ARS | Publication request: Cotton Flowers: Investigating the Inheritance of Pollen Humidity Sensitivities and Flower Shape

Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Abstract Only
Publication Acceptance Date: October 27, 2010
Publication Date: January 6, 2011
Citation: Burke, J.J. 2011. Cotton Flowers: Investigating the Inheritance of Pollen Humidity Sensitivities and Flower Shape [abstract]. National Cotton Council Beltwide Cotton Conference. Paper No. 152.

Interpretive Summary: Yield reductions commonly occur because of environmental stresses during flowering. Our previous research showed that genetic diversity for the sensitivity of cotton pollen to these stresses exists among cotton varieties. This study investigated the inheritance of pollen dehydration tolerance. The study also evaluated the inheritance of cotton flower shape (open versus cupped petals) because cupped flowers maintain higher humidity levels around the pollen than do flowers with open petals. The results of this study suggests that pollen dehydration tolerance is maternally inherited and that flower shape is paternally inherited. These findings provide cotton breeders with insights into breeding strategies to enhance cotton’s reproductive stress tolerance.

Technical Abstract: This study investigated the inheritance of flower shape (open versus cupped petals) and abiotic stress tolerance of mature cotton [Gossypium hirsutum (L.)] pollen. Inheritance of flower shape was evaluated in the F1 plants from bi-directional crosses of Stoneville 474 (STV474) by Phytogen 72 (PHY72); Deltapine 565 (DP565) by Suregrow 248 (SG248); and New Mexico 67 (NM67) by PHY72. Additionally, flower shape was evaluated in F2 populations of STV474 by PHY72. The inheritance of the moisture sensitivity of pollen was evaluated in F1 and F2 populations of bi-directional crosses between STV474 by PHY72; DP565 by SG248; and NM67 by PHY72. Molecular markers were used to evaluate the parents and F1 seedlings to ensure that the plants evaluated were F1s and not selfed offspring. Analysis of the F1s was completed and seed harvested from mature bolls for the development of Recombinant Inbred Lines. Forty flowers from each F1 plant were photographed and ranked from the most cupped to the most open flower shape. The flower shape of the 20 and 21st ranked flowers were phenotyped as an indicator of mean flower shape for the F1 plant. F2 plants (250 for each directional cross, 10 replicates per line) were evaluated for flower shape of the STV474 by PHY72 recombinant population by rating flower openness on a scale of 1 (open) to 4 (closed). Forty flowers from each F1 plant were evaluated for the time it took a pollen grain to rupture in 0.8 M sucrose. F2 plants (250 for each directional cross, 10 replicates per line) were evaluated for pollen moisture sensitivity in each of the F2 populations of the bi-directional crosses. The results of this F2 population analyses suggest that flower shape is paternally inherited and that pollen moisture sensitivity in maternally inherited. Cotton Incorporated Project #05-703.