ISHS Acta Horticulturae 560: IV International Symposium on In Vitro Culture and Horticultural Breeding
THE USE OF APOMIXIS IN CLONING HORTICULTURAL PLANTS: CURRENT APPLICATIONS AND MOLECULAR PROSPECTS |
| Authors: | A.M. Koltunow, N.S. Scott, A.M. Chaudhury |
| Keywords: | apomixis, Citrus, Hieracium, Arabidopsis, seed |
| Abstract:
Flowering plants form seed by sexual or less commonly by asexual or apomictic processes. Seeds formed by apomictic plants have a maternal genotype because their embryo is derived from cells that have not undergone the events of meiosis and fertilisation that define sexual embryo development. Instead, the embryo of the apomictic seed forms from somatic cells of the ovule. The associated formation of endosperm may or may not involve fertilization. The absence of the meiotic process and the paternal contribution in the embryo genotype means that apomixis provides a method of clonally propagating plants through seed. Importantly, if apomixis is available in crop plants it has the potential to fix hybrid vigour enabling the propagation of hybrids through many seed generations. Apomixis is genetically controlled and it is likely that many of the genes controlling sexual development are also responsible for the induction of apomixis. Apomixis occurs in apple, citrus, mango, mangosteen, Beta species, in turf and forage grasses and berries but is largely absent in other commercial crops. Recent research has focused on understanding the molecular basis of apomixis to enable the transfer of the trait to those crops that lack natural apomictic relatives as a source of these genes. Model laboratory plants are being used to investigate the initiation and progression of apomixis at the molecular level. The sexual plant Arabidopsis is being used in mutagenesis screens to induce components of apomixis. Hieracium, a model system for apomixis in dicotyledonous plants is being studied at the genetic and molecular levels to understand the molecular factors that enable high rates of viable apomictic seed set in functional apomictic plants. | |
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