Submitted to: World Congress on Allelopathy
Publication Type: Abstract Only
Publication Acceptance Date: 12/15/2012
Publication Date: 12/19/2012
Citation: Gealy, D.R., Moldenhauer, K., Jia, M.H. 2012. Field performance and genetic makeup of RU1001161, a good quality selection from crosses between weed-suppressive indica rice and commercial U.S. southern long grains. 6th World Congress on Allelopathy. Dec. 15-19, 2011. Guangzhou, China. pg. 114.
Technical Abstract: Sustainable, economically viable weed control is an ongoing challenge in U.S. rice production, particularly in light of increased resistance to herbicides in populations of Echinochloa crus-galli (barnyardgrass) and other weed species. Indica rice lines such as PI 312777 and PI 338046 have been shown to suppress barnyardgrass in southern U.S. rice fields. RU1001161 (STG06L-35-061), a selection obtained from crossing between PI 338046, Katy, PI 312777, and Drew, was first identified as a potentially weed-suppressive selection in drill-seeded field trials in 2008. It has also been confirmed to exhibit commercial quality and yield in several locations over several years encompassing large environmental variations (e.g. record rainiest season and near-record hottest seasons). In some tests, it has been nearly as weed-suppressive as PI 312777, and more suppressive than non-suppressive cultivars such as Katy and Lemont. By mid-season under optimum conditions, RU1001161 suppressed barnyardgrass in a visually distinctive manner (similar to suppression by PI 312777), reducing the weed’s growth and sometimes yellowing its leaves slightly. SSR microsatellite marker analyses are being used to assess introgression of DNA from indica parental lines into RU1001161 to identify potential chromosomal locations associated with weed suppression. From 2008 to 2010, RU1001161 generally was suppressive to barnyardgrass. However, in 2011 weed pressure was unusually high, which has resulted in little weed suppression by RU1001161. High winds and heavy rains late in the season have subsequently caused extensive lodging and crop loss. It is unclear whether RU1001161 can produce consistent weed suppression under variable environments such as those experienced in Arkansas rice fields in recent years. It should be noted, however, that the environmental variability during this time period was as extreme as any on record. The potential for such variations indicates that RU1001161 and other suppressive cultivars probably will require supplemental weed control inputs that may need to be adjusted from year-to-year. RU1001161 is presently serving as a parental line in the traditional breeding program at University of Arkansas.