36 MISSOURI AGR. EXP. STA. RESEARCH BULLETIN 49 



The oats variety test of 1919 also showed distinctly the effects 

 of competition. The border rows in this test differed in yield from 

 the interior rows by 12.78 per cent, on the average, and the mean 

 coefficient of competition was 27.67 per cent. Correlations were de- 

 termined for competition and relative yield, date of maturity, and 

 grain-straw ratio. Unfortunately the dates of heading are not avail- 

 able for all varieties in this test. The correlation coefficients are shown 

 in Table 11. 



Again no correlations of statistical significance are found, but 

 the relation of yield and earliness of maturity to competing strength 

 is at least suggestive. There was a tendency for early and high-yielding 

 varieties to profit by competition at the expense of later and lower-yield- 

 ing varieties, but the number of varieties was too small to permit the 

 drawing of positive conclusions. 



The oats strains grown on the same field showed much less strik- 

 ingly the effects of competition. The mean difference in yield be- 

 tween border rows and interior rows in these 15 strains was only 6.50 

 per cent and the mean coefficient of competition only 13.11 per cent. 

 This is undoubtedly accounted for by the fact that the differences be- 

 tween competing strains were so much less than in the oats variety 

 test. When the three strains taxonomically unlike Red Rustproof are 

 eliminated, leaving 12 strains of the same variety, the average devia- 

 tion of border yields from interior yields is reduced to 4.69 per cent 

 and the average coefficient of competition to 8.69 per cent. It is note- 

 worthy that the competition between these strains of the same va- 

 riety is decidedly less than that between different varieties. No sig- 



TABLE 12. CORRELATION OF COMPETITION WITH VARIOUS CHARACTERISTICS IN 



OATS STRAIN TEST 1919. 



Character Mean difference be- Coefficient of correlation 



tween competing with competition 



strains 



nificant correlation was found between these minor effects of compe- 

 tition (for the 15 strains) and the relative time of heading, time of 

 maturity, grain-straw ratio or yield, as is shown in Table 12, though 

 in this case again the early strains and the high-yielding strains showed 

 some tendency to profit by competition. 



