Rate Of Budburst Research Articles

Comprehensive evaluation of the resistance to shoot shriveling before and after sprouting in different varieties of Ping’ou hybrid hazelnut

IntroductionThe hybrid hazelnut is an important fruit tree species known for its high productivity and disease resistance. However, during the growth process of hybrid hazelnuts, issues such as branch withering and bud wrinkling have attracted significant attention. These phenomena severely impact the normal development and yield of the plants. This study aimed to investigate the relationship between the resistance to shoot emergence and physiological changes in six hazel tree varieties by comprehensively analyzing their resistance to shoot emergence.MethodSix widely cultivated hazelnut hybrid varieties were selected for physiological measurements and field surveys using one-year-old branches and buds as test materials. The resistance to shoot emergence of different hazel tree varieties was evaluated through correlation analysis, principal component analysis, and membership function evaluation.ResultsThe results showed that the length and width of hazel buds gradually increased while the thickness first increased and then decreased before and after bud burst. The carbohydrate levels of the ‘Dawei’, ‘Pingou 110’, and ‘84–237’ varieties were significantly higher than those of other varieties. The content of reducing sugars and starch in hazel buds generally increased and then decreased during the bud burst process, while α-amylase activity showed a decreasing trend followed by an increasing trend. The antioxidative enzyme activity of ‘Dawei’ was significantly higher than that of other varieties on different sampling dates. The soluble protein content, POD enzyme activity, and CAT enzyme activity of hazel buds for the six varieties gradually decreased. The moisture content of ‘Pingou 210’ shoots was significantly higher than that of other varieties during the peak emergence period. The correlation analysis results showed that the bud burst rate of hazel trees was positively correlated with the length, width, thickness, reducing sugar content, starch content, POD enzyme activity, CAT enzyme activity, and shoot moisture content, while it was negatively correlated with α-amylase activity and relative conductivity of shoots. Through a comprehensive evaluation using correlation analysis, principal component analysis, and membership function analysis, the resistance to shoot emergence of the six hazel tree varieties was ranked in the following order: ‘Dawei’, ‘Pingou 110’, ‘84–237’, ‘Pingou 210’, ‘Yuzhui’, and ‘Liaozhen 3’.DiscussionThis study fills a research gap regarding the physiological changes of hazelnuts before and after sprouting, and provides theoretical guidance for further research on the anti-withering ability of hazelnut trees.

Daylength effects on black spruce bud dormancy release change during endo- and ecodormancy

The effects of daylength on bud dormancy release varied throughout the dormant period in black spruce (Picea mariana (Mill.) B.S.P.) seedlings. In phase one of this trial, seedlings exposed to 8 h photoperiods to induce terminal buds were then intermittently transferred to 12, 16, 18 or 24 h photoperiods to determine dormancy status, evaluated by observing rates of terminal budburst. Buds were in a state of endodormancy initially after short-day induction, as indicated by their inability to quickly break bud when placed in longer daylengths. The time required for budburst decreased as time after bud initiation increased. Time to terminal budburst also decreased linearly with longer photoperiods. In phase two of the investigation, beginning 9 weeks after terminal bud initiation, seedlings began receiving chilling at +5°C to promote the transition from endo- to ecodormancy. During chilling, groups of seedlings were periodically removed from the cold and placed into warm temperatures at 8, 12, 16, 18 or 24 h photoperiods to observe the rate of budburst. Time to budburst in an 8 h photoperiod decreased logarithmically with the duration of chilling, decreasing more rapidly over the first four weeks of chilling and thereafter more slowly. Photoperiod always affected the rates of budburst: with eight weeks of chilling, longer photoperiods resulted in faster rates of budburst; in contrast, after 16 weeks of chilling, budburst was faster in shorter photoperiods. These results are of practical significance in tree nurseries where controlling bud dormancy release is important. In addition, this trial provides empirical observations of bud dormancy release that contribute to the understanding of environmental control of this aspect of the tree developmental cycle, which may affect tree phenology as the climate changes.

