Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: June 24, 2011
Publication Date: July 1, 2011
Citation: Burke, J.J. 2011. Cotton Flowers: Pollen and Petal Humidity Sensitivities Determine Reproductive Competitiveness in Diverse Environments. Book Chapter. p. 26-35. Technical Abstract: Genetic diversity in reproductive abiotic stress tolerance has been reported for cotton [Gossypium hirsutum (L.)] based upon the percentage of anther dehiscence of mature pollen in adverse environments. This study investigated the abiotic stress tolerance of mature pollen and identified genetic variability among six cotton lines. Similar high temperature sensitivities were observed for the SG248, STV474, DP565, NM67, Acala maxxa, and Phy72 pollen. Genetic diversity in pollen viability was observed following a 6.5 h exposure to 25% relative humidity (RH). NM67, DP565, and SG246 exhibited less inhibition of pollen germination than STV474, Acala maxxa and PHY72. Similar pollen water contents were observed for all lines. Genetic diversity in pollen tube length development at 25% RH compared with 80% RH was observed. Acala maxxa and Phy72 pollen produced tube lengths of 35-40% of controls at 80% RH, while STV474, SG248, DP565, and NM67 exhibited tube lengths 50-60% of controls. Pollen water uptake studies showed faster uptake in PHY72 and AM than the other lines. Competitive pollinations showed faster germination of PHY72, AM and SG248 pollen compared to STV474, DP565 and NM67. These findings show genetic differences in cotton pollen sensitivities to water uptake and water loss. Our findings provide breeders with a previously unexplored reservoir of genetic diversity associated with reproductive abiotic stress tolerance.