LUTHER BURBANK 



lacked this quality or had it mixed with the unde- 

 sirable quality. 



Not So Simple in Actual Work 



But, unfortunately, the simplicity of the 

 formula vanishes as soon as we come to consider 

 a second, and third, and fourth pair of unit 

 characters. 



Here also the formula has been worked out 

 in mathematical terms; and it appears that when 

 several characters are involved, we at once come 

 to deal with numbers that are no longer easy 

 to keep track of. Moreover, the various pairs 

 of unit characters may be juggled in an almost 

 infinite variety of ways. 



We are seeking, for example, (1) an early- 

 bearing cherry of (2) good size, (3) fine color, 

 (4) sweet taste, and (5) good keeping quality. 



Suppose, for the sake of argument, we consider 

 each of these to constitute, as contrasted with the 

 opposite condition, one member of a pair of unit 

 characters. 



Then it appears that, according to the theory 

 of chances which underlies the interpretation of 

 the Mendelian formula, the probability that any 

 given combination of these five qualities will 

 appear in an individual specimen of the progeny 

 of the hybrid generation is only one in about five 

 hundred. 



[222] 



