Cross‐border ‘Traffic’: Stories of dangerous victims,pure whores and HIV/AIDS in the experiences of mainland female sex workers in Hong Kong

Abstract: In recent years, dramatically increasing numbers of mainland Chinese women have entered Hong Kong to engage in sexual labour. Public discourses on the threat of HIV/AIDS increasingly locate these women's bodies as sites of danger, colluding with pre‐existing imaginations of mainland rural women as ignorant, desperate and deceptive in representing these women's penetration of Hong Kong's border as a primary means of infection of the Hong Kong body. Drawing on state, media and popular representations, and the narratives of female sex workers themselves, this paper examines the interwoven bio‐medical, gendered, sexual and cross‐border relationships that intersect in the experiences of mainland Chinese sex workers in Hong Kong. I argue that while images of disease and danger have been used to regulate these women's bodies, mainland female sex workers challenge these images by drawing on other popular stereotypes of mainland women as pure, feminine and traditional. Although images of the related but still ‘other’ figure of the mainland Chinese woman are powerful mechanisms for the regulation of these women's bodies, mainland female sex workers skilfully use inherent tensions in those images in resisting that control and in struggling to achieve their own personal and economic goals.     

Methods of overcoming interspecific barriers in Trifolium

Summary Barriers to interspecific hybridization in Trifolium were investigated by manipulation of mentor pollen treatments, ploidy levels, and compatibility and male sterility systems. Crosses involving the addition of mentor pollen produced fewer seeds and hybrids than crosses involving normal pollination. Lower seed set with mentor pollen was deduced to result from the use of less viable pollen, approximately half the pollen having been killed by alcohol. Pollinations at the diploid level resulted in more hybrids than at the tetraploid level, perhaps because genes for male sterility produced higher female sterility in the tetraploids. The self-compatible stock produced more seeds, mostly selfs, than the self-incompatible stock, but produced more hybrids only in one cross, T. pratense L. × T. diffusum Ehrh. The use of male-sterile female parents reduced selfing but produced fewer hybrids than male-fertile female parents. Techniques of this study were designed to affect prefertilization barriers, but the lack of effect may indicate that postfertilization barriers in Trifolium are of greater importance.Journal Article No. 98-3-208 of Kentucky Agricultural Experiment Station. Published with approval of the Director.     

水稻质核互作雄性不育系选育的反向杂交法研究

不同的部分保持系可能存在不同的微效恢复基因,通过有性杂交,产生基因重组,能够获得完全保持系类型,但只有在不育细胞质中才能观察得到微效恢复基因是否存在以及它们的作用大小.反向杂交法以不育细胞质为选择背景,在杂交后代植株中直接观察到微效恢复基因的表达,获得的完全不育株,在一定程度上排除微效恢复基因,不育株再通过高温处理转换为可育后自交,来自不育株的微效恢复基因可以进一步排除掉,从而产生出没有(或很少)微效恢复基因的"亲本",利用该"亲本"高温处理后仍可转换为可育的特性,作为父本进行杂交或回交育种,在其后代中获得没有微效恢复基因的完全保持系.该研究为Cp 26不育细胞质源创造出了完全保持系.如果在田间鉴定出优异的完全不育株,对其进行单倍体育种(诱导孤雌生殖或花培),选择到没有(或很少)微效恢复基因的纯合不育株.再对其进行花培,筛选可育的突变体;或者利用纯合不育株的原生质体与一个已破坏细胞核的可育系原生质体融合,都可能得到具有纯合不育株细胞核和可育细胞质的保持系,而能够完善和改进反向杂交法.反向杂交法不但能够为所谓不能保持的不育细胞质源创造出保持系,而且有利于加强新不育系选育的目标性和预见性,提高不育系配合力和培育不同类型优异不育系.     

Sexual and somatic hybridization in the genus Lactuca

Summary Various genes for disease resistance identified in wild Lactuca are difficult, even impossible to exploit in lettuce breeding, due to sexual incompatibility between L. sativa and wild Lactuca sp. We adapted two cellular biology techniques to overcome these interspecific barriers: in vitro embryo rescue and protoplast fusion. In vitro rescue of immature embryos was used successfully for sexual hybridization between L. sativa and L. virosa. Vigorous hybrid plants were produced between L. sativa and seven accessions of L. virosa. Protoplast fusion permitted the regeneration of somatic hybrids between L. sativa and either L. tatarica or L. perennis. Hybrids between L. sativa and L. tatarica were backcrossed to L. sativa.     

