Mok-Jong Kim

Impacts of Urban High Temperature Events on Physiology of Apple Trees: A Case Study of `Fuji`/M.9 Apple Trees in Daegu, Korea

In this study, we examined the effect of high temperature of urban area on the physiological response of apple tree including the photosynthesis, shoot growth, and fruit quality of ‘Fuji’/M.9 apple trees planted at Daegu urban area (DUA) and Gunwi rural area (GRA) for 2 years (2009-2010). During the apple growing season (April-October), the average air temperature of DUA was about 3.0 o C higher than that of GRA and the total rainfall of DUA was 130 mm more than that of GRA. During fruit enlargement stage (June-August), the number of days that recorded daily mean temperature of over 30 o C were ten on DUA in 2010, but there was no day when such temperature was experienced in 2009. Average air temperature of DUA during the maturation stage (September-October) was 19.8 o C, which was 4.0 o C higher than that of GRA. The higher temperature of over 30 o C during fruit enlargement stage decreased the photosynthetic rate, shoot growth, fruit weight, and soluble solid content of ‘Fuji’/M.9 apple tree. The moderate temperature of about 20 o C during maturation stage increased the photosynthetic rate and soluble solid content of ‘Fuji’/M.9 apple tree, but decreased fruit red color. In regional comparison with GRA, photosynthetic rate of DUA was changed from lower before rainy season to higher after rainy season. Fruit weight was higher in DUA than that of GRA. However, fruit weight between DUA and GRA did not show the difference when accumulated days that recorded daily maximum temperature over 35 o C of DUA was increased. Compared to the GRA, soluble solid content of DUA was higher, but fruit red color of DUA was less. These results indicate that the poor red coloring is the most problematic in ‘Fuji’/M.9 apple tree by global warming and urbanization.

Effects of Growth Regulators and Culture Environment on ex vitro Rooting and Acclimatization of Apple Rootstock in vitro Propagated

Growth of M.9 (Malus domestica Bark. cv) and M.26 (Malus domestica Bark. cv) of dwarf apple rootstock, cultured on MS agar medium in a vessel with ventilating stopper (VS) and then in vivo rooting and acclimatization under combined-treatment by some materials with IBA, were investigated. Concentration of and ethylene in the vessel with VS was lower then in the vessel with non-VS. Change of temperature and humidity in the vessel with VS was repeated by light condition. Stomatal pares of tissue in the vessel with VS were immediately closed after plantlets were exposed to room humidity but those in the vessel with non-VS were opened after 20 minutes exposure to room humidity. Leaf area and chloroplast index of tissue in the vessel with VS was higher then in the vessel with non-VS. In vivo rooting ratio and acclimatization ratio of M.9 and M.26 was highest in 300mg/L IBA＋3％ sucrose dip-treatment among other combined- treatments.

Regrowth of Axillary Buds the Current Season and Early Growth and Development the Following Year in Fruiting Young Kiwifruit as Affected by Early Defoliation

Abstract BACKGROUND: This study was conducted to investigate the effect of the unexpected early loss of leaves on a newly-bred kiwifruit on the regrowth of axillary buds the current season and the early growth and development the following year. METHODS AND RESULTS: The vines were defoliated on Jul. 18, Aug. 16, and Sep. 17 in 2012 and on Jul. 16, Aug. 13, and Sep. 12 in 2013. The vines were defoliated 0 (control), 50, and 100% of the total number of leaves on a vine. The regrowth of axillary buds at 30 days after defoliation increased in proportion to defoliation degrees regardless of the defoliated time. Defoliation the previous season did not influence percent budbreak the next season. Percentage of floral shoots of the control vines was 27.4%, each bearing 2-3 flowers. In those vines defoliated 100% in August and September, however, percent floral shoots and number of flowers significantly reduced. CONCLUSION(S): Defoliation in July, August, and September didnot affect percent budbreak the following year regardless of degrees of defoliation. A 100% defoliation in August and September significantly reduced flowering the following year compared to the control; that in August resulted in no floral buds at all.

The Influence of Insulation Wraps on the Temperature Change of Kiwifruit Trunk Surface During Winter

Received: 18 September 2014 / Revised: 10 November 2014 / Accepted: 12 November 2014 Copyright c 2014 The Korean Society of Environmental Agriculture This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Floral Bud Cold Hardiness and Cultural Safety Zone in Rabbiteye Blueberry Cultivars

Floral Bud Cold Hardiness and Cultural Safety Zone in Rabbiteye Blueberry Cultivars Hong-Lim Kim, Yong-Bum Kwack, Jeom-Hwa Han, Pill-Kyung Oh, Won-Byoung Chae, Seong-Cheol Kim, Mok-Jong Kim and Jin-Gook Kim, (Namhae Sub‐Station, NIHHS, RDA, Namhae 668‐812, Korea, Fruit Research Division, NIHHS, RDA, Suwon 440-706, Korea, Vegetable Research Division, NIHHS, RDA, Suwon 440‐706, Korea, Department of Horticulture, Gyeongsang National University, Jinju 660‐701, Korea)

Factors Involved in Rooting Response of M.9 (Malus domestica Borkh.) Dwarf Apple Rootstock to Stem Etiolation.

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.