Tomato (Solanum lycopersicum L.) is a widely grown vegetable
throughoutthe tropics and subtropics and is an important source of
vitamins A and C. Production of high value fruit and vegetables such
as tomato offer some smallholders the opportunity to change from
subsistence to commercial farming and substantially increase their
incomes . However,
tomato crops can be infected by disease-causing bacterial,
fungal, and viral pathogens that reduce yields, fruit quality, shelflife,
and nutritional content. In extreme cases, these diseases force
farmers to abandon tomato production altogether. In the absence
of resistant cultivars, farmers often depend on pesticides to control
diseases. High reliance on pesticides poses health hazards to
farmers and their families,the environment, and consumers;intensive
pesticide use also can substantially increase production costs,
which increase farmer financial risks and pass the accrued higher costs to consumers . Resistant cultivars
are among the cheapest, simplest, and most environmentally safe
ways to manage disease.