Plant breeders at the Texas AgriLife Research and Extension Center in Beaumont are working on techniques to improve rice variety yield potential, cold tolerance, nutritional value, disease resistance and other values.
Breeders and geneticists commented on some of their research at the recent field day, moved indoors this year because of heavy July rains.
Dr. Rodante Tabien, plant breeder and geneticist, said the Texas rice breeding program is producing “new and valuable breeding material for genetics studies and new variety releases.” He said the program has “greatly increased genetic stock to include a diverse collection of accessions, mutants, and elite lines.”
In 2009 the program had nurseries and replicated yield trials. “In the observational nursery with 2,647 entries, preliminary selection identified 448 lines for further evaluation and 136 lines as possible yield candidates in 2010,” Tabien said.
He said Texas had 26 breeding lines in the Uniform Regional Rice Nursery in 2009 and 38 this year. In addition to the elite lines from Texas the URRN also includes lines from Arkansas, Louisiana, Missouri and Mississippi.
“Our program has 13 promising lines,” Tabien said. He said RU0703144 is one of the best lines so far.
He said the program is looking at aromatic rice, Clearfield rice and varieties with cold tolerance. Dr. Omar Samonte, assistant plant breeder, is working on three-line hybrid rice, a process that includes a male sterile line with non-viable pollen and no seed. A parent line and R-line, with a restorer gene, makes the hybrid fertile.
Samonte said hybrid rice provides a yield advantage over inbred varieties. He said hybrid advantage in Texas in 2008 was 7 percent but increased to 21 percent in 2009.
Dr. Shannon Pinson, USDA-ARS geneticist, said her job is to “find genes and develop techniques to help breeders be more efficient. We identify good genes and bad ones,” she said. Use of genetic markers, Pinson said, makes plant breeding more precise. She said traits such as early tillering are important in developing higher yielding varieties. “Early tillering is an advantage for improved weed competition and water use,” she said.
“We’re also looking at kernel fissuring and healthier rice. Increasing certain minerals and elements in rice improves the nutritional value.” She said the process will be especially important for organic rice producers.
Dr. Fugen Dou, assistant professor in integrated cropping nutrition management, and Dr. Lee Tarpley, associate professor, plant physiology, discussed variety evaluation for nutrient management improvements and early planting.
“We are testing 16 entries for various agronomic traits on sandy soil at Eagle Lake and clay at Beaumont,” Dou said. “Some of the agronomic data collected will include: main and ratoon crop yield and milling response with fungicide treatment; different planting date and seeding rate effects on main and ratoon crop yield and milling response; the contribution of certain management practices to ratoon crop yield using Cocodrie as the test variety; economic ranking of each entry’s average main, ratoon and total crop net income; and variety characteristics, tillering potential, and growth stage data for variety-specific management.”
Tarpley said early planting may allow growers to avoid flooding during the hottest part of the season and allow ample time for a ratoon crop to develop. “But cool soil early can affect seedling vigor.” A seed treatment may be helpful.
He also said early drain increases harvest flexibility but may affect grain fill. “We’re evaluating a- Tocopherol, Glycine Betaine and Salicylic acid (to prevent oxydative damage). “Further field research is required to justify profitability of these chemical applications for rice farming,” he said.
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