Question

A true breeding plant is :-
A: Near homozygous and produces offspring of its own kind.
B: always homozygous recessive in its genetic constitution.
C: one that is able to breed on its own
D: produced due to cross pollination among the unrelated plants.

Answer 1

Hint: A true-breeding plant is one that when self-fertilized produces offspring with same traits. True-breeding organisms are genetically identical. They also have identical alleles for specific traits. The alleles are homozygous. True-breeding plants may express phenotypes that are homozygous dominant or homozygous recessive. With complete dominance inheritance, dominant phenotypes are expressed.

Complete answer:
A-Near homozygous and produces offspring of its own kind.
Breeding of its own kind means being able to inherit genetic material of its offsprings. Resemblance between the ancestors and the offspring. Is the base to which the breed concept lies.

B-Always homozygous recessive in its genetic constitution
Homozygous recessive carries two copies of the same recessive allele. A homozygous recessive allele combination contains two recessive alleles. It expresses the recessive phenotype. For example, pea plants can have red flowers.

C- One that is able to breed on its own
A plant having either a dominant or recessive allele of a gene is pure breeding or homozygous for that trait. Due to the presence of both same types of allele, pure-breeding plants produce progeny of their own kind.

D- Produced due to cross pollination among the unrelated plants.
Cross pollination of two unrelated plants produces heterozygous plants which have one dominant and one recessive allele for a gene. Pure breeding plants are obtained by self-pollination.

Thus the correct option is A- Near homozygous and produces offspring of its own kind.

Note: A pureline (True breeding plant) has homozygous genes for a single character e.g. TT for tall and tt for dwarf. Always produces characters which are true to its character.