Variation and Correlation of Oats — Part II 143 



is therefore produced by plants growing in hills as compared with those 

 grown m drills, and the variability in this character is also somewhat 

 greater for plants grown in hills. 



For average weight of kernels per plant in milligrams, the means are 

 a little greater for series 1221 and series 1259 than for series 1219 and series 

 1257, respectively. The standard deviations here are higher for series 

 1219 and series 1257 than for their corresponding series. Larger kernels 

 are therefore produced by plants grown in hills than by plants grown in 

 drills, but the difference is not so great as that which occurs in any other 

 character studied, with the exception of height of plant. The varia- 

 bility, however, in average kernel weight is greater in plants grown in 

 drills, this being probably due to the fact that the kernels on the isolated 

 plants have a more uniform opportunity to develop than do those in more 

 crowded positions. 



The results obtained for both varieties dealt with are identical in char- 

 acter. 



Regarding all characters here studied of the plants grown under these 

 two conditions, the means are greater in every case for the plants grown in 

 hills than for those grown in drills. It is evident that the full develop- 

 ment allowed to plants in more isolated positions is not permitted in more 

 crowded positions. The least difference in the means occurs in average 

 height of plant and average weight of kernels per plant. The crowded 

 conditions do not hinder the growth in height and the development of the 

 kernels so much as they hinder the increase in yield, number of kernels 

 and of spikelets, and weight of straw. 



There is greater variability in average yield of culm per plant and average 

 weight of straw per culm of plant with plants grown in hills than with 

 those grown in drills, but much less variability in average height of plant 

 and average weight of kernels. The variability in number of kernels and 

 number of spikelets is slightly greater for the plants grown in hills. The 

 standard deviation is here taken as the index of variability. 



Correlations 



The correlations of the two varieties as grown in hills and in drills are 

 given in Table 8: 



