Disease resistance and spring phenological characteristics of Ribes L. germplasm
Since the early 1930's, plant breeders have used immune black currant (R. nigrum L.) germplasm as a control tactic against the exotic WPBR, caused by the
basidiomycete fungus Cronartium ribicola J.C. Fischer. In 1999, a seedling population was generated at the NCGR from a cross involving susceptible pistillate R. nigrum 'Ben Lomond' and immune staminate parent R. ussuriense Jancz. x R. nigrum 'Consort.' To test the inheritance of resistance in the F? population, aeciospore and urediniospore treatments were applied in 2008 to single-leaf softwood cuttings under controlled conditions in a greenhouse. Resistant F? phenotypes segregated in a 1:1 ratio consistent with the pattern of simple dominant inheritance of a single gene. Artificial inoculations testing aeciospore and urediniospore infectivity produced equivalent disease severity in the experimental Ribes genotypes. Resistance to the native powdery mildew fungus, Podosphaera mors-uvae (Schwein.) U. Brown and S. Takamatsu, was also evaluated in the F? population. Individuals segregated for resistance in a 1:3 ratio after exposure to elevated disease pressure in the greenhouse. Fifteen F? genotypes were resistant to both fungal pathogens and are candidates for further breeding trials.
In a second study, five years of spring phenological survey data were analyzed using a growing degree-day (GDD) model, with the objective to identify cultivars adapted to North American conditions. Ribes section Calobotrya was the earliest group to reach "first bloom," followed sequentially by R. [superscript]xnidigrolaria Bauer hybrid species, section Symphocalyx, section Grossularia, section Ribes, and lastly, section Botrycarpum. Early and late-flowering accessions were identified for each taxon.
Advisor:Hummer, Kim E.; Mundt, Christopher C.; Stone, Jeffrey K.; Lambrinos, John G.
School:Oregon State University
School Location:USA - Oregon
Source Type:Master's Thesis
Keywords:ribes white pine blister rust flowering phenology resistance disease and pest genetic aspects control germplasm resources
Date of Publication:04/07/2009