Impact of transgenic viral resistance on seed potato certification

It was nearly 100 years ago that the decline in quality and yield observed in potato crops was attributed to the accumulation of pathogens in seed tubers saved from one field generation to the next. As a direct result of this realization, seed potato certification programs have been initiated throughout the world. While these programs have different administrative structures and employ various methodologies, they are all dedicated to the primary goal of producing a sufficient volume of high quality seed tubers as free from disease causing organisms as possible. Viral diseases are especially problematic because they have serious economic affects and their physical and biological properties make them difficult to control. Until recently, certification programs have relied on methodologies including the use of virus-free material obtained from tissue culture, strict adherence to practices that minimize the mechanical and insect spread of virus, physical inspection of seed increase plots to identify and minimize the number of virus-infected plants, and the increase of seed materials for only a limited number of years to insure that any infected materials are “flushed out” of the system. Approximately 10 years ago, it was first observed that virus resistance can be obtained by using transformation techniques to insert viral genes into the genome of plants. Subsequently, researchers in private and public laboratories have shown that potato plants produced in this way are highly resistant or immune to several viral diseases. The effect that the deployment of these materials may have on the seed potato certification process is the subject of this paper.     

施氮量对优质稻“福香占”光合特性、产量及品质的影响

【目的】烟稻轮作生产模式可以有效改善土壤生态,促进农业增效、农民增收。氮肥是影响水稻生长发育的关键因素,为明确优质稻“福香占”在福建烟后稻区的最佳氮肥施用量,充分发挥其优质、高产特性,【方法】本研究设置CK(0)、N₁(51.75)、N₂(103.5)、N₃(155.25)、N₄(207 kg/hm²) 5个氮肥(以纯氮计)水平,在大田环境下,分析“福香占”光合特性、田间产量及其构成因素、稻米品质、香味等方面的变化。【结果】随施氮量增加,“福香占”生育期逐渐延长,叶片SPAD值、净光合速率、叶绿体大小、叶片中蔗糖和淀粉含量均上升,N₃或者N₄达到最高。两年穗总粒数和田间产量均是N₂最高,结实率、千粒重随施氮量增加而降低。稻米加工品质N₂处理表现最好,外观品质和食味品质受氮肥水平影响不显著。蛋白质含量随氮肥量升高而增加,峰值黏度、热浆黏度、最终黏度、崩解值均随氮肥量增加而降低,消减值升高。N<...     

马铃薯早疫病菌分生孢子传播和病害发生的规律及与降雨的关系

本试验通过马铃薯早疫病菌[Alternarid Solani (Ell.el marl) Jones etGroul]分生孢子的空气捕捉、病害系统观察及降雨条件的记载,研究了该病菌分生孢子传播、病害发生的规律及与降雨的相互关系。1981～1986年3年的研究表明,早疲病害分生孢子在马铃薯整个生长期内均有传播,其发展形式呈“波浪”式增长;每次增长均是在雨后2～3天;降雨的数量、时期、频率和历期决定着孢子传播“波浪”的具体形式;前期降雨对整个孢子传播数量起着决定性作用;病害发生呈“S”型增长;病害每次急剧增长都出现在孢子传播高峰期后的10～20天;病害的发展直接取决于空气传播的孢子。研究结果有助于马铃薯早疫病防治策略的制定以及预测预报和指导大田防治。     

Genetically-modified herbicide-resistant (GMHR) crops a two-edged sword? An Americas perspective on development and effect on weed management

GMHR crops have been cultivated in the Americas for nearly 20 years. Prior to release, regulators asked the question, “will herbicide selection pressure for evolution of HR weeds increase significantly as a result of GMHR crop cultivation?” In hindsight, they could not have imagined the rapid, widespread adoption of glyphosate-resistant (GR) crops and subsequent chain of events: surge in glyphosate usage at the expense of other herbicides, sharp drop in investment in herbicide discovery, unrelenting rise of GR and multiple-HR weed populations, and increasing herbicide use in GMHR cropping systems. In this brief review, we outline grower adoption of GMHR soybean, maize, cotton, and oilseed rape (canola) in the Americas, and their impact on herbicide-use practices for weed management. Cultivars with stacked-HR traits (e.g., glyphosate + glufosinate + dicamba or 2,4-D) will provide a short-term respite from HR weeds, but will perpetuate the chemical treadmill and selection of multiple-HR weeds. The only sustainable solution is for government or end-users of commodities to set herbicide-use reduction targets in our major field crops similar to European Union member states, and include financial incentives or penalties in agricultural programs to support this policy. Concomitantly, industry incentives must expand to improve grower adoption of best management practices for HR weeds. New or emerging technologies will provide additional tools for reactive HR weed management in the future, but their time of arrival is uncertain.     

