Parasifisin a>ul 1 ninuiuitx. 51 



was used, as at Dookie and Longerenoiig, then Florence had .j.<J(J per cent, 

 and Genoa 4.72 psr cent, of Stinkhig Smut. In all cases the ordmary seed 

 was sown as a check and the plots were invariably free from bunt. 



II. Bookia. — There were also five plots of each variety sown here to test 

 their s'.Hceptibility to bunt, and only T. levis was used. In order to make 

 the test as severe as possible, some of the grain already dusted with spores 

 was re-smutted in the following manner. One hundred smut-balls were 

 powdered and then made into a soft paste by the addition of water. One 

 hundred grains were placed in this paste, thus allowing one smut ball on an 

 average for each grain, mixed thoroughly and allowed to soak over-night. 

 By next morning the moisture had disappeared and the seed was sown the 

 same day. Infection in the re-smutted grains was the most virulent, for while 

 it yielded 5.72 and 9.7i) per cent, of bunt respectively in Florence and Genoa, 

 there w^ as only 2 . 42 and 2 per cent respectively w' ith the ordinary dusting of 

 the grain. The general average for Florence was 4 . 45 per cent, and for Genoa, 

 6 . 85 per cent. The higher average for Genoa was largely owing to one plot 

 in which the percentage was over 16, while in a plot alongside it was only a 

 little over 6. This difference was so striking, that these two adjoining plots 

 were again carefully examined with the same result. There was no evident 

 cause for the unequal infection. 



III. Longerenong. — There were only two plots of each sown, a large and a 

 small one, together wnth the check plots, and the dusting of the seed w-as 

 entirely with the spores of T. levis. The general average w^as much higher 

 here than in the other two localities, being 9.20 per cent, for Florence, and 

 14.00 per cent, for Genoa. This may be due to the heavy rainfall in May. 



It is clear, from the experiments, that Florence and Genoa no not possess 

 the hereditary quality of bunt-resistance, and Sutton evidently suspected this, 

 as he wrote to me as follows in May, 1908 : — " I have been referring to the 

 results of our trials wdtli these wheats while they w^ere being fixed, and I find 

 that in 1905, they were at Lambrigg fairly bunty, and this may indicate that 

 they are not constitutionally resistant to bunt, but that they escape bunt 

 through some peculiar characteristic of their growth immediately after ger- 

 mination." As elsewhere pointed out they are relatively rapid in their ger- 

 mination (see Frontispiece), and this may account for their escaping the bunt 

 to a large extent. But in order to secure complete immunity and the heredi- 

 tary quality of resistance, it will be necessary to breed from a variety which 

 has shown itself to be free when exposed to the most severe infection for a series 

 of seasons. 



Experiments at Dookie Agricultural College. 



Mr. Pye, principal of Dookie Agricultural College, had been working for 

 some years in conjunction with Mr. Farrer in endeavouring to produce bunt- 

 resisting wheats by selection after seed-infection. He is still continuing this 

 work and the most promising line lies in breeding from crosses of the Durum 

 variety, that resist the bunt. He found, for instance, that Medeah is not so 

 liable to bunt as many others, and he is using this variety as a parent. The 

 seed of the progeny is then dusted wdth bunt-spores and the seed from those 

 plants which escape infection is sown next season, and so on until a strain is 

 secured which will be bunt-resisting. 



Not only have these experiments been carried on for a number of years, 

 but they are conducted on a most comprehensive scale, as during the past 

 season there were over 200 plots devoted to smuts alone. I have carefully 

 examined them and find that it is necessary to determine the bunted plants 

 when the growth is completed and all the ears are more or less mature. This 



