lo June, 1909.] WZ/ea^ Im prove moit Committee. 36'9 



sometimes shows a comparatively deep, narrow crease capable of 

 harboring occasional spores. In these cases we may account for an 

 occasional bunted ear in a crop sown with pickled seed. In another part 

 of the report mention is made of pickled and unpickled seed having 

 been sown in an infected field. The object of such an experiment is to 

 accentuate the importance of a rotation in checking diseases, ' and of the 

 necessity for pickling. 



How long a field mav remain infected, my tests have not been suffi- 

 ciently conclusive to prove. On one or two occasions bunted ears have 

 been "found in soil infected two years before. This continued infection 

 may be due to a bunt ball teing detached from a diseased plant by being 

 threshed out before the plant was pulled up and destroyed, or to some 

 such means. 



The life-historv of a spore has been worked out ; but, in order to 

 unravel the contributory causes of the prolongation of infection, it is as 

 well to consider the research under the conditions in which farmers are 

 generally placed. Mr. McAlpine, whose work shows so much painstaking 

 observation, will, no doubt, treat of the subject in his usual thorough 

 manner. A glance at the following table will show how very liable to 

 bunt is all of our commonly-grown wheats. In this set of experiments, 

 Medeah, a durum wheat, is the only one free from the disease. Although 

 not generally known to farmers, it is the best known durum variety in 

 the Commonwealth ; and for the comparative tests in bunt-resistance it_ has 

 been grown in the College plots. Early Barellett is an Argentine variety, 

 the name of which, I believe, is mis-spelled. It is somewhat translucent, 

 and of the Fife type. In the experiments in connection with bunt, I have 

 grown, adjacent to each infected row, one row of uninfected grain. This 

 was so that the comparison in all cases would be a proper one. It 

 happened in two instances that the apparently clean grain had by some 

 extraneous means become previously infected, or the infection was in the 

 grain from the first. 



One interesting experiment, and one that I have carried out for years, 

 was the sowing of apparently clean grain taken from an ear part of 

 which was diseased. It was at first thought that if the clean grains of 

 a naturally-infected ear were sown after being artificially infected, they 

 might resist the attacks of the disease. But they invariably prove to be 

 liable to infection. Thirty-two grains were taken from the apparently 

 clean portion of an ear of a Steinwedel -blooded variety, the remainder 

 of w^hich contained bunted grains. Sixteen of these apparently clean 

 grains were artificially infected with T. levis, and sown 8 inches apart. 

 The remaining 16 were sown without being artificially infected. 

 Eleven of the infected seeds, and one of the non-infected seeds produced 

 bunted plants. It is, of course, possible, in the handling of the grain 

 in a bunted ear, for a spore to fall on and infect an adjacent grain ; or 

 the mycelia may have just reached the grain, and a spore been produced 

 just about the ripening period, and so no headway was made on the 

 remaining part of the grain, as partially infected grains have been 

 found. 



Florence and Genoa, two varieties received through the Wheat Improve- 

 ment Committee, and, I believe, bred by the late Wm. Farrer, proved 

 to be bunt-resistant, but not immune from the attacks of the disea.se. It 

 mav be noted that the greater proportion of ears infected was those from 

 the secondary or late growth. It may also be noted that, in this experi- 

 ment, the germination of the moist-infected grains was comparatively 

 better than that of the clean seed and of the dry-infected grains. 



5710. N 



