Historical cultivars of Allium cepa L. (Aggregatum-Group) introduced to Sweden 1830-1860

Abstract

Abstract To deepen the knowledge of the plant material and the names use connected to cultons spread in the 19th century might be of essential value. Historical records of old growing systems and propagation methods add valuable knowledge to the preservation values tied to the genetic diversity of the gene pool for future breeding. In historical records, different cultons, now regarded as Allium cepa L. has often been taxonomically divided into vegetatively propagated shallots and seed-propagated onions (Rabinowitch andKamenetsky 2002). Furthermore, shallots have been widely known by the rural population in Sweden as "potatislök" [potato onion] and preserved as heirloom landraces (Nygårds andLeino 2013; Strese andDe Vahl 2018). Differing practices and principles regarding distinguishing between potato onions, shallots and onions in European countries have sometimes made it difficult to understand historical records. This study presents the plant material of A. cepa L. Aggregatum Group introduced and spread in Sweden between 1830-1860. The plant material exemplifies different principles regarding the denominations and shows the range of cultons available in the north of Europe by the time, but also examples of domestic local cultivars. Shallot and potato onions, later mainly vegetatively propagated, were already in the 19th century occasionally propagated and spread by true seed, in Europe and to Sweden. In addition, a Russian growing system with a true seed generation was known in literature.