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United States Department of Agriculture

Agricultural Research Service

Research Project: MANAGEMENT OF TEMPERATE FRUIT NUT AND SPECIALTY CROP GENETIC RESOURCES Title: Comparative Infectivity of Cronartium ribicola Aeciospores and Urediniospores in Genotypes of Ribes nigrum

Authors
item Dalton, Danny -
item Postman, Joseph
item Hummer, Kim

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 21, 2009
Publication Date: April 20, 2010
Repository URL: http://hdl.handle.net/10113/42902
Citation: Dalton, D., Postman, J.D., Hummer, K.E. 2010. Comparative Infectivity of Cronartium ribicola Aeciospores and Urediniospores in Genotypes of Ribes nigrum. Plant Disease. 94(4):461-464.

Interpretive Summary: Hosts for the disease white pine blister rust, include five-needle pines, currants, and gooseberries. Spores produced from cankers on diseased pines, and a second type of spore originating from infected currants can infect currants and gooseberries. The comparative infectivity of these spore types on black currants has not been reported. The objective of this study was to determine whether the spores from infected pines and spores from infected currants are equally infective on currants. To do this a cross of black currant ‘Ben Lomond’ × ‘Consort’ was made. ‘Consort,’ which contains a gene for rust immunity, was expected to confer resistance to 50% of the seedlings in the cross. Single-leaf cuttings of 62 genotypes were inoculated and placed in airtight plastic containers within a growth chamber. Inoculations of each spore type on each black currant genotype were replicated four times. As expected, half of the currant genotypes did not develop the disease under artificial inoculation. Twenty-nine genotypes were susceptible to urediniospores, and 28 were susceptible to aeciospores. No significant difference was observed between the infectivity of the two spore types . The black currants were also subjected to natural infection in a field test plot with high disease pressure. Field exposure produced infection on 28 of the 31 susceptible genotypes identified through artificial inoculation procedures. These data indicate that susceptibility in currant seedlings is not contingent on inoculation spore type.

Technical Abstract: Hosts for the fungus Cronartium ribicola, causal agent of white pine blister rust (WPBR), include five-needle pines, currants, and gooseberries. Aeciospores, produced from cankers on diseased pines, and urediniospores, originating from uredinia on abaxial leaf surfaces of susceptible Ribes, can infect Ribes foliage. The comparative infectivity of these spore types on clonal Ribes nigrum genotypes is unreported. The objective of this study was to determine whether aeciospores and urediniospores are equally infective on Ribes clones. To assess susceptibility to WPBR, an F1 population of R. nigrum ‘Ben Lomond’ × ‘Consort’ was generated. ‘Consort,’ which contains the simple dominant Cr gene for rust immunity, was expected to confer resistance to 50% of the F1 progeny. Single-leaf softwood cuttings of 62 genotypes were artificially inoculated and placed in airtight plastic containers within a growth chamber. Inoculations of each spore type on each black currant genotype were replicated four times. As expected, 31 of 62 Ribes genotypes did not develop the disease under artificial inoculation. Twenty-nine genotypes were susceptible to urediniospores, and 28 were susceptible to aeciospores. No significant difference was observed between the infectivity of aeciospores and urediniospores following artificial inoculation in the growth chamber. The black currant genotypes were also subjected to natural infection in a field test plot with high disease pressure. Field exposure produced infection on 28 of the 31 susceptible genotypes identified through artificial inoculation procedures. These data indicate that resistance or susceptibility in the F1 population is not contingent on inoculation spore type.

Last Modified: 12/28/2014
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