Submitted to: American Society of Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 9/27/2004
Publication Date: 10/31/2004
Citation: Gibbons, J., Yan, W., Jiang, J., Taylor, K. 2004. Breeding for resistance to straighthead disorder in rice [abstract]. Agronomy Abstracts. 2004 CDROM. Interpretive Summary:
Technical Abstract: Rice plants affected by straighthead disorder are characterized by erect panicles with unfilled florets that give the appearance of "parrot beaks". The disease occurs in irrigated rice of the Southern United States and the Southern Cone of South America. Control measures are the use of resistant cultivars and draining and drying affected fields prior to internode elongation. Field and milling yield losses can be very high in affected fields. The exact causal agent of straighthead is unknown, but affected plants in soil treated with arsenic mimic field symptoms. A field screening method using soil applied MSMA under continuous flooded conditions is used to evaluate cultivars and breeding lines for resistance. Ratings are based on visual observa5tion of spikelet fertility, parrot beaking, and panicle emergence. Currently grown cultivars and experimental breeding lines vary in reaction from moderately resistant to highly susceptible. Newly introduced germplasm has shown high levels of resistance and is being incorporated into locally adapted cultivars. Anther culture of crosses with resistant parents is used for production of resistant progeny. Results of field screening will be presented.