How do Mendel's experiments show that traits are inherited independently?

Explanation

Dihybrid cross involves contrasting forms of two characters. When plants that produce round and yellow seeds (RRYY) were crossed with wrinkled and green seed producing plants (rryy), the resultant Fl offspring has always been round and yellow seed producing plants(hybrid- RrYy).
When this hybrid is self fertilized, the offsprings with new trait combination were produced: Round yellow, round green, wrinkled yellow and wrinkled green.
This is possible only if the traits are independently inherited. If they were not independently inherited, then the F2 offsprings would also be either round and yellow or wrinkled and green. This clearly shows that each trait is expressed independent of each other.