days, and then counting and adjusting the emergence percent for viable seed by dividing the emergence percentage by the warm germination percent. Imbibitional cold tolerance was determined by chilling the seed in moistened rolled foam pads at 5 deg C for six hours, planting the seed in a sand media, exposing it to a constant temperature of 30 deg C for 14 days, and then counting and adjusting the emergence for viable seed by dividing the emergence percent by the warm germination percent. Varieties whose imbibitional and metabolic emergence percents were both above 80 percent ranked as having excellent cold tolerance. If both emergence percents were from 65 percent to 80 percent, the variety ranked as having good cold tolerance. Varieties that had both imbibitional and metabolic emergence percents between 50 percent and 65 percent had fair cold tolerance, and if either emergence percent was below 50 percent, the variety had poor cold tolerance.
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