Efficacy of SmartStax® insect-protected corn hybrids against corn rootworm: The value of pyramiding the Cry3Bb1 and Cry34/35Ab1 proteins

Monsanto Company and Dow AgroSciences have used conventional breeding techniques to develop the combined-trait corn (Zea mays L.) product MON 89034 × TC1507 × MON 88017 × DAS-59122-7 (“SmartStax^® corn”) that confers insect resistance against key lepidopteran pests and the corn rootworm complex (Diabrotica spp.), as well as herbicide tolerance. This product contains the Cry3Bb1, Cry34Ab1, and Cry35Ab1 proteins for corn rootworm (CRW) control. Replicated field trials were conducted in 2006 and 2007 to test the efficacy of Cry3Bb1, Cry34Ab1/Cry35Ab1, and SmartStax under both natural and controlled infestations. In both years, root damage and adult beetle emergence were significantly less for Bt-containing hybrids than for non-Bt controls. In trials with heavy insect pressure, adult beetle emergence (a measure of larval control) was significantly reduced for SmartStax hybrids compared with hybrids with the individual traits and with non-Bt controls. Similarly, strip-plot testing in 2012 in grower fields with high levels of root injury to non-Bt hybrids showed significantly lower feeding on SmartStax than on the non-Bt control or on either single-trait product. In grower fields where single-trait Cry3Bb1 products incurred heavy CRW damage in 2011, SmartStax provided consistent protection against CRW in 2012. The combination of these insecticidal proteins in a single plant provides better rootworm control than current single-trait Bt corn products and represents an effective approach for corn rootworm resistance management.     

甜菜高产高糖技术多媒体信息系统的研制

根据甜菜科研成果、专家经验和田间试验结果,采用微软ａｃｃｅｓｓ、Ｃ和ＶＢ语言,研制开发了甜菜高产高糖技术多媒体信息系统。该系统能够依据用户提供的信息,选择合理的推理机制,以甜菜专家的水平去解决甜菜生产中的技术问题,该系统操作方便,易于推广。     

Frequency of symptomatic trees removal in small citrus blocks on citrus huanglongbing epidemics

Among the recommended measures for citrus Huanglongbing (HLB) management, the systematic elimination of symptomatic trees is the most argued and difficult to be accepted and accomplished by citrus growers. Elimination of recently affected HLB trees represents a short term yield loss and cost increase due to the need of frequent inspections and removal operations. This work aimed to evaluate the effect of different frequencies of inoculum reduction applied at individual citrus blocks scale (or local inoculum reduction) on HLB temporal progress. Eight experiments were carried out in new planted and older citrus blocks with 504–1290 trees/plot. In all experiments, inspections to detect symptomatic trees were done in a fortnightly or monthly frequency. The treatments of frequencies of local inoculum reduction varied from fortnightly to 6 months. Annual disease progress rate was estimated by logistic model for each plot. No difference on HLB progress rates among treatments was observed, except in experiments 1 and 3 where less frequent tree removal resulted in higher disease progress rate. This ineffectiveness of local inoculum reduction on the disease progress rate was explained by the higher weight of primary spread on HLB epidemics than the secondary spread within plots associated with small size and narrow shape of treated plots (except for experiments 1 and 3), high dispersal capacity of HLB-insect vector among plots and groves, and strong control of psyllid within the plots (except for experiment 1, with poor insecticide spray program). Also, the high amount of inspections to detect symptomatic trees before the eradication treatment, which reduced the escapes (asymptomatic and non visual detectable diseased trees) contributed for these results. It is important to note that these results were obtained with only small citrus plots (0.8–2.9 ha) and they cannot be extended to larger groves and farms amenable to HLB management by the symptomatic tree removal and vector control.     

Potato Breeding: a Challenge, as ever!

