关键词： cultivar   Europe   genetic diversity   Genotyping-by-Sequencing   grasslands   perennial ryegrass   phylogeography   pool-Seq   Quaternary   site frequency spectrum  

摘要： Aim Grasslands have been pivotal in the development of herbivore breeding since the Neolithic and still represent the most widespread agricultural land use across Europe. However, it remains unclear whether the current large-scale genetic variation of plant species found in natural grasslands of Europe is the result of human activities or natural processes. Location Europe. Taxon Lolium perenne L. (perennial ryegrass). Methods We reconstructed the phylogeographic history of L. perenne, a dominant grassland species, using 481 natural populations, including 11 populations of closely related taxa. We combined Genotyping-by-Sequencing (GBS) and pool-Sequencing (pool-Seq) to obtain high-quality allele frequency calls of 500 k SNP loci. We performed genetic structure analyses and demographic reconstructions based on the site frequency spectrum (SFS). We additionally used the same genotyping protocol to assess the genomic diversity of a set of 32 cultivars representative of the L. perenne cultivars widely used for forage purposes. Results Expansion across Europe took place during the Wurm glaciation (12-110 kya), a cooling period that decreased the dominance of trees in favour of grasses. Splits and admixtures in L. perenne fit historical climate changes in the Mediterranean basin. The development of agriculture in Europe (7-3.5 kya), that caused an increase in the abundance of grasslands, did not have an effect on the demographic patterns of L. perenne. We found that most modern cultivars are closely related to natural diversity from north-western Europe. Thus, modern cultivars do not represent the wide genetic variation found in natural populations. Main conclusions Demographic events in L. perenne can be explained by the changing climatic conditions during the Pleistocene. Natural populations maintain a wide genomic variability at continental scale that has been minimally exploited by recent breeding activities. This variability constitutes valuable standing genetic var

关键词： Geographical distribution  

摘要： Climate change is a major factor driving shifts in the distribution of invasive pests. The oriental fruit fly, Bactrocera dorsalis, native to mainland Asia, has spread throughout Southeast Asia and sub-Saharan Africa. Recently, the species has extended its Asian range northward into regions previously thought unsuitable which presents a major new risk to temperate zone agriculture and has invaded Italy. Thus, it is necessary to study how climate change may impact on the global distribution of B. dorsalis. MaxEnt models were used to map suitable habitat for this species under current and future climate conditions averaged from four global climate models under two representative emission pathways in 2050 and 2070. The results highlighted that a total of 30.84% of the world's land mass is currently climatically suitable including parts of the western coast and southeast of the USA, most of Latin America, parts of Mediterranean coastal European regions, northern and coastal Australia, and the north island of New Zealand. Under future climate conditions, the risk area of B. dorsalis in the northern hemisphere was projected to expand northward, while in the southern hemisphere, it would be southward, especially by 2070 under RCP85 with very high greenhouse gas emissions. Future management of this pest should consider the impacts of the global climate change on its potential geographical distribution.

关键词： 盐城市   气候变化特征   农业生产   影响  

摘要： 采用1981-2018年江苏省盐城市气温、降水以及日照时数观测资料,分析了盐城市近38年来的气候变化特征,并探讨了其对农业生产的影响。结果表明,近38年来盐城市年平均温度、四季平均气温均呈显著上升变化趋势,年平均气温的气候倾向率为0.426℃/10年;春、夏、秋、冬四季平均气温的气候倾向率分别为0.574、0.392、0.382、0.355℃/10年。盐城市降水量整体上呈波动增加的变化趋势,气候倾向率为10.11 mm/10年,增加趋势并不明显。盐城市降水年际间波动起伏变化特别大,易引发旱涝灾害,给农业生产造成不利影响。盐城市日照时数主要呈下降的变化趋势,气候倾向率-117.52 h/10年。气候显著变暖,降水量年际间大幅波动以及日照时数显著下降均会影响到盐城市水热光资源的平衡性,进而对各类农作物的正常生长发育以及作物病虫害造成一定影响。只有采取科学有效的措施及时应对异常气候变化,才可以推动盐城市农业持续、健康发展。

关键词： 气候变化   农业发展   影响   吉林东部  

摘要： 农业发展依赖必要的农业气候条件.以吉林省东部地区的通化市、白山市和延边州为研究对象,分析2013—2017年的气象要素特征,结合农业发展数据,阐明气候变化对农业产业布局、粮食产量、农业病虫害、农业自然灾害、农业生产方式的影响,为吉林省农业区划和农业可持续发展提供理论依据.

