陆地棉抗病虫性和一些重要经济性状之间的相互影响

1996～1998年,分别在自然病圃、人工病圃、网室和温室对19份陆地棉品系的抗病虫性和经济性状进行了全面鉴定。结果表明,这些陆地棉品系对不同病虫害的抗性相互之间存在高度正相关。其抗性、产量和品质主要指标之间也存在密切的正向或负向相关关系。在育种中如能协调好这些重要性状的相互关系,就能培育出高产、优质和兼抗病虫的棉花新品种。     

基于多源信息融合的中文农作物病虫害命名实体识别

随着农作物病虫害研究文献的快速增长,对农作物病虫害领域文献进行文本挖掘变得越来越重要。开发有效、准确的农作物病虫害命名实体识别系统有助于在农作物病虫害相关研究报告中提取研究成果,为农作物病虫害的治理提供有效建议。本文针对中文农作物病虫害数据集缺失问题,提出了基于半远程监督的停等算法,利用该算法构建中文农作物病虫害领域语料库,大幅度减少标注过程的人工成本和时间成本;同时,提出了中文农作物病虫害命名实体识别模型（Agricultural information extraction, Agr-IE）,该模型基于BERT-BILSTM-CRF,辅以多源信息融合（多源分词信息和全局词汇嵌入信息）丰富字符向量,使其充分结合字符级与词汇级的信息,以提高模型捕捉上下文信息的能力。实验表明,该模型可以有效地识别病害、虫害、药剂、作物等实体,F1值分别为96.56%、95.12%、94.48%、95.54%,并对识别难度较大的病原实体具有较好的识别效果,F1值为81.48%,高于BERT-BILSTM-CRF、BERT等模型的相应值。本文所提模型在MSRA和Weibo等其他领域数据集上与CAN-NER、Lattice-LSTM-CRF等模型进行了对比实验,并取得最佳的识别效果,F1值分别为95.80%、94.57%,表明该算法具有一定的泛化能力。     

土壤消毒机蒸汽输送装置的设计与数值模拟

土传病虫害严重制约了设施栽培的发展。蒸汽消毒相比于其他土壤消毒方法,具有诸多优点,其利用高温杀死土壤中的病虫草害,提高了土壤的通透性和排水性,且对环境无任何污染。为此,基于脉冲式土壤蒸汽消毒机的总体结构,重点对蒸汽输送装置的注射针头以及蒸汽罩盖、针头间距、针头数目等蒸汽盘关键结构参数进行了设计。利用Fluent软件对土壤传热模型进行了数值模拟,分析了注射针头周围土壤的温度分布云图。结果表明:持续施加蒸汽7min、停止通蒸汽35min后,在半径10cm内、深度21cm范围内,土壤的温度能保持在90℃以上,验证了蒸汽输送装置结构的合理性。     

丹参开花与繁育特性研究

 通过田间观察和人工授粉等方法, 对丹参( Salvia miltiorrhiza Bge. ) 的开花生物学和繁育特性进行了初步研究。结果表明: 丹参为无限开花植物, 总状花序上通常有两性花近50朵, 单花花期5～7d, 从花前2 d到开花6 h花粉活力和柱头可授性都较大, 两者有效可遇期约为1.5 d, 可同花自交; 丹参自交结实和自然结实主要是通过同株异花传粉获得; 结合花粉/胚珠比、杂交指数以及繁育处理的结果认为,丹参不存在无融合生殖, 繁育类型为兼性异交, 自交亲和, 需要传粉者; 传粉媒介主要是蜂类。初步推断丹参为常异花授粉植物, 并对丹参育种中适宜采用的杂交方法及育种途径进行了探讨。     

Comparing fire spread algorithms using equivalence testing and neutral landscape models

