8 
. 5251-59. 1909. 
1909] CURRENT LITERATURE 307 
be readily utilized. Two years ago the reviewer read a paper? before the Ameri- 
can Breeders’ Association in which it was shown that a field of Indian corn consists 
of a large number of elementary species thoroughly hybridized in complex fashion, 
and gave evidence that the vigor necessary to the production of large yields is due 
to the degree of heterozygosis possessed by the individuals composing the crop. 
This paper closed with the suggestion that ‘‘continuous hybridization instead of 
the isolation of pure strains is perhaps the proper aim of the corn breeder.’ 
Based upon this conception the reviewer® worked out a scheme of corn breeding in 
which definite pure lines were isolated and recombined, so that the field crop would 
consist of first-generation hybrids between these two pure lines, thus insuring perfect 
uniformity as well as high yield. Simultaneously with this latter paper there ap- 
peared two other papers presenting suggestions for a similar method of corn breed- 
ing. In the first of these East® suggests the purchase by the farmer of two highly 
bred strains from the professional corn breeder, and the hybridization of these two 
Strains each year to produce the seed corn for the field crop, arguing that the 
methods used by the professional breeder are such as to render these strains already 
to a considerable extent homozygous. This method is the same as that of Mor- 
ROW and GARDNER. East recognizes the relation between this a on id 
pure-line method of the reviewer, saying that the latt 
but less practicable than the method he suggests. East gives a clear and i incisive 
discussion of the significance of the pure-line idea. Corins'® has issued a bulle- 
tin also advocating the use of continuous hybridization in corn breeding. The 
appearance of three papers ,simultaneously advocating the same innovation in 
corn breeding is likely to have great influence on the activity of those engaged in 
this work. The bulletin by CoLtins is unfortunately quite vague in its Taner 
as might be inferred from the title, ‘The importance of broad breeding in corn.’ 
Comparing the conception of ‘‘broad breeding” with the conception involved in 
the other two papers appearing simultaneously with it, both of which are expressed 
in terms of definite hybridization, gives a fair indication of the relation between 
these papers. In keeping with his title, Cortins says ‘‘had it been realized that 
diversity is as necessary to the life of the species as is chlorophyll to the life of the 
individual, it would have been evident that one might as well breed to eliminate 
the green color from the leaves as to suppress this corn variation.” He says also 
that “the appearance of so-called barren stalks in a field of corn may be thought of 
as an adaptation to avoid self-pollination,” and adds that ‘the elimination of these 
_—_ 
7 SHULL, G. oes, The composition of a field of maize, Amer. Breeders’ Assoc. 
42296-3071. 
Assoc. 
5 a pure line method in corn- Srcsaing: Amer. Breeders’ 
9 East, E. M. og distinction between development and heredity in in-breeding. 
Am. Nat. : 3:173-1 09. 
, G, N., The importance of broad breeding in corn. 
ee Uz g; Bureau 
Plant pane Bull. 1414:33, 34. 1909. 
