防治落叶松枯梢病化学药剂筛选试验

本试验对１７种杀菌剂和１８种植物调节剂进行了筛选。结果表明，７种杀菌剂对落叶松枯梢病杀菌作用强，７种植物调节剂有抑菌作用，森保１号对苗木有抑制徒长和复壮作用，混合施用时，Ａ－Ｂ－Ｂ，Ａ－Ｂ－Ｃ组合药剂最佳。     

香菇新菌株"庆科20"选育报告

以香菇主栽菌株"庆元9015"为母本,选出优良变异株"庆科20",该菌株具有独特的PCR扩增条带和蛋白电泳图谱,与"庆元9015"等菌株具有明显的遗传差异.该菌株春栽鲜菇单产比"庆元9015"和"241-4"分别增加7.7%和16.5%;秋栽鲜菇单产比"庆元9015"和"Cr02"分别增加3.3%和18.9%;花菇栽培平均单产比"135"增加20.7%.     

浅谈岩石边坡护坡植物选择

综述了护坡植物研究背景、现状、护坡植物功能、护坡植物选择的依据与标准以及常用护坡植物种类,提出了以研究野生岩生植物为突破点的解决途径。     

Intake of lambs offered ad libitum access to one of three iso-caloric and iso-nitrogenous mixed rations or a choice of all three foods

Modern practices for finishing livestock typically involve offering a single uniform food to large groups of presumably similar animals in an attempt to increase efficiency. Nevertheless, differences in physiology and behavior still cause variations in performance that may precipitate biological inefficiencies by not appreciating the importance of differences among individuals, the capacity of animals to select foods that meet ever-changing individual needs, and the dynamic nature of a nutrient's value to an animal. We examined intakes of groups of lambs offered a single food or three foods differing only in their proportions of cereal grains: High, 70%; Medium, 50%; Low, 40%. Foods consisted of the same ingredients (barley, corn, sugar beet pulp, alfalfa, soybean meal, grape pomace, feather meal, wheat straw), had similar levels of metabolizable energy (ME) and crude protein (CP), and met NRC requirements. We hypothesized that intake and performance would be greater when animals had a choice of foods because high grain concentrations would not limit intake of individuals unable to process high amounts of energy from grain. In general, lambs offered a Choice of the three foods ate more, converted food more efficiently, and cost less per unit gain than lambs fed the High food (P < 0.05). Animals fed the Low or Medium foods were intermediate in their responses between these two extremes. Within Choice, preference for High, Medium, and Low shifted from the beginning (21 d) to the finishing (21 d) periods of the trial. Though lambs in the Choice treatment preferred Low > Medium and High in the beginning stage of the trial, their preferences became pronounced as we increased the amount of grain in each food during the finishing period (P < 0.05). Collectively, our findings suggest improved intake, rate of gain, and feed efficiency can result when animals are allowed to select their diets from biochemically complementary foods, possibly enabling them to realize greater benefits than typically thought from inexpensive forages. In addition, offering animals choices is an alternative to feeding uniform diets of rapidly fermented energy, a major cause of illness in feedlots.     

Genetic correlations between osseous fragments in fetlock and hock joints, deforming arthropathy in hock joints and pathologic changes in the navicular bones of Warmblood riding horses

The results of a standardized radiological examination of 5231 Hanoverian Warmblood horses were used to investigate heritability of and genetic correlations between prevalent radiographic findings in the equine limbs. Radiographic findings were categorized by joint location and type of visible alterations and analyzed as all-or-none traits. Heritabilities and correlations were estimated multivariately for most prevalent radiographic findings in equine limbs using Residual Maximum Likelihood (REML) and Gibbs Sampling (GS). Linear animal models and linear sire models were used for REML; sire threshold models were used for GS analyses. Heritabilities and residual correlations from linear model analyses were transformed from observed scale to underlying liability scale. Osseous fragments were seen in fetlock joints (OFF) of 23.5% and in hock joints (OFH) of 9.2% of investigated horses. Deforming arthropathy in hock joints (DAH) was diagnosed in 12.0% and pathologic changes in navicular bones (PCN) in 25.8% of investigated horses. Heritabilities differed little between analyses with animal and sire models and with REML and GS. Ranges of heritability estimates were h² = 0.16–0.44 with REML and h² = 0.07–0.43 with GS. Genetic correlation estimates were larger in GS than in REML analyses. Additive genetic correlation between OFF and DAH was positive (r_g = 0.25 to 0.77). Negative additive genetic correlations were determined between OFF and OFH (r_g = − 0.17 to − 0.82), between OFH and DAH (r_g = − 0.14 to − 0.81), and between OFH and PCN (r_g = − 0.19 to − 0.26). No relevant additive genetic correlations were estimated between PCN and OFF, and between PCN and DAH. The results of the present study indicate that the prevalences of common radiographic findings in the limbs of young riding horses are relevantly influenced by genetics and probably caused by different genes. Genetic correlations between radiological health traits therefore deserve closer attention in horse breeding. The quantitatively most important radiographic findings should be concurrently considered as individual traits in order to provide for general improvement of radiological health of the limbs of young Warmblood riding horses.     

