Study aims to cut wheat losses due to drought stress
Texas AgriLife Research scientists are trying to make the best of an “extreme” situation.
Drought conditions crippled wheat crops this past year, but drought is not new; it is expected to continue and needs to be addressed.
“Texas AgriLife Research is building a very strong team to study the drought tolerance in wheat in the Texas Panhandle, which is one of the best environments in the world to work on drought,” says Jackie Rudd, AgriLife Research wheat breeder, Amarillo.
During 2011, drought stress resulted in the loss of about 240 million bushels of winter wheat in the Southern Great Plains. Texas wheat production was down 80 million bushels from the 2010 crop, Rudd says, which is “close to a $500 million hit on the Texas economy at today’s wheat prices.”
• Texas AgriLife Research work aims at reducing wheat drought losses.
• Team looks at different angles of drought stress with latest science.
• Researchers are studying how different top varieties react to drought.
The team will look at different angles of drought stress in wheat with different expertise, but all with the same objective in mind: Develop wheat varieties for the variable and unpredictable High Plains’ environment, Rudd says.
Wheat is the second-most important cereal crop in the U.S., and winter wheat, planted on 70% of the cultivated wheat area, often suffers reduced yields due to periodic drought.
Rudd is joining forces with Qingwu Xue, AgriLife Research crop stress physiologist; Shuyu Liu, AgriLife Research small-grains geneticist; and Srirama Krishna Reddy, a postdoctoral research associate, to take drought studies from the field to genetic laboratories and back to producers with more drought-tolerant wheat varieties that can reduce the yield losses.
“We chose three wheat varieties that are all among the top yielding under irrigation, but they differ in their yield response to drought,” Rudd says. “The next step is to determine what is going on inside the plant and use this understanding to move to the next level.”
The three AgriLife Research-produced wheat varieties — TAM 111, TAM 112 and TAM 304 — are widely planted, making up 3.25 million acres in 2011 on the Southern Great Plains. While it is known that each has a different response to water stress, the physiological and molecular basis of their adaptation is unknown.
TAM 112 is best when the drought is season-long like in 2011, Rudd notes. TAM 111 can take intermittent dry spells very well, but needs rain from time to time. TAM 304 yields great when fully irrigated, but usually is not in the top ranks in dry years.
Team members already have learned a lot by collecting data during two contrasting years of rainfall. 2010 was a good year for wheat yield, and 2011 was one of the driest years on record.
“Initially, we propose to use physiological measurements and yield parameters to evaluate the impact of specific drought-stress treatments on the phenotype and physiology of the plants in controlled greenhouse and field conditions,” Xue says.
“We will then employ a systems biology approach involving state-of-the-art science using high-throughput RNA sequencing, proteomic, metabolomics and hormonomic technologies to elucidate the drought-tolerance mechanisms of the above-mentioned varieties at molecular and whole-plant levels,” Krishna Reddy adds.
“We expect to identify the key genetic regulators of drought tolerance and their biochemical pathways and interactions at multiple levels,” Liu says. “That will enable us to design more effective molecular markers to be used in screening breeding populations for wheat improvement.”
Putting tools to use
The results will be validated under field conditions with a wide range of wheat genotypes. Then wheat breeders can apply the molecular tools to screen for and target drought-tolerance genes in various breeding programs, Liu says.
Rudd says the knowledge generated will help to accelerate variety development in the U.S. and in other similar environments throughout the world, and ultimately result in the release of drought-stress tolerant and high-yielding wheat varieties that benefit producers.
“Improved genetics cannot replace timely rains, but we have made significant improvements in drought tolerance through traditional plant breeding, and further improvements are likely in the future,” Rudd says. “Preliminary projects supported by the Texas Wheat Producers and the federally funded Ogallala Aquifer Program have given us valuable insight into our past accomplishments and a clear direction for future research.”
Ledbetter is with the Texas A&M Agriculture Communications, Amarillo.
This article published in the February, 2012 edition of THE FARMER-STOCKMAN.