June, 1922 



SCIENTIFIC AGRICULTURE 



323 



Now, since some tip-awned varieties may 

 have the factors BBtt and others may have 

 bbTT, a cross between one of each type 

 should produce individuals ranging from 

 bald to bearded in a l:t:6:4:l ratio. Pos- 

 sibly the infrequent occurrence of this re- 

 sult in breeding work (2) is due to the fact 

 that most of our tip-awned varieties are of 

 the same genetic constitution with respect to 

 awn character. 



The results described in this paper on the 

 inheritance of awn character in wheat agree 

 with those obtained by the Howards (9). 

 They made a number of crosses between 

 bald, tip-awned, and bearded wheats and at- 

 tempted to separate the Fo progeny into 

 nine classes according to the nine genotypes 

 present. By carrying their material through 

 the F, generation they were able to prove the 

 accuracy of the Fo classification. They found 

 that BBtt produced a different tip-awned 

 condition than bbTT. The explanation 

 given is that one of the two factors produces 

 very short awns and the other fairly long 

 awns. 



The Inheritance of Seed Colour and Awns 



Table VI shows the mode of inheritance 

 of awn character with respect to seed colour. 

 Red Bobs x Taylor's Wonder, Numbers 71, 

 77 and 79, gave a 3:1 ratio for seed colour 

 as well as for awn character. A 9:3:3:1 



ratio is obtained when these two characters 

 are considered together. Red Bobs x Tay- 

 lor's Wonder, Numbers 72 to 76, gave a 3:1 

 ratio for awn character but a 15:1 ratio for 

 seed colour, consequently a 45:15:3:1 is 

 produced when both characters are taken 

 into account. Similarly in Hard Red Cal- 

 cutta X White Bobs, Numbers 113 and 114, 

 a 45:15:3:1 ratio is obtained. In this case 

 segregation for seed colour was in a 3:1 ratio 

 and for awn character in a 15:1 ratio. Hard 

 Red Calcutta x White Bobs, Numbers 109, 

 110, 112 and 115, produced a 15:1 ratio for 

 both seed colour and awn character. Con- 

 sidering the characters together gives a 

 225:15:15:1 ratio. The results in general 

 agree unusually well with the theoretical ex- 

 pectations. 



Inheritance of Chaff Colour 



Biffin (1), in 1905, found that both red 

 chaff and gray chaff were dominant to white 

 chaff, the ratio being 3:1 in F,. Kezer and 

 Boyack (10) reported a 3:1 ratio for red 

 and white chaff in 1918. At about the same 

 time Love and Craig (11) obtained an in- 

 dication of a 15:1 ratio for red and white 

 chaff in the F, of a durum x vulgare cross. 



In the present study only a small amount 

 of material of one cross was available for 

 classification. The parents of the cross 

 were Commonwealth, an Australian wheat 



Table VI. — Inheritance of Awns and Seed Colour 



-0.53 

 10.41 

 10.41 



ro.26 



-1.41 

 11.31 

 '-0.65 

 -0.38 



.1.97 



-1.83 

 -0.91 

 10.54 



-5.14 



-3.70 

 -3.70 

 -0.98 



