SEED PRODUCTION IN CROSS POLLINATED CROPS - PART5

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Seed Production in Cross Pollinated Crops PRINCIPLES & METHODS A.K. CHHABRA Professor Department of Plant Breeding CCSHAU, Hisar © A.K. Chhabra TOPICS LAST VIEWED PREVIOUS END DISCLAIMER: Copyright of some of the figures used from internet and different web sites is duly acknowledged. The copyright stands with its original developer. The information has been gathered here for educational purpose and not for any kind of commercial purpose.

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Seed Production in Cross Pollinated Crops © A.K. Chhabra Vegetative Nuclei Generative nuclei Synergids (n) Egg cell (n) Polar nuclei (2n) Integuments (2n) Antipodal cells (n) Integuments (2n) Megagametophyte (Embryosac) Pollen grain ANDROGENESIS Pollen tube germinates….leads to hormonal trigger…….generative nuclei acts as embryo (n)….Haploid Androgenesis(n) …may lead to Diploid Androgenesis (2n) if both generative nuclei fuse PARTHANOGENESIS One generative nucleus degenerates that otherwise has to fuse with egg cell. It stimulates egg cell before degeneration and egg cell develops into embryo…c/a Haploid Parthenogenesis (n) Another generative nucleus degenerates that otherwise has to fuse with polar nuclei. It stimulates polar nuclei before degeneration and polar nuclei develops into embryo…c/a Diploid Parthenogenesis (2n) OR APOSPORY Synergid or antipodal cell form embryo directly that leads to Haploid Apospory (n) Any wall or integument cell form embryo directly that leads to Diploid Apospory (2n) VARIOUS PATH WAYS FOLLOWED BY DIFFERENT CELLS OF EMBRYOSAC LEADING TO DIFFERENT FORMS OF APOMIXIS usefulness of introgressing the apomictic gene into sexual plant species important in modern agricultural cropping systems.

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Barnase gene…produces RNAse Barnase gene…produces RNAse TA29 Barnase gene Tissue specific (tapetum layer) promoter Herbicide Resistance (Phosphinothricin) (Gene construct) Endothecium Middle layer Tapetum Bacillus amyloliquefaciens Tapetum degenerates PMCs/pollen become sterile BARNASE-BARSTAR SYSTEM TRANSGENIC GENETIC MALE STERILITY PRINCIPLE © A.K. Chhabra 2007

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Tapetum persistant PMCs/pollen are fertile Barnase gene…produces RNAse Barstar gene TA29 Barnase gene Tissue specific (tapetum layer) promoter Herbicide Resistance (Phosphinothricin) (Gene construct) Inhibits RNAse Endothecium Middle layer Tapetum Bacillus amyloliquefaciens BARNASE-BARSTAR SYSTEM TRANSGENIC GENETIC MALE STERILITY PRINCIPLE © A.K. Chhabra 2007

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Barnase gene…produces RNAse Barstar gene (fertility restorer) TA29 Barnase gene Tissue specific (tapetum layer) promoter Herbicide Resistance (Phosphinothricin) (Gene construct) Inhibits RNAse Endothecium Middle layer Tapetum Bacillus amyloliquefaciens Tapetum degenerates PMCs/pollen become sterile Tapetum persistant PMCs/pollen are fertile BARNASE-BARSTAR SYSTEM TRANSGENIC GENETIC MALE STERILITY PRINCIPLE Dominant male sterility Barstar-Barnase interaction (binding) © A.K. Chhabra 2007

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Barnase gene Tissue specific (tapetum layer) promoter Herbicide Resistance (Phosphinothricin) (Gene construct) BARNASE-BARSTAR SYSTEM TRANSGENIC GENETIC MALE STERILITY Male sterile Herbicide resistant Male Fertile Herbicide sensitive Herbicide spray PRINCIPLE © A.K. Chhabra 2007

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BARNASE-BARSTAR SYSTEM TRANSGENIC GENETIC MALE STERILITY Male Fertile KILLED PRINCIPLE © A.K. Chhabra 2007

