Comparison of inoculation methods for field studies on varietal response to verticillium wilt of potatoes

Verticillium albo-atrum, cultured on potato dextrose agar plates or on sterilized wheat kernels, was used to incite disease in field studies. Immediately prior to planting, seed potatoes were dipped in a spore/mycelium suspension that was prepared from agar plate cultures. A second inoculation treatment involved placing infested wheat kernels under the potato seed at planting time. Both inoculation methods resulted in verticillium wilt development. However, the inoculum suspension dip method resulted in slightly greater incidences of verticillium wilt than did the infested wheat method. Inoculation by means of a suspension dip immediately after cutting the seed resulted in more wilted plants than when seed was inoculated 24 hours or 7 days after cutting. The spore/mycelium suspension dip method is now routinely used for field studies on disease susceptibility or resistance in potato cultivars.     

Reduction of Seed Dormancy in Echinacea pallida (Nutt.) Nutt. by In-dark Seed Selection and Breeding

Strong seed dormancy has been an obstacle for field production of Echinacea species. Previous research on overcoming Echinacea seed dormancy has been extensive and focused on treatment methods, which involve time and expense, and are incompatible with organic production if synthetic chemicals are used. We have attempted to genetically reduce seed dormancy through selection and breeding in Echinacea, by using Echinacea pallida as a model species. Three accessions were used in this study. Nine parent plants of each accession selected from early, in-dark germinated seeds (in-dark plants) or from late, in-light seeds (in-light plants) were planted and grouped by accession and germination treatment method for seed production through a polycross method. Germination tests indicated that these in-dark plants produced seed (in-dark seed) with significantly reduced seed dormancy when tested under light or dark condition in comparison to the seed of the in-light plants (in-light seed). Among the three accessions, the in-dark seed germinated at much higher rates than did the in-light seed, more than 2× at 25 °C under light and up to an 83× increase in darkness, and up to an 8× increase over the corresponding parental seed lots under comparable germination conditions. In addition to these increases in germination, the in-dark seed showed early and synchronized germination as compared to the in-light seed. Since these results were achieved through only one cycle of selection and breeding, they strongly suggest that we have developed a very effective method for modifying seed dormancy in Echinacea.     

微波法制备莲子抗性淀粉工艺参数的优化

以速冻鲜莲为原料,用微波法制备 RS3型莲子抗性淀粉;在单因素试验的基础上,运用正交试验设计法优化莲子抗性淀粉工艺参数。试验结果表明,影响莲子抗性淀粉得率的主次因素顺序为：淀粉乳浓度＞微波时间＞微波功率。经优化后的最佳制备工艺条件为莲子淀粉乳液浓度 15%,微波时间 120 s,微波功率 640 W,在此工艺条件下莲子抗性淀粉得率为 39.53%,其得率虽低于压热法和超声波辅助压热法,但所需时间较短,操作简单,适合用于抗性淀粉的工业化生产或大批量制备。     

Effects of fungicide seed treatments on germination, population, and yield of maize grown from seed infected with fungal pathogens

Seedborne fungi can reduce survival, growth, and yield of maize (Zea mays L.). Laboratory, field, and growth chamber experiments were conducted to determine the effects of the seed treatment fungicides fludioxonil, mefenoxam, and azoxystrobin on germination, plant population, and grain yield of maize grown from low-quality hybrid seed infected with seedborne fungal pathogens. Study I used seed of four hybrids infected at 0-54% incidence with Fusarium spp., Stenocarpella maydis, Penicillium spp., Rhizopus spp., and/or Aspergillus spp. Study II used three seed lots for each of two hybrids infected at 7-37% incidence with S. maydis. Warm and cold germination for untreated seed varied among hybrids in both studies. Warm germination of the seed lot with the highest incidence of S. maydis in study II treated with azoxystrobin and fludioxonil was significantly greater (+7%) than the nontreated control. Plant population in study I was significantly affected by seed treatment, hybrid, and their interactions. Populations were greater (≥9%) for fludioxonil, fludioxonil + mefenoxam, and fludioxonil + mefenoxam + azoxystrobin treatments compared to controls. In growth chamber experiments with pasteurized soil, emergence (≥5%) and plant dry weight (≥14%) were both greater than controls only with the triple seed treatment. Plant populations in study II for all seed treatments except mefenoxam and azoxystrobin alone were greater (≥4%) than controls. Yield in study I was significantly affected by hybrid and seed treatment. Yield for one hybrid was higher (≥20%) than the control with all seed treatments except fludioxonil, whereas yield with another hybrid was consistently greater (≥26%) only with the triple seed treatment. Yield in study II was significantly affected by hybrid, seed treatment, and their interactions. Yield was greater (≥8%) than the controls for all seed treatments with one hybrid and with all (≥5%) except azoxystrobin for the other hybrid. Highest yields occurred with the triple seed treatment. Results indicate that fludioxonil and azoxystrobin can increase germination, population, and yield of maize grown from seed infected by S. maydis and other fungi.     

