Aug. 2, 1920 



Development of Barley Kernels in Clipped Spikes 469 



spikes never contain as much water as those from normal spikes. This 

 is in full accord with the results obtained at St. Paul, but the greater 

 uniformity of the development at Aberdeen emphasizes the difference 

 of behavior by removing the confusion of abnormal samples. 



In a preliminary experiment conducted at Arlington Farm, Va., the 

 relation of the length of the awn to the weight of kernel was studied. 

 The awns increase in length from the base of the spike for about one- 

 third the distance to the tip. The spikelets on the upper two-thirds of 



JLftr /ii/G. 



Fig. ij.— Graph showing water in kernels of Hannchen barley from normal and clipped spikes. 



the spike exhibit a gradual decrease in awn length, the shorter awn 

 occurring on the apical spikelet. 



Figure 13 shows a composite spike resulting from the average of the 

 data obtained. In this case the node numbers include both sides of 

 the spike and are alternate. The weights used are the average of the 

 kernels at two adjacent nodes. It will be seen in the figure that the 

 greatest difference in weight results from the removal of the longest 

 awns. The removal of the short awns near the tip affects the yield 

 only slightly. If the curve of the clipped kernels is taken as showing 

 that the normal peak due to nutrition occurs at about node 9 or 10, 

 the greater length of awn on node 6 is seen to move the peak of the 



