Steven Linscombe, Schultz, Bruce | 1/9/2007 3:21:57 AM
To keep new varieties on the market is a major priority of the LSU AgCenter’s rice breeding program. And one of the most prolific rice developers in the world is located at the center’s Rice Research Station in Crowley – Steve Linscombe.
"A rice breeder’s work is never finished," Linscombe said. "Even with a good selection of reliable varieties, farming requires continuous improvements in varietal choices to maintain or increase production levels."
The biological process of natural selection eventually makes a variety obsolete. For example, when the LSU AgCenter released Cypress in 1992, it was susceptible to a strain of the fungal disease called blast that was not plentiful. But as Cypress became a dominant rice variety, the disease became more widespread, Linscombe said.
"When we are trying to develop a new variety, we are trying to come up with something with an advantage in more than one trait," he said.
Yield has to be as good or better than a variety’s predecessor or have a clear advantage among other characteristics, such as early maturity, short stature, good milling yield and suitable grain characteristics.
Good ratoon potential is important, as well as adaptability to northern and southern areas of the state.
The tried and true approach is to make numerous crosses of good parent lines, Linscombe said.
"Everything we do is a numbers game," he said. "The more crosses we make, the more populations we look at. The more progeny rows, the more yield tests. Then the better the potential for a good variety."
The breeding program at the Rice Station grows 90,000 different lines a year, and all but a few are eliminated.
"If we release a variety or two a year, we’re doing well," Linscombe said.
More than likely, lines that could become good varieties are discarded because it’s impossible to put all material through yield testing.
A new technology called marker-assisted selection helps breeders screen lines early for specific traits, such as blast resistance.
"It can eliminate many lines that don’t have a particular gene," he said.
Field testing is still required, however, even if genetic testing shows a line has a desired trait.
Marker-assisted selection and another new technology called anther culture along with the winter nursery at Puerto Rico enable new varieties to be introduced sooner, he said. "All these things are just additional assets we have to get to the end product."
Linscombe said selecting plants in the field is based on a wide variety of characteristics. Examples include a plant’s flag leaf erectness, plant height, grain shape and plant maturity.
"What you are looking for out there is a combination of complex, desirable traits," he said.
Linscombe said continuous variety development is necessary.
"It does not have to be a really substantial improvement," he said. "A slight increase can be worth a lot to the industry."
Linscombe said check-off funds are essential to the breeding program. Farmers assess themselves 5 cents per hundredweight to fund LSU AgCenter research projects. This check-off program is up for renewal on Jan. 30. Funds from this program go to the Louisiana Rice Research Board, which distributes the money to research and extension projects to help farmers with production.
"If you look at the value of the research that comes from those check-off dollars and you look at the amount that went into the fund, it’s an exponential amount of benefits to the industry," he said.
Before farmers first agreed to the check-off program, which began in 1974, the rice breeding program depended on funding from state government. That limited the number of breeding lines to no more than 15,000 a year, compared to almost 100,000 grown in 2006.
"The Puerto Rico winter nursery is only possible because of check-off funds," Linscombe said. "That is 100 percent funded by check-off funds."
The time it took to get the variety Cocodrie available to farmers was reduced by two years through use of the winter nursery, he said, and the benefit of that variety alone has been worth the check-off investment made by farmers.