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United States Department of Agriculture

Agricultural Research Service

Title: Differential Responses of U.S. Oryza Sativa (Red Rice) Accessions to Environment, Herbicides, and Disease

Authors
item Gealy, David
item Dilday, Robert
item Lee, Fleet - UA RREC

Submitted to: International Weed Control Congress Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: June 6, 2000
Publication Date: N/A

Technical Abstract: Red Rice (Oryza sativa L.) is an economically important weed in much of the dry-seeded rice produced in the southern United States, and increasingly, throughout the world. It is an especially troublesome weed because it and commercial rice are the same species and can interbreed at low rates. Red rice accessions were collected from Arkansas and other southern rice producing states. The phenotypic diversity of their responses to environment, herbicides, and diseases have been evaluated systematically in greenhouse, field, and laboratory experiments at Stuttgart, Arkansas from 1995 through 1999. Of the approximately 160 entries presently in the red rice collection, about two thirds are strawhull, awnless types and ten are crosses with rice. Red rice plant heights range from as little as those of tall commercial rice cultivars to more than 1.5 m; heading dates range from about one week earlier to several weeks later than typical commercial cultivars; and biomass and tiller production are more than double those of commercial cultivars. While most of the red rice accessions are 'medium- grain' types, some of the crosses are 'long-grain' types, suggesting a long-grain rice parent. The red rice accessions differ moderately in tolerance to standard rates of several herbicides including post-emergence glufosinate and imazethapyr, and pre-plant incorporated molinate, and to cold temperatures. Red rice accessions differ substantially in their resistance to five races of rice blast (Pyricularia grisea), including IC-17 and IB-49, the most prevalent races in Arkansas rice fields. More than 85% of accessions were 'highly resistant' to IB-49. Collectively, this information can be useful in developing control strategies for red rice and in the eventual identification and transfer of desirable genes

Last Modified: 8/22/2014