382 Reed : The mildews of the cereals 



Sixteen plants of the hybrid were hioculated with conidia from 

 wheat in ten different tests. Of these plants, only one showed 

 any evidence of infection. In experiment i68b, a small patch of 

 mildew with conidia" appeared. 



In experiments 127c and 12yd, different leaves of the same 

 plant were inoculated, one with the rye mildew, the other with the 

 wheat mildew. No infection occurred on either leaf The same 

 method was followed in experiments 162c and i62d. The leaf 

 inoculated with conidia from rye showed a good growth of mil- 

 dew, but the leaf inoculated with conidia from wheat gave no evi- 

 dence whatever of infection. 



It is apparent from my previous work that the wheat is entirely 

 immune to the rye mildew. Twenty-four tests were made, in 

 which sixty-six plants were inoculated with rye mildew, not one 

 showing any evidence of infection. In contrast, every one of the 

 one hundred and seventy-eight plants inoculated with wheat mil- 

 dew, in sixty-six tests, became fully infected. The same thing 

 holds ti'ue in the case of rye. Twenty-five rye plants, in ten 

 tests, were inoculated with conidia from the wheat, but not one 

 plant showed any evidence of infection. On the other hand, in a 

 total of one hundred and thirty-eight plants inoculated with rye 

 mildew, in fifty-eight tests, one hundred and thirty-one plants 

 became infected. 



The experiments with the rye-wheat hybrid clearly' indicate 

 that this hybrid is resistant to both the rye and the wheat mildew. 

 It has, however, proved much more resistant to wheat mildew than 

 to the rye, for only one infection occurred with this mildew. It 

 would be interesting to know the entire history of the hybrid seed 

 experimented with. I do not know to what generation the plants 

 I worked with belonged, nor do I know whether they more closely 

 resemble rye plants or wheat plants. I am growing the plants to 

 maturity in order to deterriiine the latter point. 



In this connection it is interesting to mention an experiment by 

 Eriksson ^^ on some of Rimpau's rye-wheat hybrids. Eriksson 

 found a form of Pttccinia dispersa Eriks. & Henn. growing abun- 

 dantly upon rye- wheat hybrids obtained from Rimpau. He states 

 that the hybrid plants seemed to be more like the wheat than the 

 rye. It is well known that there are two distinct forms of Puccinia 



