A cross was carricd out between a pure bred tall pea plant and a pure bred dwarf pea plant and `F_(1)` progeny was obtained. Later, the `F_(1)` progeny was selfed to obtain `F_(2)` progeny. Answer the following questions :
(i) What is the phenotype of the F, progeny and why?
(ii) Give the phenotypic ratio of the `F_(2)` progeny.
(iii) Why is the `F_(2)` progeny different from the `F_(1)` progeny?

Explanation

(i) The phenotype of `F_(1)` progeny is Tt because `F_(1)` or hybrid plants were not intermediate between the two alternate forms of a character. They resembled only one parent. In a cross between tall and dwarf pea plants, the `F_(1)` plants were all tall.
(ii) The phenotypic ratio of `F_(2)` progeny is 3: 1.
(iii) `F_(1)` progeny resembled only one parent which is dominant in nature but in `F_(2)` progeny phenotypically three plants are tall and one plant is dwarf. But according to genotype ratio one plant is pure tall, two are hybrid tall and one plant is pure dwarf.