The Effects of Cattle and Sheep Manure Applications on Soil Physical Properties and Rooting and Shoot Development of Grapevines Cuttings

The amount of organic matter plays an important role in the structural improvement of soils and ensuring sustainable soil fertility. In this study, the effects of cattle and sheep fertilizer applications at different doses on soil physical properties, and in parallel with, the effects on rooting and shoot development of vine cuttings were investigated. In this study, 10%, 20% and 30% cattle and sheep fertilizer was mixed into the soil as rooting medium, and the rooting and shooting performances of Karaerik and Narince grape varieties were evaluated in greenhouse conditions. During the experiment, the bud burst rates of the cuttings were recorded, and at the end of the experiment, the aggregate stability values, water permeability, bulk density, total porosity of the soil and plant parameters such as the root length, the root number, shoot length and the leaf number of the grapevines were determined. In this study, it was determined that the increase in the amount of organic matter improves the physical properties of the soil and increases the aeration capacity, and has a significant effect on the bud burst rate, rooting and shooting performance of the cuttings. As a result of the study, it was determined that sheep fertilizer was more effective in root development and cattle fertilizer in shoot development of Karaerik grape variety. It has been revealed that sheep fertilizer gives more positive results on both root and shoot development than cattle fertilizer in Narince grape variety.

Soil Water Content Directly Affects Bud Burst Rate in Single-Node Cuttings of Perennial Plants

The use of single-node cuttings of shoots as explants to study bud dormancy and its physiology under controlled conditions is a common practice in grapevine (Vitis vinifera L.) or other perennial plant research. In particular, this method has been extensively used to understand the effect of different chemicals on bud dormancy and bud burst. However, the soil water content in those experiments is usually not reported and its relevance is often neglected. Here, we observed that an unevenly distributed soil water content in a tray containing multiple explants results in an uneven pattern of bud burst within the same treatment. Thus, we hypothesised that soil water content can dramatically affect bud burst. To investigate this, we first established that fresh single-node cuttings were able to transport water into the buds. We then tested the rate of bud burst at different water treatments (35%, 55%, 70%, 85%, and 100% of field capacity; FC). We observed a clear dependence of bud burst on water, in which, at very low levels of water, bud burst does not occur; after 35% FC, bud burst rate increases with water content until around 85% FC; and, from 85% FC, bud burst rate becomes independent of water content. These data highlight the critical importance of monitoring soil water content in any bud burst assay in perennials. Finally, we provide a detailed protocol for determining and controlling field capacity and other soil water content indicators.

Estimates of genetic parameters, genetic variability, and selection in the S1 generation of peach

ABSTRACT: The growing of peach in mild winter regions is made viable through the use of genotypes that have low need for cold conditions, and this is one of the main aims of breeding for these regions. Thus, the aims of this study were to estimate genetic parameters, evaluate genetic variability, and select families adapted to mild winter regions in the S1 generation of peach through mixed model methodology (REML/BLUP). For that purpose, 22 populations, 84 families, and 2090 individuals were evaluated for the following traits: bud burst rate (BR), node density (ND), plant height (PH), and trunk diameter (TD). Genetic variability was found for all the traits. Individual heritability in the broad sense was of low and medium magnitudes. The PH trait had positive genotypic correlation of high magnitude with TD. The ND trait had moderate negative genotypic correlation with PH and TD. Clustering by the Tocher method resulted in the formation of six mutually exclusive groups. Considering selection intensity of 25%, simultaneous selection for BR, ND, and TD led to predicted gains of 11.3% for BR, 9.7% for ND, -14.2% for PH, and -14.3% for TD, showing the great potential of the germplasm evaluated.

Development of a model to estimate the chilling requirement of oriental pear by standardizing dormancy depth

The objective of this study was to develop a model to estimate the chilling requirements of 10 oriental pear cultivars by standardizing dormancy depth. The dormancy depth of these cultivars was standardized to a range of 0–100 by setting the lowest bud burst rate during endodormancy as 0 and the bud burst rate immediately after the completion of endodormancy as 100. The endodormancy period was divided into periods. Stage I represented continuously increasing dormancy depth until the deepest dormancy was reached. Stage II represented the period of decreasing dormancy depth following the deepest dormancy; this stage included the breaking of dormancy. In addition, the 10 studied cultivars were classified into three types according to their dormancy depth changing pattern: stage I drop type, stage II leap-up type, and stage I·II symmetric type. A chilling accumulation model was derived based on both the endodormancy period and the dormancy depth of each cultivar. The results showed that − 1.9 to 12.0 °C was an effective range for chilling accumulation and that 2.1–4.0 °C was the most effective range for chilling accumulation. The results also revealed that negative accumulation, the reverse reaction of chilling accumulation, occurred under high-temperature conditions (above 14 °C). The results of the model verification process confirmed that the high-temperature conditions (above 14 °C) exhibited negative accumulation values due to an inverse relationship with dormancy depth during endodormancy stage I and that the chilling accumulation for the actual dormancy break mostly occurred during endodormancy stage II.

