56 



Inuminitf/ hi Cereah 



For example, all the cultivated vaiieties of T. durum and T. turgidum 

 are relatively immune to brown rust. All known wikl and cultivated 

 varieties of T. luonococcum are perfectly immune to brown rust. 



Many scattered data, which were found in old and recent literature, 

 referring to the same or other varieties, prove the correctness of this 

 conclusion (the literature is given in the above-mentioned paper 16, 

 pp. 94 — 99, 5 — 6) and allow us even to apply, in some degree, this 

 generalisation to the relation of the species of wheat to other fungi, 

 as yellow ru.st P. glumaruin. For instance, all varieties of T. mono- 

 coccuni, in accordance with published data, are perfectly immune to 

 yellow rust. The different varieties of I', durum and turgidum are 

 relatively immune to the same rust. 



In general, the characteristics of the eight species of wheat in 

 relation to the fungi by which they are attacked in Russia are as 

 follows : 



resistant 



Tr. durum Desf 

 Tr. polonicum L. 

 Tr. turgidum L. 



In relation to Puccinia triticina Eriks.' 



xusceptible 



Tr. vulgare Vill. (thei-e are a few 



immune races) 

 Tr. compactum Host. 

 Tr. Spelta L. 



perfectly immune 



Tr. manococcuiii L. 

 Tr. dicoccum Schr. has both susceptible and inumme races. 

 In relation to Ery.nphe gra minis D.C. 



tfuseeptihle resistant 



Tr. vulgare Vill. (with the exception Tr. durvm Desf. 



of a few races) Tr. polonicum L. 



Tr. compactum. Host." Tr. turgidum L. 



Tr. Spelta (a little less than the T?: monococcum L. 



preceding ones). 



Tr. dicoccum Schr. has both susceptible and iiiuuuue races^ 



• lu the paper (16) are given the coloured plate.s, illustrating the differences iu suscepti- 

 bility of wheats and oats to brown, black and crown rusts. 



- Only one race, belonging to the variety Tr. compacliiiii var. creliciim Mazz. proved to 

 be relatively resistant to mildew. (The same was observed in America by Prof. Keed.) 



'■> These characteristics of species are based on observations in fields under different 

 conditions of manure, soil and climate. In greenhouses brown and yellow rusts do not 

 develop to any considerable extent even by artificial infection ; on the contrary, the 



