Spring Frost Damage Research Articles

Assessing uncertainties in impact of climate change on grass production in Northern Europe using ensembles of global climate models

Forage-based dairy and livestock production is the backbone of agriculture in Northern Europe in economic terms. Changes in growing conditions that affect forage grass yield may have great economic consequences. This study assessed the impact of climate change on two grass species, timothy and ryegrass, at 14 locations in Northern Europe (Iceland, Scandinavia, Baltic countries) in a near-future scenario (2040–2065) compared with the baseline period 1960–1990. Local-scale climate scenarios were based on the CMIP3 multi-model ensembles of 15 global climate models in order to quantify the uncertainty in the impacts relating to highly uncertain projections of future climate. Potential yield of timothy, the most important perennial forage grass in Northern Europe, was simulated under the assumption of optimal overwintering conditions and current CO2 level, in order to obtain an estimate of the effect of changes in summer climate per se. The risk of frost and ice damage during winter was also assessed. The simulation results demonstrated that potential grass yield will increase throughout the study area, mainly as a result of increased growing temperatures. The yield response to climate change was slightly larger in irrigated than non-irrigated conditions (14% and 11%, respectively), due to larger water deficit for the 2050 scenario. However, a geo-climatic gradient was evident, with the largest predicted yield response at western locations. A geo-climatic gradient was also revealed with respect to potential frost damage, which was predicted to increase during winter in some areas east of the Baltic Sea for timothy, and for a larger number of locations both east and west of the Baltic Sea for perennial ryegrass. The risk of frost damage in spring was predicted to increase mainly in western parts of the study area. If frost damage to perennial ryegrass increases during winter, the expected increase in winter temperature due to global warming may not necessarily improve overwintering conditions, so the growing zone may not necessarily expand to the north and east of the study area by 2050. The uncertainty in impacts was frequently, but not consistently, greater in western than eastern locations.

Assessment of assisted migration effects on spring bud flush in white spruce (Picea glauca[Moench] Voss) seedlings

In a changing climate, delaying the time of bud flush may be advantageous to boreal forest species to reduce the risk of spring frost damage. In this study, we examined the potential effect of assisted migration of tree seed on time to bud flush for white spruce. Flushing times of seedlings from 23 white spruce provenances from Ontario were observed under varying temperature conditions simulated in controlled environment chambers. Results indicated that time to bud flush varied considerably among provenances. Although higher temperatures significantly promoted bud flushing for all provenances, provenance-by-temperature interactions were negligible, indicating stable performance of white spruce provenances for this adaptive trait. Spatial patterns of variation among provenances in bud flushing were not consistent with patterns found in range-wide provenance tests. Assisted migration of tree seed across relatively short distances is unlikely to delay bud flushing time in white spruce. Some southern populations may flush earlier at more northerly sites, which would exacerbate spring frost risk. Tree improvement may be an effective approach to utilize amongand withinprovenance variation to enhance this fitness trait for better climatic adaptation.

Ensemble analysis of frost damage on vegetation caused by spring backlashes in a warmer Europe

Abstract. Tree dehardening and budburst will occur earlier in a warmer climate, and this could lead to an increased risk of frost damage caused by temperature backlashes. By using a spring backlash index and a cold hardiness model, we assessed different aspects of risk for frost damage in Norway spruce forests during the present climate and for one future emission scenario. Uncertainties associated with climate modelling were quantified by using temperature data from three climate data sets: (1) E-Obs gridded observed climate data, (2) an ensemble of data from eight regional climate models (RCM) forced by ERA-40 reanalysis data, (3) an ensemble of regional climate scenarios produced by the regional climate model RCA3 driven at the boundary conditions by seven global climate models (GCM), all representing the SRES A1B emission scenario. The frost risk was analysed for three periods, 1961–1990, 2011–2040 and 2070–2097. The RCA3_GCM ensemble indicated that the risk for spring frost damage may increase in the boreo-nemoral forest zone of southern Scandinavia and the Baltic states/Belarus. This is due to an increased frequency of backlashes, lower freezing temperatures after the onset of the vegetation period and the last spring frost occurring when the trees are closer to budburst. The changes could be transient due to the fine balance between an increased risk of frost damage caused by dehardening during a period when freezing temperatures are common and a decreased risk caused by warmer temperatures. In the nemoral zone, the zone with highest risk for spring backlashes during the reference period (1961–1990), the spring frost severity may increase due to frost events occurring when the trees are closer to budburst. However, the risk in terms of frequency of backlashes and freezing temperature were projected to become lower already in the beginning of this century.