Moderate chilling requirement controls budburst for subtropical species in China

It is well known that spring phenology has advanced in temperate regions over the last few decades in response to climate change. However, we understand much less about climate-driven changes in phenology within subtropical and tropical regions, where the timing of events is less predictable and has not been well-studied. It is not known whether subtropical plants have a similar winter chilling requirement to what has been well-documented in temperate species. To explore this possibility, we established a climate chamber experiment to test the effects of photoperiod and chilling on the timing of budburst within 37 subtropical woody species. We found that both moderate and strong chilling treatments advanced budburst and reduced forcing requirements, relative to plants subjected to a low chilling treatment. Longer photoperiod enhanced budburst rate for only two species, suggesting that chilling is more important for regulating budburst for most species. With respect to future climate change, the spring phenology of subtropical species is expected to be delayed further because species could lack the ability to meet their fundamental chilling requirement. These results have important implications for the conservation and management of tropical and subtropical plant populations under future climate change scenarios.

Budburst and flowering intensity by the spraying of dormancy-breaking products in ‘Eva’ apple trees

Spraying of dormancy-breaking chemicals is a mandatory procedure to produce temperate fruits in low-chill regions. Although hydrogen cyanamide (HC) + mineral oil (MO) show efficiency enhancing budburst, the usage of HC is restricted in some countries due to its toxicity. Therefore, this research aimed to evaluate the efficiency of spraying different dormancy-breaking agents on ‘Eva’ apple tree buds, under the conditions of the Depressão Central of Rio Grande do Sul, Brazil. Different doses of Erger® (0, 2, 3, 4, 5%) + 3% Ca(NO3)2 were tested and compared with MO (4%) or MO (4%) + HC (0.6%). Budburst rate of apical and axillary buds, physiological alterations in buds, return bloom, yield and fruit weight were evaluated. Erger® treatments efficiently enhanced budburst, with a result equivalent to HC + MO treatment. The budburst rate increased as the Erger® dose increased, also causing the increment of the return bloom in the following year. However, doses of 4 and 5% caused the death of shoots. The activity of the peroxidases and the content of H2O2 in the buds were affected by the treatments. Yield and fruit mass were different in response to treatments, although the effect varied between years. Erger® + Ca(NO3)2 spraying increase budburst in apical and axillary buds of ‘Eva’ apple tree in low-chill conditions and doses up to 3% of the commercial product do not cause toxicity.

Torsion of canes and hydrogenated cyanamide in bud bursting and production of grapevine cv. Itália muscat in the São Francisco valley

Abstract The grapevine cultivated in tropical regions, such as the Sub-medium of the São Francisco Valley, exhibits a strong bud dormancy and high apical dominance, thus presenting the need for the utilization of products that promote the dormancy breaking of the buds. The aim of the present work was to evaluate the efficiency of the application of hydrogenated cyanamide and the practice of cane torsion over the breaking of bud dormancy, bud burst and yield of grapevine cv. Italia Muscat in the conditions of the Sub-medium of the São Francisco Valley. The experiment was conducted in Petrolina, PE state, during two production cycles (2015-2016). The adopted design was in randomized blocks, with treatments distributed in a 2 x 2 factorial scheme, referring to the torsion of canes (with and without) and the different doses [D1: hydrogenated cyanamide (H2CN2) 2.45%; D2: hydrogenated cyanamide (H2CN2) 2.94%], with four replicates. The use of the hydrogenated cyanamide associated to the torsion of canes influences in a distinct manner the studied variables, in the different production cycles, although increments in production and yield occur in both. Therefore, the use of 2.94% of H2CN2 along with the torsion of canes is a recommended practice for the increase in the bud burst rate and yield of grapevine cv. Italia Muscat, cultivated in the region of the Sub-medium of the São Francisco Valley.

