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United States Department of Agriculture

Agricultural Research Service


item Gealy, David
item Dilday, Robert

Submitted to: Proceedings of Southern Weed Science Society
Publication Type: Abstract Only
Publication Acceptance Date: 2/1/2001
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: As part of an ongoing effort, 57 rice cultivars were evaluated in a drill- seeded rice system at Stuttgart, AR in 2000 to determine their abilities to suppress barnyardgrass (BYD) and to maintain optimum yields in the presence of BYG. Foreign rice lines previously determined to be weed-suppressive were compared to domestic and foreign commercial cultivars and various advanced breeding lines, crosses, and hybrids. Visual BYG control ranged from 41 to 81% across all rice lines. Several commercial cultivars and advanced breeding lines (including Drew, LaGrue, and the advanced line RU9901127) suppressed BYG about as well as did the weed-suppressive group. Other cultivars and breeding lines (including Lemont, Lacassine, and RU9601096) were among the least suppressive to BYG. Semi-dwarf mutants were poor weed competitors. The rice entries that provided the greatest visual control of BYG often were able to maintain near optimum yields (relative to weed-free) under those conditions. However, some of these rice lines produced extremely low actual yields. Rice yields in BYG- infested plots ranged from 35 to 96% of the weed-free optinum and from 1540 to 6600 kg/ha. In a separate, 1998 field study, mixed root samples of rice (C3 species) and BYG (c4 species) extracted from soil were analyzed using **13C discrimination analysis to determine the distribution of roots of each species within and between rice rows. The weed-suppressive rice line, PI 312777 produced relatively greater root mass than did the commercial cultivar, Lemont. Within the row, Lemont and PI 312777 root masses were three and ten times, respectively, that of BYG. Between rows, Lemont produced only one third the root mass of BYG whereas PI 312777 and BYG root masses were equal. PI 312777 roots expanded into the soil profile much

Last Modified: 10/16/2017
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