堆型艾美耳球虫早熟株免疫雏鸡后血清抗体水平动态变化的研究

用堆型艾美耳球虫早熟株对雏鸡进行一次免疫和二次免疫试验 ,研究雏鸡血清抗体的动态变化。试验结果显示 ,在一次免疫试验中 ,各剂量组雏鸡均在免疫后 2天血清抗体出现较高的 OD值 ,之后呈下降趋势 ,11天后逐渐上升 ,到 12～ 13天时出现第 2个峰值 ,各组间的血清抗体 OD值比较 ,3 0 0 0个卵囊 /只剂量组极显著 (P<0 .0 1)高于 10 0 0个 /只、2 0 0 0个 /只和 5 0 0 0个 /只剂量组。在二次免疫试验中 ,8日龄首免、14日龄二免组雏鸡的抗体水平动态变化整体呈上升趋势 ,峰值 (0 .3 75 )出现在二免后第 10天 ,其后稳定地维持在较高水平 (平均 OD值为 0 .3 5 ) ,并且其抗体水平显著地高于 6日龄首免、12日龄二免组 (P<0 .0 5 )。抗体水平动态变化表明 ,堆型艾美耳球虫早熟株有较强的免疫保护力 ,其免疫方式可选用一次免疫 ,剂量为 3 0 0 0个卵囊 /只 ,也可采用二次免疫 ,即 8日龄首免 (15 0 0个 /只 ) ,14日龄二免 (15 0 0个 /只 ) ,从抗体动态变化的稳定性看 ,二次免疫更佳     

"双链型"草-鹅-稻生态农业模式高产高效配套技术

提出了“双链型”单-鹅-稻生态农业模式，总结了稻田套种牧草的方法和田间管理技术，探讨了种草与养鹅在时间上的相互衔接，以提高牧草的产量和利用率，进行了稻田套种牧草养鹅与种植小麦的比较效益分析。该配套技术的实施，为当前开展农业结构调整开辟了一条新路。     

一类挖坑机械钻头横向振动系统的最优控制问题

建立了一类挖坑机械钻头横向振动系统的数学模型,并以阻尼函数作为控制变量,研究了该系统的最优控制问题,得出了两个定理。     

优质高产菜豆新品种‘无筋2号''

‘无筋2号’为优质高产菜豆新品种，生长势旺盛，耐肥抗倒，播种至采鲜荚生育期45d左右，结荚性好，豆荚饱满，商品性好，适宜速冻加工出口，鲜荚产量17—18t/hm^2，高产地块可达20t/hm^2以上。     

等值线制图工具 Surfer在病虫测报上的应用研究

Surfer系统是美国金软公司开发的专门制作等值线的工具。1997年以来,笔者对其运用于稻飞虱等农作物病虫害的监测方面作了探讨和开发。阐述了病虫分布图的绘制和遮盖图编制的过程和方法。     

优质茄子新品种引茄1号的选育

引茄 1号为杂种一代 ,植株生长势旺盛 ,果实细长、紫红色 ,果面光滑 ,果肉细嫩 ,平均单果质量 6 0～70kg ,抗青枯病和绵疫病 ,产量 30 0 0～ 4 0 0 0kg·(6 6 7m2 ) -1,适于我国喜食长茄地区的保护地和露地栽培。     

晋西昕水河流域生态经济型防护林体系景观格局动态分析

本文以晋西昕水河流域为典型实例，概述了流域生态经济型防护林体系建设背景。依据流域内各类型区在不同时段的土地利用结构和生态经济特征，进行流域生态经济型防护林体系景观格局变化分析，表明了流域内景观多样性和异质性不断增加的发展趋势，以及确定各区主要发展方向，实行综合开发与治理的必要性，并提出了相应的流域生态经济型防护林体系动态调控途径。     

Multimarker and rare variants genomewide association studies for bone weight in Simmental cattle

Bone weight, defined as the total weight of the bones in all the forequarter and hindquarter joints, can reflect somebody conformation traits and skeletal diseases. To gain a better understanding of the genetic determinants of bone weight, we used a composite strategy including multimarker and rare‐marker association to perform genomewide association studies (GWAS) for that character in Simmental cattle. Our strategy consisted of three models: (i) A traditional linear mixed model (LMM) was applied (Q+K‐LMM); (ii) single nucleotide polymorphisms (SNPs) with p‐values less than .05 from the LMM were selected to undergo the least absolute shrinkage and selector operator (Lasso) in the second stage (LMM‐Lasso); (iii) genes containing two or more rare SNPs were examined by performing the sequence kernel association test (gene‐based SKAT). A total of 1,225 cattle were genotyped with an Illumina BovineHD BeadChip containing 770,000 SNPs. After the quality‐control procedures, 1,217 individuals with 608,696 common SNPs and 105,787 rare SNPs (with 0.001 < minor allele frequency [MAF] <0.05) remained in the sample for analysis. A traditional LMM successfully mapped three genes associated with bone weight, while LMM‐Lasso identified nine genes, which included all genes found by traditional LMM. Only a single gene, EPHB3, surpassed the significance threshold after Bonferroni correction in gene‐based SKAT. In conclusion, based on functional annotation and results from previous endeavours, we believe that LCORL, RIMS2, LAP3, PRKAR2B, CHSY1, MAP2K6 and EPHB3 are candidate genes for bone weight. In general, such a comprehensive strategy for GWAS may be useful for researchers seeking to probe the full genetic architecture underlying economic traits in livestock.     

The mechanical roles of the clasping leaf sheath in cereals: Two case studies from oat and wheat plants

Stem lodging is a common problem in cereal crop production and a main constraint for grain yield improvement. The leaf sheath that surrounds and protects the hollow internodes of stem could provide the plants with a great physical support. However, this biomechanical function has been ignored for several decades in cereal crops. This study aimed to examine the biomechanical properties of basal stem internodes and lodging susceptibility of the whole plants with or without the clasping leaf sheath in wheat (Triticum aestivum L.) and oat (Avena sativa L.) among different genotypes and agronomic practices (including planting densities and nitrogen application rates). The main objective was to quantify the mechanical role of the leaf sheath in oat and wheat crops by a “safety factor” method. On average, the leaf sheath contributed 40%, 68% and 38% of the overall stem bending strength, flexural rigidity and safety factor, in oat, while it accounted for 11%, 24% and 10%, respectively, in wheat plants. The significant contribution of the leaf sheath is due to its vital role in enlarging the peripheral position (i.e., second moment of area) and stiffness (i.e., Young's modulus). The contribution ratios (%) were found to be higher in oat than in wheat plants, due to the greater mass density of leaf sheath and more proficient/prevailing stay-green capability in oat genotypes. This study emphasizes the important mechanical role of clasping leaf sheath on stem internodes of cereals and indicates that the stay-green trait of the leaf sheath can be exploited to design appropriate varieties with improved lodging resistance and great yield potential.     

基于机器视觉的玉米秸秆行实时定位机器人设计

为了实现机器人玉米秸秆行的精确定位,对耕作玉米机器人的结构进行了改进,并提出了一种基于泰勒级数展开式的RSSI定位方法,提高了机器人玉米秸秆行的定位精度。定位系统使用高清晰度的摄像机采集图像,并采用PID闭环反馈的方式控制机器人的位移,利用PC主控端图像处理,实现了实时定位功能。为了验证机器人玉米秸秆行定位的可靠性,采用田间试验的方法对机器人的性能进行了测试。结果表明:RSSI定位方法的定位精度较高,且图像处理系统可以准确地标定玉米秸秆行,实现机器人在玉米田中的精确定位,避免了机器人在作业过程中对农作物造成损害。