82 EXPERIMENT STATION. [Jan. 



HEREDITY, CORRELATION AND VARIATION 

 IN GARDEN PEAS. 



J. K. SHAW. 



Duririii,' the ])ast five years a jiortion of the time devoted to 

 experimental work in the department of hortienltnre luis been 

 directed toward the solution of problems of plant breeding, the 

 work being done mostly with garden peas. Certain })hases of 

 this work have been ])revionsly reported.^ It is felt that suffi- 

 cient progress has now been made to warrant a more complete 

 and definite statement of results attained. 



The original purpose of the work was a study of variation, 

 and the subsequent development along lines of correlation and 

 inheritance has been a gradual one, with no endeavor to prove 

 or disprove any of the current theories bearing on these ques- 

 tions, but with an earnest purpose to secure facts. After five 

 seasons' work it was felt that sufficient data had been accumu- 

 lated to alford a basis for a few deductions, and following last 

 season's crop, results have been worked over and are here pre- 

 sented. This explanation may make clear the seeming lack of 

 definiteness and direction of the work towards the results ob- 

 tained. 



The work began in 1907 with a study of variation in a com- 

 mercial lot of Excelsior peas, and in 1908 a lot of First of All 

 was added ; since then various commercial sorts have received 

 more or less attention. The most important results have been 

 reached by means of the Excelsior variety. This is a second 

 early wrinkhnl pea growing usually about 40 centimeters in 

 length and beariiig about four pods to the vine. It is a sort 

 considerably grown by gardeners in New England. 



The principal characters dealt with have been vine length and 

 pods per vine. The first gives a good measure of the vegetative 



' Reports, Massachusetts Experiment Station, 20, p. 171; 21, p. 167; 22 Part I., p. 168. 



