64 H. H. Love and C. E. Leighty 



more crowded conditions than were those of other years, with the result 

 that the culms were not so tall and the number of spikelets, number of 

 kernels, and yield were all less, but the kernels were practically as large 

 as, or larger than, in any other year except 1910. 



It seems that when development is arrested by environmental conditions, 

 yield is reduced by a reduction in number of kernels per plant, per culm, 

 and per spikelet, rather than in average weight of kernels and in number 

 of spikelets produced. 



Coupled with the less plant development and yield of 1908 and 1910, 

 there is less variability, as indicated by the standard deviation, in number 

 of culms, total and average number of kernels, total yield, average number 

 of spikelets, and average number of kernels per spikelet. In average 

 weight of kernels, however, there is greater variabihty in 1908 and 1910. 



The relation of these correlation factors to oat production 



The value of correlation in breeding and development work has been 

 pointed out from time to time. When certain characters are associated 

 to a high degree, it is possible to so select plants as to increase one character 

 and at the same time increase another because of this correlation. 



The results of these studies are of importance in the breeding and pro- 

 duction of oats. In the begirming of this paper the question was raised 

 whether the tallest plants produce the most grain. Data have been 

 presented to show that there is a high correlation between these characters 

 so far as this pure line is concerned. This indicates that the growth 

 factors influence the developing plants in such a way that tall plants and 

 high yield of grain are found together. 



If these correlations represent the truth, on the whole, for oats during 

 the years represented, and if it were desired to save seed from a field, it 

 would be more advantageous to save seed from the tallest plants; for in 

 so doing one would naturally be selecting seed from the heaviest producers 

 as well. 



It is also interesting and important to note that as the plants tend to 

 increase in height, the number of culms also increases. At the same 

 time it is shown also that the average yield per culm increases as the height 

 of plant increases. This shows the possibility of obtaining plants with 

 many culms that may be high in production, which is rather important. 



