44 



The second generation of a cross between Silvermine and Black 

 Mesdag was studied during the past year. Silvermine is very 

 susceptible to both smuts, while Black Mesdag is equally resistant. 

 The progeny of two different crosses was grown and 95 plants were 

 inoculated with Ustihu/o Avcnae, of which t; (17.8 per cent.) 

 were infected. In a similar series 8<) plants were inoculated with 

 V. levis and of these 15 (16.8 per cent.) were infected. 



The second generation of crosses between 1 hill-less and Victor, 

 varieties susceptible to both smuts, and Early Gothland, a variety 

 susceptible to loose but resistant to covered smut, were also 

 studied. The second generation plants of the cross between Early 

 Gothland and Victor gave too per cent, infection when inoculated 

 with U. Avcnae. a result that might be expected on the basis of 

 the high susceptibility of both parents to this smut. On the other 

 band, out of 44 second generation plants inoculated with U. levis, 8 

 18.1 per cent. ) were infected. In the same way, second generatu >n 

 plants of two progenies between Early Gothland and Hull-less 

 were studied. In the series inoculated with U, Avcnae 93.4 per 

 cent, of the plants were infected, while in the series with U. levis 

 o'M K 1 C( ' n l wen inf< ch I, <; 1 plai f being gro 1 



The converse of this cross was also available for study. In 

 this case one parent (Hull-less) was susceptible to both smuts 

 while the other (Monarch) was susceptible to U. levis but resistant 

 to Jj . Avcnae. The second generation plants of four progenies 

 of this cross were available for study. The plants inoculated with 

 I ' . . Ivcnac gave 20.9 per cent, in 

 grown. On the other hand, o 

 U. levis 95 per cent, were infected. 



In all lliese crosses between a resistant and a susceptible variety 

 resistance to smut appeared to be the dominant character, while 

 -nsccptibility was recessive. Further, segregation in the second 

 generation appeared to occur on the basis of a single factor differ- 

 ence. While extensive studies have not as yet been made on the 

 inheritance of the morphological characters of the oat varieties, 

 yet the evidence points to the conclusion that the recombination of 

 smut resistance with the various morphological characters may he 

 successfully accomplished. 



A number of new crosses between different oat varieties were 



