• Korean journal of applied entomology
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• v.43 no.1
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• pp.15-20
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• 2004

Leaf damage by apple leafminer, Lyonetia prunifoliella, was surveyed on Fuji apple orchards with seedling rootstock from 1992 to 2001 and with M.9 rootstock from 1999 to 2001. The damage was negligible in apple orchards with seedling rootstock as 0.15% in 1992 and 0.06% in 1993. However it sharply increased to more than 3.39% since 1994, reaching at peak damage of 6.28% to 7.78% in 1996 to 1998. Damages on apple orchards with M.9 rootstock from 1999 to 2001 were higher as 6.09% to 15.3%, compared with those with seedling rootstock in the same years. In seedling rootstock apple, the damage was highest on september but in M.9 rootstock apple, the difference was not significant. Leaf damage showed no differences between cultivars including 4 Korean cultivars and Fuji. These results may explain that increase of M.9 rootstock apple orchards is responsible for the recent outbreak of the leafminer in Korea.

• Journal of Bio-Environment Control
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• v.16 no.2
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• pp.151-156
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• 2007

This work was conducted to investigate the important rooting factors through comparative analysis of a physiological differentiation after layering treatment using four apple rootstocks of different rooting abilities; M.26, M.9, O.3, and Mo.84. Mo.84 showed the highest rooting rate in from rootstocks, while O.3 was the lowest. Mo.84 also found to have the highest indole-3-acetic acid (IAA) content, although the fluctuation of IAA contents was not consistent with layering treatment. In contrast, abscisic acid (ABA) content of Mo.84 which showed highest rooting was lowest among rootstocks regardless of layering treatment. And ABA contents of all rootstocks were decreased after layering treatment than before layering treatment. O.3 which showed poor rooting rate revealed lowest in boron content. Carbohydrate/nitrogen (C/N) ratio of Mo.84 was the highest in all rootstocks. Therefor, we assumed that he IAA contents in layering treated rootstocks were not seemed to be a major rooting factor, but the changes in ABA contents and boron levels limit rooting in dwarf apple rootstocks.

• Korean Journal of Agricultural and Forest Meteorology
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• v.16 no.1
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• pp.59-71
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• 2014

This study was conducted to find out the freezing hardness of apple tree as influenced by dwarfrootstocks, cultivars, and low temperature treatments. The dwarf-rootstocks used were M.9 and M.26, and three cultivars used were early-maturing 'Tsugaru', mid-maturing 'Hongro', and late-maturing 'Fuji'. Chilling temperatures were applied from $0^{\circ}C$ to $-40^{\circ}C$. Checking points of apple tree for freezing hardness were rootstock, trunk, feather, floral bud and foliar bud. Investigations were evaluated by the measure of water loss, electrolyte leaching, and sprouting. The results did not show the differences in water loss, electrolyte leaching, and sprouting by dwarf-rootstocks. Water loss of 'Fuji' was lower than that of 'Tsugaru' and 'Hongro', but sprouting ratio of 'Fuji' was higher than that of 'Tsugaru' and 'Hongro'. Water loss and electrolyte leaching increased as treated by lower temperature, while sprouting ratio decreased. In $-35^{\circ}C$ treatment, sprouting of rootstock and trunk part were higher than that of feather, while sprouting of floral bud was lower than that of foliar bud. Sprouting of bourse shoot at the accumulated low temperature in terms of $-10^{\circ}C$ per day was 100% in the 28 days, and sharply decreased about 50% in the 35 days. In conclusion, there were no differences in freezing hardness between M.9 and M.26, but freezing hardness of late-maturing cultivar was tended to stronger than that of early-maturing and mid-maturing cultivars. Freezing hardness of floral bud was extremely weak $-30^{\circ}C$.

