Yield Stability of Winter Wheat (Triticum sp.) Cultivars and Lines

The purpose of this study was to compare responsiveness to environment as well as the stability of newly developed promising lines with traditional commercial cultivars. Subject research was conducted in Ankara between 1983-1989 on common and durum wheat cultivars and lines. Regression coefficient (b) was used as the criterion of genotypes' responsiveness to environment whereas deviation from regression (S²d) and coefficient of determination (r²) were used as stability parameters. Each experiment year was regarded as an environment and yield average of each year was used as the environmental index.
In consequence of the research, it was determined that new varieties with high yield, adaptable to diverse environments could be developed by means of hybridizations between parents having different genetic characteristics which were provided from diverse ecological regions.     

闽南—台湾浅滩渔场中国枪乌贼生物学特性研究

头足类是最具开发潜力的渔业种群之一,然而其资源易受环境变化影响,复杂的交互作用致使二者空间关系呈现非均一性。中国枪乌贼 (Uroteuthis chinensis) 是南海北部近海重要的经济物种,且在渔业群落结构中占据优势种地位,故正确理解与掌握该物种资源-环境关系的空间特征,有助于该资源的保护与利用。基于南海北部近海2014年夏季的渔业资源调查数据,构建了地理权重回归模型 (Geographical weighted regression, GWR),探索该海域中国枪乌贼的资源分布与海洋环境关系的空间特征,阐述主要影响因子。模型评价指标结果表明,GWR的最小赤池信息准则 (Akaike Information Criterion, AIC) 和校正决定系数 (Adjusted R-Squared, Uroteuthis chinensis is an important economic species in the offshore waters of northern South China Sea, occuping a dominant position in the fishery community structure. Therefore, understanding the spatial characteristics of the resource-environment relationship is beneficial to its development, utilization and protection. Based on the fishery resources survey data in the offshore waters of northern South China Sea in summer of 2014, we established a geographically weighted regression (GWR) model to explore the spatial characteristics of the relationship between the resource distribution of U. chinensis and the marine environment in this area, and to reveal the main influencing factors. The results of model evaluation indexes show that the minimum Akaike information criterion (AIC) and adjusted R-Square (相似文献   

End-of-Season Carcass and Reproductive Traits in Original and Replacement Male Broiler Breeders

Reproductive efficiency of male broiler breeders declines toward the end of a production cycle. It is common to add young, replacement males (spiking) to a breeder flock to maintain or increase fertility. To date, no study has reported if there are differences in the carcass and reproductive morphology between original and spiked males at the end of the breeding period. In this study, the weight, fleshing traits, footpad condition, and testes size of 327 Hubbard males (237 original and 90 replacement) from a commercial operation were examined. The original birds (63 wk of age) had significantly higher BW, breast weight, girth measurement, keel length, and spur length than the spiked males (48 wk of age). While external indicators of size and fleshing differed betweenreplacement and original roosters, testis weight was not affected by the age of the bird. It was found that average testis weight correlated well with BW in birds in which testicular regression had not taken place but only weakly with spur length. Because original males had a higher BW and were more heavily fleshed than replacement males, their ability to successfully complete matings may have been impeded. Further research is needed to link growth profiles with semen quality, sexual behavioral, and longevity of a male breeder in a commercial flock.     

基于空间Logistic的山西省火灾风险评价与火险区划

利用山西省2002-2012年MODIS卫星遥感数据,建立了描述火灾空间分布及其影响因子的空间Logistic风险模型,从省域空间尺度和较长时间尺度上,开展火险评价与火险区划研究。结果表明,通过空间采样构建的Logistic火灾风险模型拟合效果很好。在显著性水平为0.05的情况下,通过模型系数检验和Wald检验,相对运行特征值(ROC)为0.757。经图层运算得到火烧概率分布图,并将山西省分为无火险区、低火险区、中火险区、高火险区和极高火险区。对山西省火灾风险空间变化影响较为显著的因子为高程(GC)、土地利用类型(LT)、地表温度(LST)、归一化差值植被指数(NDVI)和全球植被湿度指数(GVMI),对火灾风险空间变化影响不显著的因子则仅有坡度(PD)和道路可达性(DL)。NDVI和LST对火灾影响在省内全局显著,而GC、LT和GVMI仅对省内部分地区的火灾影响显著。山西省按火灾影响因素可划分为7类区域,不同类型区域应确定不同的防火重点,制定差别化的防火策略。     

中蜂越夏及秋季繁殖试验

在贵州锦屏进行的中蜂越夏及秋繁试验表明，４框以上的群势越夏较为安全。越夏期间每框足蜂约需补喂白糖１．５公斤。越夏后，蜂群群势约下降１／３左右。蜂群在越夏期间飞逃的主要原因是缺蜜及巢虫危害。当地中蜂在秋季大流蜜初期发生分蜂，分蜂群势均为８框足蜂以上，７框左右不分群。为控制不同起繁群势的蜂群在秋季大流蜜初期正好繁殖到７框左右，不致因分蜂影响秋冬蜜的采集，应分期起步秋繁。根据本试验所建秋季起繁群势（ｘ）与达７框群势所需繁殖天数（ｙ）之间的回归直线方程推算，在起繁群势为１～５框蜂量时，最适的秋繁开始期，１框群为７月３１日，２框群８月１０日……蜂群的基础群势每增加一框，则秋繁开始期应相应推迟１０～１１天。     

Timing and temperature thresholds of heat stress effects on fertility performance of different parity sows in Spanish herds