Analysis of parental effects on mean vine maturity and chip colour of 4x.2x potato progenies

Summary The parental effects on progenies from potato 4x.2x(FDR) crosses were analyzed to determine anether and to what extent selection criteria used for selecting tetraploid breeding lines have to be adjusted when selecting diploid breeding lines. For vine maturity and chip colour multiple regression analysis of progeny means on means of diploid and tetraploid parents revealed high coefficients of determination (R²) for both characters, indicating good predicting power of the performance of both diploid and tetraploid parents on the performance of their 4x.2x progenies. For vine maturity the multiple regression slope for the tetraploid perents was significantly larger than for the diploid parents, and progeny means were towards the tetraploid parents. This indicates that selection criteria for vine maturity may be less stringent at the diploid level. However, diploids may be earlier maturing than tetraploids and therefore selection criteria can better be similar at both ploidy levels. For chip colour, multiple regression slopes for diploid and tetraploid parents were similar and progeny means were towards the darkest coloured parent irrespective of its ploidy level. This indicates that selection of breeding lines for chip colour can be conducted similarly at both ploidy levels.     

Meiotic restitution mechanisms and 2n pollen formation in a Solanum tuberosum dihaploid and in dihaploid × wild species hybrids*

A Solatium tuberosum dihaploid that proved to be a 2n pollen producer, exhibited two types of meiotic abnormality involved in 2n pollen formation: premature cytokinesis at prophase II and parallel/tripolar spindles in meiosis II. For this reason such a dihaploid was preferentially used as a seed parent in crosses with the diploid species S. tarijense, S. sanctae-rosae, and S. phureja. Diploid interspecific hybrids were evaluated for male fertility, for 2n pollen production and stability over three years and for meiotic nuclear restitution mechanisms. Pollen stainability ranged from 6 to 85% and 2n pollen from 5 to 35% among hybrids. The meiotic mechanism generating 2n pollen was that of spindle abnormality in meiosis II and consequent dyad/triad formation. High correlation was found between fused/parallel spindles and dyads.     

利用小穗培养克服小麦与玉米杂种的幼胚败育

本研究的结果表明,小穗培养是克服小麦与玉米杂种幼胚败育的一个有效手段。让小麦与玉米的杂交穗在植株上生长14～16天时,获得杂种幼胚的频率仅为0.2％,而在授粉后2天采用小穗培养,则使获得杂种幼胚的频率提高到4.2％,获得杂种幼胚的效率提高21倍。     

The origin of polyploids via 2n gametes in Vaccinium section Cyanococcus

Summary The production of 2n pollen (pollen with the sporophytic chromosome number) was evaluated in 4x and 6x taxa of Vaccinium section Cyanococcus. Mean frequencies of 2n pollen producers were 17.1% and 8.3% in natural 4x and 6x populations, respectively. The frequency of 2n pollen producers in the 4x species ranged from 8.6% (V. angustifolium) to 23.8% (V. pallidum). Level of 2n pollen production was genotypically variable (1% to 37.4%). The widespread occurrence of 2n pollen in 2x, 4x and 6x taxa suggests that sexual polyploidization was widespread and responsible for the origin of the polyploid species found in this genus. The frequency of 2n pollen producers was not significantly different between the 4x species and their putative 2x ancestors. These results support the origin of 4x and 6x taxa as a consequence of sexual polyploidization. Polyploids derived from sexual polyploidization would be expected to have increased fitness and flexibility due to the mode of 2n pollen formation. In blueberry species the predominant mode of 2n pollen formation is genetically equivalent to a first division restitution mechanism (FDR). FDR 2n pollen transmits a high percentage of the heterozygosity and a large fraction of the epistasis from the 2x parent to the 4x offspring.     

The frequency of natural cross-fertilisation in sequential sowings of winter barley

Summary Estimations of random mating frequency were computed for a series of sequential autumn sowings of populations of winter barley. The estimations were by means of the maximum likelihood scoring method and three varieties, each carrying a recessive genetic marker, provided three independent estimations for each population. High levels of out-crossing were found in sowings made early in September, and a trend towards absence of out-crossing in populations sown in late November was evident. Although fluctuations in this trend could be accounted for by fluctuations in meteorological factors, a more profound underlying effect was evident in that the three marker varieties behaved similarly, though to different degrees. It is postulated that the principle effect of sowing date, as it affects out-crossing, is upon the development of the flowering apex, and that environmental conditions at flowering time merely modify flowering behaviour.     

Seed set and seedling variation in greater yam (Dioscorea alata L.)

Summary A high degree of fruit and seed set was obtained in Dioscorea alata L. by hand pollination. The sexual progeny was studied in comparison with the clonal plants. In general, the seedlings were poor in growth vigour, flowering and tuber production but the variations observed in the different characters were unprecedented, indicating scope for efficacious genetic improvement in this vegetatively propagated crop.