CBSE Class 10 Science 2022 · Paper 31/2/1 · Question 14

(a) All the $F_1$ plants are tall with round seeds ($TtRr$), because tall and round are the dominant traits. (b) The recessive traits are short height (dwarf plants) and wrinkled seeds. (c)(i) On self-pollination of $F_1$, the $F_2$ generation has four kinds of plants in the ratio $9$ tall with round seeds $:3$ tall with wrinkled seeds $:3$ short with round seeds $:1$ short with wrinkled seeds. The new combinations, seen in neither parent, are tall plants with wrinkled seeds and short plants with round seeds, in the ratio $3:3$ (each $\frac{3}{16}$ of the $F_2$ plants). OR (c)(ii) (i) Tall with round seeds: $\frac{9}{16}\times 1600=900$ plants. (ii) Short with wrinkled seeds: $\frac{1}{16}\times 1600=100$ plants. Conclusion: because new combinations appear, the two characters, plant height and seed shape, are inherited independently of each other, with tall and round dominant.