INFLUENCE OF SOIL TEMPERATURE AND SOIL STERILIZATION ON THE REACTION OF WHEAT SEEDLINGS TO OPHIOBOLUS GRAMINIS SACC.

Abstract

In this investigation Marquis wheat seedlings reacted similarly to a virulent Alberta strain of Ophiobolus graminis in sterilized and unsterilized soil at low temperatures, but differently at higher temperatures. At 13 °C. for instance, the blighting was about equally severe in sterilized and unsterilized soil, but at 27 °C. most of the seedlings were killed in the sterilized soil, while those in the unsterilized soil were only slightly attacked. The protective value to wheat of the constituents of unsterilized soil against soil-borne inoculum of Ophiobolus graminis appears, therefore, to vary with temperature, being under the conditions of these studies relatively slight at soil temperatures below 20 °C.