Despite drought accounting for over 80% of agricultural losses, little progress has
been made towards improving drought tolerance in crops. My approach to identifying
traits underlying drought tolerance involved a comparison between two accessions of
the crucifer, Eutrema salsugineum, that display differential tolerance to water deficits.
The accessions, originating from the semi-arid Yukon, Canada, and a monsoonal region
of Shandong, China, were subjected to a two-step, water deficit and recovery
protocol to identify physiological characteristics that discern their drought-responsive
behaviour. Traits that discriminate between the ecotypes were used to screen recombinant
inbred lines (RILs) that were generated by crossing Yukon and Shandong
parent plants. Selected physiological measurements were: anthocyanin accumulation,
cut rosette water loss (CRWL), solute potential, relative water content (RWC), static
leaf water content (SLWC), specific leaf area (SLA), and OJIP fluorescence emission.
Of the measurements taken, CRWL measurements and anthocyanin content
distinguished the Yukon ecotype from the Shandong ecotype during the first drought
exposure whereas SLA and fluorescence responses differentiated these accessions better
after plants that experienced the first drought were rewatered and recovering or
undergoing a second drought treatment. Sixty-eight RILs were screened using SLA
and OJIP fluorescence emission. SLA and OJIP measurements varied among the
recombinant inbred lines (RILs) with many lines showing responses to water deficit
intermediate to those of the parental lines. Evidence of heritability in SLA and/or
OJIP responses to water deficits would make them useful phenotypic markers for
identifying quantitative trait loci (QTLs) associated with drought tolerance in future
work. / Thesis / Master of Science (MSc)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/27119 |
| Date | January 2021 |
| Creators | Jennifer Tropiano |
| Contributors | Weretilnyk, Elizabeth, Biology |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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