Identifying the optimal root system architecture (RSA) for Brassica crops
Term: 4 years, ending March 2024
Status: Completed
Researcher(s): Isobel Parkin, AAFC
SaskCanola Investment: $120,745
Total Project Cost: $479,977
Funding Partners: Agriculture Development Fund
Project Description
RSA has been associated with a crop’s ability to maintain yield under various abiotic and biotic stress conditions. Thus far, limited studies have been conducted to map root traits in Brassica napus. It is largely attributed to the difficulty in accurately quantifying variation for roots traits, since most methods have previously been intrusive causing significant damage to the overall root structure. The project aimed to assess the level of available diversity among B. napus germplasm and identify genomic regions associated with parameters that define RSA. The project utilized high-throughput non-invasive two-dimensional root imaging to assess the level of phenotypic diversity within a collection of 51 B. napus spring type lines which have been characterized extensively at the molecular level and in the field. These lines are the founders of a larger structured population, which will allow further dissection of any useful phenotypes that were identified. The subsequent data analyses assessed over 15 main, derived and allied root traits, and identified a range of variations. Even with controlled methods there were some issues with reproducibility for many of the traits. However, several promising lines were identified that showed consistently higher root growth rate, and correspondingly acceptable agronomic data across multiple environments. Utilizing the most consistent trait parameter, a genome-wide association study identified a number of regions of the genome associated with statistically significant single nucleotide polymorphism (SNP) markers. Further analyses of a database of identified genes that are specifically expressed in B. napus roots uncovered a number of interesting genes that warrant further study. During the project, novel B. napus lines with altered lateral root formation were developed using targeted gene editing. These lines will serve as control standards for further analyses and will allow this specific aspect of RSA to be studied in more detail. In conclusion, the project identified useful variation, identified limitations with current phenotyping methods and adopted new methods to overcome some of these limitations, generated a mineable database of root-specific genes, and identified target genomic regions associated with RSA that require further investigation.
Grower Benefits
Diverse B. napus germplasm with improved RSA were identified that could be used in current breeding programs.
Limitations in current root phenotyping methods were identified and suggestions for improvements or alternative methods were proposed.
Candidate genomic regions and underlying RSA variation were located and could be further investigated to assist with improving current germplasm, potentially assisting with crop sustainability.
Objectives
To understand the level of natural variation of Root System Architecture (RSA) in Brassica napus.
To identify the regions of the genome contributing to variation in RSA.