Genetische Diversität alter Apfel- und Birnensorten (Malus x domestica BORKH. und Pyrus communis L.) in der Steiermark und Teilen Sloweniens

Um die gegenwärtige Diversität alter Kernobstvarietäten zu erfassen, wurde eine von biotischen und abiotischen Einflüssen unabhängige genetische Differenzierungs- und Charakterisierungsmethode gewählt, die Mikrosatellitenanalyse.Das Differenzierungspotential von jeweils 3 spezifischen Apfel- und Birnenmikrosatelliten wurde anhand von 651 Apfel- und 180 Birnenaufsammlungen getestet. Durch deren Mikrosatellitenlängen konnten 248 Apfelkultivare und 86 Birnenvarietäten voneinander unterschieden werden. Es zeigte sich, dass 3 selektierte Mikrosatelliten für die genetischen Differenzierung alter Kernobstsorten ausreichen. Das Auftreten von genotypischen Varianten als Ergebnis somatischer Mutationen zeigt die prinzipiellen Grenzen der Mikrosatellitenanalyse als genetische Differenzierungspraxis auf. Durch die Einführung des neuen Sortencharakteristikums, die Allelkomposition der jeweils 3 selektierten Mikrosatelliten, wurde es notwendig, eine Referenzsortendatenbank auf genetischem Niveau zu gründen, um mit deren Hilfe die Bestimmung unbekannter bzw. mit lokalen Namensgebungen versehener Kernobstsorten zu ermöglichen. Die Apfelreferenzsortendatenbank umfasst 49 Sorten, die der Birne 6 Varietäten.Um eine möglichst umfangreiche Referenzsortendatenbank zu erhalten, ist es notwendig, auch Kernobstvarietäten aus anderen mitteleuropäischen Streuobstbaugebieten in den Datenpool zu integrieren. Mit dem Landwirtschaftlichen Versuchszentrum Laimburg (Südtirol) wurde deshalb ein Verfahren entwickelt, das die Umrechnung der in den jeweiligen Labors aufgrund der Verwendung unterschiedlichster Analysesysteme generierten relativen Mikrosatellitenlängen zu absoluten gewährleistet. Die Steiermark umfasst 113 Apfel- und 54 Birnenvarietäten. Diesen Varietäten konnten entsprechend ihres Vorkommens ihre ökologischen Ansprüche zugeordnet werden.Die Kernobstdiversität aus den Teilen Sloweniens umfasst 25 Apfel- und 19 Birnensorten.For a general screening of the current extent of the genetic diversity of old pipfruit varieties, the microsatellite method was chosen, for differentiation and characterisation, which is independent from biotic and abiotic influences.To screen the differentiation potential of three selected apple and pear microsatellites respectively, 651 apple and 180 pear collections were included in this diversity examination. 248 apple cultivars and 86 pear varieties could be distinguished by their microsatellite lenght. These results clearly showed that three selected microsatellites are sufficient for the genetic differentation of old pipfriut varieties. The appearance of genotypic variants as results of somatic mutations reveals the limits of the microsatellite technique as genetic differentiation method. By the implementation of the new variety feature, the allelic composition of the three selected microsatellites respectively, the establishment of a reference data base on genetic level is essential. This data base enables the identification of pipfriut varieties, which are unbeknown or appointed with local names. The apple reference data base involves 49 cultivars; the pear reference data base includes six varieties.To achieve a preferably substantial reference data base it is necessary to implicate apple and pear varieties from other central-European stray fruit orcharding regions. Therefore a practice was developed, in cooperation with the Research Centre of Agriculture and Forestry Laimburg (The South Tyrol, Italy), which assures the conversion of relative microsatellite length, which are generated in different labs due to the application of unequal analytical systems, to absolut allel sizes. In Styria there are 113 apple and 54 pear varieties. According to their appearance, these cultivars are attributed to their ecological requirements. The pipfriut diversity in the parts of Slovenia comprises 25 apple and 19 pear cultivars.vorgelegt von Stephan MonscheinAbweichender Titel laut Übersetzung der Verfasserin/des VerfassersGraz, Univ., Diss., 2009OeBB(VLID)20124

Activities of H2O2-Converting Enzymes in Apple Leaf Buds during Dormancy Release in Consideration of the Ratio Change between Bud Scales and Physiologically Active Tissues

