By VKSCOA DUMRAON A UNIT OF BAU SABOUR BIHAR

1. A,B & R LINES DEVELOPMENT
OF SELF AND CROSS
POLLINATED CROPS AND
THEIR MAINTENANCE
BREEDING FOR HYBRID SEED
PRODUCTION
Presented by
Mr. Buddhi Sagar Meena
Mr. Rabiranjan Sethi
Mr. Bhabesh Kumar Behera
Mr. Manish Bosak
Ms. Priti Kumari
.Presentedto
Dr. PRAKASH SINGH SIR

2. Lines defined as a group of genetically similar plants or Crops having
common parents or ancestors.
WHAT IS LINE DEVELOPEMENT ???
● Production or developement of particular type of desired lines.
● When we talk about development of lines in hybrid seed production then there
are three types of lines 1-A line
2-B line
3- R line
And two types of line system i.e. THREE LINE & TWO LINE SYSTEM

3. WHAT IS A, B & R LINES ???
A LINE
● Male sterile
● Use as female
parent.
● Desired
characteristic
s
B LINE
● Maintainer
line
● Male fertile so
use as Male
parent
R LINE
● Restorer line
● Male fertile
● Desired
characteristic
s

4. WHAT IS THREE LINE DEVELOPEMENT ???
● Based on CGMS
● A,B & R lines used
● Cytoplasm is main controller of sterility
● Nucleus contain R gene for restoration of fertility
● R: Male fertile ,r : inactive allele
● RR - Male fertility
● Rr- Male fertility
● rr- Favour cytoplasmic effects

5. CGMS SYSTEM : –
Male fertile Male fertile Male fertile
Male fertile Male fertile Male sterile
● This is the case of cytoplasmic Male sterility
where dominant nuclear gene restores
fertility.
● Discovered by Jones and Davis in 1944 in
onion.
● Now CGMS has been reported in several
Crops like onion , rice , maize ..etc.
● Cytoplasmic Male sterile line can be
maintained by crossing the Male sterile
cytoplasmic line with Male fertile cytoplasmic
line as given below..
(ms/ms) S × ( ms/ ms) F —----> ( ms/ms) S
Male sterile Male fertile Male sterile

6. FUNCTION OF A , B & R LINE :-
Function of B lines:-
B line ( Male fertile) is use to maintain A line ( Male sterile/ female line)
Sterile
cytoplasm
Sterile
cytoplasm
Characters of A line
similar with B line, so
progeny will be similar
A LINE B LINE
A LINE

7. MAINTENANCE OF A LINE IN FIELD:-
● A line is cross with B line
● Planting ratio should be 4 : 2 ( A : B )
A line (4) B line ( 2)

8. HYBRID SEED PRODUCTION:-
Hybrid seed production using A & R lines
● A line cross with R line for hybrid ssed production ( F1 progeny)
● In hybrid seed production field the plantation ratio is 4 : 2 and seed must be collected from A line.
A line rows( 4 ) R line rows (2)

9. THREE LINE SYSTEM AT A GLANCE…
A line B line
A line R line
Hybrid seed
( Male sterile) ( Male
fertile)
( Male sterile) (
Male fertile)
F 1 fertile hybrid seed

10. TWO LINE SYSTEM :
Why two line system ???
● Difficult to maintain CGMS system.
● Problems in maintenance of A line
● High seed production cost
Generally there are two approaches
1.Environment sensitive Male sterility ( EGMS)
2. Chemically induced Male sterility ( CIMS)

11. ENVIRONMENT SENSITIVE MALE STERILITY ( EGMS)
Types of EGMS
1.PGMS ( PHOTOPERIOD SENSITIVE GENETIC MALE STERILITY)
2. TGMS ( TEMPERATURE SENSITIVE GENETIC MALE STERILITY)
3. PTGMS ( PHOTOTHERMO SENSITIVE GENETIC MALE STERILITY)
Interaction between nuclear genes and environmental factors . It is more popularly termed
as Two line hybrid breeding as against Three line hybrid breeding in case of CMS system

12. PGMS ( PHOTOPERIOD SENSITIVE GENETIC MALE STERILITY)
Use in temprate countries having large changes in day length, usually practised in paddy Crops.
Conditions :
Less Than 13 hours photo periods leads to complete Male fertile plant , and more than 14 Hours photo period leads
to complete Male sterile plant.
Maintenance of PGMS line
Photo period Less than 13 hours
PGMS LINE ( Male fertile)
Selfing in isolation
PGMS LINE ( fertile)

13. Hybrid seed production using PGMS line with normal Male fertile line
Photo period more than 14 hours
PGMS line × Normal Male fertile
( Male sterile) ( Male fertile)
Hybrid seed

14. TGMS ( TEMPERATURE SENSITIVE GENETIC MALE STERILITY
Use in tropical countries in case rice like Crops
Conditions :
Less than 28 * C temperature cause complete Male fertile plant, and more than 30 * C temperature leads to
complete Male sterile plant
Maintenance of TGMS line
Temperature Less than 28 * C
TGMS line
TGMS line ( fertile)
Selfing in isolation

15. Hybrid seed production using TGMS line and Normal Male fertile
line
Temperature more than 30 * C
TGMS line × Normal fertile line
( Male sterile) ( Male fertile)
Hybrid seed

16. CIMS ( CHEMICAL INDUCED MALE STERILITY)
1. This non - genetic method including Male sterility involves the use of chemicals called
hybridizing agents or gametocides like GA3 , NAA, MH ,sodium/Zinc methyl arsonate.
2. This method is useful for plants with bisexual flowers in which it is difficult to obtain genetic or
cytoplasmic genetic Male sterility ( GMS or CGMS )
3. The ideal gametocides are
● Selectively induced Male sterility without adversely affecting the female sterility.
● Must not be mutagenic.
● Should consistently produce complete ( more than 95 % ) Male sterility.
● Should not be hazards to the environment.

17. For developing hybrids using gametocides
➢ The female line should have a synchronous flowering habit.
➢ The should response to chemical treatment
➢ The parent should possess good out crossing trait.
Important factors that's decide the efficiency of chemical
gametocides
➢ The correct doses of chemicals.
➢ Appropriate stage of treatment.

18. Advantages :
➢ Simplified procedure of hybrid seed production.
➢ Multiple and diverse germplasm available as parent .
➢ Any line could be taken as female .
➢ Increase Chance of developing desirable and heterotic hybrid.
➢ Multiple cytoplasm occurs as female parent .
Disadvantages :
➢ Environmental effect on sterility could cause seed purity problem .
➢ Incomplete Male sterility and not heritable.
➢ Multiple treatment required.

19. 😊Thank You 😊