Species-specific detection of Bipolaris sorokiniana from wheat and barley tissues

Cochliobolus sativus (anamorph: Bipolaris sorokiniana) is a fungal pathogen that can cause yield limiting diseases of barley and wheat. A PCR-based diagnostic assay was developed to detect B. sorokiniana in barley and wheat tissues using the pathogen-specific primers COSA_F/R derived from the melanin biosynthesis pathway Brn1 locus. Specificity was tested against more than 30 fungal organisms associated with barley and wheat. Limit of detection was determined to be 0.001 ng for pure fungal DNA. The species-specific primers were capable of detecting the pathogen in planta, specifically from infected barley leaves and wheat roots and stem bases.     

Microdochium nivale and Microdochium majus in seed samples of Danish small grain cereals

Microdochium nivale and Microdochium majus are two of fungal species found in the Fusarium Head Blight (FHB) complex infecting small grain cereals. Quantitative real-time PCR assays were designed to separate the two Microdochium species based on the translation elongation factor 1α gene (TEF-1α) and used to analyse a total of 374 seed samples of wheat, barley, triticale, rye and oat sampled from farmers' fields across Denmark from 2003 to 2007. Both fungal species were detected in the five cereal species but M. majus showed a higher prevalence compared to M. nivale in most years in all cereal species except rye, in which M. nivale represented a larger proportion of the biomass and was more prevalent than M. majus in some samples. Historical samples of wheat and barley from 1957 to 2000 similarly showed a strong prevalence of M. majus over M. nivale indicating that M. majus has been the main prevalent Microdochium species in Danish cereals for at least 50 years. PCA analysis of the two quantified Microdochium species in wheat, barley and triticale samples generally showed co-existence of M. majus and M. nivale in all three cereal species. Strobilurin resistance in M. nivale/majus was analysed in selected wheat samples from 2003 to 2007, selected barley samples from 2007 as well as in historical samples from 1957 to 2000 using CAPS analysis to detect the G143A substitution. The results confirm strobilurin resistance from 2003 in the Microdochium populations of wheat and also confirmed resistance in barley for the first time. The presence of strobilurin resistance should be considered in future fungicide control strategies.     

基于SmartGrain软件的小麦籽粒形态测量方法

为了提高小麦籽粒形态的分析效率,建立了一种基于SmartGrain软件分析小麦籽粒形态的新方法。结果表明,用SmartGrain软件法对30份小麦材料粒长和粒宽的测量相对误差均小于3%,其测定结果与用游标卡尺法测量结果呈极显著的线性相关。通过利用473份小麦亲本材料籽粒形态进行检验分析,证明该方法可以一次性测量籽粒的面积、周长、粒长、粒宽、长宽比和圆度等6个参数,具有准确、快捷、廉价和高通量特点,可用于小麦籽粒形态的实际测量。     