Breeding efforts for the potato sector are faced with the classical questions “What to breed?” and “How to breed?”. The answers to these questions are very diverse and challenged. Until recently these two questions were unrelated. With the increase in scientific knowledge and the public debate on modern tools, these questions have become intertwined. The “What to breed?” question has changed: breeders nowadays have to breed for wider adaptation to increasingly stressful environments with an increase in focus on quality demands by an increasingly complex and diverse food processing industry and distribution networks. The “How to breed?” question has changed also: public funding is increasingly scarce for agricultural research in general and for research on the biotechnology, molecular genetics and molecular biology of potato in particular. Young scientists also move away from the potato crop. However, the complexity of the inheritance and of the physiology of potato combined with the diverse stress to which this crop is exposed, requires large investments to be able to use modern scientific tools. Such huge investments are mostly too costly for the traditional dominant players in potato breeding despite the mergers that have taken place. The only solution for this is to link up with and stimulate international networks and use the modern information technology to obtain access to valuable scientific information. The technology used also determines public acceptance of the product, thus making the “What to breed?” and “How to breed?” questions interwoven. Another important issue that has affected the environment for potato breeders is the fact that breeders have not been defending their rights very well. Counterfeited multiplication of protected varieties has become commercially more important whereas new conventions and treaties have made the exchange and use of germplasm much more complicated. Modern potato breeders, while maintaining their classical skills, have to be prepared to be more involved in basic science, more receptive to public concerns and more proactive to protect their rights.     

Evaluation of flusulfamide for the control of bacterial ring rot of potato

The potential of flusulfamide (2’, 4-dichloro- α, α, α, trifluoro-4’-nitro-m-toluenesulfonanilide) as a control agent for bacterial ring rot of potato was evaluated by testing the bactericidal activity of this compound against the causal agent,Clavibacter michiganensis subsp.sepedonicus inin vitro tests, followed by greenhouse and field trials involving treatment of inoculated seed tubers. In thein vitro tests, significant reduction in the size and number ofC. m. sepedonicus colonies was observed with complete inhibition of growth occurring at flusulfamide concentrations of 100 mg/1 or greater. In the greenhouse and field trials, tubers of potato cultivar Russet Burbank were inoculated with the causal organism of bacterial ring rot,C. m. sepedonicus, in one of three different ways (cutting, dipping, injection) and subsequently treated by dipping in an aqueous solution containing varying concentrations of flusulfamide. The “dip” and “cut” methods of inoculation were intended to simulate transmission that would occur during normal production practices, while the “inject” treatment was intended to assess the effect of flusulfamide on existing infections. In both the greenhouse and field experiments, foliar disease incidence and infection rates were reduced, but not eliminated, in plants that were inoculated by cutting or dipping and treated with flusulfamide, whereas plants that had been inoculated by injection showed little effect of treatment with flusulfamide. Based on the results of these experiments, flusulfamide appears to have protective rather than curative properties againstClavibacter michiganensis subsp.sepedonicus.     

Control of bacterial yellowing of cardoncello mushroom Pleurotus eryngii using acetic or hydrochloric acid solutions

Yellowing or bacteriosis is the most severe disease of Pleurotus eryngii, the mushroom commonly called “cardoncello” or “Ferula mushroom” in Italy. Two cropping cycles were performed with five commercial strains, to find out how acetic acid or hydrochloric acid solutions can be used to prevent or stop the disease. Pseudomonas “reactans” and other fluorescent Pseudomonads were consistently isolated from symptomatic basidiomata. The Colony-Forming-Units of total bacteria, fluorescent Pseudomonads and fungi, found in casing soil at the end of both experiments, were significantly lower in substrate bags treated with either of the two acidic solutions. This research showed that treatments with acetic acid – and to a lesser extent hydrochloric acid solutions – can reduce the spread and severity of P. eryngii yellowing.     

A comparison of plotless density estimators using Monte Carlo simulation on totally enumerated field data sets

Background

Plotless density estimators are those that are based on distance measures rather than counts per unit area (quadrats or plots) to estimate the density of some usually stationary event, e.g. burrow openings, damage to plant stems, etc. These estimators typically use distance measures between events and from random points to events to derive an estimate of density. The error and bias of these estimators for the various spatial patterns found in nature have been examined using simulated populations only. In this study we investigated eight plotless density estimators to determine which were robust across a wide range of data sets from fully mapped field sites. They covered a wide range of situations including animal damage to rice and corn, nest locations, active rodent burrows and distribution of plants. Monte Carlo simulations were applied to sample the data sets, and in all cases the error of the estimate (measured as relative root mean square error) was reduced with increasing sample size. The method of calculation and ease of use in the field were also used to judge the usefulness of the estimator. Estimators were evaluated in their original published forms, although the variable area transect (VAT) and ordered distance methods have been the subjects of optimization studies.

Results

An estimator that was a compound of three basic distance estimators was found to be robust across all spatial patterns for sample sizes of 25 or greater. The same field methodology can be used either with the basic distance formula or the formula used with the Kendall-Moran estimator in which case a reduction in error may be gained for sample sizes less than 25, however, there is no improvement for larger sample sizes. The variable area transect (VAT) method performed moderately well, is easy to use in the field, and its calculations easy to undertake.

