The outcome of the cross between dominant and recessive true breeding parents is:
phenotype ratio= 4:0 ( 100% progeny is yellow)
genotype ratio = 4:0 ( all progeny heterozygous yellow)
Explanation:
The data given:
True breeding (homozygous) yellow seed plant = YY
True breeding green ( homozygous) green plant= yy
The cross between them will be shown in Punnet square:
y y
Y Yy Yy
Y Yy Yy
the genotype ratio is Yy 4:0
the phenotype ratio is Yy 4:0 ( heterozygous yellow seed plant)
If both the parents are dominant homozygous all the progeny will be yellow seed.
If both the parent are dominant recessive homozygous all the progeny will be green seed.
A true breeding plant is one in which it is observed that the progeny exhibit same phenotype. It can be seen from the first case that all progeny are yellow seed. Similarly, in second case also all progeny are yellow seed and in third case when the recessive parents were crossed all the resultant progeny were green.
