Tomato leaf curl virus resistant tomato lines TLB111, TLB130, and TLB182

摘要

Tomato leaf curl virus diseases (ToLCVDs) are caused by a number of different geminiviruses vectored by the whitefly, Bemisia tabaci (Gennadius) (McGrath and Harrison, 1995; Ramappa et al., 1998). ToLCVDs are a growing problem globally and constitute a major constraint to tomato production (Polston and Anderson, 1997). In Karnataka State, south India, 40,000 ha of tomatoes are grown, providing an important source of cash income for small-scale farmers (Venkatesh, 2000). The intensive cultivation of tomatoes in some districts has led to a significant increase in farmer income, but a complex of pests and diseases threatens production. Of these, ToLCVDs are the most widespread, particularly in the summer season. In a survey conducted in eight districts of Karnataka in 1984, the average incidence of ToLCVDs in summer plantings ranged from 87 percent to 100 percent (Saikia and Muniyappa, 1989). In a more recent 1997 survey of 174 tomato farmers in Karnataka, 89 percent stated that ToLCVDs were a serious problem, particularly in the hot season (Warburton et al., unpublished report). Infection in early crop growth stages results in the highest yield losses. ToLCVD infection of a susceptible cultivar 2 weeks after transplanting resulted in a 95 percent yield loss (Saikia and Muniyappa, 1989). Tomato plants infected with the south Indian strains of tomato leaf curl virus (ToLCV) exhibited a range of symptoms, from the characteristic leaf curling and vein clearing to stunting and partial or complete sterility (Ramappa et al., 1998). Three fresh-market tomato lines resistant to south Indian and Taiwan geminiviruses and tolerant to bacterial wilt were developed for tropical and subtropical farmers. This was achieved through cooperative efforts of the Univ. of Agricultural Sciences at Bangalore (UASB), India; the Asian Vegetable Research and Development Center (AVRDC), Taiwan; and the Natural Resources Institute (NRI) in the United Kingdom.