Conclusion

Plotless density estimators can provide an estimate of density in situations where it would not be practical to layout a plot or quadrat and can in many cases reduce the workload in the field.     

美国马铃薯种薯生产及认证

美国是世界上马铃薯生产最先进的国家之一。在对美国种薯生产进行实地考察和查阅相关文献的基础上,介绍了美国马铃薯种薯生产概况、种薯质量检测、种薯认证方式和认证程序等,并对种薯分级、田间检测、收获后检测标准和检测参数、病害允许率等进行了详细阐述。美国的种薯生产和认证的经验,可为中国发展马铃薯种薯生产与认证提供借鉴与参考。     

稻鱼鳅、稻鱼甲鱼立体生态种养的效益与技术

稻田立体种养技术已成为一种高效益的生态农业模式，为农业产业的可持续发展和农民增收提供了一条有效途径。开展稻田立体种养技术的规范化研究，能够提高农田和水资源的综合利用率，节省投入成本，有助于实现水稻产业绿色优质高产高效发展。但到目前为止，该种养模式在技术上尚未健全，极大限制了该模式的推广。基于龙岩市优越的生态环境和气候条件，本研究系统分析了稻田立体种养模式的经济效益，因地制宜提出一套适合龙岩地区发展的“稻+稻花鱼+鳅”“稻+稻花鱼+甲鱼”“稻+鸭”立体生态种养技术。     

The economics of Russet Burbank seed size and spacing

This study is an economic analysis of Russet Burbank seed size and spacing data. Using a representative processor contract, regression analysis was used to estimate the statistical relationship between seed size and spacing and total yield, yield of U.S. No. 1’s, yield of U.S. No. 2’s, yield of 284 gm. and larger tubers, and adjusted grower returns. Depending upon seed cost, the economic optimum seed size ranges from 31 gm. to 48 gm. at 15 cm. spacing. With seed spacing at 23 cm. optimum seed size ranges from 40 gm. to 51 gm. At 31 cm., the optimum size range is 45 gm. to 53 gm. Grower returns adjusted for seed and harvest costs are estimated to be greater at the wider spacing. The results of this analysis have been used to show how grower returns are reduced by variability in seed size and seed spacing. Under normal circumstances, reduced variability in both size and spacing could increase grower returns by $100 per hectare or more.     

东北春大豆田蛴螬防治指标研究

为明确全球气候变暖趋势下和国家“双减”方针指导下的东北春大豆田蛴螬防治指标,在沈阳春大豆田 播种后采用人工接虫的方法,研究了不同虫口密度下的东北大黑鳃金龟3龄幼虫对大豆死亡株率和大豆产量的影 响。结果表明,大豆产量（y）与虫口密度（x）呈负相关关系（y =﹣0.0135x﹢0.4232,32>x≥1,r =﹣0.990）,产量损失率 （y）与蛴螬虫口密度（x）与间存在线性相关关系（y=3.0051x﹢2.6781,x≥1,r=0.991）;x≥4,即虫口密度≥4,产量与产量 损失率均达到显著差异;基于防治收益应大于防治成本的原则,确定了东北春大豆田东北大黑鳃金龟3龄蛴螬幼虫 的防治指标应为2.33头/m2。不同时期、不同虫口密度下蛴螬危害造成的大豆死亡株率间存在较大差异。每平方米 有1~5头蛴螬为害时,大豆苗期（V1）死亡株率达到48.18%~57.87%,至大豆初花期（R1）大豆死亡株率达到65.67%~ 75.05%,V1期死亡株率远大于V1至RI阶段的死亡株率,因此要加强苗期蛴螬的防治工作。     

橡胶树红根病的蔓延速度及预测预报

橡胶树红根病菌主要依靠根系接触蔓延传染,其蔓延速度与橡胶树种植密度等有关。依据大田橡胶树发病情况调查,推导出红根病在橡胶树林段中的蔓延速度公式。运用此公式对橡胶树红根病在大田中的蔓延发展进行预测预报,结果与实际情况相似     

High pressure processing manipulated buckwheat antioxidant activity,anti-adipogenic properties and starch digestibility

