CONTHIBUTIONS TO THE GENETICS OF PISUM 353 



Iiagunda-2 and 



Ragundd-S. Probal)Iy quite identical willi Ragiiiula-I . Rayuiula-l, 

 -2 and -3 origin rroni and old pedigree, raised several years ago. The 

 three lines mentioned are new pedigrees, raised from the old one a 

 few years before the crosses were made. 



Rapid. A line of this sort, obtained in 1913 from northmost 

 Sweden. Comparatively long internodes, thin stem, number ot sterile 

 nodes 5 — 10. 



0254. Svalöf Concordia pea, a pedigree sort from an English 

 mixed sort of pea. Comparatively short internodes, thick stem, num- 

 ber of sterile nodes 13 — 19. 



Stensärt. A common commercial sort, cultivated for green har- 

 vest. Long internodes, thick stem and a large number of sterile 

 nodes. (No strict measurings were made on this sort, used as father 

 in one cross). 



The following crosses between the lines described have been 

 studied: 



Cross I: Ragiinda-1 X 0234, F-, in 1919 

 » II: Ragiinda-2 X 023 A, F, in 1919 

 III: Ragunda-3 X 023A, F. in 1920 

 » IV: Rapid X Stensärt, F. in 1920. 



In the following crosses I and II will be dealt with together, the 

 two others separately. Fi of the crosses Ragunda X 023i was re- 

 markably high, widely transgreeding both parents in respect to plant 

 highness. 



RESULTS. 



LENGTH OF INTERNODES. 



The numbers obtained in respect to this character are given in 

 table I. If only Fo is considered, the monohybrid segregation is 

 evident. In crosses I -|- II there is a minimum in the 46 — 50 class, 

 and if the 8 individuals in this class are not calculated, the material 

 segregates in 434 with long and 134 with short internodes, correspon- 

 ding — after 3 : 1 ratio — to an expected segregation in 426 : 142, 

 and thus difference, divided by standard error = D/m ^ 8,oo/lO,i6 = 0,79. 

 Of the two minimum classes, viz. 36 — 40 and 41 — 45, in cross III 

 the former may be calculated as short and the latter as long inter- 

 nodes. Then there are 386 long and 136 short, expected 391,5 and 

 130,5 and D/m = 5,5/9,86 = 0,56. So it is evident that in all three 



