The range of peach rootstocks currently available worldwide has increased dramatically in the last few decades. However, peach rootstocks in Republic of Korea still primarily use mainly seeds of different species imported from China. This kind of rootstocks is not ideal for clonal production and uniformity since it is a varietal blend of genotypes with differing physical characteristics. We collected genetic resources of 214 native peaches and determined 156 native peaches for breeding the suitable peach rootstock with easy propagation, uniform growth habit, and the resistance to biotic and abiotic stresses under domestic conditions. ‘PR1’ peach rootstock [Prunus persica (Batsch) L.] was originated from open-pollinated seeds of ‘PHJN0129’ collected in 2001 at Suncheon. ‘PR1’ peach rootstock was preliminarily designated as ‘PH193’ in 2002 and then grafted onto ‘Maotao’ (P. persica) wild peach seedling rootstocks. In Hwasung, three grafted trees were observed from 2005 to 2009 and seen to have the properties of ‘PH193’. In Suwon, one-year- old seedlings were observed from 2010 to 2014 and showed to have the commercial availability of ‘PH193’ when compared with 5 peach rootstocks (Tsukuba No.4, GF677, Nemaguard, Yumyeong, and imported peach seeds from China). ‘PH193’ was finally selected in 2014, owing to its superior seed germination, graft compatibility, resistance to nematodes and crown gall, and low mortality. It was named ‘PR1’ to indicate the first peach rootstock in Republic of Korea and was released for commercial use in 2015. (Grant Number 5896).

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.

Apple (Malus × domestica Borkh.) has gametophytic self-incompatibility (S) controlled by the multi-allelic S-locus. In the present study, S-genotypes of 24 apple cultivars including newly released Korean cultivars and seven crabapple cultivars were identified using S-allele specific polymerase chain reaction analysis. Twelve different S-alleles (S₁, S₂, S₃, S₅, S₇, S₉, S₁₀, S₁₆, S₂₁, S₂₃, S₂₆, and S₂₉) from 31 apple and crabapple cultivars were identified using 23 S-allele specific primers. Among them, S₁ (41.7%), S₃ (58.3%), S₇ (29.2%), and S₉ (54.2%) S-alleles were found to be common in 24 apple cultivars. The newly released Korean cultivars ‘Arisoo’ and ‘Hwangok’ were genetyped as S3S7 and S3S9, respectively. S-genotypes information obtained from the present study will be useful to select proper pollinzers for stable production of apple fruit and to design cross of breeding programs.