Parasitism and Imnmnity. 19 



was selling at is. 5W. to 4s. 6d. per bushel, smutty was sold at 3s. 5d. to 3s. 9d. 

 for inferior, and 3s. lOd. to -is. for better samples. It is tbis necessit}' for 

 having wheat almost absolutely bunt-free that has hitherto deterred experi- 

 menters from even making the attempt. 



Experiments with Florence and Genoa to test their Bunt-resistance 



This question of immunity to smut is a very important one, and experi- 

 ments to test how far this immunity is hereditary or transmissible, and if it 

 is maintained under different conditions of soil and climate, heat and mois- 

 ture, were carefully planned. Mr Sutton willingly supplied seed- wheat of 

 Florence and Genoa for the purpose, and a sufficient quantity of grain was 

 mixed with bunt spores to allow of its being sowii in such distinct districts of 

 Victoria as Dookie Agricultural College, in the North, under the superintend- 

 dence of the principal, Mr. Pye : at Longerenong Agricultural College, in the 

 West, under the charge of Mr. Pridham ; and at Burnley Horticultural Gar- 

 dens, near Melbourne, in the South, under my own personal supervision. 

 The seed was all dusted ecjually with spores of Tilletia levis, derived from a 

 common source, and it is important to note that the experiments were all on 

 an equal footing as far as the amount and vitality of the bunt-spores are con- 

 cerned. A bulk sample of wheat was mixed with the spores as follows : — 

 Bunt-balls were taken direct from the wheat plant and then broken up by 

 rolling them in paper. The spores were next well dusted and rubbed over 

 the moistened grains, so that every grain looked as if it had been dressed with 

 soot. The grain Avas sent out immediately afterwards for sowing. 



At Dookie, the sowing took place on 17th June, and the seed-bed was a 

 moist one. Superphosphate was applied at the rate of about 65 lbs. per acre. 

 The rainfall for April was .23 inches ; for May, 1.99 inches ; and for June, 

 4.36 inches. The bunted grain sown in a moist seed-bed was particularlv 

 liable to infection. The mean temperatures for May and June were 11 and 

 7° C. respectively. 



At Longerenong, the seed was sown on 1st June, and the seed-bed was in 

 good condition and moist. The rainfall for April was .09 inches ; for May, 

 3.22 inches ; and for June, 2.55 inches. The mean temperatures for Mav and 

 June were 10 and 7° C. respectively. 



At Burnley, the plots were sown on 16th June, the soil being a sandy loam, 

 and in a moist condition. The experimental ground was enclosed with bird- 

 proof netting so that the results were not interfered with in any way. As 

 this was the first season of the wheat experiments there, manure was sup- 

 plied at the rate of per acre, 1 cwt. superphosphate, J cwt. sulphate of am- 

 monia and I cwt. sulphate of potash. The rainfall for April was .33 inclies ; 

 fov May, .87 inches : and for June, 3.94 inches. The mean temperatures for 

 May and June were 11 and 8° C. respectively. 



Since the weather conditions exercise an important influence on the ger- 

 mination of the spores, it may be noted generally for the first quarter of the 

 year 1908, that the rainfall was scarcely 50 per cent, of the average amount 

 and this was followed by one of the driest April months ever known. The 

 brealdng up of the drought occurred in May, and the rains in June were above 

 the average, so that altogether, the conditions were favorable for the germina- 

 tion of the spores and the seed-wheat at the same tune. 



The results of the experiments have been carefully tabulated, and while 

 they show that Florence may have as much as 12 per cent, of Stinking Smut, 

 and Genoa, 22 per cent., yet on the whole, they are fairly resistant. 



