2017 ASHS Annual Conference

The object of this study was to localize the genes associated with pollen abortion and identify the flanking markers for the traits in F₁ population between ‘Whangkeumbae’ (Pyrus pyrifolia) and ‘Minibae’ (P. hybrid). Unlike ‘Whangkeumbae’, having abortive pollen, ‘Minibae’ has plenty of pollens and high compatibility to Korean-bred pears. In March 2014 and 2016, flowers were collected at pink bud stage from each tree and dried at 25 ^°C for 24 hours. Phenotype was scored as binary digit, presence (1) and absence (0) of pollen for all F₁ individuals. Segregation of presence and absence in this cross fit the ratio of 1:1 by chi-square test P ≤ 0.01 in 2014 and 2016. However, some progenies showed inconsistency of phenotypic score in 2014 and 2016. Based on genetic linkage map using 2,331 SNP markers derived from genotyping by sequencing, Kruskal-Wallis test was performed to calculate the significant markers for pollen. In total, 14 candidate SNPs for the presence and absence of pollen were successively positioned on LG14 in 2014 and 2016, whereas only 2 SNPs were peaked in 2014. These results might indicate that pollen formation is affected by one or more genes depending on environmental conditions. The results of this study should be used to demonstrate genotypes of the franking SNP loci by high resolution melting analysis and develop the STS markers for marker-assisted selection.