Identification of Korean pear cultivars using combinations of SCAR markers

Abstract

The conventional method to identify pear tree cultivars is to evaluate the morphological characteristics of the trunk, leaves, flowers, and fruit. However, it is difficult to distinguish between the closely related pear cultivars using only morphological traits, particularly if the cultivars to be compared share the same pedigree. Thus, we developed more reliable DNA markers to identify 39 pear cultivars bred in Korea and Japan. In total, 147 random amplified polymorphic DNA (RAPD) markers were developed from 40 different random primers. The resulting 51 RAPD fragments were selected, and their sequences were determined to convert them into sequence-characterized amplified region (SCAR) markers. As a result, 19 of 51 RAPD fragments were successfully converted to SCAR markers. A single polymorphic band of the same size as the RAPD fragments or smaller DNA fragments were amplified depending on primer combinations in the 17 SCAR markers, and co-dominant polymorphisms were observed using two of the SCAR markers (named PK10_514 and PK15_616). A combination of eight SCAR markers (P561_331, P561_372, PH02_405, PH15_ 452, PT16_472, PK10_514, P270_593, and PK15_616) provided sufficient polymorphisms to identify 25 Korean pear cultivars among the 39 pear cultivars tested. A combination of nine SCAR markers (P561_331, P561_372, PH02_ 405, PH15_452, PT16_472, PT14_578, P270_593, PK10_514, and PK15_616) could be used to sufficiently distinguish among the 39 pear cultivars examined in this study. These newly developed markers will be useful as a fast and reliable tool to identify Korean pear cultivars.