New pre-breeding tools for canola – facilitating canola improvement by accessing diploid variation

Project Summary

The success of future breeding programs is dependent on the availability of new genetic diversity. Considerable challenges impede our effort to reduce yield losses resulting from insect herbivory, pathogen infection and adverse weather conditions as the necessary diversity is absent from canola germplasm. This low level of diversity results from the natural history of Brassica napus as it was formed from a recent interspecific hybridization event between B. rapa and B. oleracea. Further reductions in diversity result from selection pressure in developing canola quality characteristics and other beneficial agronomic traits.

In contrast, the natural history of B. rapa and B. oleracea is much older than B. napus, providing more time for natural selection to enrich these species with valuable alleles leading to disease resistance and adaptations to abiotic stresses as they evolved to occupy an extensive range of ecological niches. This means B. rapa, B. oleracea and other wild relatives of Brassica could act as genetic reservoirs if they can be made accessible to breeders.

Accessing new variation present in related species has always been problematic for breeders of polyploid crops as the resulting material is difficult to evaluate and often poorly suited for introduction into on-going breeding programs. This project makes use of new diploid variation generated at SRDC, where the introduction of domestication alleles has developed diploid lines that can be used to bridge between diploid progenitors and elite tetraploid canola.

The goal of this project is to demonstrate the potential of these genetic bridges by facilitating the transfer of valuable diploid Brassica alleles transferring disease resistance into B. napus lines that can be readily evaluated by breeders. Additionally, new genetic and chemical tools with the potential to reduce hybridization barriers blocking Brassica allele introgression will be developed to facilitate the introduction of alleles from otherwise incompatible species.

The genetic resources developed during this project can be made available to the canola industry supporting additional efforts to introduce necessary variation required by canola breeders.