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ARS Home » Midwest Area » Ames, Iowa » Corn Insects and Crop Genetics Research » Research » Publications at this Location » Publication #64833
Title: EFFECT OF LEAF-LIGNIN CONCENTRATION ON THREE COMPONENTS OF RESISTANCE TO ALFALFA RUST

Author
item WEBB, DOUGLAS - ISU
item NUTTER, FOREST - ISU
item BUXTON, DWAYNE

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/15/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: One of the most important characteristics of alfalfa as a feed source is its digestibility. Consequently, many private and public alfalfa breeders have developed programs to select for improved digestibility. Improved digestibility is often associated with reduced lignin concentration in the herbage. Lignin is also important in plants to prevent or reduce plant injury caused by pathogens. The disease risk resulting from reduced lignin concentration in alfalfa is not known. This study was conducted to determine the effect of innate leaf-lignin concentration of alfalfa on resistance to Uromyces striatus, the causal agent of alfalfa rust. We found that the innate leaf concentration had little effect on resistance to this disease. This information will be of greatest interest to those working to improve the nutritive value and digestibility of forages.

Technical Abstract: The objective of this study was to investigate the effect of innate leaf-lignin concentration of alfalfa on components of resistance to the causal agent of alfalfa rust. Leaf-lignin concentrations were determined for individual alfalfa plants from two populations by acid detergent lignin analysis. Plants representing a range of lignin values for each populations were selected and cloned. Clones were inoculated with Uromyces striatus and three components of resistance were quantified: infection efficiency, latent period, and sporulation capacity. Regression analyses indicated that there was little or no relationship between leaf-lignin concentration and components of alfalfa rust resistance as indicated by slope parameters not significantly different from zero and low r2 values.