Inheritance of the CrGene in Ribes Nigrum

Abstract

Resistance to white pine blister rust (WPBR) disease, caused by Cronartium ribicolaJ.C. Fischer, is a critical objective for plant breeders seeking to release new black currant ( Ribes nigrumL.) cultivars in North America. Genetic immunity to the disease was discovered in the Asiatic species, R. ussurienseJancz. in the 1930s. ‘Consort,’ an immune F ₁genotype with the pedigree R. nigrumL. ‘Kerry’ × R. ussuriense, was released in 1952, and has developed neither uredinia nor telia in field or greenhouse inoculation trials. The objective of this study was to determine whether resistance in F ₂progeny of R. nigrum‘Ben Lomond’ × ‘Consort’ segregates in a 1:1 ratio. Following artificial inoculation of single leaf cuttings in a controlled environment, 40 of the 86 F ₂genotypes were susceptible to WPBR; 46 exhibited no signs of the disease. Chi-square analysis failed to reject the H ₀that segregation of the resistance trait occurred 1:1. The Crgene was inherited as a simple dominant allele in the F ₂generation. ‘Consort’ is heterozygous for the dominant Crgene.