Determination of fire blight disease susceptibilty and selection breeding on quince genotypes

This study was planned taking into account the fact that fire blight (E. amylovora Burrill) is seen in widespread and destructive dimensions in our country which is the first place in quince production in the world and that there is not enough study on this subject. It was aimed to determine of E. amylovora isolates, the incidence of the disease in the Eastern Marmara and Aegean regions, the selection of tolerant quince types and determination of some morphological characteristics, the testing of quince genetic resources with artificial inoculations against the disease in the Aegean Agricultural Research Institute (AARI). In the selection breeding studies, 15 genotypes were determined as tolerant to the disease and the disease rates varied between 0-12%. While genotype QFBNT20-3 having the highest average fruit weight with 975 g, QFBNT45-4 has attracted attention with red fruit color. In survey area; the average disease incidence was 4.24 %, in provinces; Izmir 0.54 %, Manisa 0.65 %, Bursa 2.85 %, Sakarya as 2.95 % and Denizli as 5.90 %. A total of 27 isolates were obtained and 21 of these isolates were found to be E. amylovora as a result of classical and molecular diagnostic tests. Fifty six genotypes, located in the AARI Quince Field Gene Bank, have been tested in three different periods (1 October 2016, 10 May 2017, 18 May 2017) in a fully automated climate controlled greenhouse conditions with a mixture of the most virulent isolates (163, 211 and 223 -107 cfu / ml), with artificial inoculations. As a result of the evaluation of the three periods, genotype 754 with the highest HI value (51.69 %) were noted in the "susceptible group" whereas genotype 2161 with the lowest HI (24.69 %) were detected in the "intermediate susceptible group". Of the 56 genotypes evaluated, 50 were identified in the "intermediate susceptible" group, while Ayva B35 rootstock, and Altın 35, Ege 25 and Zeybek 35 varieties, developed breeding by AARI, were more tolerant in this group. The findings indicate that Turkey's quince genetic resources are important in terms of tolerance to disease and can be evaluated as a genitor in future breeding trials.