The mechanism underlying overwintering death in poplar: the cumulative effect of effective freeze–thaw damage

We analyzed the relationships linking overwintering death and frost cracking to temperature and sunlight as well as the effects of low temperatures and freeze–thaw cycles on bud-burst rates, relative electrical conductivity, and phloem and cambial ultrastructures of poplar. Overwintering death rates of poplar were not correlated with negative accumulated temperature or winter minimum temperature. Freeze–thaw cycles caused more bud damage than constant exposure to low temperatures. Resistance to freeze–thaw cycles differed among clones, and the bud-burst rate decreased with increasing exposure to freeze–thaw cycles. Cold-resistant clones had the lowest relative electrical conductivity. Chloroplasts exhibited the fastest and the most obvious reaction to freeze–thaw damage, whereas a single freeze–thaw cycle caused little damage to cambium ultrastructure. Several such cycles resulted in damage to plasma membranes, severe damage to organelles, dehydration of cells and cell death. We conclude that overwintering death of poplar is mainly attributed to the accumulation of effective freeze–thaw damage beyond the limits of freeze–thaw resistance.

Effets De l’Acide Naphtalène Acétique, Du Type De Substrat Et De La Grosseur Des Boutures Sur Le Bouturage De Tige De Pterocarpus Erinaceus Poir. (Fabaceae)

This study, conducted in south-east Benin, aims to provide practical information on the optimal conditions for successful propagation of stem cuttings of Pterocarpus erinaceus Poir. (Fabaceae), a real alternative to its regeneration and domestication. A trial was conducted to evaluate the effect of different doses of Acid Naphthalene Acetate (ANA) (0; 500; 750; 1000 and 1500 mg/l), the type of substrate (black forest sand and fine sand) and the size of the cuttings used ([1.5-2] and [2.5-3] cm of diameter) on the recovery of these cuttings. To evaluate the effect of different treatments on budding rate, bud burst rate and degenerate cuttings rate, Generalized Linear Mixed Models and Generalized Linear Models of the binomial family with the lme4 and nlme packages were used with the R.3.2.4 statistical software. The results showed that the application of ANA does not significantly improve the cuttings recovery. The probability of budding and budding with 0 mg / l of ANA is similar to that of 500 mg/l, and 750 mg/l of ANA ; doses of 1000 and 1500 mg/l of ANA significantly reduce the probability of budding and bud burst. The diameter of the stems of Pterocarpus erinaceus does not affect the recovery of the cuttings while the substrate has a marginal effect. Levels of degenerate cuttings during the trial do not vary with the treatments.

Effects of Pre-chilling Potassium Nitrate and Post-chilling Hydrogen Cyanamide Application on Carbohydrate and Water Dynamics of ‘Housui’ Japanese Pear Spur Buds During Dormancy Under Mild Winter Conditions

Japanese pear (Pyrus pyrifolia Nakai) trees were treated with potassium nitrate (KNO3) before the onset of chilling and hydrogen cyanamide (CH2N2) after the trees had accumulated 600 chilling hours (CH) to determine the effects on bud dormancy release, carbohydrate dynamics, and water content. For the carbohydrate and water content analyses, Japanese pear spur buds were collected after 0, 300, and 600 CH, and after the accumulation of 2000, 4000, 6000, and 8000 growing degree hours (GDH) during the dormancy period. Bud burst and flowering were hastened by both KNO3 and CH2N2 application, and both chemicals affected carbohydrate and water dynamics during dormancy. Sucrose concentration tended to increase during the chilling period, and to decrease under forcing conditions. Hexose concentrations increased in buds treated with KNO3, CH2N2, or both, and were associated with advances in bud burst. Sorbitol concentration decreased early in buds treated with CH2N2, suggesting rapid sorbitol catabolism. Water content gradually increased under forcing conditions in all buds, although those treated with both KNO3 and CH2N2 exhibited the highest values. Accordingly, we recommend the use of KNO3 and CH2N2, before and after chilling, respectively, to promote the release of bud dormancy and increase bud burst rate in ‘Housui’ Japanese pear grown in regions with mild winter conditions.