Bloom, maturity, and fruit set of pistachio in response to early season application of ethephon

Spring frost damage has been a problem in pistachio producing areas. This experiment was conducted to evaluate the effect of ethephon application rate and date on bloom and maturity delay, fruit set, and yield of ‘Kalleh-guchi’ pistachio in Rafsanjan, Iran. Fourteen-year-old whole trees were sprayed with 0, 250, 500, and 750 mg·L−1 ethephon on February 10 or March 1 for single application and both dates for two applications. With increasing the application rate, timings of the initial and full bloom and the maturity were delayed by 11.2, 12.6, and 7.6 days in 2007 and 11.3, 10.7, and 5.4 days in 2008, respectively. The double spray was the most effective in delaying bloom and maturity, and in increasing yield. The double spray with 750 mg·L−1 ethephon delayed initial and full bloom, and maturity by 14, 15, and 10 days in 2007 and 15, 15, and 8 days in 2008, respectively. This treatment increased the yield by about 64% in both years. It was concluded that ethephon may be applied to pistachio in late winter to delay bloom in spring without any apparent side effects, and thus to prevent spring frost damage and increase the yield.

Frost and flowers: Predicting the effects of climate change on spring frost damage using a large pollen count dataset

Frost and flowers: Predicting the effects of climate change on spring frost damage using a large pollen count dataset

Frost and flowers: Predicting the effects of climate change on spring frost damage using a large pollen count dataset

Abstract Background/Question/Methods Climate change is resulting in warmer average temperatures in much of North America, leading to earlier flowering dates for most tree genera. However, earlier flowering dates can increase the chance of frost damage which may in turn reduce or eliminate seed and fruit production. This has important implications for both forest regeneration and the organisms which depend on these resources.Although specific examples, such as the “Easter frost” of 2007, show that frost damage can have extreme short term impacts on tree reproduction, we lack a general understanding of the frequency and importance of these events in non-agricultural contexts. Moreover, the magnitude by which climate change could increase these events is unknown.In this study we address the following questions: 1) How good of a predictor are environmental variables (such as temperature) for pollen release date and duration across multiple genera of North American trees? 2) How frequently and to what extent has frost damage affected pollen production over the last decade? 3) Based on temporal and spatial variation in environmental factors and tree pollen phenology, what can we predict for future decades?To investigate these questions we make use of a large pollen count dataset, derived from asthma related data collection efforts. This dataset consists of 55 urban sites across North America, and contains six years of data. Pollen was collected daily and identified to the genus level. We also make use of nearby municipal weather stations for detailed daily weather data. Results/Conclusions Certain genera, such as Acer, Alnus, Populus, and Quercus had relatively earlier pollen production times, putting them at higher risk of frost damage. Within each genus there was high variation in when the day of peak pollen counts occurred; for example Quercus peak days ranged from February 28th to June 7th. This variation was largely explained by environmental variables and site specific effects.We found many examples of days which had minimum temperatures sufficiently low to damage plant tissue but where pollen was still collected. For example, in the Quercus genus 223 out of 7417 pollen count observations fit these criteria, suggesting the importance of frost damage to this genus. Next, by comparing pollen count distributions between years, we show the extent to which frost damage has limited pollen production for multiple genera. Finally, we use hierarchical models to show how climate change may affect the impact of frost damage in the future.

A young afforestation area in Iceland was a moderate sink to CO<sub>2</sub> only a decade after scarification and establishment

Abstract. This study reports on three years (2004–2006) of measurements of net ecosystem exchange (NEE) over a young Siberian larch plantation in Iceland established on previously grazed heathland pasture that had been scarified prior to planting. The study evaluated the variation of NEE and its component fluxes, gross primary production (GPP) and ecosystem respiration (Re), with the aim to clarify how climatic factors controlled the site's carbon balance. The young plantation acted as a relatively strong sink for CO2 during all of the three years, with an annual net sequestration of −102, −154, and −67 g C m−2 for 2004, 2005, and 2006, respectively. This variation was more related to variation in carbon efflux (Re) than carbon uptake (GPP). The abiotic factors that showed the strongest correlation to Re were air temperature during the growing season and soil water potential. The GPP mostly followed the seasonal pattern in irradiance, except in 2005, when the plantation experienced severe spring frost damage that set the GPP back to zero. It was not expected that the rather slow-growing Siberian larch plantation would be such a strong sink for atmospheric CO2 only twelve years after site preparation and afforestation.