关键词： 农业   气象灾害   病虫害   气候变化   影响  

摘要： 引起气象变化的因素是很难把控的,一旦出现气候变化,会对农业生产产生极大的影响,如何做好预防工作,需要对其影响因素进行深层次的剖析,研究了天气变化对气象灾害和病虫害的影响,希望能够就农业生产给出可行性的意见和建议,提升农作物的产量和质量。

关键词： 气候变化   农业生产   气象灾害   病虫害  

摘要： 随着近些年全球发展所面临的环境变化风险逐渐加剧,农业生产受到气候变化的影响较为严重,在这种情况下出现气象灾害以及病虫害的情况也在逐渐加剧。因此,研究气候变化对农业气象灾害及病虫害产生的影响,对我国农业发展具有重要意义。

关键词： 气候变化   冬小麦   全要素生产率(TFP)   指数  

摘要： 农业全要素生产率除了受到制度和投资等因素影响外,还受到气候变化的作用。本文以冬小麦为例,在运用指数方法测度1986年~2016年中国冬小麦全要素生产率的基础上,探究了冬小麦生长期气候因素变化对冬小麦全要素生产率的影响。研究表明:1986年~2016年,中国冬小麦全要素生产率呈明显的波动性增长趋势,其中技术进步不断增长,技术效率波动较大;分别采用生长期积温和温度的天数分布两种气温衡量指标回归结果指出气温与冬小麦全要素生产率之间存在非线性关系,高温会显著降低冬小麦全要素生产率;高温主要通过降低冬小麦技术效率和技术进步进而降低全要素生产率,其中对技术效率的影响起主导作用。本文提出健全气象预报预警体系、调整品种布局、加强耐高温品种研发、提高科研成果转化和技术推广效率等建议。

关键词： climate change   Ghana   Structural Ricardian Model  

摘要： We apply a Structural Ricardian Model (SRM) to farm-level data from Ghana for seven principal food crops in order to model the factors which influence farmers' decisions about which food crops to grow and the revenue conditional on these choices. Our application of the SRM incorporates a flexible functional form to allow for the possibility that the effects of temperature and rainfall may not be linearly separable. We use this model as a basis for simulations of the effects of climate change. These simulations suggest that extreme climate change will lead to a significant reduction in the average net revenue per hectare from maize, which accounts for over half of current food production. Across a range of climate change scenarios, there is also substantial substitution of maize for heat-tolerant millet, and a reduction in the cultivation of other crops. Under most of the climate change scenarios that we consider, these results imply a substantial reduction in the aggregate value of agricultural production, since millet is the lowest-value crop.

关键词： Representative agricultural pathways   Climate change adaption   Agricultural land uses  

摘要： This paper investigates climate change adaptation through agricultural land uses under three regional representative agricultural pathways, using data from the Pacific Northwest of the United States of America. The three pathways are bottom-up projections of local biophysical and socioeconomic conditions, and they are consistent to downscaled regional climate scenarios. Results show that changes in agricultural land uses under future climate change and representative agricultural pathways are substantially different, compared with results not considering representative agricultural pathways. This finding suggests that climate change impacts and adaptation may be underestimated or overestimated if future biophysical and socioeconomic developments are not incorporated, particularly in regional agricultural assessments of climate change adaptation. One implication from this analysis for global adaptation strategies is the need for future infrastructure supports to maintain a climate-resilient agricultural production system due to changes in agricultural land uses.

关键词： Water evaluation and planning (WEAP)   Climate change adaptation strategies   Decision-making criteria   Multi-criteria decision making   VIKOR method   FOWA method  

摘要： Confronting climate change is a daunting challenge that requires policies for climate adaptation in the field of water resources management. This paper proposes a method for reservoir operation associated with climate-change projections aimed at ensuring the sustainability of agricultural water supply. The method is applied to the Aidoghmoush reservoir in East Azerbaijan province (Iran) employing climate-change projections for 2040-2069, and compares the future-period results with those calculated for the baseline period (1971-2000). The water-supply system depending on the Aidoghmoush reservoir is simulated using the climate-change projections. The water-supply system simulations are ranked with two multi-criteria decision-making (MCDM) methods according to their suitability for satisfying agricultural water demands and sustain cropping patterns. These are the multi-criteria optimization and compromise resolution (VIKOR) and the Fuzzy Order Weighted Average (FOWA) MCDM methods. The MCDM methods identify the best water-supply management alternatives for climate-change adaptation.