3IEXDELS PRINCIPLES APPLIED TO WHEAT HYBRIDS. 887 



In the original cross, varieties with "brown chaff" were crossed with 

 varieties with " light -coloured chaff," the result being forty-five hybrids 

 with "brown chaff" and two with " light-coloured chaff." In this case 

 the " brown " character is Dominant and the " light " Recessive. In the 

 next generation forty- three of the "brown" hybrids self -fertilised pro- 

 duced forty-three plats of hybrids, each containing two types, viz. 

 Dominant and Recessive. Table B gives the approximate percentages 

 of each type found in each plat, and it will be seen that the figures, 

 though not so regular as in Table A, fairly agree with the Mendelian 

 expectation of three Dominants to one Recessive, i.e. 75% "brown" + 

 25% "light." 



It seems probable that the individual plat figures are not so regular 

 as in Table A because the character of "brown" and "light" is not so 

 distinctly differential as " velvet " and " glabrous," and consequently more 

 difficult to classify. However, this does not appear to have affected the 

 average percentage of the forty-three plats, which works out approximately 

 73*8 Dominants to 25'I Recessives, i.e. a ratio of 2*9 : 1, being a close 

 approximation to the Mendelian ratio of 3 : 1. 



The two remaining "brown" hybrids proved exceptional when self- 

 fertilised, inasmuch as they produced the same Dominant "brown" type 

 again, with no trace of the Recessive " light " form (see Table XII., Plats 

 G7, G22). 



It will be noted that Plat G22 was also one of the exceptions under 

 Table A. 



Table C. 



(" Bald " x " bearded " heads) x self. 



Spillmaif s Table No. 





Plat Xo. 



"Bald" 



" Bearded " 





[ 





C16 



85-4 





14-0 









C18 



72-0 





27-2 



| ■ -1 







C21 



64-2 





359 









F26 



76-7 





24-2 









F30 



66-4 





30-0 









F31 



71-1 





22-7 









F32 



74-2 





26-0 





I 





Gl 



69-6 





19-2 









G3 



76-1 





24-0 









F13 



77-7 





22-5 









Flo 



65-7 





30-3 









F17 



68-0 





260 







J6 



76-2 





23-9 









J7 



75-6 





24-1 









119 



82-3 





17-6 









J3 



73-5 





26-2 









J4 



74-6 





253 



XIII . . { 







J8 



76-2 





26-4 









J9 



75-8 





23-4 









J10 



74-9 





24-9 









J12 



58-2 





41-6 









J13 



80-0 





19-6 









J14 



75-4 





24-3 