长期定位施肥对不同筋力型小麦品质的影响

为了解长期施肥对小麦品质的作用,在33年长期定位施肥试验的基础上,分析了不同施肥条件下强筋小麦品种徐麦32和弱筋小麦品种宁麦13蛋白及淀粉相关品质特性。结果表明,有机肥、无机肥以及有机肥与品种的互作对小麦大部分蛋白和淀粉特性参数有显著或极显著影响。施肥对徐麦32和宁麦13蛋白质含量、干面筋含量、湿面筋含量、SDS沉淀值及面粉糊化特性参数影响基本一致。单施氮肥处理的蛋白质含量显著高于其他处理,单施有机肥处理显著低于其他处理,其他处理间无显著差异。干、湿面筋含量、SDS沉淀值与蛋白质含量呈较明显的正相关。施有机肥处理的峰值黏度、低谷黏度、最终黏度及峰值时间均显著高于不施有机肥处理,说明有机肥能显著改善小麦面粉的糊化特性;而无论施有机肥与否,施用无机肥不能显著改善面粉糊化特性。综上所述,长期有机、无机肥配合施用有利于弱筋小麦品质的改善,而对强筋小麦品质的改善不利。大田生产中应根据不同专用品种对品质的不同要求施用不同种类的肥料。     

10.4%吡虫啉·烯唑醇悬浮种衣剂对小麦蚜虫和纹枯病的防治效果

为了解10.4%吡虫啉·烯唑醇悬浮种衣剂对小麦纹枯病、蚜虫的防治效果及最佳用药量,采用室内和田间小区试验相结合的方法,以郑麦366为试验品种,以600g.L-1吡虫啉和12.5%烯唑醇为对照药剂,设置3种不同药种质量比(1∶50、1∶60、1∶70)处理,研究不同剂量的10.4%吡虫啉.烯唑醇悬浮种衣剂对小麦蚜虫和纹枯病的防治效果。结果表明,10.4%吡虫啉.烯唑醇悬浮种衣剂包衣对小麦发芽、出苗和生长无不良影响,用药剂量越大,对小麦蚜虫和纹枯病的防治效果越好。在防治蚜虫方面,该种衣剂在药种比为1∶50和1∶60时防效分别为85.61%～97.71%和80.15%～93.38%,与对照药剂600g.L-1吡虫啉FS1∶300包衣效果差异不显著;药种比为1∶70时,在蚜虫发生前期和中后期防效分别为91.32%～94.91%和74.88%～83.27%,其中中后期防效显著低于药种比1∶50、1∶60和对照药剂处理。在防治纹枯病和枯白穗方面,该种衣剂在药种比为1∶50时防效分别为76.91%～86.64%和78.29%,与对照药剂12.5%烯唑醇WP 1∶1500拌种处理差异不显著;药种比为1∶60时的防效分别为69.14%～80.87%和72.68%,显著低于药种比1∶50包衣处理,与对照药剂差异不显著;药种比为1∶70时防效分别为60.75%～78.35%和64.43%,显著低于药种比1∶50、1∶60和对照药剂。以上结果说明,10.4%吡虫啉·烯唑醇悬浮种衣剂对小麦蚜虫和纹枯病具有良好防治效果,最佳使用剂量为药种比1∶50～1∶60。     

种衣剂减量下增施菌剂和肥料对小麦光合、产量、蚜虫及白粉病防控的影响

为探究拌种药剂减量下增施不同类型肥料对麦田蚜虫和白粉病防控及光合和产量的影响,以小麦蚜虫低感品种川麦104和高感品种内麦836为试验材料,采用大田试验,对种衣剂减量20%下,配合施用光合菌剂、微生物菌剂、硅肥或磷酸二氢钾后麦田土壤酶活性、小麦植株光合特性、病虫防治情况和产量性状的变化进行了比较分析。结果表明,拌种药剂减量20%条件下增施微生物菌剂较种衣剂常规用量处理能显著提高孕穗期川麦104的根际土壤的脲酶活性,以及内麦836的根际土壤过氧化氢酶和纤维素酶活性。在孕穗期和抽穗期,低感品种川麦104的麦蚜数量均显著低于内麦836;增施微生物菌剂和硅肥均能显著降低麦蚜和白粉病发生,对蚜虫防效和白粉病防效较常规药剂拌种用量处理分别提高8.0和10.2个百分点。拌种药剂减量20%配合施用光合菌剂、微生物菌剂、硅肥和磷酸二氢钾均能有效提高小麦旗叶氮素含量和SPAD值,改善叶片光合效率。增施硅肥下川麦104和内麦836的产量最高,较常规种衣剂用量处理分别增加16.0%和18.2%,差异均显著。以上结果说明,小麦种子种衣剂减量配合施用硅肥或微生物菌剂可有效提高麦田土壤酶活性,减少蚜虫和白粉病发生,改善小麦叶片光合特性,提高产量。     

