N. I. Vavilov 55 



of for the identification of barleys, all naked two-rowed barleys are 

 represented by one variety — Hordeum distichuvi var. nudum L. To 

 this variety we had referred, after identifying, all our naked two-rowed 

 sorts of barley. But from observation of these barleys during two years, 

 it was noticed that one of these parts (a pure line) was noticeably less 

 susceptible to Puccinia simplex Eriks. than others, although growing 

 side by side. This circumstance obliged me to pay more attention to 

 the form in question, and in the result it was found that we had a very 

 rare variety, which was wanting in the old classification of Koernieke. 

 It is distinguished from var. nudum L. by weak development of the 

 lateral spikelets (as in var. deficiens Steud.), and it was described only 

 in the posthumous article of Koernieke (8), published in 1908, under 

 the name of Hordeum distichum var. midideficiens Kcke. We i-eceived 

 this variety from Caucasus (Daghestan). 



I now append some examples of the connection of the fungal reaction 

 of cereals with their genetics. 



Ghiracteristics of the Eight Species of Wheat in relation to Rust 



and Mildew. 



After the work of Prof Biffen and Nilsson-Ehle, which proved that 

 immunity and susceptibility to fungal diseases is subject to the Men- 

 delian rules of inheritance, it would seem very natural to suppose that 

 the distribution of these characters amongst hundreds of varieties and 

 races of cereals is (piite accidental and without any definite order, as 

 immunity and susceptibility may be combined by the aid of crossing 

 with any group of morphological characters. Efspecially it would be 

 natural to suppose it to be so in such a group as wheats, seven sjjecies 

 of which {T. vulgare, T. compactum, T. durum, T. polonicum, T. tiirgidum, 

 T. Spelta and T. dicoccum) have been proved to be fertile by crossing'. 



In reality, it is far from being so. 



After investigation of about 800 sorts (represented by pure lines) of 

 spring and winter wheat, collected from diffei'ent parts of Europe and 

 Asia, with regard to fungi prevalent in European Russia {Puccinia 

 triticina Eriks. and Erysiphe graminis D.C.), and after classifying the 

 sorts and tabulating these data, we came to the conclusion that in 

 general each of the eight species of wheat, including dozens of varieties 

 and races, has a definite characteristic behaviour in relation to fungi 

 (16, pp. 29—54, 94—102). 



' See works of Vilmoiin, Beijerinck, Eimpau, Tschermak, Biffen and others. 



