If both plants in parent generation are homozygous for pea color, All plants in the F1 generation are homozygous for the yellow allele. The parents both passed on the yellow allele.
Step-by-step explanation:
In Mendelian peas it is said the yellow colour is dominant over green colour.
If in F1 generation all alleles are dominant and homozygous for yellow colour allele. All four progeny are dominant and homozygous.
R R
R RR RR
R RR RR
Punnett square
both parents passed on the yellow allele.