82 EXPERIiSIEXT STATION. [Jan. 



HEREDITY, CORRELATION AND VARIATION 

 IN GARDEN PEAS. 



J. K. SHAW. 



During the past fivo years a ]^ortion of lli(> tinio devoted to 

 experimental work in the department of horticulture has been 

 directed toward the scdution of problems of plant breeding, the 

 work being done mostly with garden peas. Certain phases of 

 this work have been ])reviously reported.^ It is felt that suiii- 

 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 develojnnent along lines of correlation and 

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

 or disi)rove 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 sniHcieut data had been accumu- 

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

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

 sented. This ex])lanation may make clear the seeming lack of 

 definiteness and direction of the work towards the results ob- 

 tained. 



The work began in 1007 with a study of variation in a com- 

 mercial lot of Excelsior peas, and in 1008 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 wriid\led ])ea growing usually about 40 centimeters in 

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

 considerably grown by gardeners in Xew England. 



The principal characters dealt with have been vine length and 

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



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



