**2. Materials and Methods**

### *2.1. Plant Materials and Genomic DNA Extraction*

A population of 62 F1 individuals was derived from a cross of 'GX50'×'GX71', which were maintained in the National Institute of Horticultural and Herbal Science, Rural Development Administration, Wanju, Korea. The F1 mapping population consists of 62 progenies from an inter-specific cross between two heterozygous genotypes.

The total genomic DNA of each parent and the progenies were extracted from young and fresh leaf tissues using the modified cetyltrimethylammonium bromide (CTAB) method [17]. The collected leaves were immediately stored in liquid nitrogen, and then transferred to the laboratory and stored at −80 ◦C until use. The extracted DNA samples were diluted to 20 ng/μ<sup>L</sup> and then used for library preparation. DNA concentration and purity were determined using a Nano stick-S (Scinco, Seoul, Korea).
