Effect of smut infection on the yield of selfed lines and F1 crosses in maize
1929
Jorgenson, L.R.
In the F1 crosses, smut-infected plants yielded less than comparable smut-free plants, regardless of the location of the galls. This also was true with the inbred lines, except where the smut occurred in the tassel. In this case, there were only three pairs of comparable plants and the odds are only 3:1 that the difference was not due to chance. In 50 paired comparisons in the selfed lines, the smutted plants yielded 39% less than comparable smut-free plants and in 366 paired comparisons in the F1 crosses they yielded 50% less. Odds are sufficiently large so that these differences were not due to chance. These results are comparable to those obtained by some recent investigators (2) who obtained differences ranging from 7 to 94% in selfed lines, using the same method. They are contrary to those obtained by others (1) who were unable to demonstrate any differences in yield, other than those due to barrenness, between smutted and smut-free plants in the F1 crosses between inbred lines. Here the two plants compared were separated by not more than three hills. Whether or not similar differences would be obtained under other environmental conditions has not been determined. The differences in yield in the F1 crosses probably approximate more nearly the condition in normal corn than do the differences in selfed lines, as the former are more nearly comparable in vigor.
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