Effect of high pressure processing (HPP) on buckwheat nutritional properties is investigated in this study. The results indicated that the digestion of buckwheat starches of untreated and HPP treated at room temperature (RT) showed an “internal corrosion” pattern. However, an “exocorrosion” digestion behavior was observed for the starches of HPP treated sample at 45 °C, which might be due to the formation of amylose–lipid complexes during the process as revealed by X-ray diffraction (XRD). HPP treatment at 45 °C increased the antioxidant activity of the buckwheat as measured using 1,1′-diphenyl-2-picrylhydrazylvalue (DPPH) and iron chelating capacity (ICC) compared to untreated sample (P < 0.05), which might be associated with the release of bound phenolic compounds. More importantly, this is the first study to investigate the ability of buckwheat extract for inhibiting the formation of fat droplets using a C3H10T1/2 mesenchymal stem cell line, and found that the extract of buckwheat after HPP treatment at 45 °C demonstrated significant anti-adipogenic effects. This study suggested the HPP treatment at an increased temperature (45 °C) achieved a better nutritional value of the buckwheat than both untreated and treated at RT.     

Does the “high sugar” trait of perennial ryegrass cultivars express under temperate climate conditions?

The objective was to evaluate water‐soluble carbohydrate (WSC) and crude protein (CP) concentration of perennial ryegrass (PRG) cultivars with different genetic potential for producing WSC under two contrasting agronomic managements in temperate climate (southern Chile). A 4 × 2 factorial design was randomly allocated to 24 plots (31 m² each, three blocks): four PRG cultivars (diploid standard cultivar, “2nSt”; tetraploid standard cultivar, “4nSt”; diploid high sugar cultivar developed in New Zealand, “2nHSNZ”; and tetraploid high sugar cultivar developed in Europe, “4nHSEU”) and two agronomic managements (“favourable,” defoliations at three leaves per tiller and nitrogen (N) fertilization rate of 83.3 kg N ha^?1 year^?1; “unfavourable,” defoliations at two leaves per tiller and N fertilization rate of 250 kg N ha^?1 year^?1). Herbage samples were collected in early spring, spring, summer and autumn. Concentration of WSC did not differ among cultivars in spring and summer, averaging 194 and 251 g/kg DM, respectively. The cultivar 4nHSEU had the greatest WSC concentration in early spring and autumn (187 and 266 g/kg DM, respectively) and the greatest CP concentration across samplings (average 230 g/kg DM). Favourable management improved WSC concentrations in early spring and summer and decreased CP in spring, summer and autumn. Annual DM yield did not vary with cultivar or management, averaging 8.43 t/ha. Within a 12‐month study at one site in a temperate environment in southern Chile, PRG cultivars have not shown a consistent expression of the “high sugar” trait, where a genetic × environment interaction might be operating.     

Field‐related quality management system for grass silage production

A model for the prediction of the silage quality was tested in several large farms in northeast Germany. The model uses data and information on the fresh grass and the application of silage additives at ensiling to evaluate the “ensilability.” During clamp filling, the model analyses information on the filling performance, activity of compacting machines and hermitic covering of the clamp and evaluates the “ensiling technique.” Both “ensilability” and “ensiling technique” are assessed as “good,” “medium” or “bad” and pooled in “silage evaluation grades” 1–5. In the present model version, the predicted silage net energy lactation (NEL) and crude protein (CP) content is between 3% (for the best grade 1) and 15% (for the weakest grade 5) lower than the fresh grass NEL and CP content. In our experiments, all the grass silage production systems were characterized by “good” “ensilability” and “ensiling technique.” Under those circumstances, the experimental results indicated a closer numerical relation between fresh grass and measured silage NEL and CP content than between predicted silage and measured silage NEL and CP content. The results reveal that the model prediction calculation should be changed compared to the present version. If “ensilability” and “ensiling technique” are evaluated as “good,” the predicted silage NEL and CP content should be forecasted in a range between 0% and 3% decrease compared to fresh grass.     

Estimates of sample size for detection and estimation of incidence and severity of corky ringspot of potato

A computer program was developed to simulate the random collection of tuber samples from potato fields with corky ringspot (CRS). Tubers were harvested from 16 plots in the 1993–94 and 1994–95 seasons, and the incidence and severity of CRS symptoms were assessed. Inputs for the program were number of healthy and CRS-affected tubers and severity tuber symptoms from each plot. The output was the mean and the standard error of the mean of disease incidence and severity for 12 different sample sizes. Accuracy and precision for each sample size were estimated to determine sample size. The sample size of 20 tubers was required to detect the presence of CRS in research plots. The binomial distribution was used. With sample sizes greater than 20, the increase in accuracy and precision leveled off regardless of disease incidence and severity values; therefore sample sizes greater than 20 may be unwarranted for evaluation of chemical control tests.