|Miklas, Phillip - Phil|
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/21/1996
Publication Date: N/A
Interpretive Summary: Common bean production in the humid tropics would benefit from the selection of varieties with greater levels of resistance to web blight disease. This will require a screening technique to detect moderate levels of resistance. We developed a greenhouse droplet inoculation method that is sensitive enough to detect moderate levels of physiological resistance to web blight. This resistance was highly heritable indicating that efficient progress in breeding for physiological resistance to web blight could be made by selecting for reduced lesion size. Varieties with resistance to web blight disease will yield more and require fewer pesticides to produce. Thus, resistant varieties will increase income to farmers and through reduced chemical use provide for a safer environment and food stuff for human consumption.
Technical Abstract: Web blight is a devastating disease of common bean in the humid tropics. Greenhouse experiments evaluated the effectiveness of a droplet inoculation technique for screening five segregating populations for resistance to web blight. Significant differences in lesion size were detected among lines within each population. Narrow sense heritability estimates for web blight treaction ranged from 0.61 to 0.79. These relatively high heritabilities suggest that selection for smaller lesion size may be effective in earlier generations. Physiological resistance to web blight, as measured by lesion size using the droplet inoculation technique, will need to be combined with disease avoidance traits such as erect architecture to obtain effective resistance in the field. Five lines from one population with smaller lesion sizes in the greenhouse had moderate to low levels of web blight infection in field experiments conducted in Puerto Rico and the Dominican Republic.