INFLUENCE OF SPRING FROST AND BLOSSOM WEEVIL DAMAGE ON STRAWBERRY YIELD FORMATION

Depending on the year, strawberry blossoms are damaged by blossom weevil and spring frost. Both damages depend largely on the cultivars, its time of flowering and frost tolerance of blossoms, or blossom weevil preference of cultivar and temperatures before and during flowering. Cv. 'Senga Sengana' was chosen for the study because it has been extensively grown in northern European countries for a long time and in all cultivar evaluation trials in Estonia it has been used as a control. Data were gathered over the eight years period (1999-2007). The data from 'Senga Sengana' were compared to the data obtained from 14 strawberry cultivars on blossom weevil damage in 2005 and 2006 and on spring frost damage in 2006. The results reveal the blossom weevil preference of cultivars. Blossom weevil prefers cv. 'Venta' most of all, cv. 'Sega Sengana' gets less damage. The damage of blossom weevil is most severe in years when average temperatures in May are over 10°C and there are no severe spring frosts. The damage of blossom weevil is extensive in years when the number of blossoms is low (with 'Senga Sengana' in 2003) 'Senga Sengana', being a late cultivar, does not suffer much from spring frosts. Over the nine-year test period only in two years (2002 and 2004) its blossoms had remarkable damage from spring frosts. In 2006 cultivars 'Gerida' and 'Wega' suffered most from spring frosts. With cv. 'Gerida' the damage rate was high partly due to low number of blossoms.

EFFECT OF CONIFEROUS NEEDLE PRODUCTS ON STRAWBERRY PLANT DEVELOPMENT, PRODUCTIVITY AND SPREADING OF PESTS AND DISEASES

Several coniferous needle products such as pine and spruce needle powder SM 87, pine and spruce needle extracts Ausma and Fitoekols IF were tested on strawberries to estimate their influence on plant development, productivity, fruit quality and spreading of pests and diseases. Strawberry cultivar 'Induka' was used in experiments. Plants were grown on open field in single rows in conventional production system. A randomized block design with four replicates was used. Ausma was applied one time per month in 0.2% concentration by watering with dose 1 L per row meter. Powder SM 87 was scattered three times per season with dose 100 g per row meter. Fitoekols IF in 4% concentration was sprayed on plants three times per season. In 2005 an additional treatment with conventional spraying system was included. Coniferous needle extract Ausma showed some positive influence on plant development in the first growing years and reduced spring frost damage, but the effect was not significant with tested dose. Coniferous needle powder SM 87 reduced strawberry blossom weevil incidence and increased the yield, but it was not so effective as treatment with chemical plant protection products. There was not observed any significant influence of tested coniferous needle products on spreading of diseases and mites and fruit quality.

Responses of a beech ( Fagus crenata Blume) stand to late spring frost damage in Morioka, Japan

Following two weeks of a warm period, beech trees at the study site began leafing. However, a spring frost occurred in the cold morning of April 21, 2001 (Day111, Julian day) and killed about 80% of the fresh leaves on a 40-year-old Siebold's beech ( Fagus crenata Blume) stand in Morioka, Japan. Leaves emerged on sprouts from latent buds (latent leaves) 36 days after the frost. Field measurements between 1999 and 2003 revealed the following: (1) Leaf area index was about 4 in normal years and about 1.2 in 2001. (2) The elongation of latent leaves took 55 days about 40 days longer, and they matured about 30 days faster than normal leaves in regular years. (3) Photosynthetic capacities were similar between the latent leaves in 2001 and the normal leaves in 2002 at the top of the canopy. A longer leafing period, faster maturation and sustained photosynthetic capacity of the latent leaves would be helpful to reduce the impacts of frost damage on growth. (4) The frost damage greatly reduced NPP from about 2100 DW g m −2 y −1 in the previous two years to about 1000 DW g m −2 y −1 in 2001. However, NPP recovered almost completely (about 1800 DW g m −2 y −1) in 2002. (5) Seasonal NPP increased similarly in 2001 with other years before Day150 for 40 days after the frost, and decreased afterwards. Shoot elongation also stopped at approximately Day150 in normal years. These findings suggested that radial and height growth in the early growing season was supported by the storage of previous year photosynthesis. (6) A regression growth model was created using meteorological data from 1999 and 2000, and the model was applied to data from 2001 to estimate the potential growth under normal conditions. The ratio of measured and estimated NPP changed seasonally, greater than 0.4 between Day150 and Day210, but below 0.25 between Day210 and Day250. This suggests that beech allocated more photosynthetic products for the next year's growth rather than the current growth in the latter growing season, thereby achieving the same initial growth with other years and amazing recovery in 2002.

