Comparison of crop and weed height,for potential differentiation of weed patches at harvest

Weeds and weed control are major production costs in global agriculture, with increasing challenges associated with herbicide‐based management because of concerns with chemical residue and herbicide resistance. Non‐chemical weed management may address these challenges but requires the ability to differentiate weeds from crops. Harvest is an ideal opportunity for the differentiation of weeds that grow taller than the crop, however, the ability to differentiate late‐season weeds from the crop is unknown. Weed mapping enables farmers to locate weed patches, evaluate the success of previous weed management strategies, and assist with planning for future herbicide applications. The aim of this study was to determine whether weed patches could be differentiated from the crop plants, based on height differences. Field surveys were carried out before crop harvest in 2018 and 2019, where a total of 86 and 105 weedy patches were manually assessed respectively. The results of this study demonstrated that across the 191 assessed weedy patches, in 97% of patches with Avena fatua (wild oat) plants, 86% with Raphanus raphanistrum (wild radish) plants and 92% with Sonchus oleraceus L. (sow thistles) plants it was possible to distinguish the weeds taller than the 95% of the crop plants. Future work should be dedicated to the assessment of the ability of remote sensing methods such as Light Detection and Ranging to detect and map late‐season weed species based on the results from this study on crop and weed height differences.     

DNA methylation status of bovine blastocyst embryos obtained from various procedures

DNA methylation is an important factor for the regulation of gene expression in early embryos. It is well known that the satellite I sequence is more heavily methylated in bovine somatic cell nuclear transfer (NT-SC) embryos than in embryos derived from in vitro fertilization (IVF). However, the methylation status of bovine embryos obtained by other procedures is not well known. To clarify DNA methylation levels of bovine embryos obtained from various procedures, we examined satellite I sequences in bovine blastocyst (BC) embryos derived from NT-SC, NT using embryonic blastomeres (NT-EM), in vivo (Vivo), IVF and parthenogenetic treatment (PA). Furthermore, in order to evaluate the efficacy of DNA demethylation by the NT procedure, we determined the DNA methylation levels in bovine embryos in which NT was recapitulated (Re-NT). Although the DNA methylation levels in the NT-SC embryos were higher than those in the other embryos, the NT-EM embryos exhibited lower DNA methylation levels. The satellite I sequence in the NT-SC embryos was more demethylated than that in the donor cells. Although the DNA methylation level in the individual NT-SC embryos showed variation, the full-term developmental efficacy of these embryos were not different. These findings suggest that the methylation level of the satellite I sequence at the BC stage is not related to the abnormalities of bovine embryos produced by NT-SC. There was no difference in methylation levels between Re-NT and NT-SC embryos. Our results indicated that the DNA methylation status differed among embryos produced by various methods and that at least some of the demethylation of the donor cell genome occurred in the recipient cytoplast after NT-SC, but the demethylation ability of the NT procedure was noted in the first NT but not in the second NT.     

亚洲部分地区东方蜜蜂mtDNA多态性研究

 就云南省7个不同样点共7群东方蜜蜂蜂群开展mtDNA内切酶位点测试和分析研究,并与菲律宾的东方蜜蜂作对比分析。内切酶DraI分析7个蜂群,共发现4个内切酶位点;云南东方蜜蜂mtDNA的tRNAleu-COII基因的序列没有长度多态性,EcoRI内切酶位点共有4个,与菲律宾的吕宋岛的东方蜜蜂属于同一单倍型。另外,对来自尼泊尔、泰国、越南、老挝以及我国北京、云南等地的共13群蜜蜂mtDNA COII基因的420个碱基对进行测序分析,发现13群东方蜜蜂分析的420个碱基序列里,位点变异从0个到5个不等,变异率从0到1.19％. 用邻接法(neighbor-joining)构建的分子系统树可以看出分枝树主要分为两个类群:高纬度或高海拔的蜂群为一个类群,它们主要来自撒营盘（2）（China 4）、丽江(China 7)、北京(1)（China 1）、尼泊尔（Nepal）、北京（2）（China 2）、河口（1）（China 8）和越南（2）（Vietnam 2）。另一个类群的主要来自低纬度或低海拔的蜂群,它们主要来自撒营盘（1）（China 3）、景洪（China 5）、越南（1）（Vietnam 1）、泰国（Thailand）、河口(2) (China 6)和老挝(Laos)。该实验为我国东方蜜蜂资源的保护和开发研究提供了重要的信息和手段。     

Variation in diosgenin levels among 10 accessions of fenugreek seeds produced in western Canada

