Establishment of core collection for Chinese tea germplasm based on cultivated region grouping and phenotypic data

Tea is an important economic crop in China. About 2665 accessions of tea germplasm (Camellia spp.) are conserved in the China National Germplasm Tea Repository. However, only a small fraction of the collections have been exhaustively used in tea plant improvement programs. The objective of the present study was to develop a core collection of tea plant to enhance the utilization of genetic resources in improvement programs and simplify their management. For this purpose, based on the cultivated region grouping and phenotypic trait data, a core collection of tea plant was established using logarithm proportion and Ward’s cluster method. Approximately 20% of the accessions were then randomly selected from these distinct groups to form a core collection of 532 accessions. Different statistical methods including comparison of mean using Newman-Keuls test, variance using Levene’s test, and frequency distribution using Chi-square test for the traits validated that the variation present in the initial collection was retained in the core collection. The Shannon-Weaver diversity index for different traits was also similar in the core and initial collection. The phenotypic correlations among different quantitative traits that may be under the control of coadapted gene complexes were also preserved in the core collection. This core collection will play an important role in the utilization of tea germplasms.     

台湾各县市休闲农业现状分析

台湾休闲农业起步早、发展快,各县市各有特色。综合休闲农业区、休闲农场和民宿的发展和经营情况分析,结果表明台湾休闲农业的地区分布以中部与东部相对发达,而县市中则以宜兰县、南投县、花莲县和苗栗县发展较好。     

柴达木地区娃娃菜的丰产栽培技术

介绍了柴达木地区娃娃菜的丰产栽培技术,包括品种选择、整地做畦、播种定植、田间管理、病虫害防治和采收等方面内容,以期为娃娃菜在该地区的推广种植提供参考。     

基于PDA的寒地大豆智能服务平台的设计与构建

为解决豆农生产过程中的技术难题、为其提供正确详细的决策和解决方案,从整体结构、功能、网络等方面构建适合寒地豆农使用的智能化大豆信息服务平台,并重点介绍PDA技术在智能软件平台开发中的应用,实现大豆专家与豆农零距离.     

寒地有机水稻栽培技术

黑龙江省是我国最北部的寒地稻作区,发展有机水稻具有得天独厚的优势。从基地选择、品种选择、培育壮秧、插秧技术以及本田管理和适时收获6方面详细介绍了寒地稻作区有机水稻的栽培技术,为生产实践提供参考。     

四川平武地区东方蜜蜂形态特征研究

 测定四川平武地区5个不同样点的15群东方蜜蜂（Apis cerana）的38个形态特征。同该地区的四川九寨沟、冕宁、西昌、会理以及甘肃岷县、临潭的东方蜜蜂的形态数据进行因素分析、主成分分析、聚类分析以及相关性分析。结果表明：这些地区的东方蜜蜂呈现3个主要类群。该地区东方蜜蜂的个体大小与海拔和纬度相关性显著,喙的颜色、小盾片的颜色和绒毛覆毛长度与海拔相关性显著。     

First documentation on status of barley diseases from the high altitude cold arid Trans-Himalayan Ladakh region of India

Cold arid trans-Himalayan Ladakh region of India bordering with Pakistan and China is one of most elevated inhabited regions of the world. This region is highly vulnerable to climate change and serious environmental threats resulting in reduction in crop productivity due to risk of agricultural pest and plant pathogens. The present work describes the various diseases attacking barley from this region where the status of barley diseases has not yet been explored. Extensive field surveys were conducted for the first time during 2004-2005 and 475 fields were inspected at the 95 locations. Yellow rust, powdery mildew, leaf spot blotch/blight, covered smut, loose smut, foot/root rot and cereal cyst nematode causing molya disease were encountered during the survey. However, yellow rust, molya and foot/root rot were found as the most destructive diseases. Excellent hotspots of the encountered diseases were identified and marked which may be used for the screening of barley genotypes and determining the impact of climate change on plant diseases.     

