Crop Type: Garden Crop
Breeding system: Predominantly autogamous
Lettuce (Lactuca sativa L.) seems to have been domesticated in the Near East, probably in ancient Egypt (Lindqvist, 1960; Ryder, 1986; Harlan, 1992). Lettuce is one of the most economically important vegetable crops worldwide with more than one million ha cultivated and more than 25 million tons produced in 2017 (FAOSTAT, 2017). Lettuce is mainly consumed by its tender leaves, which often tend to form a head, although this depends on the cultivar. This vegetable has a low energetic value and is highly appreciated for its content of vitamins (A, B and C) and minerals. It is the fourth most consumed vegetable in Spain (4.55 kg per person and year) behind the tomato, onion and pepper (MAGRAMA, 2017).
The cultivated lettuce is an autogamous plant. The Mediterranean basin is considered its natural distribution area together with their wild relatives (L. aculeata, L. altaïca, L. dregeana, L. saligna, L. serriola and L. virosa) (Harlan, 1992). L. serriola, L. saligna and L. virosa are the closest wild relatives (Hill et al., 1996); being L. serriola considered its wild ancestor (De Vries, 1996). L. serriola can be easily hybridized to the cultivated species L. sativa. It has been widely used to introgress resistance to anthracnose (Microdochium panattonianum) (Brandes, 1918), corky root (Sphingomonas suberifaciens) (Brown and Michelmore, 1988), mildew (Bremia lactucae) (Bonnier et al., 1992), and insects (Lyriomyza langei) (Mou and Liu, 2004) into L. sativa and even as source of variation for carotenoid content (Mou, 2005)
References- Bonnier FJM, Reinink K, Groenwold R (1992) New sources of major gene resistance in Lactuca to Bremia lactucae. Euphytica 61: 203-211.
- Brandes EW (1918) Anthracnose of lettuce caused by Marssonina panattoniana. J. Agr. Res. 13: 261-280.
- Brown PR, Michelmore RW (1988) The genetics of corky root resistance in lettuce. Phytopathol. 78: 1145-1150.
- De Vries FT (1996) Cultivated plants and the wild flora. Effect analysis by dispersal codes. Tesis doctoral. Universidad de Leiden, pp.129-160.
- FAOSTAT. 2017. www.fao.org/faostat/en/ (11-5-2019).
- Harlan JR (1992) Crops and Man, 2nd edn. American Society of Agronomy, Crop Science Society of America. Madison, WI.
- Hill M, Witsenboer H, Zabeau M, Vos P, Kesseli R, Michelmore R (1996) PCR-based fingerprinting using AFLPs as a tool for studying genetic relationship in Lactuca spp. Theoretical and Applied Genetics 93: 1202-1210.
- Lindqvist, K (1960) On the origin of cultivated lettuce. Hereditas, 46: 319-350.
- MAGRAMA. Ministerio de Agricultura, Alimentación y Medio Ambiente (2016) En: www.magrama.gob.es.
- Mou B (2005) Genetic variation of beta-carotene and lutein contents in lettuce. J. Amer. Soc. Hort. Sci. 130: 870-876.
- Mou B, Liu Y (2004) Host plant resistance to leafminer in lettuce. J. Amer. Soc. Hort. Sci. 129: 383-388.
- Ryder EJ (1986) Lettuce breeding, in: Breeding Vegetable Crops. Bassett MJ (Ed.), AVI Publishing, Westport, pp. 433-474.