168 EXPERIMENT STATION. [Jan. 



PLANT BREEDING STUDIES IN PEAS. 



BY F. A. WAUGII AND J. K. SHAW. 



The department of horticulture has had various plant-breeding 

 investigations under way for several years. These have in- 

 cluded studies in variation, correlation and heredity in peas. 

 Two reports on this general subject have already been made.^ 

 The year 1909 has enabled us to collect a large amount of ad- 

 ditional data, the most interesting of which are here presented. 



Character of Variation in Peas. 

 At the beginning of these experiments, a commercial strain of 

 Nott's Excelsior was made the basis of study. The same strain 

 has been maintained till the present time, so that we may now 

 discover whether or not the range and character of variation have 

 changed. In looking over the figures, it must be remembered 

 that absolute figures have been greatly aifected by the nature of 

 the growing season. Thus, in 1908, with severe drought on 

 naturally dry land, the size of plants and all other measurements 

 fell very low. With this in mind we may profitably study the 

 following table, giving statistics of variation for three years : — 



' Massachusetts experiment station report, 20, p. 171 (1908), and Massachusetts experiment 

 station report, 21, p. 107 (1909). 



