Characterization of Sorghum bicolor genotypes under varying water regimes
Date
2019
Authors
Person, Taylor, author
Jahn, Courtney E., advisor
Byrne, Pat, committee member
Gaines, Todd, committee member
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Abstract
Agriculture is the largest consumer of fresh water, accounting for 70% of use globally. The availability of water is expected to decrease in future climate models. It is imperative to develop crop varieties with improved performance under targeted limited water environments. One approach to address this aim is capitalizing on inherent variability for drought tolerance traits in crops. Depending on the nature of water stress and other environmental factors, specific root morphology, shoot morphology, and the harvest index are selectable traits that can distinguish performance of different genotypes in crops. These aforementioned parameters discriminate relative water-stressed performance in many studied crop species. Among these is sorghum (Sorghum bicolor), a grain crop adapted to many different environments, particularly where limited rainfall is an agricultural constraint. The specific objectives of the following thesis were to 1) characterize the morphology of a sorghum recombinant inbred line (RIL) population (n = 430) of Sorghum bicolor for response to varying moisture regimes and 2) evaluate 10 selected genotypes for below-ground morphology in the greenhouse and field for response to varying moisture regimes. This population expresses a wide range of phenotypes in response to varying moisture regimes in panicle weight, shoot weight, harvest index, plant height, stem diameter, tillering and days to flowering. Ten selected RILs, including the two population parents, BTx623 and IS3620C, represent the population distribution and respond uniquely to different moisture environments. When subjected to drought stress and subsequent recovery when re-watered in the greenhouse, root system response varied at both time points. Root system and stem size are indicators of this response and vascular tissue variation may play a role in these varied responses. In the field, the root system of these ten RILs, as quantified by crown root angle, had a tendency to grow more vertically than horizontally under dryland conditions while high moisture environments showed no association with root system orientation. Taken together, this study provides foundational knowledge on above and below-ground responses of RIL population BTx623 X IS3620C to varying moisture environments.
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Subject
drought
recombinant inbred line
abiotic stress
sorghum
plasticity