Seasonal Variation in Flowerbud Gossypol Content in Cotton1
- R. H. Dilday and
- T. N. Shaver2
Flowerbud gossypol content has been associated with a degree of host plant resistance in cotton (Gossypium hirsutum L.), but efforts to increase and stabilize genetic levels have been hindered by an apparent seasonal variation in gossypol content, A 4-year study (1974 to 1977) of two lines having flowerbuds with high levels of gossypol and two cultivars with normal levels of gossypol revealed a significant change in gossypol contents both within and between seasons. The gossypol contents in 1975 were significantly greater than those in 1974 and 1977 for the two lines having flowerbuds with high levels of gossypol. Also, a significant withinseason variation in gossypol contents occurred among all four genotypes that were tested. The coefficient of correlation comparing gossypol contents of the two lines having flowerbuds with high gossypol levels and of the two cultivars were 0.82 and 0.79, respectively. Whereas, the coefficient of correlation comparing the gossypol contents of the cultivars with the high gossypol lines were all less than 0.55. These data show that comparisons of flowerbud gossypol levels within a season should be based on seasonal averages or should be made as close to the same date as possible. There should not be more than a 7-day interval between dates if direct comparisons are to be made among entries within a single season.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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