A pure tall plant crossed with a dwarf plant produces all tall F1 progeny because
Pure tall genotype TT crossed with dwarf tt generates all heterozygous F1 Tt progeny. Tall phenotype predominates because tall allele is dominant, encoding functional product promoting gibberellin synthesis and internode elongation sufficient at single dose, while dwarf allele is recessive loss-of-function. Dwarf allele hidden in heterozygote, only expresses when homozygous tt. Tall recessive or dwarf dominant hypotheses predict opposite or mixed F1 phenotypes, linkage would cause distorted segregation not uniform tall, dominance concept explains observed all tall F1 result. Mastery ensures ac
Ref: Griffiths et al., Introduction to Genetic Analysis, 12th ed., Chapter 2: Dominance Tall Pea