144 SOUTHERN FIELD CROPS 



words, of the seed showing dominant qualities some are pure 

 dominants and some are mixed, though having the same appear- 

 ance as the pure dominants. 



131. Practical results. — Practical application may be 

 made of the somewhat technical statements in the last few 

 paragraphs in the following way, and in other operations 

 in plant breeding : — 



(1) After crossing pollen of a pure yellow variety on 

 silks of a pure white variety, say in 1910, practically all 

 of the grains of the current cross in 1910 may be expected 

 to be yellow or yellowish ; all the pure white grains f oimd 

 in the second generation among the descendants of this 

 cross may be considered as pure-bred so far as concerns 

 color, and these white grains may be expected in all future 

 years to produce only white grains. 



(2) After crossing pollen of a pure white variety on 

 silks of a pure red variety, all the grains of that current 

 cross will be red (because the hull of the grain is furnished 

 by the mother parent, uninfluenced by the pollen used in 

 the current cross) ; when these red grains are subsequently 

 planted, the crop will contain a majority of red grains, 

 most of which will be impure, as shown by their descend- 

 ants, bearing both red and white grains. 



On the other hand, the white grains, found in the second 

 generation in smaller number among the red grains, are 

 pure; and when these white kernels are planted, their 

 offspring will consist entirely of white kernels. 



132. Relative value of top and bottom ears for planting. 

 — When there is any considerable inequality in size be- 

 tween two ears growing on one plant, the upper ear is 

 generally the larger. 