BUD DORMANCY INTENSITY IN PEACH TREE CULTIVARS BY BIOLOGICAL AND TETRAZOLIUM TEST

ABSTRACT Temperate climate fruit trees often exhibit uneven budding and flowering, due to the low number of chilling hours that determine the occurrence of dormancy and its depth. The objective of this study was to determine the depth of bud dormancy in peach tree cultivars and evaluate the efficiency of the tetrazolium test for dormancy and comparing with biological test. Branches of the cultivars Aurora 1, Chimarrita, Chiripá, Coral, Eldorado, Granada, Leonense, Maciel, Marli, Premier, and Vanguard were collected between May and August 2008 at two locations: Curitiba and Lapa. The evaluation of dormancy was performed using a biological test of single node cuttings through the parameters: average time for bud burst, velocity of bud burst, final rate of bud burst and rate of vigorous bud burst. For the tetrazolium test, 300 mg of buds was used and the color intensity readings were obtained using a spectrophotometer. The peach tree cultivars evaluated differ in the intensity of dormancy in late fall. The most intense endodormancy cultivars found were: Chiripá, Leonense and Eldorado cultivars, and the weaker cultivars found were: Aurora 1 and Maciel. The tetrazolium test was efficient at estimating the intensity of dormancy in peach trees when the occurrence of cold was suitable for installation endodormancy. At a location with the lowest occurrence of cold (Curitiba), the tetrazolium test did not simulated successfully the biological test results.

Pavement induced soil warming accelerates leaf budburst of ash trees

Urban greening is becoming increasingly popular in cities around the world, which is leading to the planting of more and more trees in paved areas in urban environments. However scientifically it is not well understood how pavement may impact tree greening efforts. In this paper, we investigated plant responses to pavement in the suburb of Changping District, Beijing, China. We planted the popular deciduous ash tree (Fraxinus chinensis) in three different pavements: pervious bricks; impervious bricks; and no pavement (i.e., control) at three densities (0.5m×0.5m, 1.0m×1.0m, and 2.0m×2.0m apart). We investigated the influence of pavement type on plant phenology by monitoring soil temperature and moisture as well as leaf budburst rate from January to April in 2014. Our results show that pavement can significantly increase soil temperature, and decreased soil moisture except pervious pavement at the 1.0m×1.0m density. The significant relationship between the leaf budburst rate and accumulated soil temperature implies that pavement induced soil warming can accelerate leaf budburst, suggesting that pavement contributes to tree leaf budburst acceleration by probably both increasing soil and air temperatures in urban environments.

Chilling temperature and photoperiod influence the timing of bud burst in juvenile Betula pubescens Ehrh. and Populus tremulaL. trees

This research demonstrates that inadequate chilling has the potential to slow both the rate and speed of bud burst of two important European forest species; Betula pubescens and Populus tremula. The timing of bud burst in deciduous trees has been widely used as an indicator of spring warming. However, winter chilling conditions can have a significant impact on the timing of bud burst. If trees receive insufficient chilling, there may be a delay in bud burst even if spring temperatures rise. Therefore, it is important to understand the effect of chilling on spring phenology of trees. Here, we exposed juvenile (3–6-year old) birch (B. pubescens Ehrh.) and aspen (P. tremula L.) trees to a range of photoperiods, chilling durations and forcing temperatures in controlled environment chambers to assess the impact on the timing of bud burst. Analysis of variance demonstrated that longer chilling duration resulted in earlier bud burst in both species, and less thermal time was needed to reach maximum bud burst. Therefore, in warmer winters bud burst in spring may be expected to be delayed if insufficient chilling is received. However, longer photoperiod may, at least in part, compensate for shorter chilling duration. These results suggest that models predicting climate warming impacts on phenology should take winter chilling into account when considering the timing of bud burst in deciduous species.

Impacts of contrasting light on bud burst and on RwMAX1 and RwMAX2 expression in rose

Bud burst is a crucial factor in plant architecture and is strongly induced by light. In Rosa sp., this light effect was correlated with the growth of axillary buds and RwMAX1 and RwMAX2 expression within buds. In this paper, we investigated whether strigolactone pathway is involved in the regulation of axillary bud in response to light intensity. Hence, young roses were subjected to two contrasting light intensity regimes: high/high and high/low. The phenotype was characterized in both conditions and the expression of RwMAX1 and RwMAX2 genes was measured in the basal, middle and apical parts of rose primary branch. Light treatments showed a strong impact on axillary bud. The percentage of bud burst was severely reduced in the treatment high/low compared to the treatment high/high in all branch parts. In addition, the expression of RwMAX1 and RwMAX2 was strongly inhibited by high/high light regime and was conversely correlated with the rate of bud burst. In in vitro-grown axillary buds supplied with sucrose, glucose and fructose, RwMAX1 expression was significantly stimulated whereas that of RwMAX2 was significantly inhibited. Our results suggest that although RwMAX1 and RwMAX2 expression can be regulated by light, this expression does not explain the ability of bud burst.

