Progress in pipfruit resistance breeding and research at Plant & Food Research
Plant & Food Research (PFR) has breeding programmes for apple and pear scion cultivars, and apple rootstocks, all of which have introducing resistances to pests and diseases as a major objective. Over the last 20+ years, many new sources of resistance to scab, mildew, fire blight and woolly aphid identified in PFR apple germplasm have been added to a pool of sources imported from overseas. Some of these have been backcrossed into high fruit quality backgrounds and are now considered as breeding parents for cultivar breeding. For apple scab, genetic studies showed that: the resistance from 'Geneva' on linkage group (LG) 4 is complex; the resistance from 'open-pollinated 'Joe Trio' is also complex and maps to the same region; and the putative Vr gene from Russian apple R12740-7A maps to LG2. Mapping for resistance to the brown headed leaf roller resulted in the location of the Cob1 resistance gene to LG9 of 'Gala'. MAS will soon be developed for European canker resistance, now that 'Golden Delicious', 'Priscilla' and 'Robusta 5' have shown good resistance in field and glasshouse trials. In pear, a major QTL for fire blight resistance derived from 'Roi Charles de Würtemberg' was mapped to LG2 of 'Moonglow' and one for pear psylla resistance to LG8. As it is essential that resistances are durable, genetic mapping for the development of marker assisted selection (MAS) is critical to pyramiding resistance genes for each pest and disease. We present some examples of MAS for gene pyramids, as well as the Dw1 locus for dwarfing in apple rootstocks.
Bus, V., Singla, G., Ward, S., Brewer, L., Morgan, C., Bowatte, D., Bassett, H., Attfield, B., Colhoun, K., Bastiaanse, H., Walter, M., Scheper, R., Fisher, B., Won, K., Montanari, S., Volz, R., Chagné, D. and Gardiner, S.E. (2017). Progress in pipfruit resistance breeding and research at Plant & Food Research. Acta Hortic. 1172, 7-14
rootstocks, scab, mildew, fire blight, European canker