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New lettuce resistant to bacterial leaf spot

Seven new iceberg lettuce breeding lines with resistance to bacterial leaf spot (BLS) have been released by Agricultural Research Service (ARS) scientists.

BLS, caused by the pathogen Xanthomonas campestris pv. vitians, is an important disease of lettuce in California. Iceberg lettuce is the most popular type of lettuce eaten in America. Nearly all of the lettuce consumed in the United States is produced domestically. Two states, California and Arizona, produce more than 90 percent of the country's commercial lettuce.

Occurring on both leaf and head lettuce varieties, BLS thrives in wet, cool conditions. It is most serious in early spring and late fall, when it is most likely to rain in California. BLS causes black spots to form on lettuce leaves. These black spots can merge and create papery, brown-to-black patches on the head. Upon harvest, farmers must peel and discard the leaves to remove the patches, resulting in smaller heads that command less money.

by S. C.
14 april 2009, Technical Area > Science News