Submitted to: Plant and Soil
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/4/2013
Publication Date: 1/23/2013
Publication URL: http://handle.nal.usda.gov/10113/58006
Citation: Gealy, D.R., Moldenhauer, K., Jia, M.H. 2013. Field performance of STG06L-35-061, a new genetic resource developed from crosses between weed-suppressive indica rice and commercial southern U.S. long-grains. Plant and Soil. 370(1):277-293. Interpretive Summary: Sustainable weed control is challenging in U.S. rice production, due to increasing development of herbicide-resistant weed populations. Some rice lines of tropical origin are known to produce high yields and to suppress the troublesome weed, barnyardgrass, by excreting weed-inhibiting chemicals in a process known as allelopathy. Unfortunately, these lines have inferior agronomic and grain quality traits that do not meet U.S. commercial standards. In collaboration with University of Arkansas, ARS scientists at Stuttgart, AR developed a germplasm line STG06L-35-061 from a double cross between weed-suppressive rice accessions and non-suppressive commercial rice cultivars, which is a long-grain type, and possesses commercially acceptable agronomic traits, grain quality, and cooking quality, as well as weed suppression activity. DNA fingerprinting analyses indicated that small sections of DNA located on chromosomes 1 and 3 of selection STG06L-35-061 originated from the weed-suppressive parents, and thus may be a source of its weed suppression activity. This is the first improved rice cultivar in the U.S. that was derived from allelopathic parents, and may be useful in organic rice or other reduced-input production systems.
Technical Abstract: Weed control is a major challenge in U.S. rice production, particularly in light of increased resistance to herbicides in weed populations including Echinochloa crus-galli (L.) Beauv. (barnyardgrass). Indica rice cultivars can produce high yields and suppress barnyardgrass, but have not been commercially acceptable in the U.S due to inferior agronomic traits and grain quality. A breeding program was undertaken in Arkansas with the objective of combining the high yield and weed-suppressive characteristics of indica cultivars with commercially acceptable grain quality and plant types typical of southern long-grain tropical japonica cultivars. STG06L-35-061, a selection obtained from crossing indica (PI 338046 and PI 312777) and commercial tropical japonica (cv. Katy, and cv. Drew) rice, was identified as a potentially weed-suppressive selection in 2008. In some tests, its weed suppression has been nearly as high as that of PI 312777, and greater than that of its commercial parents. Its main crop yield potential is commercially acceptable, similar to Drew and cv. Cheniere, and is intermediate between PI 312777 and Katy. Its milling quality and cooking quality potential are similar to other long-grain commercial cultivars. SSR marker analyses identified introgressions from the indica parents into chromosomes 1 and 3 of STG06L-35-061.