Assessment of the field resistance of potato genotypes with major gene resistance to late blight (Phytophthora infestans (Mont.) de Bary) using inoculum comprised of two complementary races of the fungus

Summary Two races ofPhytophthora infestans, differing in virulence against four major (R) genes for resistance, were used to assess the field resistance of differential (R) genotypes, both singly and mixed together in equal proportions. The mixed inoculum led to an over-estimation of the foliage resistance of genotypes with which only one of the races was compatible, by up to two scoring categories of a 1–9 scale in field trials and, to a lesser extent, in glasshouse tests depending on the differential and the test. Assessment of tuber resistance was not significantly affected. The R₁₀ and R₂ differentials showed a higher level of field resistance in the foliage and tubers, respectively, than the other genotypes. It is concluded that assessments of genotypes which may possess R genes, using mixed inoculum, should be interpreted with caution, and apparent high levels of field resistance confirmed through genetic studies of the inheritance of the resistance.     

黑龙江省玉米大斑病菌生理小种组成及变化动态分析

明确黑龙江省不同生态区玉米大斑病菌生理小种组成及变化动态,采用Ht单基因常规鉴别寄主技术,对 2018、 2019年采自黑龙江省 39个市县的 138株玉米大斑病菌菌株进行生理小种鉴定,共鉴定出 0、 1、 2、 3、 N、12、 13、 1N、 2N、 12N和 13N号 11个生理小种。所鉴定的 138个菌株对 Ht1、 Ht2、 Ht3和 HtN抗性基因的毒性频率分别为 46.1%、 15.3%、 9.3%和 21.5%。分析 2005～2019年间黑龙江省玉米大斑病菌生理小种组成结构及变化动态规律,发现近 15年黑龙江省大斑病菌生理小种分化呈现日趋复杂化,不断有新的小种出现,从 2005年的 10个小种到现在16个小种均已被监测到。不同时期各小种组成及出现频率均在不断变化中, 0和1号小种始终是该地区的优势小种。     

家蚕育种个体、蛾区自动称量与选择系统

为提高家蚕育种效率，满足家蚕育种工作者要求，利用Visual Basic 6.0 for Windows开发设计了家蚕育种个体、蛾区自动称量与选择系统。该系统通过串行接口采用零Modem连接方式将两台电子天平与计算机相连接，通过MSComm通讯控件实现对蚕茧个体、蛾区称量数据的自动采集，采用Bayes判别函数和聚类分析法自动根据称量结果对蚕茧个体作雌雄识别，采用基于数量遗传理论设计的综合选择指数进行个体选择，并方便地实现称量数据的查询和管理。     

Virulence assessment of Australian Pyrenophora tritici-repentis isolates

The virulence of 57 Australian isolates of Pyrenophora tritici-repentis (Ptr), a necrotrophic fungal pathogen responsible for the major wheat disease tan spot, was assessed through plant infection assays. Isolates collected from the northern, southern, and western wheat-cropping regions of Australia were evaluated against 16 Australian bread wheat cultivars under controlled growth conditions. Following infection, the wheat panel displayed varying disease symptoms ranging from tiny necrotic specks to spreading chlorotic and necrotic lesions. Analysis of variance indicated that the wheat cultivar exhibited a greater effect on the disease response, explaining 62.7% of the variation, in comparison to the isolate (10.4%). The interaction between the cultivar and the isolate was statistically significant and was attributed to 9.8% of the total variation. All Ptr isolates examined were able to cause disease, but did not display a clear distinction in virulence on the wheat panel investigated, instead showing subtle differences in aggressiveness. Based on the disease responses, there was no obvious pattern between isolate aggressiveness and cropping region. Some cultivars, such as Hydra, exhibited an effective level of resistance in relation to the panel of isolates tested. All 57 Ptr isolates were found to possess the ToxA effector gene and lack the ToxB effector gene. The gene expression level of ToxA was up-regulated at 3 days postinfection in both ToxA-sensitive and -insensitive cultivars, independent of ToxA–Tsn1 recognition.     

宁夏马铃薯晚疫病菌交配型和生理小种研究

为明确宁夏回族自治区马铃薯主产区晚疫病菌的交配型种类以及生理小种的类型、组成和分布,为宁夏有针对性地选育马铃薯抗晚疫病品种提供科学依据。利用A1、A2交配型标准菌株和含有11个主效抗性基因的鉴别寄主,对2018年-2019年从原州区、泾源县、彭阳县、隆德县、西吉县、盐池县、海原县采集得到的130个马铃薯晚疫病菌菌株进行交配型和生理小种鉴定。结果表明,宁夏马铃薯晚疫病菌群体的交配型和生理小种存在多样性,采集地交配型有A1、A2、SF(自育型)3类,分别占被测菌株的30%、63.8%、6.2%;生理小种有8种类型,其中生理小种1.2.3.4.5.6.7.8.9.10.11发生频率最高,占被测菌株总数的44.62%,是宁夏马铃薯主栽区的晚疫病菌优势小种,在各测试地均有分布;次优势小种为3.4.10和1.2.3.5.6.7.8.11,发生频率分别为12.31%和10.77%。宁夏不同种植区域马铃薯晚疫病菌交配型组成复杂,采集地组成差异较大,但西吉县、原州区交配型年度间的变化基本趋于一致。宁夏马铃薯晚疫病菌群体组成日趋复杂,生产中要合理布局已有抗病品种,挖掘培育抗病水平高的新品种,综合防控马铃薯...     

