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United States Department of Agriculture

Agricultural Research Service

Title: Responses to Selection for Partial Resistance to Crown Rust in Oat

Authors
item Long, Jin - IOWA STATE UNIVERSITY
item Holland, Jim
item Munkvold, Gary - PIONEER HI-BRED
item Jannink, Jean-Luc - IOWA STATE UNIVERSITY

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 12, 2005
Publication Date: May 10, 2006
Citation: Long, J., Holland, J.B., Munkvold, G., Jannink, J. 2006. Responses to selection for partial resistance to crown rust in oat. Crop Science.

Interpretive Summary: Crown rust disease severely reduces kernel quality and grain yield in oat. The objectives of this study were to evaluate the feasibility of simultaneously improving durable resistance to crown rust, grain yield and seed weight in an oat population. A method of multiple trait selection increased the levels of crown rust resistance and grain yield and seed weight in crown rust-inoculated plots, and seed weight in fungicide-treated (rust-free) plots. These results suggest that multiple trait index selection could increase levels of crown rust resistance, grain yield, and seed weight simultaneously.

Technical Abstract: Crown rust, caused by the fungal pathogen, Puccinia coronata, severely reduces kernel quality and grain yield in oat. Partial resistance is considered to be a durable form of rust resistance. The objectives of this study were to evaluate the feasibility of simultaneously improving partial resistance to crown rust, grain yield and seed weight in an oat population, and to estimate predicted and realized heritabilities for area under disease progress curve (AUDPC) and genetic correlations between AUDPC and agronomic traits in both crown rust-inoculated and fungicide-treated plots. A single cycle of selection for partial resistance to crown rust was performed. The initial (C0) and selected (C1) generations of an oat population were evaluated in a field experiment in 2001 and 2002 at two Iowa locations. Selection on an index increased the levels of crown rust resistance and grain yield and seed weight in crown rust-inoculated plots, and seed weight in fungicide-treated plots. However, the change for the grain yield in fungicide-treated plots was not significant. In both C0 and C1 populations, AUDPC was highly heritable (H = 0.77 and 0.78 respectively), and was favorably correlated with grain yield, seed weight and test weight measured in inoculated plots. Realized heritabilities for all traits but grain yield under fungicide-treatment were consistent with predicted heritabilities. Our results suggested that index selection could increase levels of crown rust resistance, grain yield, and seed weight simultaneously.

Last Modified: 7/24/2014
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