90 PLANT HYBRIDIZATION BEFORE MENDEL 



season of maturity were the same, although the one was a very 

 early and the other a very late variety. 



"I had in this experiment, a striking instance of the stimulative effects 

 of crossing the breeds ; for the smallest variety, whose height rarely ex- 

 ceeded two feet, was increased to six feet, whilst the height of the large 

 and luxuriant kind was very little diminished." {ib., p. 2CK).) 



Despite the fact that Focke says (Pflanzenmischlinge, p. 436) 

 "he has contributed more to our knowledge of hybrids than any 

 other writer during the first half of the nineteenth century" — a 

 statement which may, of course, perhaps be seriously disputed — 

 it is nevertheless true that Knight was the first experimenter to 

 apply the science of plant hybridization to plant improvement. 

 Although endowed with scientific insight of no mean order, his 

 chief claim to recognition as a plant breeder lies in the fact that 

 he possessed a practical instinct for getting improved orchard 

 fruits into existence. Knight remarked upon the fact that it had 

 long since been ascertained by physiologists that, since the seed- 

 coats, or membranes which cover the cotyledons of the seed, to- 

 gether with the receptacles which contain them, are visible for 

 some time before the blossoms reach their full growth, therefore 

 the existence of such structures is independent of the influence 

 of the pollen. The fact is also that the seed-coats and the fruit 

 of some species reach nearly if not completely their full growth, 

 when the pollen has been entirely withheld ; therefore, from these 

 and other observations, he concludes: 



"it has been inferred that neither the external cover of the seeds, nor 

 the form, taste or flavor of fruits, are affected by the influence of the 

 pollen of a plant of a different variety or species." (3f, p. 377.) 



There exists, however, he continues, some diflFerence of opinion 

 in this regard, the experiments of Goss appearing to support the 

 opinion that : 



"The color of the seed-coat, at least, may be changed by the influence 

 of the pollen of a variety of different character." {ib., p. 378.) 



The account which Knight then gives of his experiments is as 

 follows : 



When the pollen of a grey-seeded pea was used to fertilize the flowers 

 of a white variety, "no change whatever took place in the form, or color, 

 or size of the seed ; all were white, and externally quite similar to others 

 which had been produced by the unmutilated blossoms of the same plant." 

 {lb., p. 379-) 



