Task

In four-o’clock (Mirabilis), flower colour shows incomplete dominance: RR — red, Rr — pink, rr — white. Tall stem (D) is completely dominant over short (d); the genes are on different chromosomes. A homozygous red tall plant was crossed with a white short plant. F₁ plants were intercrossed, giving 3200 F₂ plants. 1) Explain the difference between complete and incomplete dominance and why, with incomplete dominance, the F₂ phenotypic and genotypic ratios coincide. 2) Write the P and F₁ crosses and gametes and draw the F₂ Punnett square. 3) Determine the F₂ phenotypic classes and their ratio. 4) Calculate the number of plants in each phenotypic class. 5) Find the number of F₂ plants with the same genotype as F₁. 6) If the F₂ pink tall plants are crossed with white short plants, what share (%) of the offspring will be pink and tall? For each part, write out the law or method used (cross scheme, formulas, reasoning) and all calculations step by step.