Sept. t, 1930 



Genetics of Rust Resistance 



531 



plants were observed. None of these were bearded, all having either 

 intermediate or very short-tipped awns like those of the Marquis parent. 

 The evidence points to the conclusion that the hairy-chaffed plants ob- 

 tained in the F3 generation were the result of natural hybrids in the Fj 

 generation. 



Table III. — Number of hairy-chaffed tntermediate-auned plants, glabrous-chaffed inter- 

 mediate-awned plants, and glabrous-chaffed bearded plants in F-^ families grown from 

 bearded glabrous-chaffed F2 plants of crosses between Triticum, durum, and T. vulgare. 



Cross. 



Number of plants. 



Total. 



Bearded, 

 glabrous. 



Intennedi- 



ate-awned, 



hairy. 



Intermedi- 

 ate-awned, 

 glabrous. 



lumillo X Marquis: 



19^5 



196-26 



196-34 



198-21 



199-8 



199-9 



225-24 



227-4 



228-24 



228-35 



229-21 



232-13 



232-14 



Average of 26 lines 



Marquis X Kubanka (C I 2094) 



208-4 



203-10 



211-23 



214-35 



217-18 , 



218— I 



221-14 



222—10 



222-33 



Average of ^o lines 



37 

 14 



131 

 66 

 48 

 74 

 47 



114 



19 

 31 

 15 

 37 



51 

 381 



40 



43 

 60 



35 

 36 

 34 

 36 

 36 

 495 



37 



7 



114 



54 

 27 



S6 



41 



93 



8 



30 



15 



9 



33 



302 



4 

 39 

 40 

 60 

 29 

 26 



19 

 36 



30 



412 



26 



ID 



73 



5 



10 

 10 



3 



54 



3 

 29 



Table IV. — Xumber of hairy-chaffed plants and glabrous-chaffed plants in the F^fam,ilies 

 grown from intermediate- aw ned glabrous-chaffed Fn plants of cross between Triticum 

 vulgare and T. durum 



Plant No. 



223-7. 

 218-8. 

 217-5- 



211-22 

 209-4 . 

 203-38 



203-3 • 

 214-21 



