Lettuce (Lactuca sativa L.)

Diagram of cabbage lettuce from 1576	Leaf lettuces	cos lettuces	cabbage lettuces

Distribution, Yield, Use:

• Distribution:
  Cultivated in almost all countries of the temperate zones. High requirement for water and light, thrives on almost all soils.
• Yield :
  250-550 kg/100m3 cabbage lettuce
  100-200 kg/100m3 leaf lettuce
• Use:
  Salad vegetable
  Lettuce contains 95% water, 1-2% carbohydrate, 1-2% protein, 0.25% fat.

• Cultivation and Breeding:
  Lettuce is believed to be derived from Prickly lettuce (Lactuca serriola), a plant of the Steppes, which occurs in far parts of South Europe and the Near East. Salad cultivation reaches back as far as the ancient Egyptians. During the middle ages, the leaf lettuce (var. crispa), the leaves of which are curled and loose, were distributed among the cloister gardens of Europe. In the Latin countries, the cultivation of the cos lettuce (var. longifolia) developed, the elongate leaves of which form a loose head. Cabbage lettuces were not bred until the beginning of the modern period. For growing purposes, long day varieties for spring and autumn growth are distinguished from varieties which do not depend on day length and which are also suitable for summer growth.
• Breeding aims:
  The most important breeding aims are amount of growth, shoot stability, and resistance to diseases and unfavourable climatic conditions. A balanced, closed head shape is valued in Cabbage lettuces. Suitable varieties are sought for each cultivation method.

Text by Wolfgang Schuchert
Adapted to HTML by R.Saedler