8th INTERNATIONAL WHEAT CONFERENCE

of DNA sequence variations sometimes only show a few phenotypes; while a large
number of different genetic traits usually have small differences at DNA level. Although
it can be explained with the concepts of coding region and non-coding region, but it is
not comprehensive. In fact, only in a few cases, specific DNA sequences equals Mendelian
factor. The content of Mendelian factor is more than DNA sequence. Mendelian factor =
[Specific DNA sequences] × [background complexity+1]n, where n is the complexity of
the expression mechanism, n≥0. It is obvious that Mendelian factor is much complicated
than DNA sequences. The knowledge of traits is from the understanding of the effect of
Medelian factor, but in many cases is hard to find the relationship between trait and DNA
sequence.
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