SELECTION IN PLANT BREEDING IQ7 
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Fic, 2. INHERITED ABNORMALITIES APPEARING IN Maizp, All pollen from these 
plants and from their normal sister plants must be prevented from maturing. 
which bear their ears high and stalks which bear them low, stalks with 
long and stalks with short ear shanks, stalks with different leaf mark- 
ings and with notably different tendencies to produce suckers. Differ- 
ences are everywhere present even in the ears, as is shown in the accom- 
panying photograph (Fig. 1). A large number of these differences are 
simply fluctuations produced by the environment and are not inherited. 
The obscuration of heritable variations by the fluctuations and the mixed 
condition of the natural types makes it a difficult task to isolate the most 
productive types. Many variations of technique have been proposed 