Variation in spring and autumn frost tolerance among provenances of Russian larches (Larix Mill.)

Spring and autumn frost tolerance was measured using material from a range-wide (50–67° N, 38–158° E) provenance trial of four Russian larch species (Larix sukaczewii Dyl., L. sibirica Ledeb., L. gmelinii Rupr. and L. cajanderi Mayr.) growing in northern Sweden. Shoots were collected in early May and late September and frozen at −8, −12, −16 and −20°C. Cambial damage was assessed visually after development under ideal conditions for 2 weeks. Differences in frost damage among provenances were highly significant in both spring and autumn. Autumn frost damage was significantly correlated with provenance latitude and longitude and spring frost damage was significantly correlated with provenance longitude but not latitude. Frost damage was not correlated with provenance elevation. North-western provenances showed the least damage and far-eastern provenances the greatest damage in both spring and autumn. A possible explanation for less spring frost damage to north-western provenances is adaptation to maritime conditions in proximity to the Barents Sea, which is often ice free in late winter. This would counteract early loss of frost tolerance and bud flushing if warm spells occurred in late winter. North-eastern Siberian provenances did not show similar adaptation and may exhibit increased spring frost damage if global warming eventually results in the Arctic Ocean north of Siberia becoming ice free in late winter.

Preliminary results of biostimulator treatments on Crataegus and Prunus stockplants.

Biostimulators are natural growth regulators or chemicals, most of them contain plant hormones as auxin, gibberellic acid, cytokinins and aminoacids. Effects of these components increase physiological activities in plants, first of all protein synthesis. Biostimulators help plants surviving stresses. These are used for protect fruit plants from spring frost damage. They are frequently used in horticulture, but rarely in plant propagation. In our research project we intend testing of biostimulators to precondition the stock plants of cutting propagation. We worked with two cultivars of Crataegus pinnatifida, as well as rootstocks Prunus marianna 'GF 8-1' and Prunus mahaleb 'Bogdany'. The hawthorns root poorly, but the two species of Prunus root well. Three biostimulators are applied on stock plants. Kelpak® is made of brown kelp (seaweed), and contains auxin-like and cytokinin-like substances. Wuxal Ascofol® is a leaf fertilizer with seaweed extract. There is 5-aminolevulic-acid in Pentakeep®-V, which stimulates photosynthesis and increases the volume of chlorophyll. Control was untreated. Stock plants before taking cuttings were treated with the above biostimulators. Number and weight of shoots, the weight of cuttings and the leaf chlorophyll content on stock plants are measured. Preliminary results are that the biostimulators Kelpak® and Wuxal Ascofol® increase the number and the weight of shoots, and the weight of cuttings. This means that the shoots of treated stock plants reach earlier the optimum size and quality for cutting. The cuttings are rooting and the data processing is in progress.

Genetic variation in seasonal growth patterns in radiata pine in Galicia (northern Spain)

Shoot elongation patterns in 2 and 3-year-old Pinus radiata seedlings were monitored twice a month during 2003 and once a month during 2004 in three progeny tests in northern Spain. Fifty-eight half-sib families were studied. Several annual growth parameters were measured in each seedling: initiation, termination and duration of height growth and number of new buds formed each year. Total height, internode length and frost resistance were also measured in each seedling. The variation in these traits among families and sites was studied, as well as the effects of environmental parameters (temperature and rainfall) on growth phenology patterns. The extent to which bud phenology is genetically controlled and related to growth traits was examined. Families differed significantly in total summer shoot growth and number of summer flushes (lammas growth). The number of cycles produced per year ranged from one to four. Monocyclic families grew throughout the year, whereas polycyclic families grew episodically, depending on rainfall. Heritabilities within sites were moderate and very similar between years and sites for the dates of bud burst and the number of new buds formed. Bud burst was positively genetically correlated with seedling height. Thus, selection for greater growth is expected to delay bud burst. The number of new buds formed each year was negatively correlated with height and internode length, which means that monocyclic families were taller with longer internodes than polycyclic families. Thus, selection for faster stem growth in young progeny tests is expected to increase the length of internodes in the next generation, to reduce the number of flushes per year and to delay the bud burst date, thereby avoiding late spring frost damage.

