A,B& R LINE DEVELOPMENT IN HYBRID SEED PRODUCTION
- 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 😊