气候变化情景下黄淮海冬麦区降水量及其适宜度变化分析

采用双线性插值法将RegCM3模式模拟的A1B情景下该区域1951-2100年0.25°×0.25°的格点数据插值到各站点位置,然后利用黄淮海冬麦区1971-2000年83个站点逐日气象资料对其进行误差订正,再将情景数据分为1951-1980年、1981-2010年、2011-2040年、2041-2070年和2071-2100年共5个阶段,计算各阶段冬小麦主要生育期降水量及其适宜度,并分析相应的时空变化特点。结果表明：黄淮海冬麦区在暖湿化的气候情景下,冬小麦各主要生育期降水量和降水适宜度总体上呈现南方多北方少的分布特点,返青-拔节期降水量最少,抽穗-成熟期降水量最多,相应各主要生育期的降水适宜度表现为返青-拔节期和抽穗-成熟期较高、拔节-抽穗期较低的特点。分时段分析结果显示,随着时间推延,各主要生育期内降水适宜度与降水量基本呈正相位的变化关系,即降水量越大,适宜度也相应增大。返青-拔节期的降水量和降水适宜度均呈现北部增加、南部明显减少的趋势,拔节-抽穗期降水量和降水适宜度均呈减少-增加-减少-增加的波动变化趋势,抽穗-成熟期降水量和降水适宜度均呈先减少后相对稳定的变化趋势,全生育期内降水量和降水适宜度均呈先减少后增加的趋势。未来全球气候变暖情景下,黄淮海冬麦区北部可以考虑根据实际情况小幅扩大种植规模;南部可以考虑保持现有种植规模或小幅减小种植规模。     

中国粮食主产区农业科技进步贡献率的测算与分析

为了深入研究农业科技进步对中国粮食主产区农业经济增长的影响,揭示中国农业科技进步在农业经济增长中的作用机理,探讨农业科技进步对农业经济增长影响的区域差异及其产生原因。作者基于C-D生产函数的一般形式,建立固定效应变参数面板数据分析模型,并依此对中国粮食主产区农业科技进步贡献率进行了详细地测算和分析。研究表明：中国粮食主产区农业科技进步贡献率存在明显的区域差异,反映出中国农业科技发展水平呈现区域不均衡状态;1978—2012 年间全国13 个粮食主产区的农业科技进步贡献率分别在17.28%~33.82%之间,全国粮食主产区平均水平为26.22%;在生产要素的投入中,资本存量的科技含量水平对农业科技进步贡献率的影响较大;农业科技进步在中国粮食主产区农业经济增长过程中所起的作用仍然较小,中国农业经济增长所依赖的传统的高投入、高消耗、低效益、低产出的粗放式增长方式并没有发生根本性的改变。     

Development of the expressed immunoglobulin μ chain repertoire during maturation of mice B cells

In the bone marrow and spleen, the developing B cell populations undergo both negative and positive selections to shape their B cell receptor repertoire. To gain insight into the shift of the immunoglobulin heavy (IgH) chain repertoire during B cell development, we undertook large scale Ig μ chain repertoire analysis of pre-B, immature B and spleen B cell populations. We found that the majority of V_H gene segments, V_H families, J_H and D gene segments, were observed to have significantly different usage frequencies when three B cell populations were compared, but the usage profile of the V_H, D, and J_H genes between different B cell populations showed high correlations. In both productive and nonproductive rearrangements, the length of CDRH3 shortened significantly on average when B cells entered the periphery. However, the CDRH3 length distribution of nonproductive rearrangements did not follow a Gaussian distribution, but decreased successively in the order 3n-2, 3n-1 and 3n, suggesting a direct correlation between mRNA stability and CDRH3 length patterns of nonproductive rearrangements. Further analysis of the individual components comprising CDRH3 of productive rearrangements indicated that the decrease in CDRH3 length was largely due to the reduction of N addition at the 5′ and 3′ junctions. Moreover, with development, the amino acid content of CDRH3 progressed toward fewer positively charged and nonpolar residues but more polar residues. All these data indicated that the expressed Ig μ chain repertoire, especially the repertoire of CDRH3, was fine-tuned when B cells passed through several checkpoints of selection during the process of maturation.