Nov. 13, 1921 Genetic Behavior of Spelt Form in Crosses 



341 



the wheat forms (class 10), which show no trace of spelt characters. 

 The proportions between spelta and sativum forms of each of the crosses 

 taken separately and that of the totals of these two groups approximated 

 the monohybrid ratio of 3 to i. The obtained ratio of the totals of the 

 crosses was 305 speltoid and spelt forms to 113 wheats, the expections 

 being 313.5 to 104.5, respectively, showing a deviation of 8.5 with a 

 probable error of ± 6.0. 



Two of the Fj families, 13260a and 13255a, gave the results shown in 

 Table II when the F3 generation was grown. 



Table II shows that the Fj population of the families tested consisted 

 of individuals in the proportion of i homozygous spelt to 2 heterozygous 

 forms and i homozygous wheat. 



Table II. — Number of F2 plants from series ij26oa and Ij2^ja which proved to be homo- 

 zygous spelts, heterozygous forms, and homozygous wheats {i : 2 : i) when tested in the 

 /• 3 generation 



The ratios of the totals of the forms produced in the F3 generation by 

 the heterozygous Fg individuals of these two families (Table III) seem 

 to conform to the foregoing assumption, although the ratios of the 

 forms produced by each of the F2 individuals sometimes are not so 

 close to the 3 to i expectation. Of the total individuals produced by 

 the Fj heterozygous plants of series 13260a (spelt X Turkey) , 212 were 

 spelts and 71 wheats. These results were surprisingly close to the 

 expectation, the deviation from the calculated numbers being but 

 0.3 with a probable error of ± 4.9. In series 13255a (Dale Gloria X spelt), 

 the numbers obtained from the heterozygous individuals were 365 

 spelts and speltoids and 156 wheats; the deviation here was 25.8 with a 

 probable error of ±6.7. This apparent dominance of the spelt character 

 over that of the wheat and its segregation into the 3 to i ratio are in 

 accord with the observations of Pitsch, as cited by von Tschermak 

 {12, p. ijg) and of Kajanus (j). 



