Publication Date
1989
Description
The apomixis program at the Pasture Laboratory has the long-term objective of finding procedures to manipulate the type of embryo sac which develops in crop species. We would like to induce at will, formation of functional apomictic embryo sacs in obligately sexual species such as maize and wheat, and to induce sexual reproduction in obligate apomicts, such as dallisgrass. The benefits of this capability for plant breeding would be enormous : 1) desirable characteristics could be reproduced over generations in normally sexual genotypes through induced apomixis and 2) genetic variability in apomictic genotypes could be unlocked through sexual crosses. Angiosperms characteristically form a meiotically reduced embryo sac (the female gametophyte) within unreduced ovulary tissue. Fertilization of the egg initiates the unreduced sporophytic generation. An alternative mode of embryo sac and embryo formation - apomixis - occurs in more than 300 species of angiosperms including many grasses (Hanna and Bashaw, 1987). In apomixis, an unreduced embryo sac develops within the ovule, followed by spontaneous embryogenesis without fertilization. The progenies are genetically identical with the maternal parent (Nogler, 1984). This perpetuation of the maternal genotype presents the breeder with major opportunities and problems. Whether a species, or an individual within a species produces the unreduced or reduced type of embryo sac is genetically regulated. Plants or species may be considered obligately sexual or apomictic if essentially all embryos are produced only from reduced or unreduced eggs, respectively. Both kinds of functional embryo sacs are produced by facultatively apomictic plants and species. The molecular and physiological events that determine which type of embryo sac forms are unknown.
Citation
Gustine, D L.; Sherwood, R T.; and Gounaris, I, "Regulation of Apomixis in Buffelgrass" (2025). IGC Proceedings (1989-2023). 57.
https://uknowledge.uky.edu/igc/1989/session3b/57
Included in
Agricultural Science Commons, Agronomy and Crop Sciences Commons, Plant Biology Commons, Plant Pathology Commons, Soil Science Commons, Weed Science Commons
Regulation of Apomixis in Buffelgrass
The apomixis program at the Pasture Laboratory has the long-term objective of finding procedures to manipulate the type of embryo sac which develops in crop species. We would like to induce at will, formation of functional apomictic embryo sacs in obligately sexual species such as maize and wheat, and to induce sexual reproduction in obligate apomicts, such as dallisgrass. The benefits of this capability for plant breeding would be enormous : 1) desirable characteristics could be reproduced over generations in normally sexual genotypes through induced apomixis and 2) genetic variability in apomictic genotypes could be unlocked through sexual crosses. Angiosperms characteristically form a meiotically reduced embryo sac (the female gametophyte) within unreduced ovulary tissue. Fertilization of the egg initiates the unreduced sporophytic generation. An alternative mode of embryo sac and embryo formation - apomixis - occurs in more than 300 species of angiosperms including many grasses (Hanna and Bashaw, 1987). In apomixis, an unreduced embryo sac develops within the ovule, followed by spontaneous embryogenesis without fertilization. The progenies are genetically identical with the maternal parent (Nogler, 1984). This perpetuation of the maternal genotype presents the breeder with major opportunities and problems. Whether a species, or an individual within a species produces the unreduced or reduced type of embryo sac is genetically regulated. Plants or species may be considered obligately sexual or apomictic if essentially all embryos are produced only from reduced or unreduced eggs, respectively. Both kinds of functional embryo sacs are produced by facultatively apomictic plants and species. The molecular and physiological events that determine which type of embryo sac forms are unknown.