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BARNASE-BARSTAR SYSTEM TRANSGENIC GENETIC MALE STERILITY Barnase-Bar/- - /- x Sterile Herbicide Resistant Fertile Herbicide Sensitive 50% Barnase-Bar/- (male sterile, rest.) 50% -/- (male fertile, susceptible) Phosphinothricin Spray Killed , Killed , Killed , Killed X Barstar/Barstar Fertile Restorer 50% Barnase-Bar/Barstar (male fertile) 50% -/Barstar (male fertile) 100% male fertile F1 Hybrid STEP 1 Maintenance of male sterility STEP 2 Production of Hybrid © A.K. Chhabra 2007

CHEMICALLY INDUCED MALE STERILITY : 

CHEMICALLY INDUCED MALE STERILITY MALE STERILE MALE STERILE MALE STERILE MALE FERTILE

CHEMICALLY INDUCED MALE STERILITY : 

CHEMICALLY INDUCED MALE STERILITY Induced by spray of certain chemicals GA (gibberellic acid) NAA (napthalene acetic acid) MH (Maleic Hydrazide) Etheral MALE GAMETOCIDES CHAs Chemical Hybridizing Agents SUCCESSFUL EXAMPLES CHEMICAL CROP Etherel Rice, Sugarbeet, Wheat FW 450 Cotton, Groundnut, Sugarbeet, Tomato GA (Gibberellic Acid) Lettuce, Maize, Onion, Rice, Sunflower MH (Maliec Hydrazide) Cucurbits, Onion, Tomato, Wheat NAA (Napthelene Acetic Acid) Cucurbits Sodium Methyl Arsenate Rice Zinc Methyl Arsenate Rice

CHEMICALLY INDUCED MALE STERILITY : 

CHEMICALLY INDUCED MALE STERILITY Characteristics of an Ideal CHA Female fertility should be unaffected Be non-mutagenic Consistent complete male sterility Easy and economical to apply Minimum side effects Safe to user and envt. NO SUCH CHA AVAILABLE Advantages of using CHAs Effective for the generation applied No transfer of CMS required Can be applied to the variety required only B and R are not required Saves time, labour and money to develop A, B, and R lines

CHEMICALLY INDUCED MALE STERILITY : 

CHEMICALLY INDUCED MALE STERILITY Chief limitations Pollen abortion------incomplete and variable Specific developmental stages are sensitive to CHAs Effect of CHAs are short lived Female fertility may be reduced Often undesirable side effects are produced High cost of CHAs The need for repeated applications increases the cost of hybrid seed

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F1 P1 MP F1 P2 F1 F1 Relative heterosis Heterobeltiosis Heterobeltiosis Standard Variety Standard heterosis TYPES OF HETEROSIS Negative Heterosis Positive Heterosis For example: Toxic constituents Maturity Plant height Seed yield Disease resistance Quality characters etc.

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© A.K. Chhabra (1) (2) (3) (F1 performance over mid parental value) (F1 performance over better parental value) (F1 performance over standard variety)

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Seed Production in Cross Pollinated Crops © A.K. Chhabra

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Seed Production in Cross Pollinated Crops © A.K. Chhabra

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Seed Production in Cross Pollinated Crops © A.K. Chhabra GMS

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Seed Production in Cross Pollinated Crops © A.K. Chhabra GMS

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© A.K. Chhabra CMS

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Seed Production in Cross Pollinated Crops © A.K. Chhabra CGMS

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© A.K. Chhabra A B R X X A F1 POLLEN POLLEN SCHEME FOR HYBRID SEED PRODUCTION IN PEARLMILLET POLLEN POLLEN B R CGMS

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Seed Production in Cross Pollinated Crops © A.K. Chhabra CGMS

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Seed Production in Cross Pollinated Crops © A.K. Chhabra CGMS

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Seed Production in Cross Pollinated Crops © A.K. Chhabra CGMS

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CGMS

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Utilization of Self Incopmpatibility........ © A.K. Chhabra Self Incompatibility

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Seed Production in Cross Pollinated Crops © A.K. Chhabra

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Seed Production in Cross Pollinated Crops © A.K. Chhabra

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Seed Production in Cross Pollinated Crops © A.K. Chhabra

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Seed Production in Cross Pollinated Crops © A.K. Chhabra

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Seed Production in Cross Pollinated Crops © A.K. Chhabra

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Head of R-line showing abundance of pollen grains

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Multi shoot Plant of Restorer line in Sunflower

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B-line

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Collection of pollen from B-line

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Dusting B-pollen on A-line head Maintenance of A-line

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A-line showing no pollen production

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Bagging (Selfing or sib mating) in Sunflower