| Abstrakt: |
Volunteer canola (Brassica napus L.) is defined as canola germinating and emerging after the intended cropping season, and it continually ranks as a top occurring weed on the Canadian prairies. Seed dormancy is the physiological mechanism enabling the seed to remain viable in the soil seedbank for extended periods of time. Specifically, canola has a high likelihood of being induced into secondary seed dormancy under adverse environmental conditions not suitable for germination. A reduction of secondary seed dormancy in modern canola varieties may result in lower seedbank persistence; however, the effect of reducing dormancy on other seed traits is not known. This study examined a diverse collection of spring B. napus genotypes produced in differing maternal environments for secondary seed dormancy as well as seed germination, vigor, and seed quality traits. Genotype contributed the most to total variability (46%), the interactions between genotype and environment had a moderate contribution (28%), and very little contribution from maternal environment alone (4%) was observed for the secondary seed dormancy trait. The remaining variability (22%) was allocated to the residuals. No association was observed between secondary seed dormancy and germination time or seed vigor traits in genotypes examined. Significant associations with secondary seed dormancy were detected for primary dormancy, total protein, seed fiber components, glucosinolates content, seed geographical origin, and fatty acid composition. According to the results of this study, the reduction of secondary seed dormancy as a breeding objective in canola breeding programs is feasible as the trait is largely genetically controlled. Furthermore, direct selection against secondary seed dormancy is unlikely to have adverse effects on canola seed germination and vigor given no associations were detected in the current study. Core Ideas: Genetic reduction of secondary seed dormancy may help to reduce volunteer canola on the Canadian prairies.Genetics were the largest contributing factor to variability of the secondary seed dormancy trait.The current study was first to assess large number of spring Brassica napus genotypes across several environments.No associations were identified for seed germination or seed vigor traits and secondary seed dormancy.Increased seed fiber resulted in higher secondary seed dormancy, possibly due to mechanical restraint of seed coat. [ABSTRACT FROM AUTHOR] |
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