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ACHIEVEMENTS AND LIMITATIONS OF PROTOPLAST RESEARCH PDF

In this review we focus on recent progress in protoplast regeneration, symmetric and asymmetric hybridization and novel technology developments. Disadvantages of Protoplast Fusion During the mechanical method of isolation of protoplasts: 1. It yields a very small amount of protoplasts. achievements and limitations of protoplast research pdf ppt on achievements of india in space research, achievement limitation of protoplast.

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In essence, protoplast protoplasr comprises removal of cell walls and then the amalgamation of cell contents. The first successful protoplast fusion was reported between Nicotiana species over 20 years ago Carlson et al.

At that stage, the technique was viewed as a means of hybridising sexually incompatible species. Of more recent interest has been the production of asymmetric hybrids – those with fewer genes from one partner than from the other.

These may arise from spontaneous chromosome elimination in some distant combinations, or as a result of the inactivation of mitotic capacity in one partner by chemical or radiation treatment Harms This is of particular interest anf a useful gene is to be introduced to a commercial variety from a wild relative, and offers a rapid alternative to traditional backcrossing programmes.

There have been several successes, notably with species of the Brassicaceae, where new interspecies and intergeneric hybrids have been created Harmsand the Solanaceae Puite Somatic hybridisation between Nicotiana tabacum and N. Somatic hybridisation between eggplant, Solanum melongenaand its wild relative S. Both of these hybrids are very difficult to produce sexually. Disease resistance traits have been transferred by protoplast fusion from wild relatives into cultivated varieties also for oilseed rape and potato Harms The trait for male sterility carried in the cytoplasm has been transferred into tobacco from Nicotiana debneyi, by fusing the tobacco protoplasts with N.

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The X-ray treatment inactivates the nucleus without damaging cytoplasmic function. Fusion of haploid protoplasts has been used to combine cytoplasmic male sterility and cytoplasmic atrazine resistance in rape Drew Cytoplasmic male sterile cybrids of rice have been produced and used in hybrid seed production Drew Successful hybridisation has also been accomplished with Citrus species Puite It has been suggested that protoplast fusion could play prltoplast important role in the genetic improvement of many crops for which wild relatives constitute an extensive and untapped disease resistance gene resource, e.

Nevertheless, protoplast fusion is yet to be applied commercially on any scale in crop improvement programmes. In field testing, a hybrid potato clone derived from protoplast fusion between Solanum tuberosum and S.

Progress in plant protoplast research (pdf) | Paperity

Incompatibility effects Most of the successes with protoplast fusion have involved closely related parents. As noted above, spontaneous chromosome elimination may occur in more distantly related hybridisations.

In addition, nucleo-cytoplasmic incompatibility achieements been observed for inter-generic fusions in the Solanaceae, leading to chlorophyll deficiency in cybrids with the Atropa belladonna nuclear genome and Nicotiana tabacum chloroplasts Puite Poor regeneration from protoplasts Tree taxa for which plant regeneration from protoplasts has been reported include Eucalyptus, Populus alba, P.

In the case of the conifers listed, the protoplasts involved have been isolated from somatic embryos, embryogenic tissue or embryogenic cell suspensions. For most tissues from tree species, regeneration from protoplasts remains problematical.

Achievements and limitations of protoplast research pdf

In spite of continuing good progress in the field, the early expectations of protoplast fusion are yet to be realised, major limitations remain to be overcome, and most of the research is still empirical.

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Expectations of success with an untested pair of species could be expected to be low.

Many hybrids have been tested for established industrial plantation taxa such as Eucalyptus, Pinus, Picea, and Larix. A number of these hybrids are in commercial use, and it seems likely that hybrids will become of wider importance in industrial plantation achieevements. Those currently in use are mostly reasonably easy to produce sexually.

Somatic Hybridization: Aspects, Applications and Limitations

To be addressed then is the extent to which sexual incompatibility limits the production of other useful hybrids. This is difficult to assess. The introduction of disease resistance into commercial poplar clones has been limited by interspecific incompatibility, but other solutions to the problem have been identified, e. There are other instances where transfer of traits among distantly related species would be desirable – e.

Given the difficulties involved, however, and the fact that protoplast fusion research is empirical and likely to be long term anyway, genetic engineering may offer better hopes for the manipulation of such traits. Protoplast fusion has little apparent applicability to little known tropical hardwoods and non-industrial species, for which investigations of the possibilities for even traditional hybridization remain minimal.