The document describes a three line system of hybrid seed production. It involves an A line that is male sterile, a B line that is fertile and maintains the same nucleus as the A line but with different cytoplasm, and an R line that can restore male fertility in the A line. When the A line is crossed with the B line, it produces a first generation hybrid that is heterozygous. The R line is then used to restore male fertility in the A line for large-scale seed production without needing extra parent lines. Key requirements for successful hybrid seed production using this system include selecting appropriate locations, seed fields, isolation, and cultural practices.

1. Three line system of hybrid seed
production
A.Murugan
Bsc.,agri

2. Hybrids
It begins at 20th centuary.
First generation offspring of a cross between the
genetically diverse parents .
Always heterozygous.
100% cross pollination.
100% seed set is not possible.

3. Three line system

4. A line
Stable Sterility.
Well developed floral traits for outcrossing.
Easily, widespectum, strongly restored.

5. B line
Maintainable line.
Well developed floral traits with large pollen load.
Good combining ability.
A &B – nucleus should be same only cytoplasm
will vary.

6. R line
Able to restore / fertile the male fertility character.
Good combining ability.
Taller than A line.
Large pollen load, normal flowering traits.
No extra parents need for R line multiplication.

7. Success of hybrid seed production
• Choice of location.
• Selection of seed fields.
• Isolation.
• Cultural practices.