Q.What is meant by true breeding or pure breeding lines / strain?

Step 1. A true-breeding, or pure-breeding, line is one that has undergone repeated (continuous) self-pollination over many generations.

Step 2. This repeated self-pollination makes the line homozygous for the trait in question - it carries two identical alleles of the relevant gene, rather than two different ones.

Step 3. Because of this homozygosity, matings within the pure-breeding line always produce offspring with exactly the same, constant trait as the parent, generation after generation - there is no possibility of a different form of the trait appearing, since only one allele is present in the population. …

Define true-breeding as homozygosity established by repeated self-pollina …

• Confusing true-breeding with simply 'healthy' or 'high-yielding' rather than specifically homozygous. …