High temperature is an environmental factor that impairs sow fertility. In this study, we identified the critical weeks for heat stress effects on aspects of fertility performance, namely weaning-to-first-service interval (WSI) and farrowing rate (FR). We also examined the threshold temperatures above which the fertility performance deteriorated and whether there were any differences between parities regarding heat stress effects or thresholds. Performance data of sows in 142 herds from 2011 to 2016 were matched to appropriate weekly averaged daily maximum temperatures (T_max) from weather stations close to the herds. Two types of ratios (i.e., ratio for WSI and odds ratio for FR) were used to identify the critical weeks for heat stress by comparing the respective measures for two sow groups based on T_max in different weeks around weaning or service events. The ratios for WSI were calculated between groups of sows exposed to T_max ≥ 27 °C or <27 °C in each week before weaning, with the T_max cutoff value based on a recent review study. Similarly, the odds ratios for FR for the two groups were calculated in weeks around service. The weeks with the largest differences in the fertility measures between the two T_max groups (i.e., the highest ratio for WSI and the lowest odds ratio for FR) were considered to be the critical weeks for heat stress. Also, piecewise models with different breakpoints were constructed to identify the threshold T_max in the critical week. The breakpoint in the best-fit model was considered to be the threshold T_max. The highest ratios for WSI were obtained at 1 to 3 wk before weaning in parity 1 and 2 or higher sow groups. The threshold T_max leading to prolonged WSI was 17 °C for parity 1 sows and 25 °C for parity 2 or higher sows. Increasing T_max by 10 °C above these thresholds increased WSI by 0.65, and 0.33 to 0.35 d, respectively (P < 0.01). For FR, the lowest odds ratios were obtained at 2 to 3 wk before service in parity 0, 1, and 2 or higher sow groups. The threshold T_max leading to reductions in FR was 20, 21, and 24 to 25 °C for parity 0, 1, and 2 or higher sow groups, respectively. Increasing T_max by 10 °C above these thresholds decreased FR by 3.0%, 4.3%, and 1.9% to 2.8%, respectively (P < 0.01). These results indicate that the critical weeks for heat stress were 2 to 3 wk before service for FR and 1 to 3 wk before weaning for WSI. The decreases in fertility performance in parity 0 to 1 sows started at temperatures 3 to 8 °C lower than in parity 2 or higher sows.     

岩羊和马鹿对人与机动车反应的差异分析

人为干扰会对野生动物种间关系、个体适合度、群落结构和繁殖成功率等产生中长期的影响。因此,研究野生动物反干扰行为对于我们认识该物种对其生境的行为适应和进化机制具有重要意义。2017年11—12月在内蒙古贺兰山国家级自然保护区内通过建立多元逻辑斯蒂回归模型研究了岩羊(Pseudois nayaur)、马鹿(Cervus elaphus)的反干扰策略,本研究共设置33条样线,记录了10种在人为干扰下可能会影响岩羊、马鹿反应行为的变量,经模型分析发现影响岩羊反应行为的变量有5种,影响马鹿反应行为的变量有4种,共同影响因子分别是干扰源、性别、头的朝向和地形特征,而植被类型则只对岩羊产生影响。最后根据逻辑模型得出的数据计算发生比,从而了解各个分类变量与反应行为的关系。     

鲁西牛生长发育规律研究

[目的]为进一步了解鲁西牛生长发育规律及体重与各体尺间的内在联系。[方法]研究利用SPSS 26.0软件,分析鲁西牛体重与各体尺性状间的相关性,建立各体尺性状对体重的最优回归模型。[结果]结果显示鲁西牛群体I中所有体尺性状均与体重间存在极显著正相关(P<0.01),其中腹围(X5)、体高(X1)和胸围(X3)通过较强的直接作用影响体重(Y)。鲁西牛体尺(X)对体重(Y)的最优回归模型为：Y=2.374X1+2.455X3+2.721X5-923.527 (R=0.955,P<0.01)。根据最优回归模型,对鲁西牛群体II的体重数据进行预测,并将群体I和群体II进行合并为群体III,分析鲁西牛群体III体重与体高(X1)、胸围(X3)和腹围(X5)的相关性,并对相关系数进行分解。结果显示,体重(Y)相关程度最高的胸围(X3)性状对体重的直接作用最大(P=0.939),与体重间相关系数最小的体高(X1)则是通过较强的间接作用影响体重。[结论]综上,体高、胸围和腹围可作为3个重要参考指标,为后续合理评估鲁西牛生长发育性能提供理论参考。     

鄂尔多斯油蒿-本氏针茅群落生物量

在5年逐月观测基础上，利用多元分析方法，建立鄂尔多斯高原沙地油蒿－－本氏针茅群落地上生物量对气候因子影响的逐月回归模型，结果表明，气候因子在不同时期对植物生长的作用差异显著，降水因子在各月都是影响生物量的显著因子，二者呈正相关，日照时数仅在6月对生物量产生显著影响，。平均气温在各月都不对生物量产生显著影响，7－10月各月生物量都受前月生物量的显著影响，说明植物生长的持续性对生物量的形成和积累是重要的，应用本文建立的模型对3种不同气候条件下，各月生物量的波动范围进行预测，建立累积回归模型，将逐月回归模型，累积回归模型的模拟值与实测值进行比较，结果在多数年份，逐月回归模型都比累积回归模型更接近实测值，与传统的累积回归模型相比，本模型具有三方面的优越性，即可揭示气候影响植物生长的重要细节，具有预测能力以及精度更高，因此是对传统累积气候模型进行的有益改进。