Development and application of a forecasting system to avoid spring frost damage in chiana valley

Late frost is one of the more serious adversity for Italian agriculture. Several methods have been developed to protect cultivations, but their application results particularly effective (also from an economic point of view) only if supported by forecasting systems during the more susceptible period of the year. On these basis a forecasting system of late frost in Val di Chiana (an area in central Italy mainly cultivated with cereals and high quality fruits) was developed. The system consists in an empirical model, based on a preventive agroclimatic analysis of the area to identify night cooling dynamics (for several meteorological conditions) in the spring. A network of 10 thermohygrometric stations was installed in the area integrating the information obtained by a local agrometeorological station network. The final product was a forecasting bulletin emitted every three hours beginning from the 13:00 p.m. A validation of the system was performed for 2006 to verify the forecast skill.

Microclimatic studies on different aged apple plantations

The purpose of measuring parallel canopy and out of canopy microclimates was to find out in what extent climatic parameters measured in different aged canopis differ from each other and from the values characteristic to out-of-canopi areas. The importance of phytoclimatic researches seems to lie in the fact that if the reactions of fruit trees towards meteorological elements are continuously followed, we have the possibility to provide growers with information. These pieces of information are like defining the optimum time of phitotechnical interventions (summer pruning, sorting sprouts, thinning fruits, etc.), the necessity of applying mulching, defining the method and time of irrigation and applying plant protection activities. By means of phytoclimatic researches, it is possible to react to unfavourable meteorological impacts within a certain extent. It is also possible to successfully reduce the risks of late spring and early autumn frost damage, as well as the risks, content and measure of experienced heat and water stress conditions by finding out about the physical characteristics of the canopis' internal area.

Stress responses of Calluna vulgaris to reduced and oxidised N applied under ‘real world conditions’

Effects and implications of reduced and oxidised N, applied under ‘real world’ conditions, since May 2002, are reported for Calluna growing on an ombrotrophic bog. Ammonia has been released from a 10 m line source generating monthly concentrations of 180–6 μg m −3, while ammonium chloride and sodium nitrate are applied in rainwater at nitrate and ammonium concentrations below 4 mM and providing up to 56 kg N ha −1 year −1 above a background deposition of 10 kg N ha −1 year −1. Ammonia concentrations, >8 μg m −3 have significantly enhanced foliar N concentrations, increased sensitivity to drought, frost and winter desiccation, spring frost damage and increased the incidence of pathogen outbreaks. The mature Calluna bushes nearest the NH 3 source have turned bleached and moribund. By comparison the Calluna receiving reduced and oxidised N in rain has shown no significant visible or stress related effects with no significant increase in N status.

The importance of hardening and winter temperature for growth in mountain birch populations

Seedlings of five mountain birch populations ( Betula pubescens Ehrh. ssp. czerepanovii) from Fennoscandia and Iceland were raised and grown at natural daylengths at Tromsø, Norway (69°N) and different temperatures during late summer and fall season, followed by winter temperature treatment at ambient and +4 °C above ambient temperatures at Bergen, Norway (60°N). The experiment took place during two seasons (2000/01 and 2001/02). The following summer shoot and biomass growth were reduced as a result of winter warming and subsequent premature dehardening in early flushing provenances and treatments. Biomass increased in plants grown at low hardening temperature when compared with high temperature treatment. As a conclusion, increased winter temperatures would tend to increase the risk of spring frost damage and reduce growth in birch seedlings, because the differences between the frost hardening and ambient temperatures are decreasing, and because the time from budbreak to dehardening is shortened. The results are discussed in relation to simultaneous experiments with frost hardiness in the same populations and treatments.

