Something about inheritance

However, if the inheritance of a characteristic which is controlled by more than 1 single gene , can i use monohybrid inheritance to explain it?

Ans:
No, if more than 1 single gene is involved, you cannot use monohybrid inheritance to explain it. This situation is called DIHYBRID. For example, a kind of bean called pea
( 豌豆) is controlled by 2 kind of genes as follows
SSYY: S and Y are dominant controlling their shape (smooth) and colour (Yellow) respectively.
ssyy: s and y are recessive controlling their shape also (wrinkle) and colour (green) respectively.

When SSYY x ssYY to give SsYy and the cominbation for SsYy are SY Sy sY & sy
When combination of those four kinds cross again, we have 16 combination.

The table for the combination is as follows
-------------------- SY----------------- Sy--------------- sY------------------ sy
------SY---------SSYY--------------SSYy------------SsYY----------------SsYy
------Sy---------SSYy---------------SSyy-------------SsYy----------------Ssyy
------sY---------SsYY---------------SsYy-------------ssYY----------------ssYy
------sy----------SsYy---------------Ssyy--------------ssYy----------------ssyy

The ratio is typical one called 9:3:3:1
Since Y dominates y and S dominates s.
As a result, the ratio for
Yellow(when Y is present) and Smooth (when S is present) is 9
Yellow (when Y is present) but wrinkle(when double s [ss] is present) is 3
Green (when double y [yy] is present) but Smooth (when S is present) is 3
Green (when double y [yy] is present) and wrinkle (when double s [ss] is present) is 1
Again, the TYPICAL RATIO OF DIHYBRID IS 9:3:3:1

I hope you understanding my writting.