Farm and Field

Scientists engineer crops to conserve water, resist drought

By Herald-Whig
Posted: Apr. 15, 2018 12:01 am

Scientists for the first time have improved how a crop uses water by 25 percent without compromising yield by altering the expression of one gene that is found in all plants.

The research is part of the international research project Realizing Increased Photosynthetic Efficiency that is supported by the Bill and Melinda Gates Foundation, the Foundation for Food and Agriculture Research and the U.K. Department for International Development.

"Crop yields have steadily improved over the past 60 years, but the amount of water required to produce one ton of grain remains unchanged -- which led most to assume that this factor could not change. Proving that our theory works in practice should open the door to much more research and development to achieve this all-important goal for the future," RIPE Director Stephen Long said.

The international team increased the levels of a photosynthetic protein (PsbS) to conserve water by tricking plants into partially closing their stomata, the microscopic pores in the leaf that allow water to escape. When stomata are open, carbon dioxide enters the plant to fuel photosynthesis, but water is allowed to escape through transpiration.

PsbS is a key part of a signaling pathway in the plant that relays information about the quantity of light. By increasing PsbS, the signal says there is not enough light energy for the plant to photosynthesize, which triggers the stomata to close because carbon dioxide is not needed to fuel photosynthesis.

"Making crop plants more water-use efficient is arguably the greatest challenge for current and future plant scientists," co-first author Johannes Kromdijk said. "Our results show that increased PsbS expression allows crop plants to be more conservative with water use, which we think will help to better distribute available water resources over the duration of the growing season and keep the crop more productive during dry spells."

Dicamba and 2018

For many soybean producers, the 2017 growing season will be a hard one to forget after widespread dicamba use in dicamba-resistant soybeans caused equally widespread off-target damage.

The U.S. Environmental Protection Agency issued amendments to XtendiMax, Engenia and FeXapan labels, but University of Illinois weed scientist Aaron Hager says the amendment won't be enough.

He provides some steps to achieve success with dicamba in 2018 including:

º Plant dicamba soybean seed into a weed-free seedbed. This can be achieved through the use of preplant tillage, effective burndown herbicide(s) or a combination of tillage and burndown.

º Select and apply within seven days of planting a soil-residual herbicide that targets the most problematic weed species. If desired (and labeled), add dicamba and an appropriate buffer.

º Scout fields 14 days after planting. Apply dicamba at 0.5 pound per acres when weeds are shorter than 3 inches tall and when conditions allow for the application. Consider adding an approved soil-residual herbicide to the tank mix.

º Scout treated fields seven days after the dicamba application. If control is not complete or another flush of weeds has emerged, consider using non-dicamba options for complete control. Examples include alternative herbicides, cultivation and hand rogueing. The goal should be zero weed seed production.

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