An Evaluation of two <Emphasis Type="Italic">H1</Emphasis>-Linked Markers and their Suitability for Selecting <Emphasis Type="Italic">Globodera rostochiensis</Emphasis> Resistant Potatoes in the New York Breeding Program

The golden cyst nematode (Globodera rostochiensis) is a serious pest that can dramatically reduce potato crop yield. Pathotype Ro1 of G. rostochiensis was first detected in the United States in 1941 and is still present on several farms in New York State. The H1 gene confers high levels of resistance to pathotype Ro1 but screening for it with a bioassay is time consuming and expensive. In this study two known molecular markers, 57R and TG689, were evaluated for their ability to identify resistant clones among 38 global cultivars and 350 New York breeding clones. The ability of either marker to predict resistance was high – 99.7% and 98.3% for 57R and TG689, respectively – but the ability to predict susceptibility was much lower, 47% and 41%, respectively. As resistance is the trait of interest, either of these markers is sufficient to make selection decisions in a practical breeding program. Cases exhibiting discordance between presence/absence of diagnostic markers and bioassay results were investigated further. Recombination, inflow of other resistance genes, and occasional failure of marker- and/or bio-assays are discussed as potential causes.     

Controlling Properties and Cytotoxicity of Chitosan Nanocapsules by Chemical Grafting

The tunability of the properties of chitosan-based carriers opens new ways for the application of drugs with low water-stability or high adverse effects. In this work, the combination of a nanoemulsion with a chitosan hydrogel coating and the following poly (ethylene glycol) (PEG) grafting is proven to be a promising strategy to obtain a flexible and versatile nanocarrier with an improved stability. Thanks to chitosan amino groups, a new easy and reproducible method to obtain nanocapsule grafting with PEG has been developed in this work, allowing a very good control and tunability of the properties of nanocapsule surface. Two different PEG densities of coverage are studied and the nanocapsule systems obtained are characterized at all steps of the optimization in terms of diameter, Z potential and surface charge (amino group analysis). Results obtained are compatible with a conformation of PEG molecules laying adsorbed on nanoparticle surface after covalent linking through their amino terminal moiety. An improvement in nanocapsule stability in physiological medium is observed with the highest PEG coverage density obtained. Cytotoxicity tests also demonstrate that grafting with PEG is an effective strategy to modulate the cytotoxicity of developed nanocapsules. Such results indicate the suitability of chitosan as protective coating for future studies oriented toward drug delivery.     

即食米饭巴氏杀菌工艺研究

以浙粳88大米为试材,通过贮藏过程中米饭的理化指标、质构特性和菌落总数等指标的分析以及感官评价,确定即食米饭的巴氏杀菌最佳工艺参数为：85 ℃灭菌25 min,或95 ℃灭菌20 min,产品在5 ℃可以贮藏20 d。采用巴氏杀菌能较好地保持即食米饭的品质,微生物指标符合国家相关标准要求。     

蚯蚓粪对豇豆根际土壤生物学特征及微生物活性的影响

通过大田试验,研究CK（对照,不施肥）、CF（单施化肥）、VC（蚯蚓粪）和VC+CF（蚯蚓粪和化肥各提供50%的氮）处理对豇豆根际土壤微生物数量、微生物量碳、根系分级、根系分泌物、微生物呼吸及代谢熵的影响。结果表明：与CF处理相比,VC+CF处理显著增加了根际土壤微生物数量与微生物量碳,其中细菌数分别较CK,CF和VC处理增加124.13%,70.48%和17.83%。施用蚯蚓粪明显促进了豇豆根系的生长,尤其增加了毛细根的数量及在根体系中的比例。同时,VC+CF处理还显著提高了根际土壤中根系分泌物含量,并增强了土壤微生物呼吸作用,但降低了代谢熵,其中,土壤微生物呼吸分别比CK,CF和VC处理增加64.91%,36.23%和16.05%,而代谢熵分别下降10.85%,9.06%和5.32%。与VC+CF处理相比,VC处理对豇豆根际土壤微域的影响较小。综上,施用蚯蚓粪相比单施化肥能明显改善豇豆根际土壤的微生态环境,且能显著增强土壤微生物活性,尤以蚯蚓粪与化肥配施的效果更优。     

可调行距插秧机秧箱调节机构丝杠疲劳寿命预测

为预测可调行距高速水稻插秧机秧箱调节机构梯形丝杠的使用寿命,应用相关疲劳理论和方法,推导梯形丝杠螺纹牙的疲劳寿命计算公式。利用Adams软件和Ansys软件建立调节机构的刚柔耦合模型并仿真,得到梯形丝杠最大轴向载荷为53.8 N,并在Ansys软件中建立螺纹牙的有限元模型,通过静力学分析得出最大范·米塞斯应力为188 MPa,小于材料的屈服极限。以静力学分析结果为初始条件,利用Ansys/fe safe软件进行螺纹牙疲劳分析,得出梯形丝杠工作寿命为3 598 h,满足插秧机工作性能要求。     

中国规模生猪养殖效率测度及其区域差异性研究——基于DEA Malmquist指数方法

基于DEA Malmquist生产率指数法,利用2004-2012年中国15个生猪优势产区的投入产出数据,测度了中国规模化生猪养殖效率的变动情况,并对不同规模的生猪养殖效率进行差异化分析。研究结果表明,总体来看,中国规模化生猪养殖效率均呈现正向增长,其中,小规模养殖效率水平最高,中规模次之,大规模最低;从省际和区域层面看,不同省份不同区域在不同规模养殖下呈现出不同的养殖效率;从时序变化看,研究期内3种规模的养殖效率变化趋势几乎一致,整体呈“W”型。