122 



BREEDING CROP PLANTS 



In the above table mean error is used instead of probable error 

 (mean error X 0.6745 = probable error). The means, both in the 

 minus and in the plus direction, show no effect of continuous 

 selection. 



In 1914 Hutcheson published the results of 13 years of con- 

 tinuous selection in wheat carried on at the Minnesota Station. 

 Here again no significant effects of selection are found. Table XXI 

 presents a comparison of the yields for the first five-year period 

 with those of the last five-year period. 



TABLE XXI. COMPARISON OF AVERAGE YIELD PER PLANT IN GRAMS OF 



FIRST FIVE-YEAR PERIOD WITH THOSE OF LAST FIVE-YEAR 



PERIOD IN CONTINUOUS SELECTION OF WHEAT 



Average . . . 



2.06 



1.97 



In the tobacco breeding work of the Connecticut Experiment 

 Station (Hayes, 1913b) the inheritance of number of leaves was 



TABLE XXII. NUMBER OF LEAVES OF SUMATRA, 403; BROADLEAF, 401; 

 HAVANA, 402; AND CUBAN, 405 



