Development of Hybrid Cotton (Gossypium spp.) Using Honey Bees as Pollinators and Roundup ReadyŽ Gene as an Indicator Trait

The use of cotton (Gossypium spp.) hybrids in the US has seen limited use largely due to seed production costs. The objective of this study was to investigate a novel method for the production of F2 cotton hybrids using honey bees as pollinators and Roundup Ready® gene as selection trait.
Six crosses between non-transgenic and transgenic varieties were made in 2005 to obtain F1 cottonseeds using honey bees. In 2006, F2 cottonseed was obtained. In 2007, F1, F2, and parents were field tested in two locations. All crosses exhibited heterosis in the F1 hybrid populations relative to the best parent. The crosses LA1110023/PHY410R and ARKRM24-12-04/PHY410R exhibited a higher degree of heterosis for yield averaging 33.1% and 20.6%, respectively, across locations. Yield heterosis in the F2 population was 20.9% and 19.5%, respectively, and statistically different from the best parent. The ARK9506-40-05/PHY410R cross had yield heterosis averaging 15.6% in the F1 population and 13.5% in the F2 population; however, these were not significantly different from the best parent. Fiber quality descriptors from the crosses did not exhibit significant heterosis in the F2 population relative to the best parent.
In summary, the use of herbicide resistant varieties as males and Roundup Ready® gene as selection trait, conventional varieties as females and honey bees as pollinators, proved to be a viable method for developing F2 hybrid varieties. Further variety testing will be required to determine the best combination of parents.