Major Crops In China Research Articles

Effects of multi-cropping system on temporal and spatial distribution of carbon and nitrogen footprint of major crops in China

Life cycle assessments (LCA) of staple food (rice, wheat and corn) production and assessments of the associated greenhouse gas (GHG) and reactive nitrogen (Nr) releases from environmental and ecological perspectives help to develop effective mitigation options. Therefore, carbon (C) and nitrogen (N) footprint reductions in agroecosystems have become an increasingly popular topic related to global climate change and agricultural adaptation. The LCA method was used to calculate the product and farm C footprint (CF) and N footprint (NF) of double rice, rice-wheat and wheat-maize production based on governmental statistical datasets and published results. The spatial and temporal patterns of CF and NF were analyzed in China during 2004–2017, and their driving factors were analyzed to identify potential mitigation strategies. The results showed that of the various inputs, fertilizer application and diesel oil consumption contributed the most to both GHG and Nr emissions from farm inputs in the grain crop production process. The CFs for double rice, rice-wheat and wheat-maize were 0.83, 0.74, and 0.37 kg CO2-eq kg−1 year−1 at the yield scale, respectively. In addition, the NFs were 11.6, 13.4, and 15.4 gN-eq kg−1 year−1 at the yield scale for double rice, rice-wheat and wheat-maize, respectively. The largest fraction of CF and NF was the share of CH4 emissions and NH3 volatilization from the field soil, respectively. The annual CFs and NFs of the multiple crop in the southwestern provinces were higher than those in the central and northern provinces. The annual GHG and Nr emissions from the multiple crop maintained a relatively stable state from 2004 to 2017. The proportion of CO2/Nr production was partly reflected a soil C/N ratio, suggesting a higher C abundance for the double rice production, which could be used as a reference parameter for crop structure adjustment in the future. Based on our results and other studies, some effective solutions, especially optimized fertilization, farm machinery operation efficiencies and changes in regional allocation of grain cropping areas, are needed to mitigate the impacts of climate change and eutrophication on the main grain crop production in China.

A Sustainability Assessment of Five Major Food Crops’ Water Footprints in China from 1978 to 2010

Rice, wheat, corn, soybeans, and sorghum are the five major crops in China, which account for 92% of the country’s total grain production and 33% of its water consumption. Combining water footprint analysis tools with sustainability assessment tools, the water sustainability of the five major crops can be analyzed. Based on ecological economics theory, this paper constructs a sustainability evaluation system of China’s five major crops’ water footprints and analyzes the national and provincial diversity of the sustainability of the five major crops’ water footprints using three dimensions: scale, distribution, and equity. We find that the interprovincial distribution equity sustainability divergence is the key bottleneck factor that restricts sustainability (more than scale and configuration). One key strategy is to arrange grain production at the national level, on the basis of considering the differences of water-resource endowment between different provinces to break through the bottleneck of the water-resource distribution sustainability of these five major food crops. This paper determines a general management model that can improve the sustainability of water resource management at the interprovincial level by comparing and analyzing the most sustainable and least sustainable provinces for the water footprint production of these five major crops.

Crop Production Pushes up Greenhouse Gases Emissions in China: Evidence from Carbon Footprint Analysis Based on National Statistics Data

The rapid growth of crop yield in China was maintained by more fossil fuel inputs in the past years, causing concern about the greenhouse gas (GHG) emissions related to crop production. Therefore, this study analyzed historical dynamics of carbon footprint (CF) of 11 major crops in China during 2000–2016 and estimated possible GHG emissions of the system in 2020 under different scenarios. Results indicated that the GHG emissions of the Chinese crop system increased by 20.07% from 2000 to 2016, in which the grain crops contributed to more than 80% of the total emissions. The GHG emissions from grain crops including maize, wheat, and rice as well as sugar crops including sugarcane and sugar beet were increased by 28.07% and 14.27% in the study period, respectively, making up the primary factor of increased GHG emissions of crop system in China. Moreover, if the cropping pattern and agricultural practices is not improved in the future, the GHG emissions from Chinese crop system are estimated to increase by 346.19 million tons in 2020. If advanced agricultural policies and practices are implemented, the GHGs emissions of crop system in China in 2020 are estimated to be 2.92–12.62% lower than that in 2016. Overall, this study illustrated that the crop system in China contributed to the growth of GHG emissions in China over the past decades. Improving utilization efficiency of fertilizers and crop structure in China are the most important ways to reduce GHG emissions from the Chinese crop system.

