Global sources of pepper genetic resources against arthropods, nematodes and pathogens

Today India is the main producer of peppers especially the hot peppers, albeit mostly for domestic use. The thrips and mites, and the virus diseases transmitted by them along with fungal diseases like fruit rot, powdery mildew, bacterial wilt and leaf spots are the limiting factors in pepper productivity. The solution for managing these pests on a sustained basis exists in adopting eco-friendly approaches like using resistant cultivars. Fortunately huge natural genetic diversity exists in pepper and therefore, essential research efforts in finding out resistant sources and their utilization have been by and large dynamic and successful. Despite continuous scientific efforts there is a dire need for new cultivars with resistant traits for various pests suitable to varied climatic conditions, consumption and quality preferences all over the world. Efforts need to be intensified to find out useful genetic material and to introduce genes of resistance against insects, fungal and virus diseases into commercial cultivars. Genetic resources that have been used intensively in pepper breeding are for developing sweet peppers, hot peppers, bell peppers in various shapes, sizes and colors. Germplasm repositories at the World Vegetable Research Center (AVRDC) and United States Department of Agriculture (USDA) do possess number of genotypes resistant to insect pests, nematode, fungi, bacteria and virus diseases. At AVRDC resistant genotypes originating from several pepper growing countries to most virus diseases like Tobacco mosaic virus, Cucumber mosaic virus, Pepper veinal mottle virus, Chilli veinal mottle virus, Peanut bud necrosis virus etc., were identified from its rich pepper diversity. Exploitation of rich genetic diversity resulted in the development of new cultivars encompassing resistance to various pests and good agronomical traits. This has eventually resulted in meeting the demanding situations of diverse domestic as well as global production requirements. The chile database (Chile Database, 2010) highlights the exemplary utilization of germplasm and development of large number of cultivars and hybrids resistant to most diseases and nematodes around the world. This paper also depicts information on Indian sources of resistance to thrips, mites, leaf curl complex, nematodes and diseases, while presenting the scope for exploitation of diversity available in the Indian National Gene Bank and other repositories all over the world. An attempt is also made to identify the gaps in the genetic diversity and cultivars against the biotic constraints and the augmentation efforts required to be initiated toward enrichment of the gene pool for domestic as well as global use. (C) 2010 Elsevier Ltd. All rights reserved.