AFLP Molecular Identification and Genetic Relationship of Chinese and Japanese Pear Cultivars Grown in Middle European Conditions

Abstract

In this study, 30 genotypes of genus Pyrus (five European cultivars, 16 Asian cultivars, three rootstocks, four interspecific hybrids, one landrace cultivar from Czech Republic ('Krvavka'), Pyrus betulaefolia Bunge. and one intergeneric hybrid (Cydomalus)) were tested using AFLP markers. Twelve primer combinations generated a number of 1251 fragments of which 1064 were polymorphic with an average polymorphism of 85.3%. The dendrogram, created by using the UPGMA method, revealed a distinct genetic relationship between European and Asian pear groups. The intergeneric hybrid Cydomalus was separated in the cluster tree from both groups. The level of similarity coefficient between European and Asian pears was 0.75. Despite the fact that Pyrus betulaefolia Bunge was clustered in the European pear group, the average similarity coefficient between the European pear group and Pyrus betulaefolia Bunge (0.7704) was comparable to the similarity coefficient between the Asian pear group and Pyrus betulaefolia Bunge (0.768). Thus, the botanic species Pyrus betulaefolia Bunge can likely be considered as an intermediate genotype between European and Asian pears. The cultivar 'Talgarskaja Krasavica' (chance seedling of 'Forest Beauty'), which pomologically belongs to the European pear group was clustered together with the interspecific hybrid 'Wu Jiu Xinag' ('Ya Li' × 'Bartlett') which on the other hand belongs to the Asian pear group. Thus, due to its position in the dendrogram the cultivar 'Talgarskaja Krasavica' could be considered as an interspecific hybrid.

Evaluation of genetic variations and phylogeny of the most popular pear (Pyrus communis L.) cultivars in Duhok city using AFLP markers

“…The lowest number of variable fragments (47 bands, 64.4%) was observed by the primer combination P174/M307. The average percentage of polymorphic fragments obtained in this study (68.2 %) was lower than that recorded by Wolf et al, (6) who reported 89.5% of the average percentage of polymorphism within pear cultivars. The real reason of this variation is not quite clear.…”

“…The genus Pyrus (2n = 34 chromosomes), which belong to the tribe Pyreae, subfamily Pomoideae in the Rosaceae family, is widely distributed on six continents particularly in Asia, Europe, and Africa (3,5,1,6). Classically, based on domestication and the geographical distribution, Pyrus species are divided into two major native groups.…”

“…The genus Pyrus is variously described as a polymorphic fruit species which consist of 22 primary species with at least six naturally interspecific hybrids, and at least three artificial hybrids (6). However, the easily cross-pollinations and the ambiguous taxonomic status of the obtained crosses make the determination of the exact number of Pyrus species relatively difficult.…”

“…After the advent of PCR technology, the molecular methods have become very popular in molecular identification, characterization, genotyping, and to determine the genetic diversity of many fruit species including pear (12,13). Among the most popular molecular approaches are; random amplified polymorphic DNA (RAPD), microsatellite markers (SSR), restriction fragment length polymorphism (RFLP), and the amplified fragment length polymorphism (AFLP) markers, which leaded to discover new relationships between cultivated and wild species (10,6). These DNA based techniques allowed researchers to distinguish species and cultivars at the molecular level through access to the stable information carried by DNA regardless the environmental, tissue, and growth stage of the plant (13).…”

“…A DNA barcoding technology AFLP, which combines DNA restriction with PCR amplification, is being considered as a powerful and suitable technique for characterization and fingerprinting plant species at the molecular level (6). This technique has many advantages over the other molecular methodologies such as RAPD and SSR, due to its power to generate high number of polymorphic and informative bands per reaction with high reproducibility of banding patterns.…”