I'. M(1N,M;1'. - KTUDl': IJIOMKlIiinlE DKS (.ISAINKS |)| CKNUK liliASSlCA. 



BIOMETRICAL STUDY OF THE SEEDS OF THE GENUS BRASSICA 



SUMMAHV 



The foregoing paper i:^ an altempl lo a Hiomclrical classificalion ol' 8 soris 

 uf " Brassica ", preliminan lo a sliuly uf \Mrialiilily and lieredily in Ihese plants. 



Tlie frequency polygons rclaling- to tlie secdsdiamelers in lengih of niilli 

 nielres, and lo llie wcighis of a luindred seeds in cgrnis are given above under 

 Ihe iieading of eacli form' s number. Togelher w itb Uic frcqucncy polygons. 

 Ihc lollowing numerical dala iiave been worUed oui : 



The " mean vahtr" of the measured quanlily : cilhcr tiic mcan dianiclcr 

 Dm or Ihe mean weighl Pm. 



Pearsons " Slaiidard ilnrlulian " either l'or Ihc (liami'lcis, ■7(1, or loi' llic 

 weighls. (7 p. 



Johannsen's "Coefficient uf uicun ruriatlon", ^'d l'or llic diainclers. \'p l'or 

 llie weighls. This eoel'firicnl, wliicli lias been wDi'kcd mil nccdrding bi lh<" 

 formula : 



gives Ihe mean per-cenl \alue of r; l'or Ihe fiequeni-y polygons. Il is very im- 

 porlanl, as il does not dépend on Ihe absolule value of M. 



.lohnnnsen's " Coefficient of latéral asymnH'trj/ " S This C.oeflicienl gi\ esa 

 numerical value ol' Ihe curves laleral devialion from Ihe normal frequency curve. 



Johannsen's "lî.rre^s", E. This Coefficienl gives a numerical value of 

 Ihe curve's veiiical devialion from the normal frequency polygon. This excess 

 bas a négative value in Ihe ease of bimodal curves. Sucb négative values hâve 

 been found liei'e in Ihe i'ollowiiig instances : 



N" 1.3.039 and M" 1.4.040. Bimodal curves for Ihc -eeds' diameler. In 

 bolh Ihese cases, the " nnii/c " uf cach separale pln>notypc lias been wcirkcd 

 oui accoi'ding to Pearsons l'ormula : 



Mo.^r..Med 'JM. 



\»^ 1.5. 041 (Diamelers), 1.6.042, 1.7.043, 2. 2.044 (Weighls). AU thèse 

 curves are unimodal, bul wilh no definile class uf maximum frequency. 



.V table is given al Ihe end of the second [)arl of Ihis paper, showing the 

 numerical values of the mean and of the coefficienl \' and S for ail llie pheno- 

 lypes. Such of Ihese as are included in brackels, bave been found oui lo givc 

 praclically the same polygons for either liie diamelers or Ihe weighls. 



The Ihird pari of the paper gives a short accounl of the tield work needed 

 to work oui liie gencliiMl Ix'iiaviuur of thes(> phenotypcs. 



