LUTHER BURBANK 



Making use of the principles I have found suc- 

 cessful with other plants, my first thought was to 

 hybridize the brownish white berry with some 

 allied species in order to bring out the tendency 

 to variation and thus afford material for selective 

 breeding. 



CREATING A REALLY WHITE BLACKBERRY 



The first cross effected was with the Lawton 

 blackberry, using pollen from the Lawton berry. 

 The Lawton is known to be very prepotent; it is 

 of a very fixed race and will reproduce itself 

 from seed almost exactly, which is not true of 

 most cultivated fruits. Its seedlings often seem 

 uninfluenced when grown from seed pollenated 

 by other varieties. 



It was to be expected, therefore, that the cross 

 between the Lawton and the "white" berry would 

 result in producing all black stock closely resem- 

 bling the Lawton; and such was indeed the result. 



But the Lawton also imparts its good qualities 

 to hybrids when its pollen is used to fertilize the 1 

 flowers of other varieties. As a general rule it is 

 my experience that it makes no difference which 

 way a cross is effected between two species of 

 plants. The pollen conveys the hereditary tend- 

 encies actively, and so-called reciprocal crosses 

 usually produce seedlings of the same character. 



That is to say, it usually seems to make no 



[42] 



