Master Thesis Angebote


List of Master Theses 2018

Department of Crop Sciences,
Division of Viticulture and Pomology,
Prof. Dr. Astrid Forneck

1) Does pre-flowering leaf removal affect pollen viability in Vitis vinifera L.?

Pre-flowering leaf removal is an effective practice for yield control on high-yielding grapevine cultivars. Different works indicate that this practice limits carbohydrates supply to developing inflorescences, which in turn reduces the number of berries per cluster via fruit set rate affection. Fruit set is affected by many genetic factors, including pollen viability, ovule fertility and germination rate. In this regards, an inadequate carbohydrate supply to individual flowers is known to hinder a proper formation and development of viable pollen grains, which results in low viability.

The objective of this work is to analyze the effect of different levels of pre-flowering leaf removal (including no defoliation, as a control) on the reproductive performance of cv. Gewuerztraminer, focusing on its likely effect on pollen viability. This work includes the measurement of carbohydrates content of flowers and inflorescences by HPLC, and the estimation of pollen viability by the automated analysis of digitalized images of pollen-stained samples. 

Students: all students are welcome.
Start: April 2018
Duration: 6 months
Location: UFT Tulln

Advisors: Prof. Dr. Astrid Forneck, Dr. Jose Carlos Herrera,  Dr. Javier Tello

2) Genetic analysis of cluster compactness candidate genes

Cooperation project: BOKU Vienna (AT), Centro di Ricerca Viticoltura ed Enologia (IT), Instituto de Ciencias de la Vid y del Vino (ES)

Cluster compactness (or cluster density) is widely related to the incidence of important vineyard pests and diseases (e.g.: gray mold, berry moth), especially under humid and cold conditions. However, and despite its relevance in practical viticulture, little is known about its genetic basis. Recent association mapping studies have suggested the likely involvement of some genes and polymorphisms on the determination of cluster architecture, but they need of further research prior their use in marker-assisted selection programs.

In this light, the aim of this work is to analyze a series of previously described candidate polymorphisms associated with cluster compactness and/or related traits in two grapevine cultivars with marked differences for cluster architecture: Raboso veronese and Sultanina. Gene expression levels at different developmental stages will be also assessed by quantitative PCR. 

Students: all students are welcome.
Start: April 2018
Duration: 6 months
Location: UFT Tulln

Advisors: Prof. Dr. Astrid Forneck, Dr. Ulrike Anhalt and Dr. Javier Tello (BOKU/AT),  Dr. Manna Crespan (CREA-IT) Dr. Javier Ibáñez (ICVV/ES)

3) Regulated vs Sustained deficit irrigation effect on grape composition

Sustained deficit irrigation is a common practice applied in the vineyard to improve berry quality. It is well known that the key phenological stage to strongly modify berry metabolism is pre-veraison, while positive effects of post-veraison water stress remains unclear and variable. Moreover, irrigation in post-veraison stages is often considered as detrimental by viticulturist because the so-called “dilution” effect.

The experiment will be conducted in three-years old Grüner Vetliner potted grapevines. Plants will be subjected to three different water regimes (well-water control irrigated 100% ETc, sustained deficit irrigation 35% ETc from 40 days after anthesis and until harvest, and regulated deficit irrigation 35% ETc from 40 days after anthesis and until full veraison, thereafter irrigated 100% ETc). Plant physiology (leaf area, gas exchange, water potential, anatomical traits, pv-curves) and berry development (berry mass, volume, and basic composition) will be assessed during the growing season, and plant material will be collected for further analyses in the lab.

Students: students should have basic lab experience.
Start: May 2018
Duration: 6 months
Location: UFT Tulln

Advisors: Dr. Jose Carlos Herrera, Prof. Dr. Astrid Forneck,  Dr. Michaela Griesser

4) Agronomic strategies to avoid late spring frost damage in vineyards

Cooperation project: BOKU Vienna AT, Weinbauschule Krems, Growers in the vicinty of Langenlois AT.

Spring frost events can heavily damage grapevines and represent an important economic loss. Early spring growth is particularly susceptible to freeze injury as growing organs (e.g. shoots, leaves) have a high water content, which makes them susceptible to the formation of ice at freezing temperatures. The objective of the thesis is to assess the suitability of some agronomic practices able to delay the vine budbreak. By delaying the budbreak date, it is expected that the risk of experiencing spring frost damage becomes lower. Experiments will include pruning (long double spur pruning) and the use of budbreak retardant (vegetal oil vs ABA). Students are expected to participate in the pruning days, as well as during the retardant applications (pre-budbreak). Observations will include phenology, shoot and leaf growth measurements, berry development and ripening curves, harvest. 

