FRANK M. SIRFACE. — THE IIESH.T OF SEI.F(.TIN(; FU CnAïlNr, VAMIATKiNS. 'jr,! 



mère nubbins. On accounl of tlio scarcity of ears, il was impossiljle to follow 

 llie regular systeni of sampling, so tlie entire product from each plol-row was 

 collecled and ail of Ihe soiind ears and even many nubbins were selected for 

 analyses in order to oblain the results of Ihe year and Ihe sort of seed \Yilh 

 which to mainlain the experiment. The low protein plot did not sulTer so 

 badly from the drought, so Ihnt hère the sampling and sélection were made as 

 usual ". 



Ears Xo. MIT and Mo were planted in the " Spécial High-Protein Plot " 

 and ail the ears selected from thèse two lines were from this plot. In the appen- 

 dix of the bulletin mentioned, the analyses of tvventy-seven ears from Xo. 507 

 (line l'JI) are given. (^f thèse, six were selected. Similarily from ear No. .^IT) 

 (Une 1 12), the analyse of forty-five ears are given but only Ihree were selected. 

 None of thèse tliree ears were abie to get progeny in the next génération while 

 in striking contrast every o?îe of the six ears from No. 507 prodiiced ears good 

 enough lo be selected Ihe following year. Further thèse latler ears produced 

 practically ail of the High-protein corn from this time on. 



Certainly ears No. 507 and 515 al leasl had the same opporlunity to produce 

 high prolein ears. The results as shown above however are strikingly dill'erent. 



Looking at the pedigree of line 121 alone it may be said to fall into two 

 parts. The first of thèse, covering the first four générations is characterized 

 l)y medioerily in prolein productions. The second part i. e., after the foiirlh 

 génération, is characterized by the produclion of a large numlier of ears witli 

 high prolein content. 



Evidently something happened to ear \o. il.", or pcrhaps lo ear No. 507 

 which produced a prepotency lowards high protein production. What this 

 something may hâve been, can only be conjectured. It may hâve been of the 

 nature of a mutation. This is perhaps the lirst suggestion that occurs to one. 

 In this case Ihere are certain possible conlributory factors which may bave been 

 operative. The chief of thèse are lo be found in either sélective fertilization or 

 in the proper amount of inbreeding. At this time the larger amount of pollen 

 in the field was coming from Iwo or three lines. Thèse, of course, had been 

 crossed with other lines but nevertheless they were pure bred on one side. We 

 know too liltle of the elfect of such inbreeding to make more Ihan a suggestion. 



The suggestion is cerlainly close at hand that in the third or fourlh géné- 

 ration of line No. 121 a particularly happy combination oi germinal plasma 

 occurred. As a resull of this combination a line which was previously only 

 médiocre in ils protein producing ability suddenly acquired a marked increase 

 in Ihis direction. This ability to produce a large number of high protein ears 

 lias evidently been transmitled to laler générations. 



The phenomena of propotency which it seems to me is displayed in this 

 instance is one \\ hich has been discredited largely by scientific breeders in récent 

 years. Pearl ' however, has recently shown that in poullry the olïspring ol 

 certain matings transmit for several générations at least, the ability to produce 

 eilher a high or low degree of egg production as the case may be. 



One more point musl be considered hère. From table 1 (page 225) it is 

 seen that starting with a protein content of 10.92 per cent, at the end of the 



I. Inhorilanco olFecumlilv in Die « Domoslic Fowl o, Ainei-. NaL, vol. XI.V, .liinn 1911. 