We demonstrate a method to evaluate the degree to which a meta-model approximates spatial disturbance processes represented by a more detailed model across a range of landscape conditions, using neutral landscapes and equivalence testing. We illustrate this approach by comparing burn patterns produced by a relatively simple fire spread algorithm with those generated by a more detailed fire behavior model from which the simpler algorithm was derived. Equivalence testing allows objective comparisons of the output of simple and complex models, to determine if the results are significantly similar. Neutral landscape models represent a range of landscape conditions that the model may encounter, allowing evaluation of the sensitivity and behavior of the model to different landscape compositions and configurations. We first tested the model for universal applicability, then narrowed the testing to assess the practical domain of applicability. As a whole, the calibrated simple model passed the test for significant equivalence using the 25% threshold. When applied to a range of landscape conditions different from the calibration scenarios, the model failed the tests for equivalence. Although our particular model failed the tests, the neutral landscape models were helpful in determining an appropriate domain of applicability and in assessing the model sensitivity to landscape changes. Equivalence testing provides an effective method for model comparison, and coupled with neutral landscapes, our approach provides an objective way to assess the domain of applicability of a spatial model.     

The impact of thematic resolution on the patch-mosaic model of natural landscapes

We argue that thematic resolution, i.e., the level of categorical detail of a thematic map expressed by the number of classes included in the map legend, is an inherent component of the scale at which a landscape is analyzed. Changing the number of classes can change the configuration of the patch mosaic as much as changing the grain does. We address recent calls in this and other journals to deepen research in this topic. In particular, we report how thematic resolution affects the patchiness of mosaics representing natural landscapes, which have seldom been studied in this respect. We selected seven 50 × 50 km landscapes within national parks, each representative of a world biome. We applied an object-based unsupervised classification to Landsat TM imagery of these landscapes using increasing numbers of classes, between 2 and 50, and derived curves of mean patch size and patch density for each site. Our results are consistent with previous findings in that the patchiness of output mosaics increases monotonically with increasing thematic resolution, with a higher rate of increase up to eight classes that declines until it becomes roughly constant for more than 16 classes. However, this constant rate of increase is still considerable, meaning that, at least for natural landscapes, there is no threshold beyond which the patch-mosaic model is independent of the conceptual filter applied. This dependence on human fiat calls for re-thinking the patch-mosaic paradigm.     

百合鳞片扦插繁殖的研究进展

鳞片繁殖是百合种球生产过程中的关键环节.综述了迄今为止有关鳞片扦插技术、影响鳞片扦插繁殖的因素和鳞片繁殖生理等方面的研究成果,并对该领域存在的问题进行了简析,对今后的研究重点进行了展望.     

银杏丰产栽培技术

银杏为我国传统的名贵树种,其生长缓慢、结实晚,一般要20多a才能开花结实,并且产量低。阐述银杏的生物学特征、繁殖方式、栽培管理方法、修剪整形及病虫害防治等实用技术,旨在为扩大银杏园林生产、提高银杏的种植质量和产量提供有益的参考。     

水稻病虫害统防统治工作的成效与思考——来自浙江省磐安县的实践

病虫害统防统治在保障国家粮食安全和促进农民增收增效方面取得了显著成效。磐安县位于浙江省中部山区,生态环境复杂,水稻病虫害种类、种群及发生规律复杂,病虫防治压力大。本文通过2008-2016年磐安县统防统治的探索,对磐安县水稻病虫害统防统治工作的成效及存在问题进行了分析,并提出推进统防统治的对策与建议。     

2016年我国审定的水稻品种及基本特性分析

分析了2016年我国水稻品种的审定情况及通过省级以上审定水稻品种的基本特性.结果表明,2016年我国通过省级以上审定的水稻品种共有492个次(有13个品种通过两个及以上省份审定),其中,籼型常规稻36个、籼型两系杂交稻137个、籼型三系杂交稻166个、粳型常规稻87个、粳型杂交稻25个(其中19个为籼粳杂交稻)、 不育系41个.区试平均产量籼型常规稻为501.36 kg/667 m2,比区试对照增产3.86%;籼型两系杂交稻为592.54 kg/667 m2,比区试对照增产5.46%;籼型三系杂交稻为552.96 kg/667 m2,比区试对照增产5.16%;粳型常规稻为624.94 kg/667 m2,比区试对照增产7.48%;粳型杂交稻为651.96 kg/667 m2,比区试对照增产8.91%.品种品质表现是粳稻好于籼稻,常规稻好于杂交稻,优质达标率粳稻为51.79%、籼稻为43.95%,常规稻为56.91%、杂交水稻为41.77%.并列举了一些对单个病害抗性表现较好的品种.