|Danka, Robert - Bob|
Submitted to: Journal of Cotton Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/15/2013
Publication Date: 12/31/2013
Citation: Zumba, J.X., Myers, G.O., Clawson, E.L., Miller, D.K., Danka, R.G., Blanche, S.B. 2013. Developing hybrid cotton (Gossypium spp.) using honey bees as pollinators and the Roundup Ready® Phenotype as the selection trait. Journal of Cotton Science. 17(4):293-301. Interpretive Summary: Cotton is an important textile crop that has been demonstrated to have better vigor and increased fiber production when hybrid plants are grown. Commercial use of such hybrids between standard cotton lines has been limited in the United States because of technical and economic challenges to producing hybrid seed. We sought a simple, cost-effective method of seed production that could utilize the benefits of hybrid vigor to increase yields. We tested whether we could efficiently use honey bees to pollinate six conventional female cotton lines with a Roundup Ready® (glyphosate resistant) male donor line. Non-hybrid seed was eliminated from each of two offspring generations by spraying seedlings with glyphosate. First-generation hybrids (from cross pollination by honey bees) showed hybrid vigor in most crosses; in the two best crosses, fiber yield increased by 21-33% over the best parents. Second-generation seed from self pollination of these two first-generation hybrid lines showed 20-21% greater fiber yield over the parents. Fiber quality characteristics were not significantly different from those of the parents. This novel method of crossing and selection suggests a simple way to achieve hybrid vigor in cotton. Further testing will be required to determine the best combination of parental lines that may be used for commercial development of hybrid cotton.
Technical Abstract: Cotton (Gossypium spp.) is the most important textile fiber crop in the United States (US). Hybrid cotton is grown in several countries but the use of hybrids in the US has been limited 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 the Roundup Ready® gene to facilitate identification of hybrid seed. This research was conducted from 2005 to 2007 in Louisiana. Six hybrid populations were developed between non-transgenic and transgenic lines manually or by caging with honey bees (Apis mellifera L.) as pollinators. In 2007, F1, F2, and parents were field tested in a randomized complete block design at two locations. All F1 hybrid populations exhibited heterosis compared to the best parent. The crosses LA1110023/PHY410R and ARKRM24-12-04/PHY410R exhibited the highest degree of high-parent heterosis for yield averaging 33.1% and 20.6% increases in the F1, respectively, and 20.9% and 19.5% increases in the F2, respectively. Fiber quality measurements did not display significant heterosis in the F2 population relative to the best parent. Using male contributors containing the Roundup Ready® trait for selection, conventional female lines, and honey bees as pollinators proved to be a viable method for developing F2 hybrid cotton lines.