Grape (Vitis vinifera L.) is a perennial fruit tree with high heterozygosity, consisting of 38 chromosomes (2n=38), and it takes a long time for grape seedlings to grow into fruit-bearing trees. Therefore, it is difficult to study grape genetics and breeding strategies. However, it has recently become possible to discover many SNPs through whole genome resequencing or genotyping-by-sequencing (GBS) analysis. In this study, we aimed to develop high-resolution melting (HRM) markers from the detected SNPs and construct a genetic linkage map using HRM markers. In a previous study, 2,553 SNPs were identified using GBS analysis. In this study, 1,336 SNPs were used to design primer sets for HRM analysis. The developed HRM markers were used for construction of a genetic linkage map in an F₁ segregating population consisting of 192 individuals from a cross between ‘Tano Red’ (V. labrusca×V. vinifera) and ‘Ruby Seedless’ (V. vinifera). A total of 805 polymorphic HRM markers were developed, of which 363 were mapped onto the genetic linkage map of grape, with a total length of 1,453.5 cM consisting of 19 chromosomes. This SNP-based genetic linkage map and HRM markers can be used for QTL identification and marker development for important fruit traits of grape.

Although small-scaled breeding programs for apples, pears, and grapes were conducted in the 1930s and 1940s, national fruit breeding programs by the Korean government were commenced after the foundation of the National Horticultural Technical Institute on May 20, 1953, and the programs were confined to apples and pears. Peach and grape breeding programs were started after the establishment of Rural Development Administration (RDA), with the Horticultural Experiment Station as its affiliated research organization in 1962. However, because of insufficiencies in breeding infrastructure, manpower, and funds during the 1960s and 1970s, most efforts were devoted to the collection and selection of wild Akebia and Actinidia, local varieties of astringent persimmons, jujube, and apricot, and adaptability tests of foreign fruit varieties. Fruit breeding programs became more activate with the establishment of the Apple Research Institute, the Pear Research Institute and the Citrus Research Institute as subsidiary organizations of the Fruit Research Institute, RDA, in 1991, and with Fruit Experiment Stations for grapes, persimmons, and peaches as affiliated provincial research organizations in early 1990s to cope with the domestic agricultural market opened by Uruguay Round Agreements. The legislation of the Seed Industry Law in 1995 and joining the UPOV in 2002 contributed to fruit breeding activation in the private sector. The results of such breeding programs include the development of the ‘Danbae’ pear as the first fruit variety in 1967, the ‘Yumyong’ peach in 1977, the ‘Hongro’ apple, and the ‘Cheongsoo’ grape. After the Korea-Chile FTA, effective in 2004, research projects for the development of molecular markers linked to disease resistance in fruit trees and seedless grapes have been carried out to improve the competitiveness of the Korean fruit industry. However, the establishment of a molecular breeding system based on genome sequence information and collaboration among research organizations are required for competition in domestic and foreign fresh fruit markets. In this review, we analyze the achievement from the fruit breeding programs operated by central and local autonomous governments since 1945, and propose future directions and strategies.

In this study, phenotypic distribution of 15 major fruit quality traits were analyzed using 252 progenies derived from a cross between ‘Tano Red’ (seed) and ‘Ruby Seedless’ (seedless), to obtain basic data for improving the breeding efficiency of grapevine cultivars. Berry skin color was dark red-violet in 46.4% of the progenies, which is the color of ‘Tano Red’ and ‘Ruby Seedless’, and berry shape was elliptic in 48.4%. Most of the progenies were very juicy with soft flesh, and closely related to the characteristics of ‘Tano Red’. Seeds were well developed in 67.1% of the progenies, rudimentary in 30.1%, and 2.8% were seedless, with seed weight being less than 0.15 g in 84.9% of the progenies. Among the 15 fruit quality traits assessed, bunch density, ease of berry detachment from pedicel, berry weight, berry seed number, berry longitudinal diameter, berry transverse diameter, berry soluble solids, and berry acidity showed normal distributions. Heritability of berry weight, berry longitudinal diameter, berry transverse diameter, berry soluble solids, and berry acidity was 0.89, 0.82, 0.78, 0.86, and 0.93, respectively. Berry weight was positively correlated with seed weight (r = 0.486^**), presence of seeds (r = 0.483^**), and seed number (r = 0.211^**). Seed weight significantly increased with presence of seeds (r = 0.607^**) and seed number (r = 0.725^**). In addition, presence of seeds was positively correlated with seed number (r = 0.319^**). These results could be useful for the identification of quantitative trait loci associated with fruit quality to assist in grapevine breeding.