Diversity and conservation of Scottish landraces: Shetland Cabbage (Brassica oleracea L.) and Small oat (Avena strigosa Schreb.)
Scholten, Maria Anna
A national inventory of UK plant genetic resources carried out in 2003-4 covered surveys and documentation of landrace types, occurrences and threats. Among the local varieties found, those with longest histories of local cultivation occurred on the most remote Scottish islands: the Outer Hebrides and Tiree had bere (Hordeum vulgare L.), Small oat (Avena strigosa Schreb.) and rye (Secale cereale L.); bere and Small oat on Orkney and Shetland; and Shetland cabbage (B. olearacea L.) on Shetland. These landraces are not only geographically but also agriculturally marginal; they are confined to crofting agriculture and used in low-intensity pastoralism. Two of these, the oat and the cabbage, were chosen for a characterization study which formed the major part of this PhD thesis. The broad aims of the characterization study were first, to describe the existing diversity within Scotland; to document the ex situ collection of Scottish landraces; to better understand genetic structure and dynamics of the landraces; but also to explore the use of a characterization study to raise awareness about landraces. Morphological and microsatellite results showed distinct identities for both landraces in relation to the respective outgroups; in the oat distinct regional identities were found. High diversity was found, most of the genetic variation however, was within populations, for both inbreeder (oat) and outbreeder (cabbage). This can be attributed to frequent and widespread seed exchange and seed swapping within island groups, while the small but significant regional distinctness is maintained through isolation between the three islands groups. The morphological characterization of Small oats was carried out in situ, on a croft in the Southern Outer Hebrides, aiming at education and raising awareness about landraces among secondary school students, maintainers and the local public in general. The extension and education element of the study seemed useful in raising the issue of landraces locally. Carrying out the trial in the area of origin and amidst maintainers had the additional advantage of identifying and communicating with stakeholders groups. Integrated conservation of ex situ collection and maintainers has been achieved through the Scottish Landrace Protection Scheme. By retaining the link between landraces and maintainers during the characterization, a springboard may have been created for feedback of the genetic results into the local seed system and to discuss further support options for landraces and maintainers.