RED-CLOVEB SEED PRODUCTION. 



25 



RELATIVE EFFICIENCY OF BRUSHES WHEN THE CLOVER HEADS WERE STRUCK 



VERTICALLY. 



In order to test the efficiency of brushes in promoting cross-pollina- 

 tion by carrying pollen from one plant to another on the bristles of 

 the brushes, experiments were conducted at Ames, Iowa, in the 

 summer of 1911 on plats 13 to 20 with different pairs of brushes. A 

 vertical stroke on each of three mornings, three days apart, was 

 given. The plats were 4 feet square. At maturity all heads from 

 each plat were collected, kept separate, and later thrashed. 



The experiments on plats 21 to 28 were the same in all respects, 

 except that one treatment when the flowers were in early bloom, 

 instead of three treatments, was given each plat. Plats 9 and 10 

 were used as checks. The results are presented in Table IX. 



Table IX. — Average seed yield per head obtained when clover heads were struck vertically 

 with different types of brushes at Ames, Iowa, in 1911 . 



Brush used. 



Strokes 

 per 

 treat- 

 ment. 



Plats given three treat- 

 ments. 



Plats given a single treat- 

 ment. 



Plat 

 No. 



Heads 

 worked. 



Seeds per 

 head. 



Plat 

 No. 



Heads 

 worked. 



Seeds per 

 head. 



Check 





9 

 10 

 13 

 14 

 15 

 16 

 17 

 18 

 19 

 20 



532 

 470 

 366 

 490 

 440 

 521 

 416 

 476 

 510 

 462 



55.4 

 50.9 

 37.0 

 42.0 

 42.1 

 45.3 

 39.3 

 37.7 

 41.8 

 44.7 



9 

 10 

 21 

 22 

 23 

 24 

 25 

 26 

 27 

 28 



532 

 470 

 442 

 440 

 420 

 415 

 380 

 400 

 430 

 436 



55. 4 



Do 





50.9 



B 





46.8 



A 



33.8 



E.... 



45.0 





38 9 



F 



54.5 



T) 



45.9 



Cx 



48.1 



H 



49.0 







Table IX shows that with the exception of plat 25 the treatment 

 considerably reduced the yield below that of the lowest yielding check 

 plat. The results of the treated plats 13 to 20, inclusive, taken as a 

 whole show a decrease of four seeds per head less than the yield of 

 plats 21 to 28, inclusive. This may be accounted for by the fact that 

 plats 13 to 20, inclusive, received two more treatments with the 

 brushes than plats 21 to 28, inclusive, and were therefore subject to 

 more injury from the bristles of the brushes. It will be seen from 

 these experiments that the vertical strokes with the brushes proved no 

 more efficient than the horizontal strokes in the production of seed. 



RELATIVE EFFICIENCY OF BRUSHES WHEN PRESSED TOGETHER BELOW THE CLOVER 

 HEADS AND PULLED UPWARD. 



Experiments were conducted in the summer of 1911, at Ames, Iowa, 

 to determine the efficiency of pressing a pair of brushes together below 

 the clover heads and pulling them upward with considerable force, 

 but still not enough to break off the heads. The plats were 4 by 4 

 feet in size. Pair A of the brushes was used. Three treatments 



