CHARACTER CHANGES IN INDUCED MUTANTS OF BRAMLEY'S SEEDLING APPLE
Six thousand V2 generation Bramley's Seedling apple trees derived from 266 grafts irradiated with 6–7 kR of gamma rays from a Cobalt 60 source and screened for dwarf mutants. Of the 99 dwarfs selected 12 are still considered to show commercial promise after a four year trial. Selection for dwarf habit at the V1 stage increased the proportion of dwarf mutants selected at the V2 stage, but the increase was not statistically significant. The selected mutants showed continuous variation in tree height, diameter and volume, fruit yield and fruit size. Tree size and yield were reduced in nearly all clones, but the cropping density and the fruit size of the mutants showed variation above and below the control mean.
Lacey, C.N.D. and Campbell, A.I. (1977). CHARACTER CHANGES IN INDUCED MUTANTS OF BRAMLEY'S SEEDLING APPLE. Acta Hortic. 75, 51-62