玉米定向精播种粒形态与品质动态检测方法

为满足玉米定向精播对种子外形和品质的要求,设计了一种玉米种子精选装置,并研究了玉米种粒动态检测算法。经过脱粒并筛除杂质的种粒投入玉米种子精选装置,分两列两层传输,完成玉米种粒的动态检测。通过计算种子胚根尖端的方向,排除了种粒的重复检测现象;以人工选取的100粒标准种粒外形参数为基础建立合格种粒特征参数库,实现对种粒外形的检测;依据合格种粒和重度霉变种粒表皮亮度差异较大的特点,基于图像饱和度分量对重度霉变种粒加以检测;依据轻度霉变种粒表皮呈现块斑的特点,利用种粒的R、G、B颜色平均值检测轻度黑色霉变;以种粒黄色区域补洞后对应原种粒(B-R)的值,判断种粒的轻度白色霉变和轻度破损;对于外形和霉变检测合格的种粒,通过分析种粒区域中白色区域的大小,进行玉米种粒胚芽朝向的判断,为后续种粒定向包装和定向播种提供了依据。对280粒各品种玉米种子进行实时检测,每粒种子的平均检测时间约为14 ms,重复种粒判断准确率为95%,种粒合格性检测准确率为96.1%,胚芽朝向判断准确率为97.1%。     

Bias—Is it a problem,and what should we do?

Observational studies are prone to two types of errors: random and systematic. Random error arises as a result of variation between samples that might be drawn in a study and can be reduced by increasing the sample size. Systematic error arises from problems with the study design or the methods used to obtain the study data and is not influenced by sample size. Over the last 20 years, veterinary epidemiologists have made great progress in dealing more effectively with random error (particularly through the use of multilevel models) but paid relatively little attention to systematic error. Systematic errors can arise from unmeasured confounders, selection bias and information bias. Unmeasured confounders include both factors which are known to be confounders but which were not measured in a study and factors which are not known to be confounders. Confounders can bias results toward or away from the null. The impact of selection bias can also be difficult to predict and can be negligible or large. Although the direction of information bias is generally toward the null, this cannot be guaranteed and its impact might be very large. Methods of dealing with systematic errors include: qualitative assessment, quantitative bias analysis and incorporation of bias parameters into the statistical analyses.     

日光温室西瓜嫁接砧木筛选试验

为了筛选出适合内蒙古地区温室西瓜嫁接栽培的优良砧木,以西瓜品种‘国豫2号’为接穗,与引进的7个南瓜砧木品种进行了嫁接试验,试验对不同砧木嫁接西瓜与自根苗西瓜的嫁接成活率、田间生长表现、果实性状及产量等进行了比较分析。结果表明:‘铁木真’、‘京欣砧3号’、‘正大亲兄弟’作砧木的嫁接西瓜苗综合性状较好,表现为嫁接成活率达到了95%以上,亲和力好,定植后生长势较强,抗病性强,667 m2产量达到3 500 kg,对果实品质基本无影响,适宜作为当地日光温室西瓜嫁接栽培的砧木。     

宁夏核桃新品种引进选优和栽培研究

在对清香、新疆(温)185、新疆幸福、新疆33、香玲、上宋6号、辽核1号等全国各地核桃优良品种进行引进选优及适应性调查研究的基础上,筛选出了适宜宁夏生长的晚实核桃优良品种清香,早实核桃优良品种辽核1号;提出了在宁夏发展核桃产业要以清香为主栽品种,辽核1号为搭配授粉树种的种植模式,特别是总结出清香核桃在宁夏表现出的十大优势,对宁夏发展核桃产业具有一定的指导意义。     

The effects of inbreeding on performance traits of adult Pacific oysters (Crassostrea gigas)

Understanding the effects of inbreeding is critical to the long-term viability of shellfish breeding programs, especially as breeders attempt to develop selected lines in hatcheries with small effective population sizes. Inbreeding depression in shellfish is well documented among the offspring of selfed individuals and full-sib crosses. This study was conducted to determine if crossing more distantly related parents would result in measurable inbreeding depression of performance traits in adult Crassostrea gigas raised in a commercial intertidal growing environment. Families were created with expected inbreeding coefficients (F) of 0, 0.0625, and 0.203. Average family yield, individual growth rate, and survival were recorded after the first and second growing seasons. Significant inbreeding depression in yield, individual growth rate and survival was observed after the first growing season in families with F=0.203 (P<0.0001), but not in families with F=0.0625 (P>0.058). After two growing seasons, significant inbreeding depression of yield and individual growth rate was observed in families with F=0.0625 (P<0.01) and F=0.203 (P<0.001). Significant depression of survival at harvest was observed only in families with F=0.203 (P=0.009). These results emphasize the importance of maintaining pedigree records in shellfish breeding programs to help avoid the deleterious effects of inbreeding depression, even among crosses of distantly related parents.