234 IV' r/iNFiaiRNCE INTriiWTlONAI.E M CKNKTiorr:. 



TMîl.K 7. 



Tahlr shdwnni lin' iiiiiriiiiiiiii iiii/l mhihiniiii /in-, ni/, o/' iimlriii m llir cars sr/erlrrl /'ar iilinilini/ 

 II, llu- Imlli-iimlrhi filnh. 



vEAn. \n\nicM. MiMinvi. 



I8!)() i:,,87 11,89 



1897 i:,,C,-2 II S9 



ixng i4,!i'i \-i,x, 



isnt) ii.7s ir,,ni 



imm i.-,,7i lijii 



moi l(;.l-j i',,ii.- 



1002 i:),(ll I3,ti8 



100,- 17.-.- Ii,60 



•1904 17,79 15, Xr. 



100r> 17. .-9 l:,,52 



1000 17,117 l.-,,lti 



From Ihis inl)lo il is cleiir llinl tlic maNimum has been movod permanontly 

 in Ihe diroclion of llie seloclion. To oblaiii a more reliablc basis for comparison 

 \\c may average Ihe maximum pcr ccnl. ol' prolein in Ihe firsl Uiree years, and 

 in liie last lliree years. Thèse averages are 14.1 i per ceni, and 17.02 per cenl., 

 respeelively, or a dilTerence of .'.iS per cenl. Fiiriher il is seen IhaL in Ihe lasl 

 four years Ihe minimum per cent of prolein in the seleeled ears is grealer Ihan 

 Ihe maximum during the first Iwo years. 



Clearly we are dealing hère nol nierely wilh Ihe isohilion of a genolype but 

 with a definite evointionary change. The whole variai ion polygon has l)een 

 moved definilely in the direction of Ihe sélection'. 



Yel I think Ihat no one can study table T» and still mainlain that il was Ihe 

 simple sélection of lluctuating variations that lirought about the change in pro- 

 lein |)ro(luction. Cerlainly somelhing \vas aciingin line No. 121 \\hich was nol 

 alfecling Ihe olher lines. 



The récent inlerestingexperiments of Siinll and East in dealing wilh liomo- 

 zygous strains of corn may hâve some bearing in Ihis connection. Thèse au- 

 Ihors hâve shown ^ thaï when Iwo strains of corn which hâve been inbrcd for 

 several générations are Ihen crossed the resnlting progeny are far superior to 

 either parent inyield. It is quite possible Ihal a somewhal similar explanalion 

 would acconnt for Ihe great development of line Xo. 121, aller Ihe fourlh gêne- 

 rai ion. 



Il is of interesl to note hère Ihe similarily hetween thèse expcrimenls and 

 Ibe sélection work with poultry al the Maine Agricultural ExperimenI Station. 

 Il has been shown' that after nine years of intensive sélection of poultry for 

 increased egg production the average production of Ihe llock was nol changed. 

 A possible explanalion of the dillerenl resuit reached by thèse two similar expc- 

 rimenls may lie in the l'act that the corn plot was started with only twenty-four 

 individual ears, whilc in the poultry experimenis, sevenly birds were used in the 

 first year's breeding. In the succeeding years a very much larger number of 



1. Tins question as to tlie aniiiunt of sliillinj; of (lie entire variation polygon was sliidietl to somp 

 extent. but it was Heemed that ilie publislicd data was not suflicient to draw trnslworlhy conclusions. 



2. Siior.i. (G.-II.j. .\ pnre line melhod in corn breedin;;, Rpl. Amn: Breeilers Assc, vol. V. pp. .")l-59 

 — E\ST (E.-M.j. Amer Xat. Vol. Xl.lll p. I7.--IX2. 1909. 



5. Peari. (R.) andScRFACE. F.M.. f.S. Dopt. Aj;r., Bnr. .\nim. Iml. nul. 110, j,!. I. 1909, /ni. f. 

 Inàticl. AhsI.-u.-Vererb-lfhre., lîd. 2, 19(10. pp. 2.")7-27:i. 



