Induced mutants of Cox's Orange Pippin apple with increased self-compatibility. Pt. 1

More than 7000 MV2 trees derived from 225 MV0 grafts of Cox's Orange Pippin apple that had been treated with approximately 7.5 kR gamma-rays were grown as a solid block with no pollinators in an isolated orchard. The orchard was sited in South Wales well away from any external source of apple pollen and due to this lack of pollination the great majority of the trees produced very few fruit. However, a few individual trees produced acceptable quantities of fruit under these conditions. Twelve trees maintained this performance for seven years and these trees have been selected for trial to test for mutants with increased self-compatibility. (orig.)