This project is funded by the High Plains Underground Water Conservation District, Texas Corn Producers Board, Texas Department of Agriculture, and the Ogallala Aquifer program funded by the U.S. Department of Agriculture-Agricultural Research Service.

"Once you stress corn you will see leaf rotting, reduced plant height, stapling traits – that's what you (the producer) are seeing," Xu said. "But for breeders, what is most important is what happens inside the husks, the ears. That takes a lot of labor; we have to hand harvest the ears and rate for seed setting and grain quality, those kinds of things."

Those traits are what his selections are based upon, he said.

"At the end of the day what you really care about is still yield, yield, yield," Xu said.

The plots at Etter are planted under a center pivot irrigation system and then watered simultaneously at four levels of crop water use or evapotranspiration, also known as ET: 100 percent; 75 percent; 65 percent and 50 percent.

Xu said irrigation water management is a key part of his breeding tests.

Finding best combination

"What is the best combination to choose hybrids and plant population and irrigation scheduling?" he said. "We have 10 hybrids growing under each of those regimes with three plant populations: medium, high and low."

Thomas Marek, AgriLife Research senior research engineer and superintendent of the research field, said the target is to apply about 32 inches of water, which is equal 100 percent ET, a combination of rainfall, irrigation and stored soil moisture.

The requirement of 32 inches is down from 36 inches in the past due to improved genetics, Marek said.

The plant populations used in the breeding trials are: 33,000 plants per acre for high, 28,000 plants per acre for medium and 23,000 plants per acre for low.

In 2008, under 100 percent ET, the average yield was 266 bushels per acre for the high population, 255 bushels for the medium and 234 bushels for the low, Xu said. Under 75 percent ET, the yields were 268 bushels per acre, 263 bushels and 255 bushels in the medium and low, respectively.