Inheritance of Compact Growth Type in Apple1

Abstract

Abstract Test crosses within the progeny of ‘Golden Delicious’ × ‘McIntosh Wijcik’ confirmed the hypothesis that the typical growth habit of ‘McIntosh Wijcik’ is determined by a single dominant gene, Co . A small but consistent deficiency in the compact class suggested the presence of modifier gene or genes. Two independently originated natural mutants, ‘McIntosh Wijcik’ and ‘McIntosh Bendig’, were considered identical. The compact-growth seedlings, particularly the homozygous dominant genotypes from backcrosses and sib-crosses, constitute valuable breeding material. Compact segregates, evaluated as mature trees, were deemed to be suitable for very dense plantings.