In a different investigation, a scientist crossed tomato plants that had purple stems (DDDDDD) with tomato plants that had green stems (dddddd). The dominant allele for purple stems is shown as DDD.
The Punnett square shows the genotypes of the offspring from this cross.
| D | D | |
|---|---|---|
| d | Dd | Dd |
| d | Dd | Dd |
Explain a conclusion that can be made from the results of this cross.