Variability of different pear hybrid populations in terms of hybridization performance and the response to fire blight (Erwinia amylovora) attack

The production of pear, which is one of the most important fruits in Turkey, was restricted by the occurrence of the fire blight disease. There isn't a certain chemical management against fire blight, although plant activators have been used, at present. It's very important to improve resistant varieties in terms of an integrated management of bacterial diseases. With this purpose, different crosses have been made between resistant cultigens and P. communis varieties that have good fruit characteristics. Besides, self-pollination and open pollination treatments have been carried out in parental plants. Pollen viability and germination ratio, fruit set ratio, total and mean seed number, seed germination ratio, the ratio of hybrid losses by root rot at early stage and the ratio of hybrid losses by natural fire blight infection were determined. The highest values of the properties such as pollen viability and germination ratio, fruit set ratio, mean and total seed number were obtained from the crosses with 'Kaiser Alexandre', 'Ankara', 'Akça', 'Conference' and 'Santa Maria' cultivars, in general. As a result of natural fire blight infection in Izmir-Turkey conditions, the resistance level of the hybrids from various combinations differed through the cultivars used for cross pollination, and it is very important to evaluate these hybrid pear populations through their response to fireblight disease in terms of obtaining new resistant cultivars and using these populations as disease resistant genetic resources in the future