水稻新质源不育系K17A的异交习性观察

通过对水稻新质源不育系Ｋ１７Ａ与野败型珍汕９７Ａ、印尼水田谷型Ⅱ－３２Ａ的异交习性对比观察，发现Ｋ１７Ａ具有开花期较集中且高峰期较明显；每天花时高峰期较早且明显，与父本花时相遇率较高；颖花柱头外露率高、柱头较长、面积大，对花粉附着力强；柱头生活力强，开花后活力下降慢等特点，利于提高异交结实率，获得较高的繁殖、制种产量     

柑桔树体性状与产量的相关研究

通过对血橙、温州蜜柑的调查和统计分析,探明了柑桔冠径、千周、叶面积系数和末级梢数对幼树早期产量有极显著影响,其中冠径、干周是早期丰产稳产的重要树体结构基础。树冠投影面积和复盖率与群体产量的关系较密切,二者共同对产量作用的决定程度最大,又互为制约和消长。为早果丰产栽培提供了依据。     

2017—2018年西藏拉萨市养殖场及活禽交易市场禽流感流行病学调查

为了解拉萨市禽流感流行情况,2017年11月—2018年3月,在拉萨市6个养殖场和11个活禽交易市场,随机采集1 394份棉试子进行禽流感病毒分离和分型鉴定。结果显示： H9亚型禽流感病毒阳性率为2.87%,未检出H3、H5、H6、H7等其他亚型病毒;活禽市场H9亚型阳性率（4.64%）显著高于养殖场阳性率（0.35%,P<0.01）。结果表明,拉萨市高致病性禽流感流行风险较小,低致病性禽流感流行以H9亚型为主,且流行率不高,但应进一步加强养殖环节的防疫、检疫,以及活禽市场的清洗、消毒等工作,防止禽流感传入和流行。     

2017年河南省病死猪常见病原分布调查

为了解河南省病死猪常见病原分布规律,采用横断面研究方法,对2017年河南省病死猪常见病原分布情况进行调查。以病死猪聚集地——无害化处理厂为采样单元,按病死猪体重进行分层抽样,采集不同阶段病死猪的扁桃体、淋巴结、肺脏、肝脏、脾脏、肾脏等样品进行猪瘟病毒（CSFV）、猪繁殖与呼吸综合征病毒（PRRSV）、口蹄疫病毒（FMDV）、猪伪狂犬病毒（PRV）、猪细小病毒（PPV）、猪圆环病毒2型（PCV2）、猪传染性胃肠炎病毒（TGEV）、猪流行性腹泻病毒（PEDV）、副猪嗜血杆菌（HPS）和弓形虫（TP）的病原学检测,并对检测结果进行时间、空间和群间分布分析。结果显示：共检测样品526份,未检出FMDV、TGEV和PEDV,其他7种病原的检出率在0.76%~58.17%之间;春夏季节检出的病原种类较多,检出率也较高,秋冬季较少;不同区域病原种类分布情况差异较大,豫西检出病原种类最少,豫中检出病原种类最多,不同区域内各病原检出率差异较大;不同体重猪群的病原种类数量有差异,体重越小,检出病原种类越多。调查结果表明,河南省常见猪病病原复杂,不同区域、不同季节、不同生长阶段猪群的病原流行情况并不一致,需通过加强监测,制定相应的防控措施。     

小麦吸浆虫防治适期研究初报

选择不同杀虫剂、不同时期对小麦吸浆虫的防治效果试验表明，在秋季麦播前土壤处理，防效不理想；在吸浆虫蛹期、羽化高峰期防治虽能获得较好的防治效果，但需要专业技术人员掌握发育进度，不适合指导群防群治；而小麦抽穗露脸70％～80％时，正值吸浆虫产卵始盛期，此期防治能获得事半功倍的效果，这一物侯现象群众容易掌握。此前及此后羽化的成虫多为无效虫源。所以，把小麦抽穗露脸70％～80％作为吸浆虫的防治适期符合当前的生产现状。     

直纹稻苞虫虫源性质研究初报

国内有关文献均记载直纹稻苞虫以幼虫或卵、蛹在当地越冬.本研究通过两年对南阳市直纹稻苞虫初见雌成虫卵巢发育情况解剖分析和对当地发生情况系统调查表明本地每年始见雌成虫卵巢发育均在四级以上,且均已交配,末代幼虫在杂草上不能发育到蛹即死亡;越冬期多处调查未发现任何虫态;当地上、下两代幼虫发生数量悬殊;该虫成虫和稻纵卷时螟成虫有明显的同步发生现象.据此认为,河南南阳直纹稻苞虫每年初始虫源来自南方.     

