A novel Brassica rapa L. genetic diversity found in Algeria

Abstract

To gain new insights into the complex evolutionary history of Brassica rapa, we investigated the genetic diversity of wild and domesticated populations from an unexplored area in its center of origin (Mediterranean basin). These populations were collected in Algeria, which presents a wide ecogeographic range and an exceptional bioclimatic gradient. We wanted to answer the following questions: (1) Were the local landraces domesticated from the local wild forms? (2) Do these populations offer a new diversity never described? (3) How is this diversity related to B. napus? Morphological traits and SSR markers were analysed to explore the genetic diversity among 18 Algerian B. rapa accessions that were compared to those previously analysed in this species and to B. napus varieties. Among worldwide B. rapa diversity, the wild and cultivated Algerian groups showed the highest allelic richness, suggesting that breeding has not significantly eroded genetic diversity in Algerian local landraces. Wild and cultivated B. rapa accessions from Algeria formed two clusters regardless of their local geographic origin and were distinct from all the B. rapa groups already described. Surprisingly, B. napus accessions clustered either with wild Algerian group or with the group containing mainly Asian accessions. This new diversity will be of high interest for B. rapa and B. napus breeding.