| Genetically modified plants (GMP) have been cropped on large scale so far in many countries, which plays a great role in creasing economic benefits. While the same time, an increasing attention had also been paid for the ecological risks brought about by the release of GMPs. It is difficult to predicate the occurrence and extent of long termed environmental effects when GMPs are introduced into ecosystems. Through genetic engineering, GMPs may potentially create changes that enhance and an organism's ability to become aggressive weeds or invasive in natural habitats. They are possible to spread wildly in ecosystems and caused unintended degradation of natural ecosystem. It was reported recently that transgenic oil-seed rapes change into weed in Canada. Gene flow between GMPs and their wild relatives is also a potential invasive risk. By pollen transfer or other ways, the introgression of transgene into natural related species might occur. As lots of transgene disperse into wild gene pool, which may have a harmful effect on the genetic diversity of wild relatives. The release of GMPs into environments where weedy relatives exist should be carefully assessed. In the past few years, modern biotechnology has been increasingly played an important role in improving crop agriculture. The manipulation of whole organisms and nucleic components holds much promise for improving crop productivity. So far, debate and study focus mainly on potential risks, whether release of GMPs is harmful to non-target insects, such as monarch larvae, silkworm, bee and so on. Recently, event that tradition maize landraces in Mexico is introgressed by transgenic DNA also raise hot debate.1. Transgenes make the risk of gene escape between oryza sativa ssp. japonica and Indica decreaseThe risk of gene escape of oryza sativa ssp.japonica was investigatedwith three transgenic japonica rice cultivars and their wild types and seven ssp.indica representative cultivars. The results suggested that the transgenic japonica rice showed a decreased ability to donate pollen to indica mothers compared with their wild types. The most indica rice cultivars were less likely to be fertilized by the pollen of transgenic japonica rice rather than their wild types, while one of them was more. It is a noticeable fact that transgene shouldn't make the risk of gene escape between the two subspecies of oryza sativa increase. But this situation is not always for all species (cultivars) and the principle of "case by case" is necessary for ecological risk assessment.2. Using crossing method to evaluate the transgenic impacts on plant genetic diversityThe manipulation of whole organisms and nucleic components holds much promise for improving crop productivity and an increasing attention had also been paid for the ecological risks, such as whether release of Genetically modified plants (GMPs) are harmful to non-target insects (monarch larvae, silkworm, bee etc.) or plants (such as Mexico traditional maize landraces). Genetic diversity refers to the variation of genes within species and is an important part of biodiversity (the totality of genes, species, and ecosystems in a region). It is a tough job to evaluate the potential impacts of transgenic plants on genetic diversity. A new method, so-called "Crossing" method, which transgenic plant and its wild-type groups (they can be as populations or species with a same genetic background except the foreign gene) arecrossed by a representative cultivars group and the transgenic impacts on genetic diversity are evaluated by genetic variations of important agronomic characters among their offspring, was proposed. As an example, three different transgenic rice cultivars and their wild-types and a paternal group (include 7 representative cultivars) were employed. After selfing of F1 hybrids, 30 F2 hybrids seeds (15 pairs of transgenic rice and its wild-type groups) were obtained. The variation of some important traits (plant height, settingrate, filled spikelets per panicle, panicle number per plant,...
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