CLASSIFICATION AND INHERITANCE OF SMALL GRAINS 97 



factorily explain the results. Nilsson-Ehle obtained trans- 

 gressive segregation in F z in a cross between medium early and 

 late maturing varieties. Progeny from 112 F z plants were grown 

 in F 3 . Of these 112 plants, 98 gave segregating progeny for 

 maturity and 14 seemed to be homozygous. Homozygous 

 forms were obtained which were earlier than the early parent 

 and others which were later than the late parent. 



Linkage of Characters. Association of numerous characters 

 in inheritance has been mentioned in the discussion of crosses 

 between the wild A. fatua and cultivated varieties of A. saliva. 

 Aside from the general characters mentioned, linkage has been 

 found between the factor for black color of the lemma and one 

 of the factors for pubescence. 



In crosses between Burt, A. sterilis, and Sixty Day, A. saliva, 

 Fraser (1919) has found that the factors for the articulated base 

 of the lower grain, the awned condition, and the production of 

 medium basal hairs were linked in inheritance. In the following 

 diagram A represents the factor for awning, B for Burt base, and 

 C a factor for the production of medium basal hairs. 



4.14 5.00 



A B C 



The percentages of cross-overs were determined for F 2 and 

 F 3 . As has been pointed out, each of the characters depends on a 

 single factor for its development. Five per cent, of cross-overs 

 occurred between the factors for awning and basal hairs; 4.14 

 per cent, between awning and the factor for Burt base, and 1.79 

 per cent, between Burt base and basal hairs. 



False Wild Oats. False wild oats differ from the cultivated 

 varieties in the production of heavier awns, in heavy pubescence, 

 and in the basal articulation. False wild oats resembling culti- 

 vated varieties in color and panicle characters have been found 

 by numerous investigators. Nilsson-Ehle (191 la) has reported 

 false wild oats in eleven pure-line selections and in two commer- 

 cial varieties belonging either to A. saliva or A. saliva orienlalis. 

 A heterozygous false wild form was found in the second genera- 

 tion of a cross between saliva varieties. It gave a ratio of 1 

 cultivated, 2 heterozygous to 1 false wild form. The heterozy- 



