Submitted to: American Journal of Plant Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/27/2015
Publication Date: 1/30/2015
Citation: Gitz, D.C., Baker, J.T., Burke, J.J., Xin, Z., Lascano, R.J. 2015. The microenvironment within and pollen transmission through paper and polyethylene sorghum pollination bags. American Journal of Plant Sciences. 6:265-274.
Interpretive Summary: Bagging sorghum panicles in germplasm maintenance or breeding operations is a labor intensive exercise. Bird-resistant spun polyethylene bags reduce the need for laborers to repeatedly walk the field to cover plants with additional bags as bird damage occurs during seed development, they exclude pollen as well as the conventional bags, and they lead to seed yields indistinguishable to yields from paper. These bags are easily made to different dimensions so they can be adapted to sorghum with large open panicles such as broom sorghums. Pollination bags induce micro-environmental changes that should be considered when designing experiments. Hot pin perforated polyolefin bags might be suitable for greenhouse applications where mold is a concern and where ambient air velocities are low or in field settings where pollen production by the panicles being covered is high.
Technical Abstract: Bird damage is a problem in sorghum breeding and germplasm maintenance operations. Paper pollination bags are damaged by rain and provide minimal deterrent to birds. Earlier we reported upon bird resistance of spun polyethylene pollination bags. Herein, we report the potential for pollen transmission through, and the microenvironment within, hard form (HfT) and soft form (SfT) spun polyethylene pollination bags as compared to traditional paper pollination bags. Within paper pollination bags morning temperatures were 10-15 °C above ambient and high temperature excursions as high as 45 °C were measured. Heating in Sft and HfT was 25% and 50% that of Paper, respectively. Temperature differences between bags were attributed to differences in albedo and air permeability of the bag materials. No difference in pollen transmission through Paper and HfT was found. Although SfT allowed 35-40% wind borne pollen through the pores as compared to controls, male sterile plants covered with SfT produced only 30 seeds/panicle, about 1% of a self-pollinating fertile plant. Our results suggested that SfT could adequately reduce or eliminate cross-pollination in self-pollinating plants while maintaining near ambient environmental conditions.