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Gewählte Master / Diploma Thesis:

Stefan Peter Ryall (2017): GENOTYPIC VARIATION IN TRANSPIRATION RESPONSE TO PROGRESSIVE SOIL DRYING IN A SET OF POTATO (Solanum tuberosum) CULTIVARS.
Master / Diploma Thesis - Abteilung Pflanzenbau, BOKU-Universität für Bodenkultur, pp 90. UB BOKU obvsg FullText

Data Source: ZID Abstracts
Abstract:
Improving transpiration efficiency (TE; i.e. ratio of produced biomass to water transpired; g l-1) is widely considered as an avenue for improving crop adaptation to water-stress conditions. Plants generally experience water-stress when their transpiration rate exceeds the rate of water supply. The underlying hypothesis of this research work was that cultivars exhibiting an earlier reduction in transpiration rate in response to the fraction of transpirable soil water (FTSW) would conserve water and use it more efficiently later at yield-forming stages. The objective of this research was to investigate genotypic variation in TE among seven potato cultivars grown under well-watered (WW) and water-stressed (WS) conditions in a glasshouse pot experiment. Their daily rates of transpiration and final dry biomass production were recorded. In line with the research hypothesis, all potato cultivars responded to progressive soil drying by restricting their transpiration rate (-51 %). The FTSW-thresholds ranged from 0.25 (cultivars Diamant, Mondial) to 0.32 (cultivar Spunta). The average TE of WW plants was 7.13 g l-1, for WS-plants 20% higher. There were no significant differences between the cultivars in their TE under WS-conditions (average 7.84 g l-1), except for Caesar, which performed roughly 25 % higher than average. The underlying hypothesis was rejected, as no correlation between the FTSW-thresholds and TEs were found. Furthermore, WS-conditions reduced the dry mass of stems (-27 %), leaves (-24 %) and tubers (-49 %) in all cultivars. However, the relative reduction in biomass production was lowest in Caesar. Furthermore, the less vigorous cultivars (e.g. cultivars Caesar and Diamant) survived longer under WS-conditions. The results of this research suggest that intrinsic vigour plays an essential role in plant response to water-deficit as less vigorous genotypes can exhibit lower FTSW-thresholds despite having a higher TE at the cost of reduced biomass production.

Beurteilende(r): Manschadi Ahmad M.
1.Mitwirkender: Kaul Hans-Peter

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