42 



H. H. Love and C. E. Leighty 



yield is made up of the total number of kernels, such a condition is to 

 be expected unless excessive variation in size of kernels should exist; 

 which is not the case, as kernel weight is one of the least variable characters. 

 The higher correlation of total yield with total number of kernels than 

 with average number of kernels per culm results from the process of 

 averaging, since there are a number of low-producing culms whose 

 results affect the average yield per culm for many of the plants. 



The correlation between total yield of plant and average weight of 

 kernels per plant (Figs. 35, 36, 37), determined for three years, varies 

 from .035±.034 for 1910 to .220±.032 for 1912. This correlation is 

 fluctuating, and never very high, which indicates that large kernels are 

 obtained from plants either low or high in yield in about the same pro- 

 portions. In other words, the kernels produced by plants whether of 

 large or small yield do not vary considerably in average size. 



The correlation between total yield of plant and average number of 

 spikelets per culm per plant (Figs. 38, 39, 40), determined for three years. 



*0- 



.1- 



.2- 



.3- 



.4- 



.5- 



.6- 



.7- .8 



.8- .9 



.9-1.0 

 1.0-1.1 

 1.1-1.2 

 1.2-1.3 

 1.3-1.4 

 1.4-1.5 

 1.5-1.6 

 1.6-1.7 

 1.7-1.8 



'-' 



lO 



o 



lO 



o 



^ 



g 



CO 



^ 





25 



21 



4 

















8 



83 



72 



10 



78 



4 

 4 



2 

 6- 















9 



94 



40 



5 



1 













1 



26 



82 



8 



1 















3 



40 

 15 



1 

 1 



40 

 39 



11 

 6 

 3 



2 



1 



4 

 15 

 14 



6 

 6 

 6 



1 

 1 

 1 



1 



1 

 3 

 1 

 6 



1 

 1 



2 



1 



2 

 2 



1 

 1 



1 



1 



33 186 215 187 123 56 14 



50 



107 



160 



149 



118 



88 



69 



27 



16 



10 



16 



4 



2 



4 



1 



2 







2 



825 



Fig. 38. — Total yield of culm in grams, subject 



Average number of spikelets per culm, relative. 

 Coefficient of correlation = .879 ± .005 



1908 



* Since, as before noted, the data were taken on culms this year, the classes for yield differ from those 

 Oi" the other years. 