Students: students should have basic lab experience.
Start: Jan 2018
Duration: 9 months
Location: UFT Tulln, Krems

Advisors: Dr. Jose Carlos Herrera, Prof. Dr. Astrid Forneck,  Dr. Michaela Griesser

5) Welche Signale gibt die Reblausinfizierte Rebe (unter- und oberirdisch) aus?

Volatile Signals below- and above ground of phylloxerated plants

Cooperation project: BOKU Vienna (AT), Faculty of Sciences and Technology Free University of Bolzano (IT)

Volatile compounds mediate communication between plants (among plants) and insects). Plants under phylloxera attack relaes VOCs either at the site of attack (Lawo et al. 2014) or systemically to either benefit or damage the herbiore. Here we will analyse VOCs (constituvely) from unattacked roots and leaves of gall feeding phylloxera (Daktulosphaira vitifoliea) and compared below and above ground VOC releases. The experiment will be performed in „rhizoboxes“ to observe leaves or roots of an infested plants. The analyses will be performed by GCMS chromagrophy. One focus will be the deeper understanding of methyl-salicilate acting als stress signal and induction of resistance within the upper part of the plants. The treatments will cover infected leaves vs. infected roots vs. infected leaves & roots vs. uninfected plants. Studying this interaction will allow a deeper understanding on the plant–insect interaction. The information optabined will further allow modeling on the spread of phylloxera within vineyards.

Students: all students are welcome.
Start: April 2018
Duration: 6 months
Location: UFT Tulln, Vineyards around Krems

Advisors: Prof. Dr. Astrid Forneck, Dr. Sergio Angeli

6) Beeinflusst die Reblausinfektion an Wurzeln die Anfälligkeit der Rebe gegen Echten Mehltau?

Are there effects of phylloxeration on the resistance of Grapevine against downey mildew?

Cooperation project BOKU Vienna, AT & Weinbau Institut Freiburg, GER

Phylloxera infection on roots alters the metabolism of the grapevine, both on rootstock on fruit bearing scion. The stress signalling involving phyto hormons is as well affected and may result in a changed resistance or susceptibility against pathogens attacking the leaves of the plant.

In a greenhouse experiment artificial inoculations will be perform and the resistance will be studied on phylloxerated vs. non infected plants by visual measures and by analysing the expression of the key genes known fort he Oidium–grapevine interaction. 

Students: need first experiences in molecular genetic techniques.
Start: May 2018
Duration: 6 months
Location: project runs in Tulln (2 months for preparation work) and Freiburg/DE for screening work and molecular analysis.

Advisors: Prof. Dr. Astrid Forneck (BOKU),  Prof. Dr. Kassemeier and Dr. M. Breuer (WBI Freiburg)

7) Effizienz von Unterstockpflegemaßnahmen im Vergleich in Weingärten

Efficiency of In-row management effects in vineyards

Cooperation project: BOKU Vienna AT, Weinbauschule Krems, Growers in the vicinty of the wine region Wachau, AT.

In-row treatments: Dauerbegrünung (full cover), Rollhacke (new device, hash like), Fräse (rotary milling), Herbizid (Glyphosate) are frequently applied for soil management in the vineyards. Plant communities of green covers (permanent and temporal) affect the choice of treatment and determine their efficiency. Furthermore soil condition and micro climate play a role on the frequency of treatments applied in the field. Our main question is to understand the effects on recovery and changes of the plants within the green cover community (in-row) both in time and quantity. Experiments in vineyards will be conducted to determine the composition of green cover (in-row vs. row), the determination of soil and climate parameters. Additional parameters tested are: soil moisture, soil enzyme activity and mesofauna.

Students: all students are welcome.
Start: April/May 2018
Duration: 6 months
Location: UFT Tulln, Vineyards around Krems

Advisors: Prof. Dr. Bernhard, Dr. Michaela Griesser,  E. Kührer, Prof. Dr. Astrid Forneck

8) Wie wirkt sich hoher Kalkgehalt auf Wurzelmorphology und -anatomie aus?

High lime content effects on root morphology and anatomy?

Grapevine rootstocks are used worldwide in viticulture as the most important measure to prevent vine death through phylloxera infestation. By using different genetic background, rootstocks gained additional important traits apart from regulating phylloxera infection. These traits are: tolerance to calcareous soils and drought.

Lime tolerance is an important trait for viticulturists affecting nutrient uptake and growth. The biochemical background of different tolerance levels is still obscure, but root morphology and architecture may play an important role as well. Experiments in Rhizoboxes will be conducted to determine root morphology under different conditions and microscopic techniques will be applied to study anatomical differences/adaptations of genotypes to environmental conditions.

Students: all students are welcome.
Start: March 2018
Duration: 6 months
Location: UFT Tulln LAB

Advisors: Prof. Dr. Astrid Forneck,  Prof. Dr. Irene Lichtscheidl,  Dr. Michaela Griesser