g& Plant Genetics 



Mendelizing characters are known, and these cases may 

 be used as illustrations of non-Mendelian inheritance. 



In connection with his work on Mirabilis Correns (2) 

 uncovered the following situation. The ordinary race of 

 Mirabilis has pure green leaves, but one was discovered 

 with variegated leaves. The leaves were green for the 

 most part but showed irregular white patches, an 

 examination showing that in the white areas the chloro- 

 plasts were more or less bleached out. Correns 

 named this race the albomaculata type, a name which 

 appears frequently in the hterature of genetics. 



The behavior in this type of inheritance was as 

 follows. When self-fertilized it bred true, but the pollen 

 from albomaculata, when used in crosses, behaved as if 

 it had come from normal green plants. For example, 

 Correns took pollen from an albomaculata plant and 

 used it to pollinate a normal green plant. The indi- 

 viduals of the Fi generation were all normal green, 

 and the natural MendeUan conclusion would be that 

 albomaculata is a recessive condition appearing when 

 the determiner for normal green leaves is lacking. But 

 when the Fj generation was inbred the progeny con- 

 tinued to be normal green generation after generation. 

 If albomaculata pollen had introduced a recessive 

 character into the hybrid, this would have reappeared 

 in the later generations, but it did not reappear. The 

 obvious conclusion was that albomaculata pollen is just 

 like the pollen of the normal green plants and that all 

 pollen carried the determiner for the development of 

 normal green plants. 



This raised the question as to the result from using 

 pollen of normal green plants to polUnate albomaculata. 



