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MISSOURI AGR. EXP. STA. RESEARCH BULLETIN 49 



son and Red Rustproof check plots, and that between adjacent strains 

 of the same variety, 58 cases of competition between different strains 

 of Kherson and Red Rustproof remain. In these the mean yield of 

 border rows differed from that of interior rows by 14.06 per cent and 

 the mean coefficient of competition was 30.86 per cent. In every case 

 the Kherson strain outyielded the adjacent Red Rustproof strain, 

 though the advantage in yield varied from 27 per cent to 165 per cent. 

 Similarly, the Kherson strains were earlier in maturity and heading, 

 and taller, in each case, but with a rather wide variation in the extent 

 of their advantage. In all but three of the 58 cases the Kherson strains 

 showed a greater advantage in yield over the adjacent Red Rustproof 

 strains in their competing border rows than in their interior rows. 

 The average yields of the 30 Red Rustproof strains and 29 Kherson 

 strains, in interior rows and competing border rows, were as follows : 



The Kherson strains outyielded the Red Rustproof strains by 70 

 per cent in their interior rows and by 122 per cent in their competing 

 border rows. The coefficients of competition, like the relative yield, 

 earliness, and height, varied rather widely. Correlations were there- 

 fore measured for the advantage of the Kherson strain of each adjacent 

 pair in competition and its advantages in yield, date of heading, date 

 of maturity, and height. The coefficient of correlation in each case 

 was insignificant. 



Discussion. In each of these tests, with the exception of the 

 oats strain test of 1919, in which most of the strains compared be- 

 longed to the same variety, border rows differed from interior rows in 

 yield by more than 10 per cent. Differences as great as this will change 

 materially the relative standing of varieties. In single-row tests the 

 effects of competition would be considerably greater than in these 

 border rows, affected by competition on only one side. Furthermore, 

 in each test, of course, there were many cases in which competition 

 caused much larger differences in yield than are shown by average 

 figures. 