Relationships between biomass allocation, axis organogenesis and organ expansion under shading and water deficit conditions in grapevine.

The relationships between whole-plant growth and morphogenetic processes under abiotic stresses are still partly unknown. Whole-plant biomass growth can be decreased by many abiotic stresses, including water deficit and shading. Two experiments were performed on potted plants of one grapevine cultivar (Vitis vinifera L. cv. Syrah) subjected to watering and shading treatments. Under water stress, plants reduced their primary and secondary axis leaf production rate, whereas secondary axis budburst was relatively unaffected. Individual leaf area was reduced and a strong decrease in leaf expansion rate was observed. Under shading, primary axis organogenesis was maintained, both secondary axis budburst rate and phytomer appearance rate were decreased, and individual leaf area slightly increased. Specific leaf area did not change under soil water deficit, whereas it increased under shading. These results confirm the existence of dynamic changes in organ sink strength and biomass allocation patterns to favour plant leaf area growth under shading, and to reduce plant leaf area and water losses by transpiration under water stress. From a modelling point of view, this study shows that functional structural models based on a C balance are not fully relevant for simulating plant growth under abiotic constraints if they do not include non-trophic relationships (hormonal signalling or plant hydraulic properties) that modify organ sink strength according to abiotic constraints.

Growth and Fruit Characteristics of ‘Cheongsoo’ Grape in Different Trellis Systems

수형은 포도 과실의 품질과 수확량에 영향을 주는 주요한 요인이다. 또한 몇몇 포도 품종들은 다양한 기후와 토양조건에서 고유한 특성을 드러내기 위해 적합한 수형을 요구한다. 본 연구는 '청수' 품종의 우리나라에서의 재배에 적합한 수형을 평가하기 위해 수행되었다. '청수' 품종의 수형에 따른 광 환경을 비교한 결과 수광량이 높은 수형은 커튼형, 이중커튼형, 개량일자형 순이었다. 최대 광량의 경우 개량일자형은 약 <TEX>$670{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$</TEX>인데 비해 커튼형과 이중커튼형은 약 1,654와 <TEX>$1,649{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$</TEX>로 나타났다. 대기온도는 세 수형 모두 비슷하게 나타났다. 광도 <TEX>$1,500{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$</TEX>에서 개량일자형은 이산화탄소동화율이 <TEX>$8.3{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$</TEX>인데 비해 커튼형과 이중커튼형은 13.4, <TEX>$13.7{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$</TEX>로 나타났다. 주지횡단면면적과 발아율은 세 수형간에 유의한 차이를 보이지 않았다. 눈의 수와 신초 수는 54.4개와 47.0으로 이중커튼형에서 가장 많았으며 커튼형에서는 눈의 수는 34.7개, 신초 수는 31.3개로 가장 적었다. 신초의 길이는 개량일자형의 경우 243.9cm로 가장 길었으며 이중커튼형은 151.5cm로 가장 짧았다. 초생엽과 부초엽의 엽면적의 경우에도 개량일자형이 다른 수형에 비해 월등하게 높게 나타났다. 수관 내부 잎 수와 전체 잎에 대한 수관 내부 잎의 비율은 이중커튼형이 높게 나타났다. 과립 무게, 과립의 종경과 횡경은 수형간 차이가 나타나지 않았다. 그러나 과방중은 이중커튼형에서 203.66g으로 가장 높았으며 개량일자형에서는 130.10g으로 가장 낮았다. 나무당 과방수 또한 이중커튼형이 136.8개로 개량일자형의 86.28나 커튼형의 97.42개에 비해 많았다. 산도는 이중커튼형에서 0.45로 다른 수형에 비해 유의하게 낮았다. 따라서 '청수' 품종은 단위면적당 수확량을 높이면서도 과실의 품질이 저해되지 않는 이중커튼형으로 수형을 관리하는 것이 적합한 것으로 판단되며 이는 '청수' 품종의 농가 보급 및 재배에 중요한 정보가 될 것이다. Trellising is an important cultural practice that affects grape quality and yield. Some grape cultivars require different trellising under different climate and soil conditions. To find suitable trellis conditions for grape cultivar 'Cheongsoo', we measured growth and fruit characteristics with three different trellis systems: curtain, Geneva double curtain (GDC), and modified T. The maximum light exposure of clusters in the curtain, GDC, modified T trellis systems was 670, 1,654, and <TEX>$1,649{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$</TEX>, respectively. However, there was no difference in air temperature among the three trellis systems. Net <TEX>$CO_2$</TEX> assimilation rate at <TEX>$1,500{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$</TEX> light intensity was 13.4, 13.7, and <TEX>$8.7{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$</TEX> in curtain, GDC, and modified T trellis systems, respectively. Trunk cross section area (TCSA) and bud burst rate were not significantly different among the three systems. Shoot number was 31.3, 47.0, and 37.0 in curtain, GDC, and modified T trellis systems, respectively. The shoot length was higher (243.9 cm) in the modified T trellis system than in the single curtain (171.1 cm) and GDC (151.5 cm) systems. Interior leaf number and leaf layer number were higher in the GDC system, in which there are two primary branches, in comparison to the modified T and curtain systems, which utilize one primary branch. Primary leaf area and lateral leaf area were significantly higher in the modified T trellis system in comparison to the GDC system. Berry weight, length and diameter, and total soluble solids were not significantly different among the three trellis systems. However, cluster weight and cluster number per tree were significantly higher in GDC. Titratable acidity was significantly lower in GDC. Collectively, our data suggest that the GDC trellis system is preferable for grape 'Cheongsoo' to maintain fruit quality and quantity in Korea.

