新台糖16号在广东两年区试结果分析   总被引：1，自引：0，他引：1  

龙永惠  曹干  陈景益  陈大钊 《亚热带农业研究》1999,(3)

两年６点新植、宿根区域试验结果表明,新台糖１６号主要农艺性状较好,是个早熟而不孕穗的高糖品种。早熟性和蔗糖分优于新台糖１０号,略差于新台糖１号。新植、宿根的公顷产蔗量均高于粤糖６３－２３７、新台糖１号和新台糖１０号。新台糖１６号公顷含糖量显著高于粤糖６３－２３７,略高于新台糖１号和新台糖１０号。  相似文献   

DISTINGUISHING RHINITIS AND NASAL NEOPLASIA BY RADIOGRAPHY     

M. Russo  DVM  C.R. Lamb  MA  VexMB  S. Jakovljevic  DVM  MSc  DVR 《Veterinary radiology & ultrasound》2000,41(2):118-124

To compare the incidence of radiographic signs in dogs with rhinitis and primary nasal neoplasia and to assess the performance of observers for distinguishing these conditions, the nasal radiographs of 72 dogs with either rhinitis (n = 42) or primary nasal neoplasia (n = 30) were examined by two independent observers using custom-designed forms to record their interpretations. Rhinitis was associated with a higher incidence of focal or multifocal lesions, localised soft tissue opacities, lucent foci, and a lack of frontal sinus involvement. Neoplasia was associated with soft tissue opacities and loss of turbinate detail that affected the entire ipsilateral nasal cavity, signs of invasion of the bones surrounding the nasal cavity, and soft tissue/fluid opacities within the ipsilateral frontal sinus. The signs with the highest positive predictive value (PPV) for rhinitis were absence of frontal sinus lesions and lucent foci in nasal cavity (PPV of each 82%), and invasion of surrounding bones for neoplasia (PPV 88%). There were no significant differences in the position of the lesion within the nasal cavity, incidence of unilateral versus bilateral lesions, calcified lesions, or absence of teeth. There was moderate agreement between observers about the diagnosis (kappa 0.59). Areas (SE) under ROC curves were 0.94 (0.03) and 0.96 (0.03) for observers A and B, respectively (not significantly different; P = 0.68). These results indicate a high accuracy for radiologists examining dogs with nasal diseases. Differentiation of rhinitis and nasal neoplasia should be based on finding combinations of radiologic signs that together have a high PPV. Differences in interpretation between experienced observers in this study suggest that certain signs are potential sources of error.  相似文献   

INDO-BLIGHTCAST – a model for forecasting late blight across agroecologies     

B.P. Singh  P.M. Govindakrishnan  Islam Ahmad  Shashi Rawat  Sanjeev Sharma  J. Sreekumar 《国际虫害防治杂志》2016,62(4):360-367

A late blight forecasting model “INDO-BLIGHTCAST” has been developed at the Central Potato Research Institute, Shimla, India using meteorological data and late blight appearance dates at four locations in the Indo-Gangetic plains. The model involves computation of physiological days (P-days) and mean relative humidity (RH) of the night, accrued over seven consecutive days. Late blight was predicted to appear within 15 days if moving cumulative effective temperature (P-days) and RH exceeded 52.5 and 525, respectively for seven consecutive days. The developed model was also tested against independent data sets at three locations in the plains, two in plateau region and three in the hills. Statistical comparisons of observed and predicted dates of late blight appearance showed that the mean absolute error was 10.48, while the residual mean square error was only 13.17 indicating that the errors were quite low. The Willmott D index was 0.84 which is quite close to unity thus indicating high accuracy of model predictions and its applicability across regions and seasons. Receiver operating characteristic analysis also confirmed the superiority of this combination (accuracy of 73.6%, AUC of 0.725) to predict late blight appearance as well as its non-appearance in unfavourable years.  相似文献   

