68 H. H. Love and C. E. Leighty 



correlations into consideration, it is seen that yield may be increased by 

 selecting the taller plants, which will at the same time have a high average 

 number of spikelets per plant associated with a high average number of 

 kernels per spikelet. 



These correlations indicate that it is possible to use certain vegetative 

 characters as a basis for selection when improvement work is to be con- 

 sidered. If from a mixed population tall plants, with a high average 

 number of spikelets per head and with these spikelets well filled with 

 kernels, are selected, one "^nll be selecting plants that will on the whole 

 be high in production. 



More evidence is also given in regard to the question of light and 

 heavy seed. The results seem to indicate that for certain years it may 

 be reasonable to expect heavy seed to give a large yield, while for other 

 years the reverse may be the case. 



SUMMARY 



From the data herein presented the following conclusions may be 

 drawn : 



1. Environmental conditions such as exist in different years cause changes 

 in the means. Conditions that generally result in reduction of plant 

 jdeld also result in reduction of height, number of kernels, and number 

 of culms, but in increase in size of kernels. 



2. Yield is reduced by decrease in number of kernels produced, rather 

 than by decrease in their size. 



3. Variability decreases with decrease in the means. 



4. Correlations are more or less responsive to environmental conditions, 

 and may be divided into fluctuating and stable, according to their behavior 

 under differing enviromnents. 



5. There are high, positive, and fairly stable correlations between 

 average height of plant and (a) total and average yield, (b) total and 

 average number of kernels produced, (c) average number of spikelets 

 per culm; the correlations between average height of plant and (d) average 

 weight of kernels, (e) number of culms, are fluctuating, being high or low 

 on occasion. 



6. There are high, positive, and stable correlations between total yield 

 and (a) culm yield, (b) total and average kernel production, (c) spikelet 

 production, (d) culm production. 



