Ali Saghafian Larijani - Department of Horticulture, Science and Research Branch, Islamic Azad University, Tehran, Iran
Hassan Hajnajari - Temperate and Cold Fruit Research Centre, Horticulture Science Research Institute, Agriculture Research Education and Extension Organization, Karaj, Iran
Mahmood Khosrowshahli - Department of Biotechnology and Plant Breeding, Faculty of Agricultural Sciences and Food Industries, Science and Research Branch, Islamic Azad University, Tehran, Iran
Amir Mousavi - Department of Plant Molecular Biotechnology, National Institute of Genetic Engineering and Biotechnology, Tehran, Iran

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 ۲۰۰۳. The present study was achieved on the ۴- and ۵-year-old trees, spindle formed, planted in ۳.۵×۴ m, and drop irrigated in ۲۸ combinations (four cultivars onto ۵+۲ 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' F۱ 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 F۱ half-sib seedling rootstocks positively influenced the pomological and organoleptic traits and improved the fruit's quality.

Crab apple, fruit quality, Genetic improvement, Pomology, Seed rootstock