Selection of Promising Early Ripening Progenies and Assessment of Earliness Heritability in the Breeding Program of Apple

摘要

The experiment was conducted on 560 apple progenies, 6 and 7-year-old, in a pre- ultimate selection of breeding program for early and mid-early cultivars in 2014-2015. The progenies were assessed for crop bearing precocity, pomologic, organoleptic characteristics and ripening time as well as bloom beginning, flowering period, yield per tree and tree vigor. The initial screening was performed based on ripening time, yield per tree and tree vigor. The selected 63 progenies with the highest performance were then classified in 9 distinct ripening groups by use of a modified ripening phenology scale of apple descriptor (D.U.S). Overall, 53 hybrids were individuated as very early, early, mid-early and mid-ripening fruits with high fruit acceptability. The selected hybrids benefitted both lofty bloom densities and low to moderate tree vigor. The progeny classification was achieved also by cluster analysis for which were formed 3 distinct groups and more sub-clusters. Nine early-ripening, high-yielding with moderate to weak vigor were native half-sib progeny of newly released ‘Sharbati’, ‘Sheikh Ahmed’ and red big fruit sized ‘Heidarzadeh’, together with introduced ‘Jonathan’, ‘Yellow Spur’ and ‘Glockenapfel’ parents. ‘Sheikh Ahmed’ progenies had the highest frequency. Some superior types as the full-sib ‘Heidarzadeh’בEarly Red One’ were also individuated.