An Analysis on Some Reciprocal Pear Hybridization Combinations in Terms of Transferring Resistance to Fire Blight

Since it has a wide variety, pear can be grown in all temperate zones and high-altitude areas of tropical and subtropical climates of the Earth. On the other hand, most of the cultured pear varieties are susceptible to fire blight caused by Erwinia amylovora, and their susceptibility is threatening pear cultivation. The lack of a certain solution to fire blight, the harmful effects of the chemicals on environment and human health and the increasing demand for organic products, give priority to breeding new resistant rootstocks and varieties in control of the disease. Due to the polygenic nature of fire blight resistance and the complexity of its mechanism, controlled hybridization is generally used in breeding programs. In order to determine the effect of the parents for the transmission of fire blight resistance, hybridizations are also carried out reciprocally. In the study which was carried out for this aim, susceptibility levels of the F1 hybrids, obtained from the reciprocal combinations of fire blight resistant 'Kieffer' and the susceptible 'Williams', 'Santa Maria' and 'Akca' cultivars, were evaluated. While 'Kieffer' x 'Santa Maria' was found the most resistant combination to fire blight, 'Akca' x 'Williams' was found as the most susceptible one. In addition, it has been determined that F-1 hybrids obtained from 'Kieffer' x 'Santa Maria' and 'Akca' x 'Williams' hybridization combinations and their reciprocals are different in terms of disease resistance, while there was no difference in resistance in F-1 hybrids of 'Williams' x 'Santa Maria' combination and its reciprocal combination.