Unsung forage legume can be improved
The value of lablab, an annual tropical legume, as potential quality forage has long been known, but that doesn’t mean it can’t be made a lot better, said a Texas A&M AgriLife Research plant breeder.
Dr. Gerald Smith, AgriLife Research plant breeder at the Texas A&M AgriLife Research and Extension Center at Overton, is currently working with hundreds of crosses looking for superior qualities.
“We need a new forage crop in Texas that fits our seasons and works for us in the summer,” Smith said. “We have a lot of summer annual grasses, but we need a forage legume that works in the summer like those grasses.”
Lablab fits that need very well, he said. It’s a great crop for cattle; they readily graze it and get good weight gains on it, and it’s drought tolerant.
It’s also a great plant for wildlife browsing, particular white-tailed deer, Smith said. And as an added benefit, lablab, being a legume, fixes nitrogen from the air, which offsets high fertilizer prices.
And unlike many other legumes, such as cool-season clovers, lablab seed can be produced in Texas.
“Lablab is deep-rooted and drought and heat tolerant, but does require soil moisture to germinate and establish,” Smith said. “This does narrow the utility of this plant to eastern and central Texas where annual rainfall is at least 30 inches per year.”
Because of all these benefits, Smith has been working with lablab lines for the last 10 years. Rio Verde lablab, which he also developed at the Overton center, was released by AgriLife Research in 2006.
Planted in May, Rio Verde will start flowering in late August and continue producing forage until the first frost. The crude protein of its leaves is 25 percent or higher, and 12 percent in the stems.
As good as Rio Verde is, there is a need for an earlier flowering and more diseaseresistant variety, which Smith is continually working on, he said.
From the hundreds of second-generation crosses he currently has in Overton center greenhouses, Smith is looking for types that not only have improved disease resistance and drought tolerance, but also demonstrate other traits such as small seed size, early flowering and seedling vigor. All these traits will make a better fit into Texas forage-production systems.
To this end, he has crossed existing anthracnose-resistant lines with small-seed, deep-rooting types that are closely related to ‘wild’ lablab lines.
“The parents that we crossed are quite different,” he said. “What we are doing now is selecting for flowering times that will fit Texas.”
Next, he’ll take the most promising progeny to field tests in 2013 and further select for desired traits.
If all goes well with field tests, Smith expects new cultivars to be ready to start the release stage in three years. The approval and subsequent release of seed to seed-production companies usually takes an additional two years. — Robert Burns, Texas A&M Extension