Efficiency of marker assisted selection (MAS) for the Vf scab resistance gene

Apple cultivars can exhibit different levels of resistance or susceptibility to scab in the greenhouse and field. Devising a more reliable method for screening resistant and/or tolerant seedlings in breeding programmes is thus an important step in selecting genotypes and developing resistant cultivars. The analytical data from inoculum-based trials in greenhouse and field conditions were compared to the results of marker-assisted selection (MAS) to determine the extent of any mis-classification. The findings underscore that both greenhouse and field assays are needed for more accurate evaluation and that MAS makes selection procedures more efficient, i.e, some of the plants (about 5%) showing resistance in the greenhouse are susceptible in the field. in addition, it was found that MAS-identified homozygous Vf plants are more resistant than heterozygous ones.