May 8, 1916 



Occurrence of Sterile Spikelets in Wheat 



241 



Table III. — Effect of date of planting on the number of sterile spikelets in 25 spikes of 

 two varieties of wheat on fertilized and on unfertilized soil 



RED WAVE (BEARDLESS) 



Date of planting. 



Total number of 

 spikelets. 



Fertilizer. 



No ferti- 

 lizer. 



Number of sterile 

 spikelets. 



Fertilizer, 



No ferti- 

 lizer. 



Percentage of sterile 

 spikelets. 



Fertilizer. 



No ferti- 

 lizer. 



Sept. 17. 



24. 



Oct. I . . 



IS. 

 22 . 



Average . 



21. 4 

 20. 5 



20. o 



21-5 



21. 3 

 19.7 



17.7 

 18.4 

 20.3 

 18.8 

 19.9 

 20. 9 



2.8 

 2. 2 

 2. 2 

 2. I 

 2. 2 



1-5 



1.6 



20. 7 



19. 



1-7 



13-4 

 II. I 

 II. I 

 10. I 

 10. 6 

 5-4 



10.3 



12. I 



9-7 



10.8 



8.4 



8.4 



5-7 



9-3 



MIRACLE (BEARDED) 



Sept. 



Oct. 



24. 



IS- 



Averao;e. 



10. 4 

 8.5 

 II- 5 

 12. 1 

 10. 9 

 2.8 



9.4 



Table III shows that the number of sterile spikelets per spike varies 

 considerably from the earliest seeding, September 17, to the latest, 

 October 22, but in no regular manner. The latest seeding in every case 

 shows the smallest number of sterile spikelets. This holds true for both 

 varieties and under both soil conditions. If the average is taken of the 

 number of sterile spikelets under the six different dates of seeding, it is 

 found that there are more sterile spikelets where fertilizer was used than 

 where no application was made. This also holds true for both varieties. 

 Expressed as a percentage, the average of sterile spikelets for the different 

 rates of seeding with the beardless variety is 10.3 per cent where ferti- 

 lizer was used and 9.3 per cent on untreated soil. That of the bearded 

 variety was 13.3 per cent of sterile spikelets as an average for the different 

 dates of seeding on treated soil and 9.4 per cent on the untreated. It 

 will be noted that the latest seeding of each variety has as many spikelets 

 as the earliest, and that there are more than twice as many sterile spike- 

 lets in the latter than in the former. This may be partially accounted 

 for b)' the fact that the later plantings did not have a full stand of plants, 

 thus giving the individual wheat plant more space. This explanation 

 is in accord with results obtained under the different methods of seeding 

 (see Table I) — that is, that fewer sterile spikelets were found in the 

 thinner plantings. 