• Journal of Plant Biotechnology
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• v.46 no.3
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• pp.228-235
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• 2019

Apple (Malus pumila) is one of the most economically important fruits in Korea. but virus infection has decreased the sustainable production of apples and caused serious problems such as yield loss and poor fruit quality. Virus or viroid infection including apple chlorotic leaf spot virus (ACLSV), apple stem pitting virus (ASPV), apple stem grooving virus (ASGV), apple mosaic virus (ApMV) and apple scar skin viroid (ASSVd) have been also reported in Korea. In many cases, as apple gets infected with virus and viroid with no specific symptoms, the damage and symptoms caused by the viruses are not detected. In our research, viruses in the rootstock were eliminated for a virus-free apple dwarfing rootstock of M.9 and M.26. The virus elimination methods were apical meristem culture, thermotherapy ($37^{\circ}C$, 6 weeks) and chemotherapy($Ribavirin^{(R)}$). The detection of apple viruses was accomplished by Enzyme-linked Immuno-Sorbent Assay (ELlSA) and reverse transcription-polymerase chain reaction (RT-PCR). RT- PCR method was 10 ~ 30% more sensitive than the ELISA method. The efficiency of virus elimination was enhanced in apical meristem culture method. The acquisition rate of virus-free apple dwarfing rootstocks was 30 ~ 40% higher in apical meristem culture. After the meristem culturing of M.9, the infection ratio of ACLSV, ASPV and ASGV was 45%, 60% and 50%, respectively. In the apple dwarfing rootstock of M.26, the infection ratio of ACLSV, ASPV and ASGV was 40%, 55% and 55%, respectively. Based on this study, the best method for the production of virus-free apple dwarfing rootstocks was the apical meristem culture.

• Journal of Practical Agriculture & Fisheries Research
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• v.21 no.1
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• pp.5-13
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• 2019

The first commercial planting of sweet cherry in Korea is thought to be done in early 1920s. The planting area of sweet cherry in Korea is about 500 ha in 2017. Although sweet cherry is considered a minor fruit in Korea, it is one of premium fruits in market and popular among children and women, especially among pregnant women. The import of sweet cherry fruits has increased dramatically in recent years. Seedlings of Prunus lannesiana or clones of 'Colt' (P. avium × P. pseudocerasus) were usually used as sweet cherry rootstocks in Korea. During recent decades new dwarfing rootstocks for cherry such as 'Gisela' series were developed in Germany. Among them, several 'Gisela' series have been mainly used in international nurseries. In this study, we investigated optimum rooting condition of a dwarfing rootstock 'Gisela 5' in summer season cuttings. Among eight soil conditions tested, saprolite + commercial nursery soil (1:1) and saprolite + vermiculite (1:1) showed higher rooting percentage than others, showing 93.6% and 88.9%, respectively. More than 95% of 'Gisela 5' rootstocks produce roots when it was treated with IBA for several seconds just before cuttings, irrespective of concentrations (500 to 2000 mg·L^-1).

• Journal of Bio-Environment Control
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• v.25 no.3
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• pp.168-172
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• 2016

The effect of different exposed length of M.9 rootstock on growth and yield was tested in the new apple cultivars. The 'Seohong', 'Summer Dream', and 'Hongguem' grafted on M.9 rootstock were planted in March 2010. The trees were planted in such a way that the exposed length of the rootstock to be 10, 20 and 30 cm. The result showed that as decreasing exposure length, TCA of 'Seohong', 'Summer Dream', and 'Hongguem' was increased between $3^{rd}$ and $6^{th}$ year after planting. The TCA of 20 cm and 30 cm exposure length showed respectively 70% and 60% in 'Seohong', 88% and 66% in 'Summer Dream', and 55% and 41% in 'Hongguem' of the TCA with 10 cm exposure length on 6-year-old trees. Tree height, canopy width, shoot length and terminal shoot length were also increased according to decreased exposure length in 6-year-old trees. The cumulative yield of three cultivars was higher in the tree with a lower exposure length between $4^{th}$ and $6^{th}$ year after planting. The cumulative yield of 20 cm and 30 cm exposure length showed respectively 77% and 63% in 'Seohong', 85% and 76% in 'Summer Dream', and 73% and 58% in 'Hongguem' of the cumulative yield with 10 cm exposure length in 6-year-old trees. Considering tree growth and yield, the optimum exposure length of M.9 was 10 cm for 'Seohong', 'Summer Dream' and 'Hongguem'.

