Submitted to: American Society of Agronomy Meetings
Publication Type: Abstract Only
Publication Acceptance Date: 10/31/2004
Publication Date: 11/4/2004
Citation: Burke, J.J., Percy, R.G. 2004. Vegetative and reproductive stress tolerance in cotton[abstract]. October 31-November 04, 2004, Seattle, Washington. American Society of Agronomy Meetings. 2004 CD-ROM.
Technical Abstract: Cotton germplasm evaluation in the field is sometimes hampered by seasonal variability in weather patterns that fail to provide stress levels at desire developmental stages needed to identify genotypic differences. This study evaluated greenhouse-grown cotton and laboratory techniques to aid geneticists in selection of germplasm with improved heat tolerance. Putative heat tolerant lines (SG248, DP565, and Stoneville 474) and high fiber-quality lines (Phy72, Acala Maxxa, and NM 67) were grown in a greenhouse with a 40C day/ 27C night regime. Heat tolerance of the leaves of the cotton cultivars was evaluated at the 7th mainstem leaf stage. Distinct differences in tissue 'Metabolic Fitness Indices' were observed after a 7h dark incubation at 39C. SG248 exhibited the lowest MFI, followed by DP565 and Stoneville 474. Acala Maxxa and Phy72 had the next highest MFI, and NM67 always showed the highest MFI. Flower fertility was evaluated on three dates by harvesting one flower at random per plant and recording the percent dehiscence of the anthers. NM67 and SG248 showed the greatest fertility, followed by Phy72 and Stoneville 474, and then Acala Maxxa and DP565. The results showed genetic diversity in heat tolerance among the six greenhouse-grown cotton cultivars. Based upon these results, vegetative tissue Metabolic Fitness Indices and reproductive heat tolerance should be determined for each cultivar to obtain a more meaningful measure of cotton heat tolerance.