SNP Markers for Marker-assisted Backcross (MABC) and Selection of Homozygous Inbred Lines in Watermelon (Citrullus lanatus)

다국어 초록 (Multilingual Abstract)

Watermelon (Citrullus lanatus) in an important vegetable crops consumed worldwide. Genomic variations including single nucleotide polymorphisms (SNPs) of multiple breeding lines have been identified for increasing breeding efficiency. However due to the lack of conversion of SNPs to practical markers, marker-assisted backcross (MABC) is not widely used for breeding. In this reason, we re-sequenced the 30 elite lines of Korean seed companies with diverse phenotype and detected 12,674 high-quality SNPs based on C. lanatus ‘97103’ genome (v2). A total of 384 markers were designed as Fluidigm SNP genotyping system and used to genotype watermelon germplasm. Successively converted 341 markers were distributed 24 ‒ 36 for 11 chromosomes and the average distance between markers were 1.06 Mbp. Using selected 341 markers, 28 BC1F1 individuals were genotyped and showed 74 ‒ 100% recovery rate which was correlated with the fruit phenotype including skin thickness and seed weight. In addition to the Fluidigm markers sets, 28 KASP markers were designed for seed purity test and breeding inbred lines. KASP markers could distinguish F1 and breeding lines with homozygosity 78 ‒ 100%. The SNP markers reported in this study will be useful for MABC, genetic mapping of a novel trait and selection of inbred lines of watermelon.