5o Plant Genetics 



so that the hybrid breeds true to its intermediate 

 character. 



Another explanation of pure-breeding hybrids devel- 

 ops from the mathematical possibilities of chance mating 

 when the character in question is due to numerous 

 separate factors. Without going into the details it 

 may be said that in such a case the conclusion is reached 

 that the intermediate hybrids must of mathematical 

 necessity go on producing intermediates with but a 

 remote chance of giving back either of the extreme parent 

 types. 



In these various ways the Mendelians explain away 

 pure-breeding hybrids. In doing so they discard a 

 great deal of recorded data which seem to them un- 

 substantiated. A definite statement of the situation may 

 be obtained from a paper by EAST (5), published in 1910. 



It is believed by many that there are kinds of inheritances 

 other than Mendelian; that is, inheritance in which no segrega- 

 tion occurs. Far be it from me to deny this. / simply slate 

 the fact that there are no exact data extant proving other kinds of 

 inheritance. Such data may be found, but it is useless to specu- 

 late upon other laws without such evidence. There are several 

 cases in which either new characters that breed true or blended char- 

 acters that breed true appear to have been formed, but they have 

 not been studied with sufficient care for analysis of their mode of 

 inheritance to be accurate and final. 



In 1913 EMERSON and EAST (6), in a joint paper, 

 stated that there are on record only two indisputable 

 cases of non-Mendelian characters. These will be 

 considered later in their proper connection. Neither of 

 them, however, is a case of pure-breeding intermediate 

 hybrids. 



