306 MAINE AGRICUIvTURAI, EIXP^RIMENT STATION. I91O. 



idea of Johannsen with, of course, the Hmitations implied by 

 the fact that it is an open fertilized plant. In so far these gen- 

 eral results agree with the analytical studies of Shull and of 

 East* having particularly to do with this point. We find the 

 results of this experimental investigation to be very difficult (if 

 not altogether incapable) of rational interpretation in accord- 

 ance with the biological implications of the "law of ancestral 

 inheritance." 



10. The, experiments, so far as they go, give no evidence that 

 there is a cumulative effect of the selection of small fluctuating 

 variations in sweet corn, though, of course, it is recognized that 

 too short a period of time is covered to give any definite evidence 

 on this point. It is believed (as already indicated in 8 and 9) 

 that the observed favorable results which have followed selec- 

 tion in this work are to be explained as the result of the separa- 

 tion of a number of already existing genotypic lines possessing 

 desirable qualities from the still more heterogeneous strains with 

 which the work was begun. This is obviously, however, in the 

 present case merely a matter of interpretation. It does not in 

 any way influence the practical conclusion to be drawn from the 

 empirical results, namely that if improvement does follow (as 

 is the case) it is wise to practice selection. 



11. A wide distribution of selected sweet corn seed over the 

 State in 1908 demonstrated the importance of the factor of local 

 adjustment (Cook) in the improvement of this crop by breeding. 

 The good effect of selection may be quite obliterated as a result 

 of planting the seed in a new locality. The emphasis which 

 such results place upon the importance of (a) selecting for local 

 adjustment, and (b) growing the seed in the locality in which 

 it is to be used is obvious. During the summer of 1910, while 

 this bulletin was passing through the press, a field trip was 

 made by the writers covering a considerable part of the corn 

 growing region of the State. The observations made in the 

 present year confirm completely those made in connection with 



* Shull, G. H.^ — The Composition of a Field of Maize. Rept. Ameri- 

 can Breeders Assoc. Vol. IV., pp. 296-301, 1908. See also a further 

 paper by the same author having the title "A Pure Line Method in Corn 

 Breeding: Loc. cit. Vol. V., pp. Si-59> I909- 



East, E. M. The Distinction between Development and Heredity in 

 Inbreeding. Amer. Nat., Vol. XLHI., No. 507, pp. 173-181, 1909. 



