Influence of Improved Seedling Rootstocks on Pomological and Organoleptic Traits of Four Apple Cultivars

The influence of five open-pollinated seedling rootstocks and two marketed seed lots (as the controls) were assessed on pomological, biochemical, and organoleptic traits of four apple cultivars (Malus×domestica Borkh.), grown in Meshkin Abad Horticultural Research Station (Karaj, Iran). The maternal parents, as the three crabs 'Zinati', 'Morabbaei', and 'Azayesh' along with the standard trees 'Northern Spy' and 'Golden Karaj' were selected as the seed sources through a breeding program in 2003. The present study was achieved on the 4- and 5-year-old trees, spindle formed, planted in 3.5×4 m, and drop irrigated in 28 combinations (four cultivars onto 5+2 rootstocks, distributed in four distinct parcels). The investigation was carried out on pomological traits based on UPOV scales, as well as biochemical and organoleptic traits. Higher fruit length, diameter, and weight were recorded for the cultivars grafted onto 'Northern Spy', followed by 'Zinati' and 'Morabbaei' seed sources. 'Zinati' F1 crab seedling induced higher flesh firmness combined with the four scions. The crab seedling rootstocks 'Zinati' followed by 'Azayesh' caused a higher organoleptic scent, flavor, and sweetness attributed by the panel members. Moreover, pH, TA, and TSS were influenced by scion, while rootstock effect was negligible. These results indicated that F1 half-sib seedling rootstocks positively influenced the pomological and organoleptic traits and improved the fruit's quality.