Written by Roy Browne University of Cambridge. This is the report from a BSPP Senior Fellowship. Click here to read more/apply for one yourself.
Breeding for resistance against Fusarium head blight (FHB) has high priority in many breeding programmes but progress has been slow due to complex polygenic nature of disease resistance, the diversity of resistance sources and poorly understood interactions when combining these diverse resistance sources. This BSPP Fellowship was to study cultivar resistance against FHB and comprised of two parts the firstly visiting the FHB research and breeding programme at CIMMYT, Mexico and secondly conducting experiments at the Swiss Federal research centre Agroscope RAC Changins.
Using the detached leaf assay and resistance against Fusarium spp. in the seed germination assays we have previously identified important components of partial disease resistance (PDR) in European wheat, although it is clear that many other components of partial disease resistance are not detected in either assay including factors such as heading date. Nevertheless evaluating FHB resistance as the sum of individual components of partial disease resistance allows the possibility of a more directed breeding strategy by pyramiding genes from complimentary resistance sources. One of the important components of partial disease resistance in European wheat includes the ability of a cultivar to delay sporulation measured using a Microdochium nivale detached leaf assay and which has been most closely related to resistance to FHB disease spread.
Specific objectives of this Fellowship were to begin to evaluate application and validation of resistance breeding incorporating selection based on components of partial disease resistance. In addition we evaluated over 100 genotypes derived from wide crosses and synthetic wheat, provided by Maarten Van Ginkel, CIMMYT, to investigate if novel sources of specific components of partial disease resistance from wide crosses could be identified to provide sustainable resistance in wheat of utility for breeding purposes.
Experiments were conducted at Agroscope RAC Changins in Fabio Mascher’s Laboratory with the technical support of Stefan Kellenberger, Matthieu Canales, Eveline Martin, and Celia Bequain. Within the Swiss spring wheat disease resistance breeding programme, we evaluated a range of genotypes using the detached leaf and seed germination assays. Utilising multivariate analysis we identified additional components of partial disease resistance that could form part of pre-screening for FHB resistance in addition to marker assisted selection and whole plant evaluation of disease resistance. Among the CIMMYT genotypes derived from wide crosses and synthetic wheat we identified genotypes as potential sources for enhancing the PDR component latent period (ability to delay sporulation measured using the detached leaf assay).
We have previously found latent periods in related Graminaceae well in excess of those found in commercial wheat cultivars. The present findings suggest that synthetic wheat and wide crosses may be a source of enhanced resistance for this PDR component in wheat and warrants further screening of a wider range of material using the detached leaf assay to identify the best potential sources for enhancing this PDR component.
The Fellowship from the BSPP provided a valuable and very productive opportunity for me to meet with international scientists and plant breeders and I am particularly grateful to the wheat breeders at CIMMYT for the discussions and providing material from their breeding programmes to conduct experiments in Switzerland. My thanks to Carmen Velaquez and both Mari and Moni in the Phytopathology laboratory at CIMMYT for introducing me to Mexican cuisine and the traditional fiesta and to all those in Switzerland for great evenings enjoying the famous Swiss cheese dishes: large pots of Fondue and loafs of Raclette.
I wish to thank the BSPP and Agroscope RAC Changins, for their support which enabled me to undertake this Fellowship to begin to put research findings to practical use within wheat breeding programmes.