In theory, grain sorghum should yield just as much as corn in Kansas, given the same amount of fertilizer and with substantially less water, according to Kansas State University agronomist Tesfaye Tesso.
In practice, this has not yet happened consistently. New experimental lines in advanced testing at K-State are about to change that, however, said Tesso, who is a sorghum breeder with K-State Research and Extension. These advancements are thanks in large part to funding from the Kansas Grain Sorghum Commission.
"Sorghum has high yield potential, much higher than what we're getting now. We know that," Tesso said. "We have been working to find new compatible parental lines that will be able to produce hybrids that can come closer to realizing sorghum's yield potential. At the same time, we need to make sure any new line has an acceptable maturity range, good standability, drought tolerance, good head exsertion, and other necessary agronomic traits."
Tesso began developing promising seed parent lines in 2009, right after he became a member of the agronomy faculty at K-State. He and his team, along with Ramasamy Perumal, sorghum breeder at K-State's Agricultural Research Center-Hays, have been selecting and testing the lines since then.
"There are many challenges to developing seed parent line for release (to seed companies). We have to find out if it will carry over its good traits into a hybrid once it is crossed with a male line. Then we need to find out if it can perform in different Kansas growing environments and in different types of growing seasons," Tesso explained.
All this becomes a challenge in a breeding program with limited land and equipment resources. For that reason, one of Tesso's main objectives is to work with private seed companies who are interested in some of his lines. The companies take the lines they like, cross them with their own male lines, and test the resulting hybrids at several locations.
In 2013, hybrids from some of Tesso's experimental pollinator lines topped the 200-bushel per acre mark on dryland tests in Manhattan, yielding greater than the top commercial check hybrid there and proving that dryland sorghum can achieve yields comparable with that of dryland corn, Tesso said.
In K-State performance tests that year, dryland corn averaged 184 bushels per acre at Manhattan while dryland sorghum averaged 134 bushels per acre. Some of the new experimental hybrids in Tesso's trials either bested or evened out that yield differential between dryland sorghum and corn.
Tests of the experimental lines in 2014 at Hays confirmed the higher yield potential of the new experimental lines compared with the commercial hybrids used as checks, and much higher than the yield of the highest-yielding dryland corn in Ellis County in the 2014 K-State Corn Performance Tests.
"We think these new experimental lines represent a real breakthrough in the yield potential of grain sorghum in the near future. According to our release policy, we will be offering these new pollinator and seed parent lines to commercial seed companies. Some of our new lines already have been released. If the seed companies are able to produce agronomically acceptable hybrids from these lines, there should be a new generation of higher-yielding grain sorghum hybrids coming to producers in the near future," Tesso said.
Tesso's team also has several promising new ALS-resistant lines in advanced stages of development. These lines are resistant to a newly-developed herbicide that inhibits acetolactate synthase (ALS), a plant enzyme.
"We cooperated with a private company to have our new ALS lines tested at one of the company's test locations in Texas in 2014. This was a test on poor ground, but 22 of the test hybrids using our new ALS-resistant seed parent lines out-yielded all of the company's hybrids in the test by an average of 33 bushels per acre. In addition, in 2013 one of the hybrids from our experimental ALS-resistant pollinator lines yielded more than 200 bushels per acre in Manhattan," Tesso said.
From these results, Tesso is confident there will be no yield drag in ALS-resistant sorghum hybrids from his program. These experimental seed parent lines will be re-tested in 2015, and will be released to private seed companies if results continue to be good.
All this is very good news for sorghum producers, said Clayton Short, producer from Saline County and chairman of the Kansas Sorghum Commission.
"I'm excited about these new conventional and ALS-resistant experimental lines from the K-State program. This could help increase the acres of grain sorghum in Kansas," he said.