December 6, 2002
Alfalfa varieties make the 'cut' in Purdue performance trials
WEST LAFAYETTE, Ind. To measure the performance of today's alfalfa varieties one need only compare them with varieties of the past. What better way than to plant an alfalfa variety that's nearly 50 years old?
Purdue University Cooperative Extension Service forage researchers do just that when they conduct alfalfa performance trials. The results of their most recent study are contained in Extension Bulletin B-817, "Performance of Alfalfa in Indiana, 1999-2002."
The publication is available through county offices of Purdue Extension and on the Internet.
"This publication gives you an idea of what available seed is out there and how it will yield if managed correctly," said Jeremy Sweeten, a graduate research assistant in Purdue's Department of Agronomy and performance trial supervisor. "It also gives a producer a range of varieties to pick from of the higher yielding ones. With that information they can work with the seed dealer that they're familiar with or is close to them."
Researchers tested 31 commercially available alfalfa varieties at Purdue agricultural centers near West Lafayette and Wanatah, Ind. The varieties represented 22 seed companies and dealers. Thirty-eight experimental entries also were tested.
Purdue's performance trials measure dry matter yield in alfalfa test varieties. They also show how varieties stack up against a benchmark variety from a generation ago.
Alfalfa is a legume widely grown for hay and forage.
"We use as our check variety Vernal, which goes back to 1953," said Keith Johnson, Extension forage specialist. "We're fortunate that we're still able to get certified Vernal seed. I believe it provides a good measure of yield improvement through the decades."
Vernal is a winter-hardy variety with bacterial wilt resistance. It is still marketed to farmers.
"We have seen yield improvement over the years as compared to that variety," Johnson said. "It may be as little as 15 percent some years, but if you get the right pathogen attack, you'll find that the top varieties will be 50 percent higher yielding than a variety of the past, like Vernal."
Overall, alfalfa plots performed well under less-than-ideal weather conditions this year, Sweeten said.
"We saw 9 to 10 tons of dry matter yield per acre this year. That's pretty decent," he said. "About the only way a producer could get that is if they were chopping for silage, because there are measurable field losses when dry hay production occurs.
"This year we took four cuttings at both performance trial locations. In some years we have been able to take five, but this year the rainfall wasn't ample enough in late summer to get that fifth cutting up and going before the harvest restriction."
While late season dryness prevented additional production, early season storms delayed alfalfa seeding, Sweeten said. Soils were wetter at the Purdue Agronomy Research Center near the university campus than at the Pinney-Purdue Agricultural Center at Wanatah, he said.
Researchers manage the trial plots the same way farmers maintain their alfalfa crops. Pastures are fertilized and, if necessary, sprayed for alfalfa weevil and potato leafhopper two major alfalfa pests.
A few varieties were entered in trials where no pesticides to control potato leafhopper were applied. Many alfalfa varieties have some resistance to the potato leafhopper because they have glandular hairs, which reduce potential losses caused by the insect.
"I was impressed with the potato leafhopper trial results from Wanatah," Johnson said. "Potato leafhopper resistant varieties are certainly worth considering maybe more so today than when they were first released, because there is more resistance in the product."
Sweeten agreed that insect and disease resistance should factor into a farmer's decision when choosing alfalfa varieties.
To view "Performance of Alfalfa in Indiana, 1999-2002" online, log on and click on the publications link.
Writer: Steve Leer, (765) 494-8415, firstname.lastname@example.org
Sources: Jeremy Sweeten, (765) 494-5825, email@example.com
Keith Johnson, (765) 494-4800, firstname.lastname@example.org
Ag Communications: (765) 494-2722; Beth Forbes, email@example.com; http://www.agriculture.purdue.edu/AgComm/public/agnews/
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Purdue News Service: (765) 494-2096; firstname.lastname@example.org