9.
Illinois chemical strains.
The 1949 crop completed the 50th generation of continuous selection in the Illinois oil and protein strains. The results of this long‑term experiment in mass selection are now being summarized, and publication in some detail will follow in due course.
Results of the "regular" phase of this
experiment through 1947 were briefly summarized in last year's Maize News
Letter. The analyses of the 1949 crop have not been completed at the time of
this writing. Mean oil and protein contents of the 1947, 1948, and 1949 crops
are shown in the following table:
|
|
% oil |
% protein |
||
|
Year |
High Oil |
Low Oil |
High Protein |
Low Protein |
|
1947 |
13.45 |
.76 |
19.24 |
5.11 |
|
1948 |
14.25 |
1.04 |
19.14 |
5.50 |
|
1949 |
15.36 |
1.01 |
not complete |
|
The mean oil content of the 1949 crop of Illinois
High Oil was more than one per cent above that of any preceding crop.
Conditions were exceptionally favorable for the development of high oil content
in this strain during 1949, yet there appears to be evidence that progress is
still being made by selection in this strain.
The first crop of the "reverse selection"
experiment described in the last News Letter was grown in 1948. As shown by the
table following, one generation of this selection markedly affected the
composition of both "high" strains. Ear‑rowing of seed ears of
"reverse" high protein in 1949 indicated that the plant and ear types
of the "reverse" strains are very similar to those of the
"regular" strains. There seemed to be no indications that recent
outcrossing was involved in the marked changes in chemical composition.
|
|
% oil |
% protein |
||
|
Selection |
High oil |
Low oil |
High protein |
Low protein |
|
Regular |
14.25 |
1.04 |
19.14 |
5.50 |
|
Reverse |
13.45 |
1.10 |
18.20 |
5.53 |
Earl R. Leng and
C. M. Woodworth