加入WTO对江西花卉产业结构调整的思考

就江西省花卉产业的现状进行了分析,并阐述了中国加入WTO后,江西进行花卉产业结构调整的思路。     

Out-crossing frequency and genetic analysis of hybrids between transgenic glufosinate herbicide-resistant rice and the weed, red rice

The potential of transferring herbicide resistance from transgenic rice (Oryza sativa L.) varieties to sexually compatible weeds is of paramount importance for development of effective weed control strategies. The objective of this research was to determine the genetic control and frequency of natural outcrossing between a transgenic, glufosinate-resistant rice line and a Louisiana biotype of red rice (Oryza sativa L.). Molecular and phenotypic data showed that outcrossing in field plots between a non-transgenic purple marker line and red rice did occur within one field season, but at a low rate of <1%. Similarly, molecular and phenotypic data demonstrated that glufosinate resistance was transferred from the transgenic line to the red rice biotype in the field within one year at a low frequency of 0.3%. Compared to parental lines, the transgenic-red rice hybrids were extremely late, tall, and never set seed during the normal field season. Genetic analyses in all F₂ populations showed glufosinate resistance behaved in a Mendelian fashion as a single, dominant gene. Presence of the bar gene for glufosinate resistance did not increase fitness or seed fecundity in hybrids or subsequent progeny. The genetic analyses and outcrossing results from this study suggest that an effective management program can be developed to prolong the usefulness of transgenic, glufosinate herbicide technology. This revised version was published online in July 2006 with corrections to the Cover Date.     

稻属间杂种花粉植株的细胞遗传学研究

以栽培稻０２４２８与紧穗野生稻间不育Ｆ１杂种（２ｎ＝２４，ＡＣ）为材料进行花约培养，共接种花约３２６８８个，获得再生绿苗１３株及白化苗两株，愈伤诱导率与分化率分别为０．１４％和３４．７８％。有９朱花粉绿苗长至成熟，均表现长芒、紫柱头、强感光及易落粒等野生亲本的特性。细胞学结果进一步表明，其中４株为二倍体（２ｎ＝２４），形态上琚的Ｆ１杂种相似，花粉母细胞中期Ⅰ亦只能见到少数二价体；另５株则为四倍体（     

Occasional loss of expression of phosphinothricin tolerance in sexual offspring of transgenic oilseed rape (Brassica napus L.)

The commercial and economic value of genetically modified crops is determined by a predictable, consistent and stable transmission and expression of the transgenes in successive generations. No gene inactivation is expected after selfings or crosses with non-transformed plants of homozygous transgenic oilseed rape plants if the expression of the transgene in homozygous or hemizygous nature in such plants is stable. The segregation ratios of phosphinothricin (PPT) tolerance in successive generations of selfings and mutual crosses of a few independent transgenic PPT-tolerant oilseed rape plants indicated a dominant, monogenic inheritance. In within-variety and between-variety crosses no transgene inactivation was observed. However, after selfings and backcrosses with non-transgenic oilseed rape infrequent loss of the expression of the PPT tolerance transgene was observed independent from its homozygous or hemizygous nature. Molecular analysis of PPT-susceptible plants showed that the loss of expression was due to gene inactivation and not to the absence of the transgene. Methylation and co-suppression are mechanisms that might cause reduced or even loss of expression of the transgene in later generations. The implications of this observation for seed multiplication of varieties and breeding activities with transgenic oilseed rape are discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

The biotechnology of crop legumes

Summary The absence of variety-independent gene transfer methods for major agronomic species has, until now, limited the usefulness of recombinant DNA techniques to crop improvement programs. Until recently, only Solanaceous crops could be used to study fundamental and applied problems in plant sciences. During the past five years rapid advances in cell biology, in combination with the development of novel gene transfer methodology allowed utilization of the tools of plant molecular biology in conventional breeding programs. Cereal and leguminous species were considered to be recalcitrant to genetic manipulation. As a result of the development of direct DNA transfer methodology into organized tissue, we are now in a position to introduce any foreign gene into almost all of the major cereals and legumes. This can be achieved efficiently, often in a variety-independent fashion. The object of this review is to provide a comprehensive account of the state of the art in gene transfer for the cultivated leguminous crops. Important oilseed and feed species primarily in industrialized countries, as well as minor but equally important species for sustaining growth populations in developing countries will be examined. Advantages of the various gene transfer methods that were shown to be useful for specific crops, as well as limitations and problems associated with each crop and gene transfer method will be discussed. Data from field trials of transgenic legumes, where available, will be presented.     

