Answer:
The phenotype of mutant pea plant must be short in appearance with more lateral branches than of the wild type phenotype.
Step-by-step explanation:
Cytokinin is the growth hormone that is important in plant growth because it promotes the cell division in actively growing plant tissue and it is important in the growth of lateral buds, therefore, it helps in providing the bushy appearance to the plant.
Gibberellin is another growth hormone that helps in the elongation of cells and responsible for making a plant taller. Therefore if gibberellin is underexpressed in mutant plant than it will have short height than the wild plant and if the cytokine is overexpressed than more lateral branches will be present in the mutant plant.