Evaluation of Water-Deficit Responses in Wild-by-Cultivated Rice Introgression Lines
Abstract
Rice (Oryza sativaL.) is a staple crop consumed globally. Increased variability in rainfall in much of the world is a predicted consequence of climate change and drought is predicted to be a major cause for concern for rice production. One approach to mitigating water-deficit stress is integrating beneficial (drought-tolerance) loci from wild rice donors into elite rice cultivars. Bi-parental interspecific chromosome segment substitution lines (CSSLs) and near introgression lines (NILs) are genetic resources that contain genetic introgressions from wild rice but are otherwise genetically identical to the cultivated parent, known as the recurrent parent. For this study, 12 CSSLs and NILs were selected for having wild rice introgressions on chromosomes two and five, previously shown to be beneficial under field conditions. In the current work, these lines were evaluated under water-deficit conditions for their potential of serving as future pre-breeding material. The recurrent parents, Cybonnet and Jefferson, two U.S. cultivars adapted to the Southern Rice Belt, were additionally included in this study as controls. In total, three trials took place: two at Purdue University under controlled environments (West Lafayette, Indiana) and one in the field at the Dale Bumpers Rice Research Center (Stuttgart, Arkansas). Traits such as yield components, gas exchange, leaf water content, leaf water potential and chlorophyll fluorescence were measured during predawn and midday timepoints. Results from the three trials did not show consistent genotype rankings in yield component traits, which was expected due to the different ways in which water-deficit treatments were approached (continuous water-deficit application versus transient drought and recovery). While many of the CSSLs outranked Cybonnet in mean values, none were significantly different, likely due to low replication. Despite not having identified superior genotypes, the yield component, physiology, and high-throughput phenotyping datasets published here can provide the foundation to address future questions about physiological linkages and methodology development associating high-throughput data with ground-truth measurements. All data associated with this work are publicly available through Purdue University Research Repository.
Degree
M.Sc.
Advisors
Wang, Purdue University.
Subject Area
Physiology|Agronomy|Atmospheric sciences|Genetics
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