E. R. Saunders 307 



when two eversporting races are bred together, doubles will, on the 

 other hand, occur in each F^^ family as well as in each family in all later 

 generations, just as when either race is repeatedly self-fertilised. 



The evidence at present available in each case may be summed up 

 as follows : 



Red Race. 



87 individuals were tested directly by self-fertilisation. The pedigree 

 of these plants is shown below. 



1 Parent plant (A) 



11 Fi Plants derived by self-fertilisation from the parent plant A 



64 F^ ,, ,, ,, ,, 11 of the Fi individuals 



3 ^3 „ ,, „ „ 3 „ ^2 



7 ^4 „ „ „ ., 1 „ F3 



1 Pi „ „ „ „ 1 „ F^ 

 Total 87 



Doubles occurred in each of the 87 families (see Table III). Thus 

 every attempt to breed out the doubles proved unsuccessful, and the 

 evidence shows that this form, at least so far as the material used in 

 these experiments is concerned, is eversporting. Efforts to obtain from 

 other seed on the market a true-breeding (no-d) strain of this race 

 proved equally unsuccessful. Two or three large firms to whom 

 application was made were unable to supply such a strain'. 



' In the catalogues of the large Stock Growers the various stock races are catalogued 

 in different colours, but not as a rule according as they do, or do not, produce doubles. 

 It has however been found that commercial seed, stated to give only singles, does in fact 

 breed true; and that from seed stated to yield doubles, doubles are obtained in such 

 abundance that for testing purposes small sample saviugs are sufficient. It might 

 perhaps be supposed that, since the aim of the grower is to produce seed which will 

 yield as high a percentage of doubles as possible, a true-breeding strain, should it by 

 chance appear, would be at once discarded ; and hence the fact that it had not been 

 found possible to obtain such a strain in the red race, might not necessarily indicate that 

 no true-breeding individuals occurred when the race was cultivated without selection. 

 But this assumption does not explain the fact, that in the case of the other sap-coloured 

 forms employed, true-breeding seed is on the market and easily obtainable. There is no 

 reason to suppose that modern taste demands a pure-breeding single in various other 

 shades but rejects it if coloured red. Nevertheless there is no doubt that a pure-breeding 

 red strain could at once be made by crossing an eversporting red with a no-d type. 

 If the resulting crossbreds are self-fertilised, F2 will contain a proportion of glabrous 

 red singles some of which will be found to breed true. We may therefore safely class the 

 red race with the other sap-coloured types as one which can exist both as a pure-breeding 

 and a double-throwing foiTa. Whether a non-double-throwing sulphur-white race, i.e. to 

 say a white race composed entirely of individuals throwing a proportion of creams but 

 breeding true to singleness, can exist, or not, we cannot tell. At present no such race 

 is known, and we are unable to make it. 