Effect of dietary vanadium and vitamin C on egg quality and antioxidant status in laying hens

This study assessed the effect of dietary vanadium (V) and vitamin C (VC) on production performance, egg quality and antioxidant status in laying hens. A total of 360 laying hens (31‐week‐old) were randomly allotted into a 3 × 3 factorial arrangement treatments (four replicates and 10 chicks per replicate) with three levels of dietary V (0, 5 and 10 mg/kg) and three levels of vitamin C (0, 50 and 100 mg/kg) for 12 weeks. The effect of V and VC did not alter egg production, egg weight, average daily feed intake and feed conversion ratio during 1–12 week. Albumen height and Haugh unit value were linearly decreased (p < 0.001) by addition of V, whereas the effect of 100 mg/kg VC was observed to counteract (p < 0.05) this effect in V‐containing treatments during 1–12 week. Hens fed V‐containing diet laid lighter (linear effect, p < 0.05) coloured eggs (higher lightness value, lower redness and yellowness value), and the VC exerted no influence on it during 1–12 week. The serum superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH‐Px) activities, ability to inhibit hydroxyl radical, were significantly decreased, and the malondialdehyde (MDA) and V contents were increased (p < 0.05) by effect of V during 4, 8 and 12 week. The effect of VC alone and the interactive effect between VC and V were shown to increase serum (p < 0.05) SOD activity in 4 week and decrease MAD levels in 12 week. The result indicate that V decreased the egg quality and caused the oxidative stress at level of 5 mg/kg and 10 mg/kg, and the addition of 100 mg/kg vitamin C can alleviate its egg quality reduction effect and can mitigate the oxidative stress to some extent.     

Impact of fitting dominance and additive effects on accuracy of genomic prediction of breeding values in layers

Most genomic prediction studies fit only additive effects in models to estimate genomic breeding values (GEBV). However, if dominance genetic effects are an important source of variation for complex traits, accounting for them may improve the accuracy of GEBV. We investigated the effect of fitting dominance and additive effects on the accuracy of GEBV for eight egg production and quality traits in a purebred line of brown layers using pedigree or genomic information (42K single‐nucleotide polymorphism (SNP) panel). Phenotypes were corrected for the effect of hatch date. Additive and dominance genetic variances were estimated using genomic‐based [genomic best linear unbiased prediction (GBLUP)‐REML and BayesC] and pedigree‐based (PBLUP‐REML) methods. Breeding values were predicted using a model that included both additive and dominance effects and a model that included only additive effects. The reference population consisted of approximately 1800 animals hatched between 2004 and 2009, while approximately 300 young animals hatched in 2010 were used for validation. Accuracy of prediction was computed as the correlation between phenotypes and estimated breeding values of the validation animals divided by the square root of the estimate of heritability in the whole population. The proportion of dominance variance to total phenotypic variance ranged from 0.03 to 0.22 with PBLUP‐REML across traits, from 0 to 0.03 with GBLUP‐REML and from 0.01 to 0.05 with BayesC. Accuracies of GEBV ranged from 0.28 to 0.60 across traits. Inclusion of dominance effects did not improve the accuracy of GEBV, and differences in their accuracies between genomic‐based methods were small (0.01–0.05), with GBLUP‐REML yielding higher prediction accuracies than BayesC for egg production, egg colour and yolk weight, while BayesC yielded higher accuracies than GBLUP‐REML for the other traits. In conclusion, fitting dominance effects did not impact accuracy of genomic prediction of breeding values in this population.     

苜蓿、小麦、玉米经济效益比较

基于甘肃省5个样本县的调研数据,对农户苜蓿(Medicago sativa)、小麦(Triticum aestivum)和玉米(Zea mays)种植的投入和产出、要素产出弹性和要素边际产出进行测算并比较。结果表明,苜蓿在三者中投入最少,玉米产出最高,而苜蓿产出最低;现阶段小麦和玉米处于规模报酬递减阶段而苜蓿处于规模报酬递增阶段,苜蓿产业有很大的上升空间;小麦和玉米各要素边际产量基本趋近于零,苜蓿种子投入和肥料投入的边际产量均远大于零,增加苜蓿种子和肥料投入可实现苜蓿增产。     

一种茶园小绿叶蝉抗药性快速检测方法的研究

茶小绿叶蝉具有虫体较小易隐蔽、行动活跃易逃脱、若虫脆弱易死亡等特点,导致室外捕虫工作量大、室内挑虫分装处理困难,是阻碍该虫抗药性研究进展缓慢的重要原因.通过采集叶蝉发生茶园嫩梢于室内水培、培育小绿叶蝉;通过调节改进的粉尘采样设备的不同采样流量收集叶蝉于带芽离心管;最后,通过联苯菊酯处理离心管内芽叶,测定管内小绿叶蝉的LC50值,校验方法的可行性.研究结果表明,田间虫口密度为1.538(头·梢-1)的茶园,室内水培7 d后可孵化出若虫至3.181(头·梢-1),收集室内叶蝉可减少室外采虫工作量.采用10 L·min-1的采虫流量,叶蝉收集速度快,且存活率为100%,改进的设备可简化挑虫难题.联苯菊酯对叶蝉的LC50为163.55 mg·L-1,毒力测定方法快速简便.