ABSTRACT
This chapter discusses the value of germplasm in programs searching and/or breeding for resistance to arthropods in vegetable crops. Because of the great diversity of vegetable crops in terms of their number and taxonomic breadth, variation in their agricultural, economical, and nutritional importance, and limitations of space and available information, a comprehensive treatment is not attempted. The existence of sufficient genetic diversity is a fundamental requirement if programs breeding for resistance and other crop improvements are to meet future crop production needs. Instead, the value of arthropod-resistant vegetable germplasm in a cropping system context is discussed followed by a review of arthropod-resistant germplasm for selected vegetable crops. Theories regarding the evolutionary origin of resistance are central to the question of where to search for useful sources of resistant germplasm. Lettuce, a cool season leafy vegetable, has been cultivated for over 4,500 years. Insect resistance has been found in celery cultivars and in related Apium species.