A collection of 10 accessions of fenugreek (Trigonella foenum-graecum L.), an annual legume, was grown during two summers at three plot locations in western Canada to assess whether genetic (accession) and environmental factors (site and year of production) influenced levels of diosgenin, a steroidal sapogenin. The 60 harvested seed samples, each analyzed by single determinations on three subsamples of defatted and dried seed material, were hydrolyzed by a microscale procedure in water containing 2-propanol (70%) and sulfuric acid (1 M). The extracts were analyzed by capillary gas chromatography with 6-methyldiosgenin as internal standard. Diosgenin levels from mature seeds ranged from 0.28 to 0.92% (28-92 microg/10 mg). Analysis of variance on combined diosgenin levels from the three sites and two years revealed that accession, accession x year, and site x year effects were significant for diosgenin content, whereas site, year, and site x accession effects were not. Four accessions, CN 19062, CN 19067, CN 19070, and CN 19071, were identified with high levels of diosgenin on the basis of the 2-year data set. In these accessions, mean levels of diosgenin plus yamogenin from seven site years were estimated at 0.70, 0.98, 0.84, and 0.87%, respectively.     

Mottle necrosis of sweet potato caused by <Emphasis Type="Italic">Pythium scleroteichum</Emphasis> in Japan and varietal difference in susceptibility to the disease

Severe mottle necrosis (Shirogusare-byo in Japanese) was found on mature tubers of sweet potato (Ipomoea batatas) in Ibaraki Prefecture in October 2004. The causal organism was identified as Pythium scleroteichum hitherto unknown in Japan. Sweet potato cultivar Purple Sweet Lord was more susceptible than cultivars Beniazuma, Benimasari, Koukei-14, and Tamayutaka to the pathogen at 25°C, while this difference in the susceptibility was not clear at 15°C.     

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。     

Screening wild plants of Capsicum annuum for resistance to pepper huasteco virus (PHV): Presence of viral DNA and differentiation among populations

Plants collected in thirteen wild populations of Capsicum annuum from Northwest Mexico were tested for resistance to the pepper huasteco begomovirus (formerly subgroup III) (PHV) that is transmitted by the white fly Bemisia tabaci Genadius. Plants were inoculated using both grafting and biolistic methods. Presence of viral DNA was detected by dot blot hybridization and densitometry. Populations varied in their resistance to PHV. Plants of only two of the populations either did not develop disease symptoms or showed very light symptoms after inoculation. In some cases, symptoms appeared several days after inoculation. In plants of these populations viral DNA was detected by dot-blot hybridization assays but they appear to be a good source of resistance (symptomless) for use in breeding programmes. This revised version was published online in August 2006 with corrections to the Cover Date.     

Assessment of Biogas use as an Energy Source from Anaerobic Digestion of Brewery Wastewater

Energy recovery from a crossflow ultrafiltration (UF) membraneunit employed in order to improve the performance of an anaerobic contact digester for the treatment of brewery wastewater was assessed. The performance of the pilot-scale anaerobic UF membrane system was studied for over 15 months. At steady-state conditions, an organic loading rate of 28.5 kg COD m^-3 d^-1, a hydraulic retention time of 4.2 days and overall COD and BOD removal efficiencies of 99% and almost 100% were achieved, respectively. Percent methane in biogas was found to be in a range of 67–79% with the corresponding methane yield of 0.28–0.35 m³ CH₄ kg^-1 COD_removed. The potential energy recovery from the system treating brewery wastewater at an OLR of 28.5 kg COD m^-3 d^-1 was 87 MJ d^-1 which would enable to maintain all energy requirements of the feed pump, mixing and heating of the reactor contents. In addition to this, 71% of the energy requirement for recirculating the reactor content through the membranes would also be recovered.     

Action research on alternative land tenure arrangements in Wenchi,Ghana: learning from ambiguous social dynamics and self-organized institutional innovation

This study reports on action research efforts that were aimed at developing institutional arrangements beneficial for soil fertility improvement. Three stages of action research are described and analyzed. We initially began by bringing stakeholders together in a platform to engage in a collaborative design of new arrangements. However, this effort was stymied mainly because conditions conducive for learning and negotiation were lacking. We then proceeded to support experimentation with alternative arrangements initiated by individual landowners and migrant farmers. The implementation of these arrangements too ran into difficulties due to intra-family dynamics and ambiguities regarding land tenure. Further investigations to find out how ambiguities could be tackled revealed that the local actors themselves had taken initiatives towards developing institutional innovations to reduce ambiguities. However, there is still considerable scope for further development of these self-organized innovations. The article ends with a reflection on inter-disciplinary action research, where it is argued that making “mistakes” is an inherent and necessary characteristic in action research that aims to address complex social issues.