Genetic variability of the Juglans regia L. natural populations from Oltenia-Romania

The Oltenia region is situated in the South West of Romania and is of major interest as a genetic center in which different populations of Juglans regia L. were formed. In this area, a large number of natural hybrids, which belong to different populations of walnut, occurred. More then 550 natural hybrids from the local populations were studied. The populations and the individuals among them are characterized by a large genetic variability. Some traits have large limits of variability (fruiting capacity, dichogamy, fruit size, kernel percentage, resistance to low temperatures, tolerance to Xanthomonas campestris pv. juglandis and Gnomonia leptostyla, etc.). On the other hand, other traits show a limited variability (type of bearing, plant vigor). The genetic variability, which is present inside these populations of Juglans regia L., is creating the possibility of using them in the breeding programs and in genetic resources conservation.