June, 1922 



SCIENTIFIO AGRICULTURE 



321 



concludt'd that there was incomplete domin- secured similar results in 1918. The Ho- 

 ance of softness, two factors being present wards (9), in 1915, found upon crossing 

 and giving six degrees of starchiness for a bearded with a tip-awned wheat, that the 

 grain texture, owing to the endosperm being Fj displayed an intermediate condition as 



the result of double fertilization and the manifested by very short awns. The F, se- 



effect of the factors cumulative. gregated into tip-awned, intermediate, atid 



Table III. — Inheritance of Seed Texture in F, 

 Cross or Percentage texture Total 



parent 30 3-5 40 4.5 50 55 60 65 70 7.5 80 85 90 



R. B 2 i i i 3 8 



T. W 112 1 5 



R. B. X T. W. ; . 10 43 46 43 36 42 29 20 19 10 2 300 



H. R. C 2 3 4 1 10 



T. W 112 1 5 



H. R. C. X T. W. 7 5 7 8 6 114 1 49 



Kit 113 5 



Com 4 2 6 



Kit. X Com.. .. 1675410412 40 



The data on seed texture is summarized in fully awned (bearded) in a 1 :2:1 ratio. They 



Table III. Texture is represented on a also observed that when a bald wheat was 



scale of 30 to 90, 30 standing for soft crossed with a bearded wheat the inheritance 



starch}' seed and 90 indicating hard vitreous of awned character appeared to be govern- 



seed. The distribution for Red Bobs x Tay- ed by two factors. To explain their results 



lor's Wonder approximates that of the they supposed that bearded wheats had two 



parent varieties but the number of parent in- factors. B and T, in a homozygous condition; 



dividuals classified was too small to ap- that tip-awned wheats, like Marquis or Red 



proach a normal curve of probability. The Fife, had either B or T in a homozygous 



distribution for Hard Red Calcutta x Tay- condition; and that bald (awnless) wheats 



lor's Wonder and for Commonwealth x Kit- lacked both factors. 



chener approaches the extremes of the In Table IV a summary is given of the 



parents. The range for each of the parents data on awn character obtained in the pres- 



probably would have been more extensive ent study. A cross between Red Bobs (bald) 



had a larger number of individuals been and Taylor's Wonder (tip-awned) yielded 



used. The general evenness of the distribu- in the F, 230 tip-awned and 69 bald, or a 



tion through various grades of texture be- ratio of 2.92 : 1.08. This is very close to a 



tween soft and hard would seem to indicate 3:1 ratio and indicates the presence of one 



that seed texture in wheat is dependent on factor. With a single factor difference the 



several factors. Fo should contain three classes of individuals, 



_ . ., „ . „. ^ homozvgous bald, heterozygous tip-awned 



Innentance of Awn Character j u ,.■ /a i. • err- 



and homozygous tip-awned. As it is diffi- 



Various investigators have studied the in- cult to separate individuals of the last two 



heritance of awns in wheat. In 1905, Biffin groups it was thought best to leave them 



(1) obtained a 3:1 ratio of tip-awned and together, especially as the number of indi- 



bearded plants in Fo. Kezer and Boyack (1) viduals classified was not large. 



Table IV. — Inheritance of Awns in Fj 



i = ° 

 .2 -o i:% I I 



«T3'C z ^ = =-2 



= Si's ^C C'C ^ 



O HCC-.;:=3C5 < a, cS Pho QO, 



R. B. X T. W. . . 230 69 2.92:1.08 0.08 ±0.07 1.14 



H. R. C. x T. W.. . 38 ... 11 .. 3.10:0.90 0.10 ±0.17 0.59 



H. R. C. X W. B. ... 204 16 .. 14.83:1.17 0.17 ±0.08 2.12 



