Somatic Reduction of Chromosome Number in a Ribes Hybrid following Treatment with para-Fluorophenylalanine

Abstract

THE Ribes breeding programme at East Malling involves considerable use of widely different species as donor parents. From some of these species, genes of potential economic value are being transferred to cultivated varieties of currant and gooseberry (all of which are diploid, 2n = 16). In many cases the inter-species F₁'s are completely sterile so that, to regain fertility, it has been necessary to make allotetraploids by colchicine treatment. In transferring genes from gooseberry (R. grossularia; G genome) to black-currant (R. nigrum; B genome) and vice versa, a technique of back-crossing to commercial diploid varieties via the triploids BBG and BGG respectively has met with considerable success^1–3. Nevertheless, with a 2–3-year cycle between seed sowing and flowering, any short cut to the production from alloploids of fertile or partially fertile diploid plants having a minimal genic content from the donor species would offer considerable advantages.