Field Fungal Diversity in Freshly Harvested Maize

Maize is a major crop in China and maize production in Heilongjiang Province ranks No.1 in the country in annual maize production in the whole country. Maize is prone to invasion by fungi and mycotoxins produced by these fungi are proven to be serious threats to animals as well as human health. Through high through-put sequencing we detected the dominant phylum to be Ascomycota; Dothideomycetes, Sordariomycetes, Eurotiomycetes and Tremellomycetes, Saccharomycetes were the dominant classes; Hypocreales, Eurotiales, Capnodiales, Saccharomycetales, Tremellales, and Pleosporales were the main orders; Nectriaceae, Trichocomaceae, Cladosporiaceae, Debaryomycetaceae, Tremellaceae, and Pleosporaceae were major families; Gibberella, Cladosporium, Papiliotrema, Penicillium, Scheffersomyces, Talaromyces, and Epicoccum were the most abundant phylotypes at the genus level. Epicoccum_nigrum, Gibberella_zeae, Papiliotrema_flavescens, and Scheffersomyces_shehatae were the dominant fungal species. Great fungal diversity was observed in the maize samples harvested in the five major maize-growing regions in Heilongjiang Province. Maize-1 in Nenjiang County was observed to have the greatest fungal diversity and abundance among the five regions. Since some of the fungal species are mycotoxin producing, it is necessary to take precautions to ensure the maize is stored under safe conditions to prevent the occurrence of mycotoxins and the growth and reproduction of other fungi which results in deterioration in the quality of maize.

Spatio-temporal analysis of the geographical centroids for three major crops in China from 1949 to 2014

Spatial distribution changes in major crops can reveal important information about cropping systems. Here, a new centroid method that applies physics and mathematics to spatial pattern analysis in agriculture is proposed to quantitatively describe the historical centroids of rice, maize and wheat in China from 1949 to 2014. The geographical centroids of the rice area moved 413.39 km in a 34.32° northeasterly (latitude 3.08°N, longitude 2.10°E) direction at a speed of 6.36 km/year from central Hunan province to Hubei province, while the geographical centroids of rice production moved 509.26 km in the direction of 45.44° northeasterly (latitude 3.22°N, longitude 3.27°E) at a speed of 7.83 km/year from central Hunan province to Henan province. The geographical centroids of the maize area and production moved 307.15 km in the direction of 34.33° northeasterly (latitude 2.29°N, longitude 1.56°E) and 308.16 km in the direction of 30.79° northeasterly (latitude 2.39°N, longitude 1.42°E), respectively. However, the geographical centroids of the wheat area and production were randomly distributed along the border of Shanxi and Henan provinces. We divided the wheat into spring wheat and winter wheat and found that the geographical centroids of the spring wheat area and production were distributed within Inner Mongolia, while the geographical centroids of winter wheat were distributed in Shanxi and Henan provinces. We found that the hotspots of crop cultivation area and production do not always change concordantly at a larger, regional scale, suggesting that the changing amplitude and rate of each crops’ yield differ between different regions in China. Thus, relevant adaptation measures should be taken at a regional level to prevent production damage in those with increasing area but decreasing production.

Increasing concentration of major crops in China from 1980 to 2011

ABSTRACTThe concentration of crop cultivation can be measured in terms of spatial clustering and of inequality in the distribution of the cropland area. We used official agricultural statistics at the county level (N = 2,354) for each year from 1980 to 2011 for all of China to analyse the changes in spatial clustering and inequality of overall cropland and of the harvested areas of the five major crops (rice, maize, wheat, soybean, and potato). We quantified the spatial clustering with global and local Moran’s I and assessed the inequality in the distribution of crop cultivation with the generalized entropy index. The results showed that the cropland area and harvested areas of the major crops indeed became more homogeneous over time, and the major crops concentrated in fewer areas and in the major historic breadbaskets. Increasing concentration may offer opportunities in specialization and positive agglomeration effects but can reduce the resilience of food systems and agricultural sustainability.

