Development of a sdCAPS Marker Associated with Bitterness in Korean Cucumber

Cucumber plant or fruit may have a bitter taste because of cucurbitacins. Recently, Huang and colleagues characterized three genes, Bl, Bi, Bt regulated bitterness in cucumber. In order to develop PCR-based markers associated with bitterness, Korean cucumber lines, DG1 (Bitterness) and DG5 (Non-bitterness) were used to identify polymorphisms using Bl, Bi, Bt genes. From Bt gene, no polymorphism was found where Bl and Bi genes showed two SNPs (named as Bl-SNP-1329 and Bi-SNP-185, respectively) between DG1 and DG5 cucumber lines. Consequently, PCR-based sdCAPS markers for those two SNPs were developed and F2 populations developed from DG1 x DG5 cross were subjected for a bitter taste on cotyledon and genotype screening for Bl-SNP-1329 and Bi-SNP-185 markers. Bl-SNP-1329 marker showed 55% concordance rate with the phenotypes of bitterness where genotypes of Bi-SNP-185 were matched 100% with bitterness phenotypes. Therefore, we concluded that Bi-SNP-185 marker would be a useful tool for non-bitterness cucumber breeding.