Location: National Clonal Germplasm RepositoryTitle: Inheritance of the Cr Gene in Ribes nigrum) Author
Submitted to: Journal of American Pomological Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/1/2009
Publication Date: 10/1/2009
Citation: Dalton, D.T., Hummer, K.E. 2009. Inheritance of the Cr Gene in Ribes nigrum. Journal of American Pomological Society. 63(4):142-144. Interpretive Summary: Resistance to white pine blister rust disease, is a critical objective for plant breeders seeking to release new black currant cultivars in North America. Genetic immunity to the disease was discovered in an Asian species, from Siberia in the 1930’s. ‘Consort,’ an immune cultivar with a pedigree of the common European black currant by this Asian species, was released in 1952. It has not shown any signs of the disease in field or greenhouse trials. The objective of this study was to determine whether resistance in half of the offspring of a black currant called ‘Ben Lomond’ with ‘Consort’ remain free of disease. Following treatment of single leaf cuttings with spores from the fungus, 40 of the 86 offspring showed symptoms; 46 did not. Statistical analysis indicated that these numbers meant that about half of the offspring showed these symptoms. This gene was inherited in a simple fashion where the immune parent produces offpring, half of which were also immune.
Technical Abstract: Resistance to white pine blister rust (WPBR) disease, caused by Cronartium ribicola J.C. Fischer, is a critical objective for plant breeders seeking to release new black currant (Ribes nigrum L.) cultivars in North America. Genetic immunity to the disease was discovered in the Asiatic species, R. ussuriense Jancz. in the 1930’s. ‘Consort,’ an immune F1 genotype with the pedigree R. nigrum L. ‘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 F2 progeny 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 F2 genotypes were susceptible to WPBR; 46 exhibited no signs of the disease. Chi-square analysis failed to reject the H0 that segregation of the resistance trait occurred 1:1. The Cr gene was inherited as a simple dominant allele in the F2 generation. ‘Consort’ is heterozygous dominant for the Cr gene.