Finbarr G. Horgan, International Rice Research Institute, Los Baños, Philippines
A workshop with the title ‘New Paradigms in Ricehopper Resistance’ will be held at IRRI, Los Baños – Philippines, between 18 and 22 October 2010. The workshop is supported by ADB, CSISA (Bill and Melinda Gates), the Japanese Ministry of Agriculture and IRRI. A separate, concluding session will be held at the third International Rice Congress in Hanoi on 9 November 2010. The workshop will bring together over 30 scientists from Asia, Europe and Latin America, each working on issues of host-plant resistance. The scientists will join delegates from IRRI during four days of deliberations addressing paradigms related to the application of varietal resistance for the management of planthoppers in Asia. These experts in plant genetics and breeding, entomology, ecology and sociology are expected to evaluate the utility of current paradigms and create a consensus for new, constructive ideas to facilitate advances in the development and deployment of resistant varieties.
Over the past 5-10 years, white-backed and brown planthoppers have seriously limited rice production in South and South-East Asia and many national institutes are anxious to use new resistance sources to combat these insects. Researchers can help deliver improved planthopper-resistant varieties to national systems with the aid of recently discovered rice resistance genes that have the potential to impede the build-up of hopper populations. Furthermore, advances in molecular genetics will speed-up the introgression of these genes into modern high-yielding varieties. Expectations are high; however, with planthopper populations currently at unprecedented high densities throughout much of Asia, scientists will need to realistically evaluate the potential impact that resistant varieties can have. Improved impact will require the development of optimal deployment strategies based on contemporary and relevant entomological field-data.
Experience has shown that hoppers can adapt to some resistant varieties within 2-3 years, such that current deployment strategies are unsustainable. During the workshop, scientists hope to initiate research and planning for resistance management associated with conventionally-bred, planthopper-resistant varieties: Management strategies that are specific to the Asian context will be sought, which demands input and advice from social scientists, geographical information analysts, evolutionary ecologists and economists. This is a new field that has been overlooked in the past, but can initially draw concept support from work on the management of transgenic-resistance. At the workshop, directions for resistance-management research as related to conventionally-bred varieties will be mapped and promoted.
Scientists recognize that they hold often widely differing opinions and that sometimes confusion exists around issues of planthopper adaptation (‘biotypes’), screening designs, the application and value of NILs (near isogenic lines) and PYLs (pyramided lines), and the impact of hybrid varieties on planthopper community structure and/or population densities. After the workshop, delegates should have developed improved definitions of such concepts to help elucidate their applications in the research and development of improved planthopper-resistant rice varieties.
Details available in workshop announcement.