THE EFFECT OF LEAF RUST ON THE YIELD AND QUALITY OF THATCHER AND RENOWN WHEAT IN 1938

Abstract

A study was made at Winnipeg in 1938 to determine the effect of leaf rust on the yield and quality of Thatcher and Renown wheat. In one experiment, Thatcher and Renown were sown late in 1/400-acre plots; in another, Thatcher only was used and was sown early in rod-row plots. Half the plots of each variety were kept as free from leaf rust as possible by frequent applications of sulphur dust, but the remaining half became heavily infected. In the 1/400-acre plots, leaf rust reduced the yield of Thatcher and Renown by 51.17 and 29.61%, respectively; in the rod-row plots of Thatcher, it reduced the yield by 37.02%. The decrease in yield was due more to reduction in kernel weight than to reduction in number of kernels per head. All the non-dusted plots ripened approximately three days earlier than the dusted, and the grain from them graded one grade lower than that from the corresponding dusted plots. In both varieties, the protein content was diminished while the carotene content was increased.