Effects of nitrogen fertilization on insect pests,their parasitoids,plant diseases and volatile organic compounds in Brassica napus

Nitrogen (N) availability is a key factor influencing the yield of Brassica napus L. Thus, mineral fertilization is widely used to improve the quality and quantity of seeds. In this study, we conducted field experiments to determine the impact of nitrogen fertilization on B. napus pests, their parasitoids and plant diseases. The results showed that N treatment had an impact on the abundance of pollen beetles (Meligethes aeneus Fab.) and cabbage seed weevils (Ceutorhynchus obstrictus Marsh.) as well as dark spot disease (Alternaria brassicae (Berk.) Sacc.). Since pest abundance was not correlated with the flower and silique numbers, the feeding and oviposition sites, plant smell bouquets were analysed to determine potentially attractive or repellent volatile organic compounds. We detected 19 different compounds among which acetic acid and several lipoxygenase pathway products were emitted at higher levels from N-treated plants. Emission of a few other terpenoid compounds was correlated with the pest abundance in field conditions. Abundance of parasitoids of both pests was related to the host availability rather than to the fertilization treatment. Therefore, we suggest that plant chemical cues play a minor role in localization of hosts in close proximity to parasitoid. Dark spot disease levels decreased with increasing N availability, possibly reflecting enhanced emissions of acetic acid, a known antifungal volatile. This study demonstrates the effects of N fertilization on bud and flower volatile bouquets, which might play a role in B. napus insect pest host selection and in resistance to fungal plant diseases. Further studies are necessary to investigate the behavioural responses of insects to the changed volatile bouquets.     

欧山羊草6Ub染色体附加对小麦萌发期抗旱性的改良作用

为探究欧山羊草U~b染色体附加对普通小麦抗旱性的遗传改良作用,选取2个普通小麦-欧山羊草异附加系(Ae9041和Ae9061,均附加了一对6U~b染色体)和3个普通小麦品种为材料,以聚乙二醇(PEG6000)模拟干旱胁迫,研究了不同小麦材料干旱胁迫后种子发芽势、发芽率、胚芽鞘长度、种子根数、胚根长度、幼苗高度以及贮藏物质利用率等抗旱相关指标的变化。结果表明,干旱胁迫抑制了各供试材料的种子萌发,且胁迫程度越大,抑制越明显。在相同浓度PEG6000处理下,两个异附加系的种子发芽势、发芽率和贮藏物质利用率的表现较为一致,且差异不显著。与耐旱品种晋麦47和节水品种石4185相比,Ae9041和Ae9061的幼苗胚芽鞘长、种子发芽率和贮藏物质利用率在干旱胁迫下均较高。在30%PEG6000胁迫下,Ae9041和Ae9061的种子发芽势、发芽率、幼苗胚芽鞘长、胚根长、幼苗高度均显著高于亲本中国春。由此可见,普通小麦-欧山羊草异附加系种子在干旱胁迫下能迅速吸水并整齐萌发,以发达的根系和较长的胚芽鞘促进幼苗地上部生长,并将胚乳营养快速转运至幼苗中,从而促进其较快地进行形态建成,也说明欧山羊草U~b染色体的附加能够改良小麦萌发期的抗旱性。     

Water use and yield of wheat/maize intercropping under alternate irrigation in the oasis field of northwest China

