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Description:
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The decision to plant early leads to a critical question . How will the planted seed perform at cool temperatures ? Plants of tropical origin are extremely sensitive when exposed to temperatures below 15°C (Herner , 1986 ) . Cotton , being of tropical origin and therefore considered chilling sensitive (Wang , 1990 ) , has shown reduced germination and stand establishment when planted at temperatures below 20°C (Cole and Wheeler , 1974 ) . Further , planting cotton at sub -optimal temperatures has resulted in a 40 % decrease in stand establishment (Staus and Hopper , 1983 ) . The poor establishment encountered in these situations is problematic for producers . To establish a proper stand , farmers must plant extra seed to compensate for low stand establishment associated with cooler planting temperatures . By planting a higher seed population per acre , seed costs increase . Another loss producers may face is a yield decrease , especially if stand establishment is extremely low . To limit losses , a better understanding of chilling injury , a physiological disorder that affects plants at any developmental stage (Wang , 1990 ) , is needed . Further , breeders need to develop new cultivars that have enhanced tolerance to chilling temperatures . Therefore , the objective of this study was to develop a test that breeders could use to screen their breeding lines for seedling cold tolerance . |