Egypt as one of the centers of lettuce domestication: morphological and genetic evidence

Egypt is considered one of the centers of cultivated lettuce (Lactuca sativa L.) domestication. However, traditional Egyptian lettuce landraces and their sympatric wild relatives have not been comprehensively described. We assembled a set of 35 lettuce samples from Egypt (landraces of L. sativa Cos and Oilseed types plus L. serriola L.), and compared them with a set of European L. sativa germplasm accessions and an outgroup of wild Lactuca spp. Altogether, 19 morphological and three developmental traits were assessed under greenhouse conditions for the duration of the plants' life cycle. Species identifications and L. sativa morphotypes were verified. Cluster analysis of 17 qualitative and quantitative morphological traits showed a clear separation of samples into three major clusters, corresponding to clustering based on 689 AFLP markers. The seed weight of Oilseed types was significantly higher than those of other types. All Cos-type samples, either from Egypt or advanced cultivars, remained free of natural powdery mildew infection. The origin and potential contributions of lettuce from Egypt are discussed in relation to the broader history of lettuce cultivation and varietal improvement.

Automated summary

This study comprehensively described traditional Egyptian lettuce landraces and their sympatric wild relatives. Cluster analysis showed distinct differences among different types of lettuce samples. The study also discussed the origin and potential contributions of lettuce from Egypt.