Target Region Amplification Polymorphism (TRAP) for Evaluating Genetic Diversity In Malus Mill. Genus

Malus belongs to Rose family and has 8-55 (78) species depending on various classification systems.  Also, many synonyms and homonyms were existed. There are more than 7500 apple cultivars and more than 500 flowering crabapple cultivars in the world. Most of them were bred by open pollination and a few of them were controlled crosses. TRAP (Target region amplification polymorphism) was applied for elucidating genetic relationships in Malus genotypes. TRAP is a novel PCR-based molecular marker technique which uses gene-based information for primer design. 43 Malus samples from 27 species and varieties, 8 hybrid species and 8 cultivars were selected for TRAP maker system analysis. Two fixed primers, designed using matK gene sequences of Malus sieboldii, paired with two arbitrary primers, were used to conduct TRAP PCR. A UPGMA dendrogram was generated based on a total of 197 unambiguous bands. Among them, 182 were polymorphic with an average of 45 polymorphic bands per primer combination.The bands ranged in size from 75 to 700 bp.  TRAP PCR cluster analysis revealed that the closer relationships in the dendrodram of Malus samples are in agreement with the originations of these genotypes. TRAP is a potentially useful marker technique for genetic diversity studies in Malus genus.