Feb. 4.1918 New-Place Effect in Maize 241 



the types of plants best adapted to the conditions where the experiment 

 was tried. The entire effect of selection would be to favor the home- 

 grown seed, and that the transferred seed was not superior to the home- 

 grown in every instance may not be held to vitiate the cases in which 

 significant differences in favor of the transferred seed were observed. 



The results indicate, however, that the stimulation is more pronounced 

 in some stocks than in others. Thus, in the 191 6 comparisons Boone X 

 Hickory King stands out as a conspicuous exception. In all other stocks 

 the transferred seed produced taller plants than the home-grown seed; 

 but with Boone X Hickory King, the home-grown seed exceeded the 

 transferred by 6.2 per cent, a difference not to be ascribed to chance, 

 being more than eight times the probable error. Of the three stocks 

 in which the yield was taken, Boone X Hickory King is also the only 

 one to show superiority for the home-grown seed. Taken alone, the dif- 

 ferences in yield could not be considered significant, but the agreement 

 with the results for height confirms the reliability of these results. 



The insignificant increase in the case of Boone may be explained by 

 the fact that the Arizona-grown seed was more closely selected to fit 

 the Arizona conditions than were the other kinds. At Sacaton the pure- 

 seed Boone was obtained by selling. This procedure would restrict the 

 plants from which seed was secured to those able to produce both ears 

 and pollen under Arizona conditions. With cross-pollinated seed and 

 hybrids, plants that produced no ears would be represented in the progeny 



as male parents. 



DISCUSSION OF RESULTS 



Three classes or degrees of new-place effects ("neotopism") have been 

 recognized by Cook S chiefly with reference to cotton: (i) Those in which 

 there is merely a stimulation of growth; (2) those in which there is also 

 a definite general change of the hereditary characteristics of the variety; 

 and (3) those in which the new conditions call forth a promiscuous 

 mutative diversity. 



The results here reported give evidence under the first of these cate- 

 gories only. With respect to the more pronounced changes that fol- 

 low the transfer of varieties from the Tropics to a temperate climate 

 it may be said that many such changes do occur in maize, some of which 

 at least are inherited. For conclusive qualitative evidence on this point, 

 however, there is lacking definite information regarding the behavior 

 of the introduced varieties in their native countries. 



Roberts- has pointed out that the striking effects which have been 

 ascribed to acclimatization in maize are to be referred either to cross- 

 pollination with native varieties or to the results of selection. The effect 

 of cross-pollination, which misled early investigators, has presumably 



' Cook, O. F. aspects op kinetic evolution. In Proc. Wash. Acad. Sci.. v. 8. 1906, p. 336. 1907. 

 2 Roberts. H. F. acclimatization with reference to corn breeding. In ist Aon. Rpt. Kans. 

 Com Breeders' Assoc, [i9os]/o6, p. 60-64. 1906. 