The Experimental and Commercial Release of Transgenic Crop Plants

With advances in recombinant DNA methods and transformation procedures, it is possible to transfer genes into crop plants from unrelated plants, microbes and animals. Many of the modifications being carried out, or envisaged, are for disease and pest resistance, product quality and tolerance to environmental stress, but there are additional opportunities to modify crops to give specialized products for industrial or pharmaceutical use. Some of the characteristics of transgenic plants are considered, including: transgene copy number, position, expression, stability, pleiotropy, selectable marker genes and somaclonal variation. There have been several hundreds of field trials with transgenic plants, and the first transgenic varieties are likely to be approved for commercial production in 1993. Before releasing transgenic plants, it is necessary to carry out a risk assessment to determine whether the transgenic variety will behave differently from a conventionally bred variety. Assessment procedures are being harmonized internationally by various organizations. There is a growing commitment to apply these genetic modification methods to crops in developing countries, as genes relevant to their crops and environments become available.     

Homozygous transgenic rice lines expressing GNA with enhanced resistance to the rice sap-sucking pest Laodelphax striatellus

Homozygous transgenic rice lines expressing snowdrop lectin, Galanthus nivalis agglutinin (GNA), were investigated for resistance to the rice small brown planthopper (SBPH), Laodelphax striatellus, an important rice sap‐sucking pest causing yield losses and serving as vector for some important rice viruses. Insect bioassay results revealed that both the GNA‐expressing homozygous lines tested significantly inhibited SBPH by decreasing its survival, its overall fecundity and retarding development. This is the first report on homozygous transgenic rice lines expressing GNA conferring enhanced resistance to SBPH. This result suggests that transgenic rice expressing GNA will be useful in rice pest resistance breeding, as an alternative to conventional breeding for the control of SBPH, and potentially alleviating damage caused by the viruses it transmits.     

旱塬地玉米耗水特点及提高水分利用率途径

研究结果表明,农田耗水主要在１m以上土层,玉米对０－５０cm土层的水分利用 率达６０％;玉米农田棵间土壤水分蒸发占农田蒸散的４７．６％－７７．５％,整个生育期棵间蒸发与叶面积指数呈负相关,玉米产量与蒸腾呈正相关;秸秆覆盖可有减少棵间土壤水分蒸发;合理施肥能促进玉米对土壤水分的利用。     

转Bt基因棉杂种优势及性状配合力研究

采用NCⅡ设计方法,选用我国构建的Bt(Bacillus thuringiensis)基因棉GK3和美国构建的Bt基因棉新棉33B等Bt基因棉为父本,配制杂交组合,分析了含Bt基因杂交棉组合的性状优势表现及配合力效应。性状优势分析表明,组合的中亲优势和竞争优势明显,皮棉产量中亲优势率达100％,竞争优势率达86．7％,多数品质性状较对照为优,表明转Bt基因棉品系与常规品种间杂种优势利用潜力较大;通径分析表明,在增产因素中,铃重和铃数所起贡献较大;配合力分析表明,父本间和母本间的GCA均方值均达显著或极显著水平,组合的SCA均方值除子、皮棉声量性状外,其余均不显著,在F1性状的遗传中,各性状的加性效应起主导作用;F1的性状表型值与父、母本的GCA呈高度正相关,并达显著水平,表明选配含Bt基因杂交组合时,选择GCA值大的亲本较为可靠。