The Cultivated Asian Rice(Oryza sativa L.) being a highly domesticated crop, has several major pathogens due to its long history of dependence on humans. Early breeding efforts during the green revolution focused more on grain yield because of pressing worldwide problem on poverty and population growth. In the past two or three decades, however, disease resistance has been included as one of the major objectives of breeding programs worldwide.
Last month, we tackled bacterial leaf blight, a disease caused by a bacterium and occurs frequently during the wet season. To continue with our series on major diseases in rice, we will discuss rice blast, a fungal disease common in aerobic and upland conditions.
ECONOMIC IMPORTANCE
Rice blast has been reported in at least 85 countries worldwide. In temperate countries, it is highly destructive in lowland rice, while in tropical countries like the Philippines, it primarily affects upland rice and lowland rice grown in aerobic and drought conditions. In India, more than 250,000 tons of rice are being lost annually, which is about 1.0 percent of the county’s yield. In Japan, the disease infects more than 850,000 hectares of ricefield.
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Posted on November 25th, 2008 under Rice. Tags: Disease, Rice. Comments: None