Three line Hybrid Seed Production PLANT BREEDING SEED SCIENCE & TECHNOLOGY K VANANGAMUDI TNPSC AO, HO, ADH, AAO, AHO EXAMS ICAR AIEEA JRF & SRF for PG admissions ICAR NET, ARS & STO (T-6) IBPS – AFO CGMS system OF HYBRID SEED PRODUCTION

1. Three-line Hybrid Seed Production
Prepared by
Dr. K. Vanangamudi
Formerly Dean (Agriculture), AC & RI, Coimbatore
Dean, Adhiparashakthi Agricultural College,Kalavai
Professor and Head - Seed Science and Technology,
Tamil Nadu Agricultural University, Coimbatore.
Techniques of Hybrid Seed Production
1. Single line breeding
2. Two-line breeding
o Two-line hybrids can be evolved through
 Mechanical means (Hand emasculation and pollination, Detasseling)
 Application of gametocides
 Use of cytoplasmic male sterility (CMS)
 Use of genic male sterility (GMS)
 Use of environmentally induced genic male sterility (EGMS)
o TGMS & PGMS
3. Three-line method or CGMS system
Involving three lines
100% male sterility can be maintained in three-line breeding system.
A line is a sterile (Female) line
B line is a fertile (Maintainer) line
A (no pollen) and B (Pollen) are isogeneic lines except pollen fertility.
R line is restorer line
Requirements for 3 lines hybrids
 A-line
1. Stable sterility
2. Well developed floral traits for outcrossing
3. Easily, wide spectrum and strongly to be restored
 B-line
1. Well-developed floral traits with large pollen load
2. Good combining ability
 R-line
1. Strong restore ability
2. Good combining ability
3. Large pollen load, normal flowering traits and timing
Characteristics of parental lines
Female parent Male parent
High seed yield
Good seed characteristics
Pest resistance
Male sterility
Lodging resistant
Good pollen production
Long shedding period
Plant height
Fertility restoration

2. Three-line method
A x B B R
- Breeder stage
A B R
A x B B R
- Foundation stage
A B R
A x R
- Certified stage
F1
Examples
 Rice, sorghum, bajra, sunflower
Advantages and disadvantages of the 3-line hybrid system
Advantages Disadvantages
o Stable male
sterility
o Limited germplasm
source (CMS, Restorer)
o This system requires an
extra step for parental
seed production
o CMS breeding is time
consuming
Examples of Hybrids
1. Single line hybrid
 NB 21 grass
2. Two line hybrids
 Hand emasculation and dusting
 Cotton, Tomato, Chilli, Bhendi
 Detasseling
 Maize
 Use of male sterile lines
a) Cytoplasmic male sterility (CMS)
 Ornamentals
b) Genic male sterility (GMS)
 Redgram, Castor
o Use of environmentally induced genic male sterility (EGMS)
 Rice
o PGMS (Photo sensitive Genic Male Sterility)
 Rice

3. o TGMS (Thermo sensitive Genic Male Sterility)
 Rice
3. Three line hybrids
 Cytoplasmic - genic male sterility (CGMS)
o Rice, sorghum, bajra, sunflower
Diagrammatic representation of development of hybrids