番茄黄化曲叶病毒北京分离物侵染性克隆的构建与其致病性

为明确番茄黄化曲叶病毒北京分离物（Beijing isolate of tomato yellow leaf curl virus,TYLCV-BJ）致病性的强弱,以感染TYLCV-BJ的番茄叶片DNA为模板PCR扩增获得该分离物基因组全长序列,并构建该分离物的侵染性克隆,将其分别接种到番茄、烟草和拟南芥植株上,比较该分离物和TYLCV上海分离物2(TYLCV-Shanghai 2,TYLCV-SH2)致病性的差异。结果显示,该分离物基因组全长序列同TYLCV-SH2的相似度为99.03%,在番茄和烟草植株上TYLCV-BJ比TYLCV-SH2发病更早,症状更重,TYLCV DNA和外壳蛋白积累量更高。TYLCV-BJ可以通过农杆菌Agrobacterium tumefaciens注射法在拟南芥中复制和系统侵染,而TYLCV-SH2不能有效侵染拟南芥。表明TYLCV-BJ的致病性强于TYLCV-SH2,所建立的侵染性克隆有广泛的研究和应用价值。     

桑蚕鲜茧干壳量的可见/近红外光谱无损检测

选择Savitzky-Golay平滑作为光谱数据的预处理方法,根据偏最小二乘模型的回归系数进行有效波长的选取,最终筛选出了桑蚕鲜茧干壳量指标在可见/近红外光谱谱区的7个有效波长,并结合多元线性回归建立干壳量的检测模型.该模型运算简单且检测精度较高,预测决定系数和剩余预测偏差分别为0.7587和2.0464,是应用可见/近红外光谱检测桑蚕鲜茧干壳量的理想模型.     

Phenotypic diversity analysis of grain yield and yellow pigment content in germplasm collected from Iranian durum wheat (Triticum turgidum L.) landraces

This study was undertaken to compare patterns of agronomic characters and yellow pigment content diversity between Iranian durum landraces and modern varieties. In four field experiments, a collection of 127 accessions of landraces and 23 modern cultivars tetraploid wheat representing Iranian and global genetic diversity were tested under optimum and rain-fed conditions. Across the environments, the yellow pigment concentrations ranged from 1.85 mg kg^?1 to 8.95 mg kg^?1 in the field-grown samples. Multivariate analysis detected five groups, four including landraces and one comprising modern cultivars. As a group, modern cultivars were the most productive and showed high mean values for harvest index, grains per spike and yellow pigment, but they had the lowest plant height. Landraces had the highest mean number of spikes per m² and 1000-kernel weight, but were characterized by low plant height and yellow pigment content. Clustering analysis also showed that, based on yield and yellow pigment content, the accessions in different groups were of different origins, suggesting that there was no clear relationship between accessions and geographical diversity. According to our results, Iranian landraces can be particularly useful as germplasm in breeding programmes to improve spikes per m² and 1000-kernel weights.     

江河源区植被水分利用效率遥感估算及动态变化

为了获取高寒地区在资料短缺条件下的陆地生态系统碳循环和水循环的变化特征,该文以遥感数据、气象数据和实际观测数据相结合,利用基于光能利用率的CASA（carnegie ames stanford approach）模型和FAO Penman-Monteith方法对江河源区2000-2010年植被水分利用效率进行估算和动态分析,得出以下结论：1）所选模型较好的反应了区域植被水分利用效率的时空分布特征。近11 a来,长江源区和黄河源区多年平均水分利用效率（以C质量计,下同）分别为0.54 g/(mm·m2)和0.56 g/(mm·m2),江河源区植被水分利用效率呈减少趋势,其中黄河源区植被水分效率减少速度大于长江源区。2）江河源区典型高寒草甸和高寒草原水分利用效率年际变化总体呈下降趋势,其中黄河源区减少趋势较长江源区更明显。长江源区高寒草甸和高寒草原水分利用效率呈现明显单峰现象,黄河源区呈现为阶梯增加和减少现象,表明长江源区在单位面积上植物消耗单位水分的固碳能力要好于黄河源区。3）主成分分析表明：江河源区植被水分利用效率变化与NDVI、温度、降水、太阳辐射以及蒸发密切相关;长江源区以NDVI、降雨为主导,黄河源区以NDVI、降雨和温度为主导。该研究可为江河源区水资源合理利用,实现区域生态环境可持续发展提供科学参考。     

模拟沼液淋溶灌溉对土壤下渗水的影响

采用动态淋洗试验分析施加不同浓度沼液后土壤下渗水的变化过程,以明确沼液灌溉对土壤下渗水的影响.结果表明,沼液浇灌后,黄壤下渗水pH呈先下降后升高的趋势,紫色土下渗水pH呈缓慢下降趋势,但二者变化均不大;2种土壤下渗水COD、TN、TP含量较沼液明显降低,且与浇灌沼液的浓度呈正相关关系;2种土壤下渗水Cu、Zn含量均在GB/T 14848-9第Ⅲ类标准以下,而Pb、Cd含量均超过GB/T14848-9第Ⅳ类标准.黄壤较紫色土对下渗水COD、TN、TP的污染风险小,而紫色土较黄壤对下渗水重金属的污染风险小.