LETTUCE (LACTUCA SPP.) AN UNDERUTILIZED CROP

Abstract

Lettuce (Lactuca spp.) is the world's most important and widely-consumed
leafy salad vegetable. It represents a large genus of the Asteraceae (Compositae)
family (x = 8,9,17) which includes approximately 100 species of annual and
perennial plants and is allied with other genera, such as chicory (Cichoriunl
intybus) and dandelions. They occur most abundantly in the temperate regions
of the old world. The common cultivated salad lettuce, Lactuca sativa, is one
of the four species with 9 pairs of chromosomes (i.e., 2n=18), the other three
being Lactuca serriola, L. virosa, and L. saligna. The latter three species have
now become obsolete and are rarely cultivated. All four species are native to
the Mediterranean basin and are interfertile with each other thus facilitating
exchange of desirable genes among them for breeding purposes. Despite its
cultivation under varied conditions it remains largely an underutilized crop.