The purpose of this study was to examine the potential utility of marker-assisted selection (MAS) based on storability-associated molecular markers in apple breeding and to provide genotype information for the markers Md-ACS1, Md-ACO1, and Md-PG1 in apple genetic resources as basic data for the use of breeding materials. We analyzed 750 apple genetic resources to assess the allelic composition of Md-ACS1 and Md-ACO1, which play roles in the ethylene biosynthesis pathway, and Md-PG1, which is involved in cell wall degradation. For 108 of the genetic resources used for genotyping, we measured fruit firmness using a texture analyzer (10 mm plunger) at harvest and after 20 days of room temperature (20~25℃) storage. Md-ACS1 and Md-PG1 were found to be associated with changes in fruit firmness (the difference between firmness at harvest and after storage), with ACS1-2/2, PG1-1/1, and PG1-2/2 showing the lowest changes in fruit firmness. In addition, we found that changes in fruit firmness were smallest in late-harvest species, even for the same genotype. In contrast, Md-ACO1 appeared to be unrelated to the storability of fruit. Of the 750 apple genetic resources screened, the genotypes ACS1-2/2, and PG1-1/1 or PG1-2/2 were detected in 3.6% of accessions, including ‘Fuji’, bud mutation cultivars of ‘Fuji’, ‘Chubu’, and ‘Iwakami’. The Md-ACS1 and Md-PG1 markers could have potential utility in assessments of storability and applied in MAS to improve the efficiency of apple breeding.

A strawberry variety ‘Kuemsil’ was derived in 2007 as an artificial cross between ‘Maehyang’, a high fruit firmness variety and ‘Seolhyang’, a high-yielding variety. The lines were selected from 2009 to 2011, and yield trials of ‘08MS-62’, the final selected line, were conducted to evaluate its characteristics in forcing cultures from 2012 to 2015. After farmer field trials in 2016, the line was renamed ‘Kuemsil’. The general characteristics of ‘Kuemsil’ include upright growth habit, elliptical leaves, and strong vigorous growth. The fruit are conical and light red. This variety is suitable for forcing culture because of the early flower bud differentiation (late August), early first harvest (late November), and continuous formation of next flower clusters. The first cluster bore about 22.4 fewer flowers compared with those of the check varieties (‘Maehyang’ and ‘Seolhyang’), which could reduce the labor cost needed for fruit thinning. ‘Kuemsil’ was high in sugar content (11.1 °Bx) and had optimal fruit firmness (21.9 g/mm²), which is comparable to ‘Seolhyang’. The fruit weight was about 24.6 g, higher than that of the check varieties. The marketable yield was 566.9 g, 14% higher than that of ‘Maehyang’ and 13% less than that of ‘Seolhyang’. Unlike ‘Maehyang’, which is harvested in unripe stage, ‘Kuemsil’ fruit should be harvested at 80% coloration to intensify their deep flavor. ‘Kuemsil’ is more susceptible to Phytophthora crown rot compared with the check varieties, which requires complete disinfection of the soil area (or substrate) of the crown rot. ‘Kuemsil’ was registered with the Korea Seed and Variety Service (KSVS) for commercialization in 2018 (Registration No. 7345).

‘Sweet Gold’ is a new promising kiwifruit variety developed for high soluble solid content and firmness at the Research Institute of Climate Change and Agriculture, National Institute of Horticultural and Herbal Science, Rural Development Administration, Korea, in 2010. This variety was selected from seeds obtained by the cross between Actinidia chinensis ‘First Emperor’ and A. chinensis ‘Okcheon’ in 2000. Seedling and line selections were conducted from 2001 to 2008, and characteristic trials were carried out from 2009 to 2010. Shoots of ‘Sweet Gold’ sprouts were similar to those of ‘Jecy Gold’ with green leaves. The fruit shape was oblong and fruit skin color was yellow brown without hair. The average fruit weight was 88.7 ±12.37 g. The fruit had a central soft core, yellow or yellow green pericarp, and fragile and juicy flesh. The soluble solid content was higher than that of ‘Jecy Gold’ at 16.3° Brix when ripe and the firmness was higher, at 21.4N, than that of ‘Jecy Gold’. The harvesting time was about 7 days earlier than that of ‘Jecy Gold’. ‘Sweet Gold’ was officially registered as a new cultivar in 2014 in accordance with the Plant Variety Protection Act by the Commissioner of the KSVS (Grant Number 5151).