May 8, 1916 



Occurrence of Sterile Spikelets in Wheat 



249 



Table XII. — Correlation between the percentage of sterile spikelets per plant and the average 

 number of spikelets per spike per plant in wheat ^ 



' r — — o.iS24±o-0375' 



Table XIII. — Variation constants in wheat 



Coefficient of correla- 

 tion. 



Sterile spikelets and number of tillers per plant 



Sterile spikelets and yield of grain per plant mgm . 



Sterile spikelets and average yield of grain per spike mgm. , 



Sterile spikelets and average length of culm per plant cm. 



Sterile spikelets and average length of spike cm. , 



Sterile spikelets and weight of kernel per plant mgm. . 



Sterile spikelets and the average number of spikelets per spike, 

 per plant 



-o. o75±o. 038 



- .3o6± .035 



- .S89± 



- .448± 



- •45i± 



- . 421 ± 



024 

 031 



031 

 032 



- . i52± .037 



SUMMARY 



(i) The number of sterile spikelets per spike in wheat is directly 

 affected by the rate of seeding or the spacing of the plants. The more 

 space allowed each plant the smaller the number of sterile spikelets on 

 each spike. 



(2) The bearded varieties of wheat as a class have a higher percentage 

 of sterile spikelets than the beardless varieties. Of the 188 varieties 



