Identification of quantitative trait loci for pod shatter tolerance in Brassica napus L.
| dc.contributor.author | Gislason, Lauren | |
| dc.contributor.examiningcommittee | Gulden, Robert H. (Plant Science) | |
| dc.contributor.examiningcommittee | Badreldin, Nasem (Soil Science) | |
| dc.contributor.supervisor | Duncan, Robert W. | |
| dc.contributor.supervisor | Chawla, Harmeet Singh | |
| dc.date.accessioned | 2025-01-15T20:17:59Z | |
| dc.date.available | 2025-01-15T20:17:59Z | |
| dc.date.issued | 2025-01-02 | |
| dc.date.submitted | 2025-01-02T16:35:50Z | en_US |
| dc.degree.discipline | Plant Science | |
| dc.degree.level | Master of Science (M.Sc.) | |
| dc.description.abstract | Brassica napus L. (canola and rapeseed) is the second most produced oilseed crop worldwide and is of substantial economic value to Canadian agriculture. However, pre-harvest seed loss due to pod shatter and pod drop poses a substantial threat to canola production. Both pod shatter and pod drop present key concerns: economically, they reduce yield and lead to lost revenue, while agronomically, the dropped seeds become competitive weeds in subsequent growing seasons. This study focuses solely on pod shatter. Pod drop was not examined. Pod shatter is a quantitative trait that is primarily genetically controlled but is also highly influenced by environmental factors, including hail, heat, humidity, precipitation and wind. In this study, quantitative trait loci (QTL) analysis was conducted to identify genomic regions and molecular markers associated with pod shatter tolerance using a doubled haploid (DH) population consisting of 192 genotypes derived from a cross between 13R4497 (pod shatter susceptible) and 13R3973 (pod shatter tolerant). The genotypes were planted in a randomized complete block design across two Manitoba field sites in 2022 and 2023, for a total of three site-years. Pod shatter tolerance was assessed using a rating scale of one (susceptible) to nine (tolerant) following a high-speed wind event simulated with a leaf blower. Genomic DNA was extracted, and parental and DH genotypes were genotyped using the Brassica 90K Illumina Infinium™ SNP array. A genetic linkage map covering 988.1 cM and containing 535 SNP markers was anchored to the B. napus ‘Darmor-bzh’ v10 reference genome. Inclusive composite interval mapping identified 13 additive-effect QTL on chromosomes A03, A04, A05, A06, A08 A09, C01 C03, C04 and C09. QTLs associated with pod shatter tolerance explained 4.01 % to 17.00 % of the phenotypic variation observed in the population. Three of the QTLs were present in more than one site-year and in the combined site-year data. Four QTLs were selected for candidate gene screening based on the criteria of appearing in more than one site-year or explaining over 15 % of the phenotypic variation. Based on gene ontology annotations, a total of 23 candidate genes were identified as potentially contributing to the genetic control of pod shatter tolerance in the DH population, including the AG and NST1 genes, which have been associated with pod shatter tolerance in Arabidopsis. The results of this research may provide a foundation for developing molecular markers linked to QTLs associated with pod shatter tolerance, advancing marker-assisted selection, and enhancing our understanding of the molecular control of pod dehiscence in B. napus. | |
| dc.description.note | February 2025 | |
| dc.identifier.uri | http://hdl.handle.net/1993/38822 | |
| dc.language.iso | eng | |
| dc.subject | Brassica napus | |
| dc.subject | quantitative trait loci | |
| dc.subject | QTL | |
| dc.subject | pod shatter | |
| dc.subject | canola | |
| dc.subject | rapeseed | |
| dc.title | Identification of quantitative trait loci for pod shatter tolerance in Brassica napus L. | |
| local.subject.manitoba | yes |