• Korean Journal of Plant Tissue Culture
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• v.28 no.1
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• pp.33-36
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• 2001

The experiments were conducted to establish the in vitro culture system of apple rootstock M.9. The meristem tissue of M.9 were pre-treated in antiox: dant solution containing 100 mgL$^{-1}$ ascorbic acid and 150 mgL$^{-1}$ citric acid for 30 minutes, transferred to the MS liquid medium added with 0.1 mgL$^{-1}$ IBA, 0.5 mgL$^{-1}$ GA, and 30 gL$^{-1}$ sucrose, which shaked by 50 rpm for 2 weeks, and then, cultured in same composition of MS agar medium. This treatment stimulated shooting from the tissue, the most favorably, compared with other treatments. All young shoots produced normal roots when they were shake-cultured on the 1/2MS liquid medium added with 0.5 mgL$^{-1}$ IBA, 30 gL$^{-1}$ sucrose and 1,000 times diluted solution of Hormex by 50 rpm for one week, and subsequently transferred to the 8 gL$^{-1}$ agar medium of the same composition as pre-culture medium minus Hormex.

• Journal of Life Science
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• v.19 no.6
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• pp.832-835
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• 2009

The main objective of this research was to improve rooting of M.9 apple rootstock through layering time, shading, layering material and water content of the layering part. Among the treatments, rooting was improved by mother plant shading or an earlier covering (layering in shoot length 2 cm) of shoots. Rooting and root growth of sawdust, chaff or vermiculite treatments were significantly higher than those of the control (soil). In the study of layering material water content, -40 kPa treatment increased rooting ratio, number of roots and root growth compared to -60 kPa treatment and control. These results suggest that early-covering, layering with sawdust, chaff, or vermiculite, and keeping the water content in the layering part at -40 kPa could improve rooting and root growth in M.9 rootstock propagation.

• Journal of Plant Biotechnology
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• v.42 no.1
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• pp.49-54
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• 2015

Based on the results in this study, here we propose a systematic micropropagation process for 'Gisela 5' that is one of the important dwarfing cherry rootstocks. When the apical tips detached from newly developed shoot in spring season were cultured on the half strength MS media with 0.5 mg/L IBA and 0.5 ~ 1.0 mg/L BA, the cultures scored the highest acquisition rate at 90% for normal shoot with vigorous growth and without hyperhydricity. As next step, the young shoots maintained in vitro well multiplied on the full strength MS medium supplemented with 0.5 mg/L IBA and 0.5 mg/L BA, in which multiplication rate was approximately nine-fold. Given the half strength MS medium containing 2.0 mg/L IBA, each transplanted shoot further developed robust roots. Finally, the plantlets were easily acclimatized in the compost consisted of vermiculite, perlite, and peatmoss in the proportion of 1:1:1. We expect that the results are useful for cherry cultivation and its rootstock production.

• Journal of Plant Biotechnology
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• v.32 no.3
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• pp.181-186
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• 2005

This work was conducted to evaluate the effects of rooting on tissue cultured M.9 (Malus domestica Bork. cv, tcM.9) after layering in field. We investigated an appearance period of first root in shoot, rooting ratio, contents of indole-3-acetic acid (IAA), abscisic acid (ABA), inorganic matters, sugars, and lignin in rooting areas of stems by layering. First root in shoot of tcM.9 and natural M.9 appeared 25 and 30 days after layering (DAL), respectively. Rooting ratio was much higher in tcM.9 than in natural M.9. The content of IAA was higher in tcM.9 than in natural M.9 before layering, but it was reversed at 20 and 30 DAL. In contrast, the content of ABA was much higher in natural M.9 than in tcM.9 in case of both before and 10 and 20 DAL. The contents of N, B, Mn, and Zn were significantly higher in tcM.9 than in natural M.9 both before and 10 and 20 DAL. The contents of sugars in tcM.9 had the similar pattern of the contents of inorganic materials. There were statistically significant differences in the contents of sucrose and glucose at 30 DAL as well as the content of maltose at 20 and 30 DAL. The content of lignin was significantly higher in tcM.9 than in natural M.9 before layering and 10 and 30 DAL while there was no difference 20 DAL. Therefore, improvement of rooting ability in the tissue cultured root stock M.9 might be due to the changes of inorganic matters or lignin rather than that of sugars and hormones.