Submitted to: Weed Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 28, 2012
Publication Date: July 1, 2012
Citation: Gealy, D.R., Yan, W. 2012. Weed suppression potential of 'Rondo' and other indica rice germplasm lines. Weed Technology. 26:517-524. Interpretive Summary: Weeds are one of the most difficult and expensive pests to control in rice production fields. Some rice cultivars have been identified that have natural weed suppressive capabilities. A new high-yielding rice cultivar, 'Rondo', originally derived from a cultivar from China through mutation breeding, has been released for production in U.S. rice systems. It is resistant to several important rice diseases, and appears to be suppressive to major rice weeds like barnyardgrass. We evaluated the weed suppression potential of Rondo, a sister line (4484-1665), and other indica cultivars against barnyardgrass in field plots in Stuttgart, AR, using very low herbicide inputs. In the presence of weeds, these varieties produced grain yields comparable to those of highly weed-suppressive standards. Their yields were about 50% greater than those of common non-suppressive commercial varieties. Rondo is presently being used in commercial organic rice production fields in Texas because of its high yield, and an ability to suppress or tolerate rice pests, including weeds. Our results suggest that its ability to suppress weeds is better than that of many commercial varieties, and it will be well-suited to production of rice in organic or low-herbicide-input systems.
Technical Abstract: A high-yielding indica rice, 'Rondo' (4484-1693; PI 657830) which carries resistances to major rice diseases, was previously developed. We evaluated the weed suppression potential of Rondo, a sister line (4484-1665), and other indica lines against barnyardgrass in field plots in Stuttgart, AR, using minimal herbicide inputs in two three-year studies. Under weed pressure, Rondo and the sister line generally produced yields that were comparable to those of weed-suppressive indica standards and approximately 50% greater than those of commercial cultivars such as 'Kaybonnet', 'Katy', and 'Lemont' which do not have weed suppressive properties. Rice yield under weed pressure was correlated with weed-free yield and mature height. Indicas tended to produce more tillers than the commercial cultivars, but tillering was not strongly correlated with weed suppression or yield under the weed density used in these tests. Rondo is presently being used for commercial organic rice production in Texas, in part due to its high yield potential and ability to suppress or tolerate rice pests, including weeds. Our results suggest that the weed-suppressive ability of Rondo and the other indicas evaluated in this study are superior to that of many commercial cultivars.