Evaluation of Adaptability, Vegetative and Reproductive Chrachteristichs of Quince Genotypes and Cultivars

Iran is one of principle centers of quince diversity in the world. Our first program of quince genotype detection and propagation resulted in establishment first quince collection composed of 40 genotypes obtained from various regions of Iran. At the first step, the collected quince genotypes were evaluated for resistance to the fire blight. At this stage, vegetative and reproductive traits of these genotypes were evaluated based on UPOV quince descriptor, containing totally 38 traits of tree, shoots, leaves, blooms and fruits, at 2010 and 2011. The first collected set of genotypes were consisted of 28 accessions from Isfahan (14), Khorasan (7) and Guilan provinces (8). Isfahan derived genotypes named as ET1, KM1 (Torsh), KVD1, KVD2, KVD3 (Isphahan), KVD4, NB1, NB3, NB4, PH2, PK2, SHA1, SVS1 and SVS2. Khorasan genotypes were labelled as Khosro, Grdandar, Esfahan Oghaf, Dizbad, Moghavem 1, Moghavem 2, Sahel Borje Moghavem , and Guilan genotypes were listed as AS1, AS2, ASP1, ASP2, ASM1, ASM2, ASM3, and Unidentified (M9). The results demonstrated high level of variation among the evaluated traits, specially in fruit quality; as high in Isfahan genotypes, followed by Khorasan and then lowest fruit quality that is not acceptable for fresh market among Guilan genotypes. Isfahan genotypes usually expressed high level of growth, but diversity level among them was significant. Guilan genotypes were mostly dwarf and they seem to be adaptable for rootstock breeding programs. In addition, various level of foliar chlorosis level was observed in the genotypes. The highest yield was founded in KVD1, KVD2, KVD4 and NB2. Additionally to the growth characteristics, fire blight susceptibility were monitored by three indices including index of Beltsville, developed by USDA (IUSDA), index of susceptibility of varieties (ISV) and index of frequency (IF), and the results were compared with total percentage of fire blight damage on trees (IT). IF had the highest correlation with IT, but each single index demonstrated various efficiency to evaluate real disease damage and severity on the quince trees, and due to this contradictory results, the genotypes were classified differently in resistant classes. In order to obtain more reliable judgment on the susceptibility of quince genotypes by accumulated indices, using cluster analysis of the results demonstrated more effective scaling of susceptibility, compared to a single index. Based on these results, quince Guilan genotypes were marked as most tolerant to fire blight, so they can be used as the source of resistance in breeding programs.