SELECTING APRICOT TREE GENITORS FOR THE OBTAINING OF NEW CULTIVARS RESISTANT TO THE PLUM POX VIRUS

Right now in Europe, the Plum pox virus (PPV) causes one of the most serious diseases that affect the stone fruit-growing species (plum tree, apricot tree, peach tree, nectarine tree, almond tree and cherry tree) in all countries that cultivate them. Romania is one of the countries in which this virus has been present for several years now and where the contamination level is very high. The disease causes considerable damage because the infected trees have few fruit, which are small, deformed, lacking in flavour and with a low content of sugar and which can neither be consumed, nor industrialized. Therefore, for the areas in which the Plum pox virus is present, the cultivation of highly resistant (tolerant) genotypes represents the only possibility available in order to reduce this damage. In this view, the purpose of the research performed within this paper was to identify the varieties which are tolerant to the attack of this virus and to monitor the manner in which the resistance gene is transmitted to their hybrid descendants. The material which was studied consisted of apricot tree varieties from the national collection of the Research Station for Fruit-Growing Constantza. The presence of the Plum pox virus was determined by of the biological method consisting in tests performed on the GF305 wooden indicator and the serological method through the ELISA test. The varieties which were identified as having a higher resistance to the attack of the Plum pox virus, such as Stark Early Orange, NJA 17, Sulmona, were used as genitors in intraspecific hybridizations for the selection of hybrids to which this characteristic was transmitted. Among these, we noted the following selections VT 48/45, VT 51/45, VT 47/112 and H 9/5.