S-allele typing in indigenous hybrid apple cultivars presenting an approach for pollination management and breeding enhancement

Apple crops experience significant yield and quality losses due to the incidence of apple scab, caused by the fungal pathogen Venturia inaequalis. This study presents the development of six hybrid apple varieties for economically important traits such as scab resistance, high yield, better fruit quality and better pollinizer ability. Morphological characterization, biochemical analysis, and hybridity confirmation through S-allele typing were conducted. The scab-resistant variety 'Prima,' which carries the Vf resistance gene, was utilized as the donor. This resistance gene was introgressed into other commercially significant apple varieties. Three apple hybrids, viz., 'CITH-Priame' (CITH-Ambri-1 x Prima), 'CITH-PRIDE' (Red Delicious x Prima) and 'CITH-Pritor' (Top Red x Prima) were developed for scab resistance carrying Vf gene confirmed through three dominant markers (AM19, Rvi6 & U1400) and one codominant marker (AL07). The hybrids, viz., 'CITH-AMMOL' (CITH-Ambri-1 x Mollies Delicious) and 'CITH-Ambrit' (CITH-Ambri-1 x Top Red) were produced for the better fruit quality, having total soluble solids (TSS) of 13.06 and 13.8 degrees Brix, respectively. One more apple hybrid 'CITH-Golden Snow' (Golden Delicious x Snowdrift) was identified as pollinizer with better quality traits. S-allele typing is being used for compatibility studies in apple through identification of suitable pollinizer. This is the first report for use of S-alleles in identification of hybrids.