Assessing the potential impacts of climate change on the alpine habitat suitability of Japanese stone pine (Pinus pumila)     

Masahiro Horikawa  Ikutaro Tsuyama  Tetsuya Matsui  Yuji Kominami  Nobuyuki Tanaka 《Landscape Ecology》2009,24(1):115-128

To assess the potential distribution of Pinus pumila, a dominant species of the Japanese alpine zone, and areas of its habitats vulnerable to global warming, we predicted potential habitats under the current climate and two climate change scenarios (RCM20 and MIROC) for 2081–2100 using the classification tree (CT) model. The presence/absence records of P. pumila were extracted from the Phytosociological Relevé Database as response variables, and five climatic variables (warmth index, WI; minimum temperature for the coldest month, TMC; summer precipitation, PRS; maximum snow water equivalent, MSW; winter rainfall, WR) were used as predictor variables. Prediction accuracy of the CT evaluated by ROC analysis showed an AUC value of 0.97, being categorized as “excellent”. We designated Third Mesh cells with an occurrence probability of 0.01 or greater as potential habitats and further divided them into suitable and marginal habitats based on the optimum threshold probability value (0.06) in ROC analysis. Deviance weighted scores revealed that WI was the largest contributing factor followed by MSW. Changes in habitat types from the current climate to the two scenarios were depicted within an observed distribution (Hayashi’s distribution data). The area of suitable habitats under the current climate decreased to 25.0% and to 14.7% under the RCM20 and MIROC scenarios, respectively. Suitable habitats were predicted to remain on high mountains of two unconnected regions, central Honshu and Hokkaido, while they were predicted to vanish in Tohoku and southwestern Hokkaido. Thus P. pumila populations in these regions are vulnerable to climate change.  相似文献   

喀斯特森林植被自然恢复过程中土壤有机碳库特征演化   总被引：7，自引：0，他引：7  

黄宗胜  符裕红  喻理飞 《土壤学报》2013,50(2):306-314

采用空间代替时间的方法,研究了茂兰喀斯特森林自然恢复过程中土壤有机碳库特征,结果表明:土壤容重(0～10 cm土层0.94～1.15 g cm-3,＞30 cm土层0.98～1.19 g cm-3)、石砾含量(0～10 cm土层19.93 ～26.61％,＞30 cm土层20.36 ～32.11％)随恢复进展而减少,随土层加深而增加;土壤容积(0～10 cm土层20.13 ～22.02 m3,＞30 cm土层4.16～6.87 m3)、有机碳含量(0 ～10 cm土层21.14 ～52.67 g kg-1,＞ 30 cm土层11.15 ～25.93 g kg-1)、有机碳密度[(0 ～ 10 cm土层1.91 ～4.03 kg m-2,＞ 30 cm土层0.39～1.96 kgm-2)、有机碳储量(900 m2样地0 ～ 10 cm土层0.538 ～0.883 t,＞30 cm土层0.039 ～0.137 t)、易氧化碳含量(0～10 cm土层5.28 ～33.25 g kg-1,＞ 30 cm土层5.98 ～ 14.13 g kg-1)均随恢复进展而增加,随土层加深而减少;随恢复进展0 ～ 20 cm土层有机碳稳定性增强、活性降低,＞20 cm土层则相反;随土层加深有机碳稳定性增强、活性降低;土壤有机碳随恢复进展总体上具碳汇效应,且早期其量少质低、表聚性强、碳汇效应不显著、固碳潜力大,后期则相反.加强保护喀斯特森林,使其自然恢复,有利于土壤质量的提高和有机碳的累积.  相似文献   

Botanical Epidemiology: Some Key Advances and its Continuing Role in Disease Management   总被引：1，自引：0，他引：1  

Laurence V. Madden 《European journal of plant pathology / European Foundation for Plant Pathology》2006,115(1):3-23

