SEGREGATION OF COMPACT GROWTH TYPES IN CERTAIN APPLE SEEDLING PROGENIES

Abstract

Two-year-old apple seedlings of six progenies resulting from crosses between cultivars of standard growth or their compact mutants were classified for standard or compact growth type. A natural compact mutant of McIntosh (Wijcik) in combination with Golden Delicious transmitted compact growth habit to 43.9% of its progeny, whereas the radiation-induced compact mutant of McIntosh (8F-2-27), in the same combination did not transmit this characteristic. Number of side shoots, internodal length, and the ratio of length to diameter of one-year-old shoots were useful characteristics in distinguishing between the standard and compact growth types in two-year-old seedling trees. As the segregation of seedlings of compact growth habit is of great interest both from theoretical and practical aspects, a careful assessment of the transmissibility of compactness by mutant and non-mutated cultivars in various cross-combinations is suggested.