Genetic and molecular analysis of stem rot (Sclerotinia sclerotiorum) resistance in Brassica napus (canola type)

Identifying the molecular and genetic basis of resistance to Sclerotinia stem rot (Sclerotinia sclerotiorum) is critical for developing long-term cost-effective management this disease in rapeseed/canola (Brassica napus). Current cultural or chemical options provide, at best, only partial and/or sporadic control. Towards this, a B. napus breeding population (Mystic x Rainbow), including parents, F1, F2, BC1P1 BC1P2, was utilised field study determine inheritance pattern (based on lesion length, SLL). Broad sense heritability 0.58 SLL 0.44 days flowering (DTF). There significant negative correlation between diameter (SD) (r = −0.39) DTF −0.28), suggesting co-selection SD traits, along with SLL, should assist improving overall resistance. Non-additive variance evident DTF, SD. In genome wide association (GWAS), quantitative trait locus (QTL) identified SLL. Several putative candidate marker associations (MTA) were located within QTL region. Overall, has provided valuable new understanding S. sclerotiorum, QTL, MTAs transgressive segregants high-level resistances. Together, these will foster more rapid selection multiple traits associated resistance, by enabling breeders make choices towards selecting/developing cultivars enhanced devastating pathogen.