High-throughput phenotyping-based QTL mapping reveals the genetic
architecture of the salt stress tolerance of Brassica napus
Salt stress is a major limiting factor that severely affects the
survival and growth of crops. It is important to understand the salt
tolerance ability of Brassica napus and explore the underlying related
genetic resources. We used a high-throughput phenotyping platform to
quantify 2,111 image-based traits (i-traits) of a natural population
under 3 different salt stress conditions and an intervarietal
substitution line (ISL) population under 9 different stress conditions
to monitor and evaluate the salt stress tolerance of B. napus over time.
We finally identified 928 high-quality i-traits associated with the salt
stress tolerance of B. napus. Moreover, we mapped the salt
stress-related loci in the natural population via a genome-wide
association study (GWAS) and performed a linkage analysis associated
with the ISL population, respectively. The results revealed 234
candidate genes associated with salt stress response, and two novel
candidate genes, BnCKX5 and BnERF3, were experimentally verified to
regulate the salt stress tolerance of B. napus. This study demonstrates
the feasibility of using high-throughput phenotyping-based QTL mapping
to accurately and comprehensively quantify i-traits associated with B.
napus. The mapped loci could be used for genomics-assisted breeding to
genetically improve the salt stress tolerance of B. napus.