Cold Tolerance in a Hexaploid Cotton 1

Plants of a recently introduced strain of hexaploid cotton, 6X‐3, produced up to six true leaves after 4 months in a cold phytotron environment (average of 14 C); whereas a number of common cultivars produced only one or two true leaves and then died, apparently from a fungus. The true leaves of the hexaploid were blue green. Those of the other cottons were very chlorotic. Since seedlings of the hexaploid have been observed to survive brief periods of chilling in the field, while those of common cultivars did not, the differences observed in the phytotron would appear to be a good indicator of a form of cold tolerance.