A field experiment was carried out to investigate the effects of alternate irrigation (AI) on the yield, water use and water use efficiency (WUE) of wheat (Triticum aestivum L.)/maize (Zea mays L.) intercropping system in an oasis region of northwest China in 2006-2008. Three planting patterns, i.e., sole wheat, sole maize and wheat/maize intercropping. Three irrigation levels were applied for each treatment during 3 years. Results showed that land use efficiency of wheat and maize was significantly enhanced by intercropping system; land equivalent ratio (LER) of wheat/maize intercropping system in different treatments was all greater than 1.0. Moreover, significant difference in grain yield was observed between intercropping treatment and sole cropping treatment, in which the yield of intercropped wheat was 55.37-74.88% of sole wheat, and intercropped maize was 66.63-78.87% of sole maize. Wheat/maize intercropping treatments increased water use by 1.8-16.4% than half of the total water use of sole-cropping wheat and maize. Compared to sole cropping wheat treatments, wheat/maize intercropping with alternate irrigation significantly improved water use efficiency (WUE) by 30.5-57.7%, 55.5-71.4% and 12.0-19.8%, and increased by 32.7-37.8%, 9.5-15.8% and 4.0-20.8% than sole cropping maize treatments in 2006-2008, respectively. Our results suggest that AI should be a useful water-saving irrigation method on wheat/maize intercropping in arid oasis field where intercropping planting is decreased because of limited water resource.     

放线菌剂使用方法对晚播冬小麦生长及光合性状的影响

为探究放线菌剂使用方法对晚播冬小麦生长及光合性状的影响，以长6990为供试小麦品种、娄彻氏链霉菌（D74）为供试菌剂，在大田设置T1（种子包衣+拔节期、灌浆期喷施D74菌剂）、T2（种子包衣+拔节期喷施D74菌剂，灌浆期喷施清水）、T3（种子包衣+拔节期、灌浆期喷施清水）、T4（种子不包衣+拔节期、灌浆期喷施D74菌剂）和CK（种子不包衣+拔节期、灌浆期喷施清水）5个处理（包衣中含有菌剂D74），比较分析了不同处理间小麦产量及其构成要素、表型性状、光合特性及干物质积累的差异。结果表明，放线菌剂处理下晚播小麦的产量较CK均不同程度提高，增产幅度为7.35%~25.00%，且不同处理的产量表现为T4>T1>T2>T3>CK，其中T1、T4处理与CK差异显著(P＜0.05)；不同处理间株高无显著差异(P>0.05)， T1和T4处理的穗长、穗粒数和千粒重显著高于CK，T2处理穗粒数和千粒重也较高。在光合性状中，放线菌剂处理主要影响晚播小麦灌浆后期的光合效率。花后28~35 d，T1、T4处理的旗叶净光合速率，T1~T4处理的旗叶叶绿素相对含量（SPAD）和氮含量，T1、T2和T4处理的叶面积指数均显著高于CK。放线菌剂使用后晚播小麦的花前干物质转运量及其对籽粒产量贡献率有所降低，但不同处理间差异不显著。T1、T2和T4处理的花后干物质的积累量较CK增加了37.93%、29.42%和50.92%；花后干物质积累对籽粒产量贡献率也有所提高，但不同处理间差异不显著。综合来看，放线菌剂能够有效增加晚播小麦的光合持续能力，延缓叶片衰老，促进花后干物质积累、穗部发育和籽粒灌浆，增加穗粒数和千粒重，进而提高产量，其中放线菌剂种子包衣效果不明显，叶面喷施放线菌剂效果较突出，拔节期和灌浆期叶面喷施放线菌剂的效果最佳。     

化肥减量配施有机肥对小麦生长、光合和产量的影响

为研究化肥减量配施有机肥对小麦生长和产量及经济效益的影响,以小麦品种新冬42号为材料,进行了常规化肥减量25%配施有机肥(CF+M25)、常规化肥减量50%配施有机肥(CF+M50)、常规化肥减量75%配施有机肥(CF+M75)、常规化肥(CF)、空白对照(CK)5个处理的田间试验,分析了不同化肥配施有机肥处理下小麦生长、光合相关指标和经济效益的差异。结果表明,与CF处理相比,CF配施有机肥处理的冬小麦株高、叶面积指数无显著变化,CF+M25处理小麦叶片的比叶重显著增加,增加幅度3.7%,CF+M50处理使小麦叶片单株分蘖数增加了7.89%;有机肥配施处理对冬小麦SPAD和光合参数有一定影响,但与CF处理比较规律性不明显;CF+M50处理显著增加冬小麦穗部干物质积累量,并且有较高的地上部生物量。常规化肥减量25%和减量50%配施有机肥能促进小麦增产且有效降低化肥施用量,可作为新疆伊犁地区有机肥与化肥配施的推荐用量。