BCAT- based marker for marker-assisted selection in Vietnam cucumber breeding

Abstract: Yield imporovement is one of major breeding objectives of cucumber improvement. Gynoecious, an important agricultural trait which highly correlates with yield, was proved to be controlled by F locus. Conventional plant breeding approach has some limitations in terms of potential inaccuracies and time-consuming. Molecular marker - assisted breeding is, therefore, an effectively alternative solution. F locus– linked molecular marker was previously reported. The main aim of this project was to evaluate the potential applicability of this F locus– specific marker for marker–assisted selection in Vietnam cucumber breeding program. Three different cucumber populations e.g., pure lines, F2 and F3 population were utilized with 13, 131 and 84 plants, respectively for each population. Plant sexual phenotypes were determined. Sequencing reactions were performed for BCAT 3’UTR of 3 gynoecious and 2 monoecious pure lines. Plant genotypes were determined by standard PCR with a primer pair amplifying a 56 bp-deletion region in BCAT 3’UTR. A 56 bp-deletion was found in BCAT 3’UTR of gynoecious pure lines as compared with monoecious lines. The marker based on this 56 bp-deletion region in BCAT 3’UTR could help to separate cucumber plants having homozygous and heterozygous sex phenotypes. The marker genotype absolutely corresponded with monoecious trait. Especially, the marker could precisely explain for 80 % gynoecious trait. The marker highly explained for Vietnam cucumber sex traits and could be applied for marker-assisted selection in cucumber breeding program in Vietnam in future.