Effects of Summer Pruning and Cropload on Summer and Winter Bud Carbohydrates in Sweet Cherry

Orchard management practices have the potential to influence carbohydrate supply to storage organs, including buds. This study was designed to assess if bud carbohydrates could be manipulated by orchard practices in sweet cherry (Prunus avium). Additionally, we investigated the impact of any such changes on subsequent bud burst and fruit quality the next season. We examined the effect of pruning at different fruit growth stages and cropload on summer and winter bud non-structural carbohydrates (NSCs) and on fruit quality at harvest the next summer in two cultivars. Buds were collected postharvest in summer and after the onset of dormancy in winter, and individual soluble sugars and starch were extracted. The next growing season, flower number and fruit set were recorded. When fruit reached full maturity, fruit were harvested for quality assessment. We observed qualitative changes in NSCs from buds collected in summer and winter. Pruning significantly reduced available NSCs in late summer buds but made little difference by winter; only early pruning showed slight changes in sucrose and glucose. However, early pruning positively influenced the next season’s fruit grade. High cropload resulted in higher NSCs in winter buds than the low cropload. Significant changes in sucrose from summer to winter were observed, and levels of sucrose in the buds differed between cultivars. Different levels of winter bud sucrose between cultivars corresponded to different rates of bud burst. Although pruning was able to manipulate NSCs in buds within a few weeks, these changes were not sufficient to influence the rate of bud burst within a cultivar, but pruning did influence fruit quality in the next season.

Variation in the chilling requirement and budburst rate of wild Vitis species

Cultivated grapevine (Vitis vinifera) is one of the most important agricultural fruit crops in the world and grapevines are often grown in environments very different than the Mediterranean climate from where they were domesticated. To meet the environmental demands of varied climate, grapevine breeders often utilize wild grapevine species for adaptive traits, particularly in regard to abiotic stress resistance. In this study, we characterized both the chilling requirement and days to budburst phenotypes in wild grapevine species. Using survival analysis, we examined the effect of varied lengths of low temperature on budburst in 27 different genotypes of grapevine, including seven wild grapevine species, three cultivated grape varieties, and four hybrid varieties. Results of our two-year study demonstrate a wide range in both intraspecific and interspecific variation in these traits. Trends within the data allow us to categorize low and high chill species. Correlated with these categories are fast and slow maximal budburst phenotypes. When compared with geographic distribution of species and genotypes, patterns between northern and southern populations suggest that chilling requirement and budburst rate are adaptive traits.