Format:
229 Seiten
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Illustrationen, Diagramme
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29,5 cm
Content:
At least 10,000 years ago, humans began domesticating crop plants into consistent, high-yielding food sources. Plants continue to provide 90% of human food energy intake worldwide. However, as human populations increase and arable land becomes scarce or unproductive due to climate instability, plant food sources may no longer be able to sustain human nutritional requirements. Plant populations must become more productive. This dissertation uses an ecological model plant, Nicotiana attenuata, to evaluate the contexts and scales at which plant populations can increase their productivity. I explore the current uses and future potentials of three functional traits that can be selected for, or genetically modified, in crop cultivars to improve agricultural yields. First, I test the efficacy of current agricultural pest-resistance technology in increasing yield. The pest-resistance technology (Cry1Ac expression), conferred through genetic modification to N. attenuata, did not increase yield in comparison to endogenously defended, or even undefended N. attenuata lines. Due to the scarcity of Cry1Ac-targeted insects in this field season, plants with more flexible use of their direct defenses were able to be more productive, demonstrating the benefit of naturally evolved defenses in the face of yearly-inconsistent pests. Resource-use traits such as plant water-use or association with arbuscular mycorrhizal fungal (AM) networks that facilitate nutrient access are as important to agricultural productivity as pest-resistance. Current screenings for water-use traits among agricultural varieties are insufficient: they do not account for varying rates of soil water consumption or plant development in applying drought treatments, and therefore, do not lead to reproducible results in the field. We use variance decomposition to quantify the extent to which these factors, when left uncontrolled, can significantly change observed results. I then apply the ecologically established biodiversity-productivity phenomenon to attempt to increase population yields by varying the percentage of plants with a low water-use efficiency trait among control plants in N. attenuata field populations. Low percentages of this trait caused overyielding. Using both novel and developed methodologies, I advance the understanding of the mechanisms behind this effect by identifying one of its genetic bases, and narrowing the spatial scale and plant tissue at which it occurs. Finally, we develop a method for screening agricultural cultivars for association with AM fungal networks by using a high-throughput leaf molecular marker rather than traditional microscopy methods, which are laborious and destructive. This work emphasizes the benefits of methodological development, which can both improve screenings for agriculturally-relevant functional traits and allow for application of ecologically-informed alternatives to increase population yield (e.g. intraspecific diversity).
Note:
Kumulative Dissertation, enthält Zeitschriftenaufsätze
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Tag der Verteidigung: 10.03.2020
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Dissertation Friedrich-Schiller-Universität Jena 2020
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Zusammenfassungen in deutscher und englischer Sprache
Additional Edition:
Erscheint auch als Online-Ausgabe McGale, Erica, 1993 - Determining the context and scale at which functional traits increase Nicotiana attenuata yields Jena, 2020
Language:
English
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German
Keywords:
Nicotiana attenuata
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Hochschulschrift
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