Identification of parent-offspring relationships in 55 Japanese pear cultivars using S-RNase allele and SSR markers

Abstract

S-RNase alleles and 18 simple sequence repeats (SSR) markers were used to analyze 55 Japanese pear cultivars, including 47 hybrid cultivars, 6 bud sport mutants, and 2 derived from open pollinations. Fifteen cultivars used in the breeding of some of the hybrid cultivars were also examined. Each cultivar was genotyped at the S-locus and SSR loci. Parent-offspring relationships were analyzed by comparing genotypes among the cultivars. Of the 47 crossbreeding cultivars and selections, parent-offspring relationships of 37 were re-confirmed because the hybrids inherited S-RNase and SSR alleles from both parents without any discrepancies. Discrepancies at 3 or more SSR loci were found between 10 hybrid cultivars ('Kisui', 'Tanzawa', 'Niitaka', 'Seiryu', 'Akemizu', 'Atago', 'Echigonishiki', 'Ishiiwase', 'Shusui', and 'Yachiyo') and their previously reported parents, suggesting that these hybrid cultivars have different parents than reported. Furthermore, 'Momoeduki' and 'Sanko', which were previously reported as bud sports of 'Niitaka' and 'Kosui', respectively, exhibited SSR genotypes that were different from their reported parents. Paternal cultivars were previously unknown in 'Shinko' and 'Yoshikaori', which are open-pollinated seedlings of 'Nijisseiki'. SSR genotypes revealed that their paternal cultivars are 'Amanogawa' and 'Chojuro', respectively. JSHS © 2008.