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#gynogenesis

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Plant tissue culture 2

Gynogenesis differs from androgenesis because it uses:

Gynogenesis differs from androgenesis because it uses female gametophyte components unfertilized ovules ovaries or embryo sacs as explant source rather than anther pollen. In gynogenesis egg cell synergid or antipodal cells within embryo sac are induced to develop sporophytically into haploid embryo without fertilization, typically by culturing unpollinated ovaries or ovules on sucrose enriched medium with auxin cytokinin combination. Female gametophyte origin ensures captured genome is that of maternal parent, contrasting with androgenesis capturing paternal genome from microspores. Gynogenesis became important in crops where androgenesis is recalcitrant or produces high frequency of albino plantlets such as sugar beet onion cucumber barley where pollen culture fails. Culture conditions differ often requiring high sucrose 8-10 percent to mimic ovary environment and dark incubation initially. Induction rate generally lower than androgenesis but avoids genotype dependent albinism. Both pathways converge on production of haploid plants that are initially sterile n and require colchicine mediated chromosome doubling to generate doubled haploid lines fully homozygous valuable for hybrid breeding and marker assisted selection programs.

Ref: Yang & Zhou Theor Appl Genet gynogenesis; Bohanec 2009 haploid production review.

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Plant Breeding 4

Gynogenesis involves culture of:

Gynogenesis derives haploid plants from female gametic lineage, typically through in vitro culture of unpollinated ovules, ovaries, or isolated embryo sacs under defined media conditions. Under specific culture conditions, cells of embryo sac such as egg cell, synergids, antipodals, or nucellar tissue undergo sporophytic development without fertilization, forming haploid embryo with maternal genome and maternal cytoplasm. Unlike androgenesis that samples male gametes, gynogenesis recovers maternal genotype useful when male gametophyte is recalcitrant or expresses self-incompatibility leading to albinism. Sugar beet, onion, cucumber, and melon routinely use ovule culture to generate haploids because anther culture produces predominantly albino or low-response plants in these species. Procedure involves surface sterilization of flower buds, aseptic excision of ovules before anthesis, placement on inductive media enriched with sucrose and growth regulators, and sequential regeneration steps before chromosome doubling to create maternal doubled haploids capturing maternal combinations. In some species, unfertilized ovule culture also generates diploid plants through somatic tissue of integuments, requiring marker analysis to distinguish true gynogenic haploids from somatic clones; careful flow cytometry and microsatellite genotyping ensure true haploid origin and maternal inheritance before chromosome doubling and field evaluation.

Ref: Hosoki T & Asahira. Gynogenesis – ovule culture; Bohanec B 2009 – review of gynogenic haploid breeding

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