ALTERNATIVE ESTIMATION TECHNIQUES FOR ASSESSING PROBABILITY OF FROST DAMAGE IN SUBALPINE FIR TREES

Subalpine fir (Abies lasiocarpa var. lasiocarpa) is commonly used for nursery stock and Christmas tree applications. Spring frost damage to new buds, however, can jeopardize the longterm investment of growers and reduce the quality of the resulting fir trees. Hence, it is important to evaluate the risk of frost damage when considering prospective growing sites. A prediction model for bud development based on heat units can be used in conjunction with historical climate data to assess the likelihood of frost damage. That is, given the probability of a frost event at a given location and time, and the corresponding probability of bud break at that time, the probability of frost damage can be estimated. Factors affecting estimation, such as multiple environments inherent in the data, as well as temporal variation, must also be considered. These issues will be explored using parametric, non-parametric, and computer intensive estimation techniques. Examples will be demonstrated using data collected from replicated bud break experiments conducted in northern Idaho.

Genetic Variation of Spring Frost Damage in 3-year-old Fraser Fir Christmas Tree Plantations

A series of open-pollinated progeny tests of Fraser fir [Abies fraseri (Pursh) Poir.] was analyzed to determine genetic variation of spring frost damage to the terminal leader and lateral branches after a late season frost in May of the third year in the field. The level of spring frost damage was also compared with bud flush dates that had been measured in the nursery before field planting. Seed sources differed significantly for lateral branch frost damage, and families within source differed significantly for both terminal leader and lateral branch frost damage. Greater terminal and lateral frost damage were significantly associated with greater height for all years. As expected, parent elevation was negatively associated with progeny height. Less lateral frost damage was also associated with later terminal and lateral bud flush dates in the nursery. In addition, higher parent elevation was associated with later lateral bud flush dates of progeny in the nursery. Terminal and lateral bud flush dates in the nursery showed high individual tree within-population heritability values of 0.85 and 0.73, respectively. Similar heritability values for the frost damage measurements were low, 0.045 for terminal leader damage and 0.14 for lateral branch damage. Many of the fast-growing families quickly made up for any loss of height from frost damage so that frost damage should not greatly affect the rotation length.

Studying on the frost damage of some peach and nectarine varieties

To be able to grow stone fruit species, the peach and the nectarine varieties, yield stability is very relevant. However, the climate is suitable in Hungary for growing stone fruits. We have to calculate with damage. Important winter damage and spring frost damage occur in every second year on the Great Pplains. To reveal the frost tolerance of cultivars and to clarify the differences among growing areas is the most important point of peach and nectarine production.We, made our experiments in the winter of 2005 (January-February), at Pallag, Zsombó, Siófok, Sóskút and Szatymaz. These former places are determinant in peach and nectarine growing in Hungarian respects.In our experiments we analyzed 10-10 fruit shoot from 82 varieties, and we measured the frost damage and the flower bud density.The minimum and the maximum frost damage values (%) at the different growing places were 7.6-38.7 at Siófok, 6.5-31.3 at Sóskút, 34.3-100 at Szatymaz, 83.7-99.6 at Pallag and 51.9-99.6 at Zsombó. There were expressive differences between the same cultivars depending on the growing area.The frost damage of „Suncrest” variety was 7.6% at Siófok, 8.2% at Sóskút but it was 69.8% at Szatymaz. The „Maystar” variety had 17.6% at Siófok, 12.4% at Sóskút and 87.2% frost damage at Szatymaz. In case of „Redhaven” variety the frost damage values were 16.8% at Sóskút, 54.6% at Szatymaz. We collected fruit shoots from three different heights in case of „Cresthaven” variety. In case of 1 meter height the frost damage was 74.6%, at 2 meter height 44.7%, and 25.2% at 3 meter.We experienced also big differences in flower bud density (flower bud/10 cm) of varieties. The following cultivars had the highest flower bud density (6-7 bud/10 cm): „Suncrest”, „Meystar, „Maria Luisa” and the „Maria Bianca”, „Redhaven”, „Michellini” had the lowest flower bud density (2-3 bud/10 cm).After our experiments we established that there were very expressive differences among the frost damage of peach and nectarine varieties from different climatic conditions and there are also big variance between the frost damage values of those fruit shoots, what were collected from different heights, but from the same variety. It conspicuous very good among our items, that difference of the flower bud density is very big among the varieties.To be able to grow peach and nectarine successfully, the suitable variety (low frost damage value, high flower bud density) and the suitable growing are is determinant.