Task

In peas, yellow seed colour (A) is completely dominant over green (a) and round seed shape (B) over wrinkled (b); the genes are on different chromosome pairs. A homozygous yellow round plant was crossed with a green wrinkled plant. F₁ plants were intercrossed, giving 1600 F₂ plants. 1) State Mendel’s laws (uniformity, segregation, independent assortment) and the conditions for them (with their cytological basis). 2) Write the P and F₁ crosses, show the F₁ gametes and draw the F₂ Punnett square. 3) Calculate the F₂ phenotypic ratio and the number of plants in each class. 4) Find the number of F₂ plants heterozygous for both genes and the number homozygous for both genes. 5) How many F₂ yellow round plants give no segregation in a test cross? Calculate their share (%) among yellow round plants. For each part, write out the law or method used (cross scheme, formulas, reasoning) and all calculations step by step.