  相似文献   

生态调度专刊—鱼类产卵行为与生态水文指标响应关系研究-以长江四大家鱼为例          下载免费PDF全文

班学君  樊博  刘瀚  俞立雄  林俊强  夏继红  张迪 《水生态学杂志》2024,45(1):67-74

四大家鱼作为我国重要淡水经济鱼类，近年来产卵规模大幅衰减，水文条件作为影响家鱼自然繁殖的重要因素，确定四大家鱼产卵行为与生态水文指标响应关系对保护四大家鱼早期资源具有重要意义。本文采用ROC曲线、分类回归树、Logistic回归等方法以长江中游宜昌段为研究区域，将生态水文指标对家鱼产卵刺激划分为“无效、低效、高效”多分类问题，应用不同数据挖掘方法，分析家鱼产卵行为与生态水文指标响应关系，并对比研究了不同方法间的性能与优缺点。结果显示，ROC曲线判别准确率、预测准确率、模型鲁棒性均最优，认为ROC曲线是本次研究中判定生态水文指标对四大家鱼产卵规模影响的最优方法。当流量日增量大于1370m3/s且两次洪峰间隔时间大于7.5d时可以引起四大家鱼高效产卵响应。辨识出高效刺激家鱼产卵的生态水文指标及其阈值，将对生态调度的优化改进具有重要的现实意义。  相似文献   

甘蔗品种新台糖20号、新台糖18号农艺性状试验初报     

杨景  陈兆 《亚热带农业研究》1998,(3)

以当家品种“粤糖６３／２３７”作对照品种进行对比试验，结果表明，“新台糖２０号”、“新台糖１８号”的产量和蔗糖份，均高于对照品种，增产增糖均达到极显著水平，各性状表现良好。“新台糖２０号”和“新台糖１８号”均是适合遂溪县蔗区种植的、很有早熟高产高糖苗头的甘蔗品种。  相似文献   

冬植甘蔗新台精1号高产栽培生态学研究──Ⅰ.生长规律与生长模型的研究     

谢贵水  蒋菊生  林位夫  王岳坤  蔡明道  陈俊明 《热带作物学报》1998,(4)

分析比较7种常用的一元生长模型，采用非线性最小二乘法的Marquardt迭代同步求解模型参数的方法，对冬植甘蔗新台糖1号的生长模型进行拟合，得到株高的最佳生长模型为：模型的拟合精度高、适用性强，可在儋州市那大镇附近蔗区应用（其他地区可作参考）。经模型性质分析，得出植后94d（4月下旬）甘蔗开始进入快速生长期，生长速度最快出现在植后157d（6月下旬），植后233d（9月中旬）甘蔗开始进入工艺成熟期。  相似文献   

新台糖系列品种后代实生苗甘蔗黑穗病抗性研究     

夏红明  胡鑫  姚丽  赵俊  昝逢刚  刘家勇  赵丽萍  吴才文  杨昆  覃伟  赵勇  陈学宽  吴转娣  赵培方 《中国糖料》2019,(3):19-22

新台糖系列甘蔗品种是我国重要的甘蔗品种和亲本,利用其作为亲本,易于培育出更为优良的杂交后代。本研究利用7个新台糖系列甘蔗亲本,配制20个组合,对其杂交组合进行黑穗病抗性评价,结果表明:20个组合人工接种黑穗病菌后全部发病,参试组合平均丛感病率与平均茎感病率为极显著正相关;组合间丛感病率和茎感病率均为极显著差异,说明人工接种胁迫试验能够将抗病性强、中、弱的组合鉴别出来,从而将感病严重的组合进行淘汰;通过聚类分析,20个组合抗病性可分为3种类型,组合3和12号聚为一类,发病最重,平均丛感病率、平均茎感病率分别为24.74%、11.5%和28.48%、18.44%,该类组合可以予以淘汰,组合7、10、11和13号聚为二类,发病中等,其余组合聚为三类,发病较轻。  相似文献