Speed Breeding for Multiple Disease Resistance

A new method for rapid generation advance, called ‘speed breeding’, has considerable advantages over DH technology for spring wheat and barley because it provides increased recombination during line development and enables selection in early generations for disease traits. The system has been refined over the past 8 years at The University of Queensland, utilizing controlled temperature regimes and 24-hour light to accelerate plant growth and development. The low-cost management system enables up to 6 generations of wheat and 5 generations of barley annually.

We have developed methods adapted for use in the speed breeding system, which permit year-round high-throughput screening for multiple disease resistance in wheat, including; biotrophic, necrotrophic and fusarium pathogens. In this presentation, we describe the protocols, explain how phenotypes relate to field-based measures and highlight how the system can also handle diverse germplasm.

We have applied similar techniques in barley. Within a two-year period, we combined speed breeding and a novel phenotypic screening protocol to transfer resistance to four foliar diseases into European cultivar Scarlett, which is widely grown throughout Argentina. Assessment of the introgression lines in disease nurseries and preliminary yield trials revealed the population was enriched with multiple disease resistance and some lines out-yielded Scarlett by 50%. Further, micro-malting results indicate elite lines display a quality profile similar to Scarlett.

This approach presents new opportunities for cereal breeders to rapidly introgress multiple disease resistance into genetic backgrounds preferred by industry, enrich breeding populations with disease resistance genes or efficiently combine target genes in top crosses.