STUDIES ON OAT BREEDING. 12$ 



Table 6 shows the variation constants 14 for the 1915 plots 

 based upon the observed yields. The varieties are arranged in 

 the order of their coefficients of variation. 



The following points may be noted from this table : 



1. The standard deviation ranges from 2.73 bushels per acre 

 to 9.69 bushels. This is a somewhat smaller range than has 

 usually been observed for . a similar number of commercial 

 varieties. 



2. The coefficient of variation is to be regarded as the 

 better measure of variability in cases like this. This constant 

 varies from 3.52 per cent to 12.47 per cent with an average 

 of 7.86. 



3. With regard to the coefficient of variation, the table falls 

 into two parts. The first five varieties have a coefficient of 

 less than 6 per cent and may be regarded as showing a low 

 degree of variability. The remaining lines have a coefficient 

 of from 8.5 to 12.5 per cent and thus have a medium variability. 

 Two of the higher yielding lines, viz., 340 and 357, are included 

 in the first part of the table. Insofar as the evidence goes 

 these varieties are to be regarded as more desirable than those 

 with an equal yield, but greater variability. 



Too much reliance should not be placed upon these constants 

 which are derived from a relatively small number of plots and 

 for one year only. They may, however, serve to help point out 

 the desirability of certain lines which for other reasons are 

 believed to excell in quality. 



Mean Production eor the Three Years. 



The 12 pure lines grown in 19 15 have now been tested for 

 three years. While the tests have not included the same num- 

 ber of plots each year, the number of plots and other condi- 

 tions were nearly the same for each line in each year. There- 

 fore, the yields in individual years ought to afford some expres- 

 sion of the relative merits of the different lines under the 

 conditions of that year. Although the data are not all that 

 could be desired, some information can be obtained by averag- 



"The meaning and the method of determining these constants and 

 their probable errors has been given by Surface and Barber (Loc. cif.) 



