Breeding of Vegetable, Spice and Tuber crops (2+1)

Backcross Method – Definition

What is Backcross Method – Definition?

• Backcross method is the one whose main objective is to incorporate desired gene, either dominant or recessive, to the highly productive, commercially successful variety which lacks that specific gene.

What is Backcross Breeding

• Backcrossing has been used by plant breeders for decades to transfer specific character into elite lines.
• The variety which receives gene is ‘recipient parent’ and variety which is the source of gene is called as ‘donor parent’.
• Recipient parent is used repeatedly hence also named as ‘recurrent parent’.
• Donor parent is used only once and hence known as ‘non-recurrent parent’.
• Repeated backcrossing leads to homozygosity at the same rate as in case of selfing.

Use of Backcross Breeding Method

• Backcross to transfer dominant gene

Requirements of a Backcross Programme

• For the successful development of a new variety through the backcross method, the following requirements must be fulfilled.
• A suitable recurrent parent must be available, which lacks one or two characteristics.
• A suitable donor parent must be available.
• The donor parent should have the character to be transferred in a highly intense form.
• The character to be transferred must have high heritability.
• Preferably, it should be determined by one or a few genes.
• A sufficient number of backcrosses should be made so that the genotype of the recurrent parent is recovered in full.
• Ordinarily, 6-7 backcrosses are sufficient for the purpose. In practice, 4-6 backcrosses are usually made.