SMALL GRAIN VARIETY AND DISEASE RESPONSES TO CHLORIDE

Authors: Riedell, Walter; OSBORNE, LAWRENCE - SOUTH DAKOTA STATE UNIV; Osborne, Shannon

Submitted to: Experiment Station Bulletins
Publication Type: Experiment Station
Publication Acceptance Date: 2/25/2004
Publication Date: 3/21/2004
Citation: Riedell, W.E., Osborne, L.E., Osborne, S.L. 2004. Small grain variety and disease responses to chloride. 2003 Progress Report # Soil PR-03-39. Ag. Exp Stn., Plant Sci. Dept. South Dakota State University.

Interpretive Summary: For spring wheat, chloride fertilizer added to low chloride-testing soil results in a positive yield gain 70 % of the time. Some, but not all, of these yield responses have been attributed to chloride interaction with disease susceptibility. Because soil fertility and disease suppression are among the most important management tools used by farmers, additional research on the interaction between chloride fertility and disease suppression is needed. Our objective was to measure the chloride and disease responses of two hard red spring wheat cultivars under controlled environments. A greenhouse experiment was conducted in which nutrient solutions containing different levels of potassium chloride were applied to different hard red spring wheat cultivars ('Butte 86' -- moderately leaf rust resistant; and 'Ingot' -- moderately leaf rust susceptible). Plants were subsequently inoculated with leaf rust and evaluated for shoot dry weight, shoot chloride, leaf rust severity, and lesion type after two weeks. The cultivar 'Butte 86' had significantly higher shoot dry weight and significantly less shoot chloride, rust severity, and less severe lesion scores than 'Ingot' across all nutrient solution treatments. In both cultivars, shoot dry weight decreased while shoot chloride concentrations increased when the level of chloride provided in the nutrient solution increased. We measured a significant reduction in rust severity in plants receiving the highest level of chloride when compared to the other nutrient solution treatments. This reduction in leaf rust severity was not accompanied by a consistent change in the lesion type.

Technical Abstract: For spring wheat (Triticum aestivum L.), chloride fertilizer added to low chloride-testing soil results in a positive yield gain 70 % of the time. Some, but not all, of these yield responses have been attributed to chloride interaction with disease susceptibility. Because soil fertility and disease suppression are among the most important management tools used by farmers, additional research on the interaction between chloride fertility and disease suppression is needed. Our objective was to measure the chloride and disease responses of two hard red spring wheat cultivars under controlled environments. A greenhouse experiment was conducted in which nutrient solutions containing different levels of potassium chloride (0, 20, or 80 mM) were applied to different hard red spring wheat cultivars ('Butte 86' -- moderately leaf rust resistant; and 'Ingot' -- moderately leaf rust susceptible) that were grown in sand culture for 3 weeks. Plants were subsequently inoculated with leaf rust (Puccinia triticina Ericks.) and evaluated for shoot dry weight, shoot chloride, leaf rust severity, and lesion type after two weeks. The cultivar 'Butte 86' had significantly higher shoot dry weight and significantly less shoot chloride, rust severity, and less severe lesion scores than 'Ingot' across all nutrient solution treatments. In both cultivars, shoot dry weight decreased while shoot chloride concentrations increased when the level of chloride provided in the nutrient solution increased. We measured a significant reduction in rust severity in plants receiving the 80 mM chloride when compared to the other nutrient solution treatments. This reduction in leaf rust severity was not accompanied by a consistent change in the lesion type.