294 PLANT HYBRIDIZATION BEFORE MENDEL 



"In this generation there' re-appear, together with the dominant char- 

 acters, also the recessive ones with their peculiarities fully developed, 

 and this occurs in the definitely expressed average proportion of three 

 to one, so that among each four plants of this generation three display 

 the dominant character, and one the recessive. This relates without ex- 

 ception to all the characters which were investigated in the experiments. 

 The angular, wrinkled form of seeds, the green color of the albumen, 

 the white color of the seed-coats and the flowers, the constrictions of 

 the pods, the yellow color of the unripe pod, of the stalk, of the 

 calyx, and of the leaf venation ; the umbel-like form of the inflorescence, 

 and the dwarfed stem, all re-appear in the numerical proportions given 

 without any essential alterations. Transitional forms were not observed 

 in any experiment." (Italics inserted.) (p. 344.) 



It will be interesting to give in this connection, the actual data 

 of the experiments themselves. 



It is seen from the table on page 295, that the ratios throughout 

 are nearly or quite 3:1. In the two seed experiments, each pod 

 usually produced both kinds of seed. As Mendel says : 



"in well-developed pods which contained on the average six to nine 

 seeds, it often happened that all the seeds were round or all yellow J 

 on the other hand there were never observed more than five wrinkled or 

 five green ones in one pod." (1, p. 344.) 



The net result of Mendel's investigation of the Fo and the F.< 

 generations is expressed as follows : 



"The ratio of 3 to 1, in accordance with which the distribution of the 

 dominant and recessive characters results in the first generation, resolves 

 itself therefore in all experiments, into the ratio of 1 pure dominant ; 

 2 hybrids ; 1 recessive, if the dominant character be differentiated accord- 

 ing to its significance as a hybrid character or as a parental one." {ib., 

 p. 349.) 



In other words, the 75 per cent of plants which show the domi- 

 nant form in the F2 generation were found by Mendel's analysis 

 (i.e., by growing them another year) really to consist of two 

 parts hybrids, which go on splitting In the original ratio of 3:1 ; 

 and one part pure dominants, which continue to breed true as 

 such. 



Mendel summarizes the matter in the following significant 

 sentence : 



"since the members of the first generation (F^) spring directly from 

 the seed of the hybrids (Fj), it is now clear that the hybrids form seeds 

 having one or the other of the two differentiating characters, and of 

 these, one-half develop again the hybrid form, while the other half yields 

 plants which remain constant, and receive the dominant or the recessive 

 characters respectively in equal numbers." (Italics as In original.) (p. 349.) 



