SELECTION OF CASTANEA SATIVA MILL. GENOTYPES RESISTANT TO INK DISEASE IN GALICIA (SPAIN)

Abstract

Hybrid chestnut plants for reforestation are available in Spain since the 60's, when the Forestry Research Center of Lourizan (Pontevedra, Spain) compiled the plant material resulting of Vieitez and Gallastegui breeding programmes and started propagating it. However, the genetic base of these breeding programmes was poor, because the Castanea sativa parental trees did not even go through mass selection and all of them came from the same geographic area. A selection of Castanea sativa genotypes is being carried out by TRAGSA throughout Galicia, with two different criteria. In low, coastal areas which went under intense Phytophtora spp. attacks, we selected old trees whatever their growth habit. The aim of the selection in this case, is to collect germplasm of possibly ink resistant trees (PhR) (i.e. trees that due to their age, suffered the disease conditions and are still alive). In high, not ink-affected areas, the aim is to select trees or even stands with good adaptative traits (plus genotypes, PG). Castanea sativa stands to survey are chosen using data in the Forestry Map of Spain and the 3rd National Forestry Inventory and field located with GPS. All genotypes are being established in tissue culture where they are performing quite well despite their age. PhR trees are nowadays going through ink resistance tests and isoenzyme analysis to find out whether the possible resistance comes from spontaneous hybridation or not. PG trees, depending on trial results, will be the base of a future Castanea sativa seed orchard.