Nov. 12, 1921 Genetic Behavior of Spelt Form in Crosses 363 



The speltoid form "Gatineau" when crossed with wheats gave also a 

 3 to I segregation of spelts and wheats, but the curves showing the 

 classes of spelts produced by this cross were entirely different from the 

 curves produced by the spelt-wheat crosses which segregated in the same 

 ratio. 



Aside from the factor or factors for spelting, there is positive evidence 

 showing the presence of intensifying and diluting modifiers which tend 

 to affect the degree of spelt characters without affecting to any extent 

 the ratios of spelts to wheat. Some of the diluting modifiers tend to act 

 as inhibitors. 



The progeny of all heterozygous spelts of the Ss type do not produce a 

 similar spelt curve. There are wide discrepancies in the spelt inheritance 

 of the progeny of these forms. These variations within the spelt classes 

 have been found to be hereditary and to be caused by modifiers. 



The theoretical possibility of producing synthetic wheats in crosses 

 between certain pure-breeding spelts is shown. 



Experimental evidence also is presented showing that, in spite of the 

 fact that the spelt character is dominant over the wheat form, the former 

 may be synthetically produced by crossing certain wheats, provided one 

 of the wheats carries a spelt factor together with an inhibitor and that 

 the other wheat carries neither. 



It is shown that, if intensifying, inhibiting, and diluting modifiers are 

 introduced in a cross, wide departures may be expected from the 3 to i 

 and 15 to I ratios. 



LITERATURE CITED 

 (i) BosHNAKiAN, Sarkis. 



1918. THE MECHAmCAL FACTORS DETERMINING THE SHAPE OF THE WHEAT 

 KERNEL. In Jour. Amer. Soc. Agron., v. lo, no. 5, p. 205-209, fig. 27. 



(2) Castle, W. E., and Phillips, John C. 



1914. PIEBALD rats and SELECTION ... 56 p., 3 pi. Washington, D. C. 

 (Carnegie Inst. Wash. Pub. 195). Bibliography, p. 31. 



(3) Kajanus, Birger. 



1912. 0BER EINEN SPONTAN entstandenen weizenbastard. In Ztschf. 

 Pflanzenziicht., Bd. i, Heft i, p. 13-24. 



(4) 



1918. KREuzuNGSSTUDiEN AN winTERWEIzen. In Bot. Notisef, 1918, Haftet 

 5, p. 235-244. 

 (5) Love, H. H., and Craig, W. T. 



1918. the relation between color and other characters in certain 



AVENA crosses. In Amer. Nat., v. 52, no. 620/621, p. 369-383. 



(6) 



1919. THE SYNTHETIC PRODUCTION oP WILD WHEAT FORMS. In Jonr. Heredity, 



V. 10, no. 2, p. 51-64, 10 fig. 

 (7) and McRosTiE, G. P. 



1919. THE INHERITANCE OF HULL-LESSNESS IN OAT HYBRIDS. In Amer. Nat., 



V. S3, no. 624, p. 5-32, 7 fig. 



