Answer:
Although statements are not given in the question, we could make the most possible deduction as follows:
The allele for purple flowers is dominant whereas allele for white flowers is recessive.
Explanation:
According to the question,
Here we have one possibility that both parents were homozygous but in their own traits. Purple flower plants were "PP" and white flower plants were "pp" So, the first progeny (direct offsprings) would have "Pp". So, as per considerations, purple is dominant allele which will mask the recessive allele thus defining the color of all offsprings as purple. However, further cross of their generation will definitely end up into purple and white flowers (3:1) but this condition is not mentioned in the statement.