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Multi-disease resistant chili lines for higher yields and income Monday, September 29, 2008
TAIWAN, China - Almost half of the world`s 28.41 million tonnes of chilies are produced in China, India, Indonesia and Thailand.
Chili is a good source of cash for subsistence farmers, generating up to four times the income of cereal crops under optimal conditions and providing a major source of employment for women. However, average chili yields in the Asian tropics are generally low (about 5-10 t/ha) and unstable due to preand post-harvest diseases.
Severe yield losses are caused by insect-transmitted Cucumber mosaic virus (CMV), Chili veinal mottle virus (ChiVMV) and Chili leafcurl virus (CLCV) as well as fungal diseases such as anthracnose and Phytophthora blight and also bacterial wilt. Smallholder farmers often try to minimize yield losses by applying pesticide cocktails every 3-7 days. Improving the resistance of the crop to diseases is a more sustainable option. If supplemented by improved crop management practices this can improve yields, reduce risks to farmers and produce a crop that is also safer for consumers.
"Understanding the diversity of the pathogens and their virulence is a prerequisite to developing stable multi-disease resistant lines," says Dr. Sylvia Green, the virologist at AVRDC - The World Vegetable Center. In a German-funded project, pathogen isolates were collected in all participating countries, and tested against a broad array of lines with different resistance genes. Efficient specific diagnostic methods for all six pathogens, including molecular markers were developed and shared with the national partners.
The results evoke optimism. Multiple distinct strains of virus and pathogen species causing the diseases have been identified, and several sources of resistance have been detected. These resistant lines have been crossed by participating national agricultural research and extension systems with their preferred local chili cultivars. Advanced selections displaying resistance to as many as four of the target pathogens have been identified, and are currently being multiplied and tested in farmers` fields, using improved management practices such as drip irrigation and starter solutions to further increase yields.
"Sources of resistance and multiple-disease resistant chili lines will be freely distributed as international public goods," says Sylvia Green. "We hope that more than 30% of farmers will adopt the improved chili cultivars and management practices." Chili yields are expected to increase by 20% and the area under production by 10%. Most importantly, pesticide inputs will be lowered significantly, improving the safety of chili farmers and their communities, reducing the environmental impact, and providing safer, lower cost chilies for all consumers.
© 2008 AVRDC - The World Vegetable Center
Source: The World Vegetable Center
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