Hydrogen peroxide-converting enzyme activities in leaf buds of the apple cultivar Idared during the transition from dormancy release to the ontogenetic development were investigated. For this purpose, leaf buds were collected from 26 March 2021 (DOY = day of the year 85) to 23 April 2021 (DOY 113) and the air temperature was continuously monitored. Enzyme assay protocols for catalase (CAT), intracellular peroxidase (POX), and cell wall-bound peroxidase (cwPOX) in apple leaf buds were successfully established based on published protocols. All enzymes showed considerable changes in activity during the observation period. Fluctuation in daily mean air temperatures seemed not to affect the activities of POX and CAT, whereas severe drops in daily mean air temperature may have interrupted the assumed trajectory of cwPOX activity during the stage of ontogenetic development. In addition, the importance of considering changes in the ratio between physiologically active tissues and bud scales when investigating physiological changes in buds during the phase of dormancy release and ontogenetic development is discussed. A new reference system, namely the “adjusted dry weight” [aDW], is proposed to circumvent this shift in ratios when working with scaled buds

Activities of H₂O₂-Converting Enzymes in Apple Leaf Buds during Dormancy Release in Consideration of the Ratio Change between Bud Scales and Physiologically Active Tissues

Hydrogen peroxide-converting enzyme activities in leaf buds of the apple cultivar Idared during the transition from dormancy release to the ontogenetic development were investigated. For this purpose, leaf buds were collected from 26 March 2021 (DOY = day of the year 85) to 23 April 2021 (DOY 113) and the air temperature was continuously monitored. Enzyme assay protocols for catalase (CAT), intracellular peroxidase (POX), and cell wall-bound peroxidase (cwPOX) in apple leaf buds were successfully established based on published protocols. All enzymes showed considerable changes in activity during the observation period. Fluctuation in daily mean air temperatures seemed not to affect the activities of POX and CAT, whereas severe drops in daily mean air temperature may have interrupted the assumed trajectory of cwPOX activity during the stage of ontogenetic development. In addition, the importance of considering changes in the ratio between physiologically active tissues and bud scales when investigating physiological changes in buds during the phase of dormancy release and ontogenetic development is discussed. A new reference system, namely the “adjusted dry weight” [aDW], is proposed to circumvent this shift in ratios when working with scaled buds

Spring frost risk for regional apple production under a warmer climate

<div><p>Spring frosts, as experienced in Europe in April 2016 and 2017, pose a considerable risk to agricultural production, with the potential to cause significant damages to agricultural yields. Meteorological blocking events (stable high-pressure systems) have been shown to be one of the factors that trigger cold spells in spring. While current knowledge does not allow for drawing conclusions as to any change in future frequency and duration of blocking episodes due to climate change, the combination of their stable occurrence with the biological system under a warming trend can lead to economic damage increases. To evaluate future frost risk for apple producers in south-eastern Styria, we combine a phenological sequential model with highly resolved climate projections for Austria. Our model projects a mean advance of blooming of –1.6 ± 0.9 days per decade, shifting the bloom onset towards early April by the end of the 21st century. Our findings indicate that overall frost risk for apple cultures will remain in a warmer climate and potentially even increase due to a stronger connection between blocking and cold spells in early spring that can be identified from observational data. To prospectively deal with frost risk, measures are needed that either stabilize crop yields or ensure farmers’ income by other means. We identify appropriate adaptation measures and relate their costs to the potential frost risk increase. Even if applied successfully, the costs of these measures in combination with future residual damages represent additional climate change related costs.</p></div

Number of frost days (temperature below –2.2°C) coinciding with blocked days (dark blue) as a function of the day of the year.

<p>Number of frost days during randomly drawn days, mean (light blue) and standard deviation (black bars) based on a Monte Carlo test with 1000 repetitions.</p

Apple production and prices in Austria from 2000 to 2017 (based on [26]).

<p>The prices for apples for processing are only available until 2015.</p

Spring frost risk for regional apple production under a warmer climate - Fig 5

<p>Panel (a) Distribution of apple farmers’ annual income. The dark red area refers to the probability of a reduction in yield as experienced in 2016. The light red shading shows the probability of an income reduction higher or equal to the one experienced in 2017. Panel (b): Exceedance probability curve describing the average annual income loss (AAL) faced by Styrian apple farmers. The numbers are inflation adjusted and correspond to EUR 2005 values.</p

Evolution of the blossoming day of apple in Weiz from 1951 to 2100 from the 5-year smoothed multi-model mean (green line) plus standard deviation (green shading) as well as from phenological observations from 1951 to 2006 (gray line).

<p>Potential frost damages (temperatures below –2.2°C occurring within 10 days after blossoming) are indicated for different regional climate models under RCP4.5 (colored dots). The dot size indicates how many grid points around Weiz are affected. Note that climate projections are not initialized with recent climate observations so that the variability of the simulated blossoming in the historical period does not match the observations.</p