High-throughput identification of novel molecular markers for the detection of blackleg (Leptosphaeria spp.) resistance genes in rapeseed

Abstract: Blackleg disease caused by the Leptosphaeria spp. fungal species complex, is one of
the most important diseases of Brassica napus, responsible for severe yield losses worldwide.
Breeding for genetic resistance is widely used tool for controlling this disease and minimizing
the impact on yield. To speed up the selection process between resistant and susceptible
rapeseed lines, the identification of novel molecular markers linked to blackleg resistance genes is essential. For this purpose one hundred and eighty three double haploid (DH) rapeseed lines were assessed in field conditions for resistance to Leptosphaeria spp. on a 0-9 severity scale. DArTseq-based Genome-Wide Association Study (GWAS) was performed to identify molecular markers linked to blackleg resistance. A total of 133,764 markers (96,121
SilicoDArT and 37,643 SNP) were obtained. Nine DArT and six SNP type molecular markers
were associated with plant resistance to Leptosphaeria spp. at the highest significance level, p
< 0.001. Moreover, eleven of those 15 markers were located within ten B. napus genes located
on chromosomes A06, A07, A08, C02, C03, C06 and C08. The highest concentration of
markers was observed on chromosome A06 and A07.