240 



Journal of Agricultural Research 



Vol. VI, No. 6 



Table II. — Arrangement of bearded and beardless varieties of wheat with reference to the 



percentage of sterile spikelets 



Percentage of barren spikelets. 



II to 15 



i5to 17 



17 to 19 



19 to 21 



21 to 23 



23 to 25 



25 to 27 



27 to 29 



29 to 31 



Total 



Total 

 number of 

 varieties. 



12 

 27 

 32 

 30 

 31 

 25 

 17 



5 



Number of 

 beardless 

 varieties. 



12 



19 

 18 



14 



7 



80 



Number of 

 bearded 

 varieties. 



o 

 8 

 14 

 16 

 24 

 23 

 17 

 5 



108 



Percentage of each class 

 to total number of — 



Beardless 



varieties. 



10. O 

 15-0 

 23-7 

 22. S 



17-5 

 8.7 



2-5 



o 

 o 



Bearded 

 varieties. 



7-4 

 12. 9 

 14.8 



22. 2 

 21. 2 

 15-7 



5-5 



Table II shows that the bearded varieties as a class have a higher 

 percentage of sterile spikelets than the beardless wheats. There are 20 

 of the 80 varieties of beardless wheat which have more than 15 per cent 

 of sterile spikelets, while not a single variety of bearded wheat has less 

 than 17 per cent of sterile spikelets. Of the 108 bearded varieties 45 

 have not less than 25 per cent of sterile spikelets. Only two of the 80 

 beardless varieties have 25 per cent of sterile spikelets. The average 

 percentage of sterile spikelets for all the beardless varieties is 17.8; for 

 the bearded, 24.1; a difference of 6.1 per cent in favor of the beardless 

 varieties. The individual variety having the lowest percentage, 11.5, 

 was beardless, while the variety having the highest percentage of sterile 

 spikelets, 36.7, was bearded. All of the varieties Vv^hich are mentioned 

 above were sown under like conditions of soil preparation and fertilization 

 and planted at the same time. 



EFFECT OF TIME OF SEEDING ON STERILITY 



The next step was to determine the effect of time of seeding and of soil 

 treatment on the frequency of sterile spikelets. As it happened, an 

 experiment was already under way on different dates of sowing wheat, 

 including two varieties, one bearded and the other beardless, on both 

 fertilized and unfertilized soil. These plants were in hills 6 inches apart 

 each way. In the manner followed above, the total number of spikelets 

 and that of sterile spikelets per spike were combined, and the average 

 was determined for the two varieties under different dates of planting 

 on both treated and untreated soil (Table III). 