Opportunistic Market‐Driven Regional Shifts of Cropping Practices Reduce Food Production Capacity of China

AbstractChina is facing the challenge of feeding a growing population with the declining cropland and increasing shortage of water resources under the changing climate. This study identified that the opportunistic profit‐driven shifts of planting areas and crop species composition have strongly reduced the food production capacity of China. First, the regional cultivation patterns of major crops in China have substantially shifted during the past five decades. Southeast and South China, the regions with abundant water resources and fewer natural disasters, have lost large planting areas of cropland in order to pursue industry and commerce. Meanwhile, Northeast and Northwest China, the regions with low water resources and frequent natural disasters, have witnessed increases in planting areas. These macroshifts have reduced the national food production by 1.02% per year. The lost grain production would have been enough to feed 13 million people. Second, the spatial shifts have been accompanied by major changes in crop species composition, with substantial increases in planting area and production of maize, due to its low water consumption and high economic returns. Consequently, the stockpile of maize in China has accounted for more than half of global stockpile, and the stock to use ratio of maize in China has exceeded the reliable level. Market‐driven regional shifts of cropping practices have resulted in larger irrigation requirements and aggravated environmental stresses. Our results highlighted the need for Chinese food policies to consider the spatial shifts in cultivation, and the planting crop compositions limited by regional water resources and climate change.

First Report of Fusarium pseudograminearum Causing Root Rot on Soybean (Glycine max) in Henan, China

Fusarium pseudograminearum has previously been reported as a pathogen of wheat and barley in Henan Province of China (Li et al. 2012; Xu et al. 2017), but not of soybean (Glycine max L.). In 2017, soybean plants exhibiting symptoms of root rot characterized by brown lesions on the tap and lateral roots at the beginning pod (R3) growth stage were collected from 15 fields representing eight counties in Henan Province. The symptomatic root tissues were surface-sterilized with 70% ethanol for 50 s and rinsed in sterilized water three times. Small pieces of symptomatic tissue were then placed on potato dextrose agar (PDA) and incubated at 25°C for 5 days in the dark. A total of 132 Fusarium-like colonies were isolated, and hyphal tips were transferred to fresh PDA plates to obtain pure cultures. Single-conidia isolates were then produced by dilution plating conidia from pure cultures and then subculturing from colonies that developed from the single-conidia isolations. The average mycelial growth rate was 5.3 to 8.7 mm/day at 25°C on PDA, and the colonies produced aerial mycelium varying from rose to yellow white, and rose to burgundy pigment in agar. Macroconidia of the isolates were produced on carnation leaf agar (CLA) incubated under black light and observed to be abundant, relatively slender, almost straight, commonly 3- to 7-septate, averaged 38.6 × 4.1 μm, matching that reported for F. pseudograminearum (Aoki and O’Donnell 1999). No perithecia were observed. DNA of isolates YB17SN07 and YB17SN08 from Yuanyang County and isolate YB17SN09 from Yongcheng County was extracted using the CTAB method. The translation elongation factor 1 alpha (EF1-α) gene was amplified and sequenced (O’Donnell et al. 1998). Results of sequences were deposited in GenBank (accession nos. MG189598 to MG189600). BLASTn analysis of the EF1-α gene shared 99 to 100% similarity with those of F. pseudograminearum (HBZX1675 and CBS131261). The pathogen identity was further confirmed using species-specific PCR primers, Fp1-1 and Fp1-2 (Aoki and O’Donnell 1999). To test pathogenicity, inoculum was grown for 10 days at 25°C on 100 g of sterilized boiled wheat grain and sand (3:1 v/v) after infesting with a 1-ml spore suspension (10⁸ conidia/ml) of either isolate YB17SN07, YB17SN08, or YB17SN09. Five grams of this inoculum was placed 3 cm below the surface of autoclaved soil in 15 × 20 cm pots prior to planting pregerminated soybean seeds (cv. Wandou 35). Six plants were grown per pot, five pots were used per isolate, and the experiment was repeated three times. Noninoculated plants were grown in autoclaved soil amended with sterile wheat/sand mix and served as controls. Plants were grown in the greenhouse with a 14:10 h day/night cycle. After 42 days, the root system of all inoculated soybean plants exhibited dark brown lesions over the entire taproot. Noninoculated plants did not exhibit symptoms. The fungus was reisolated and identified from infected plants for each isolate as described above. This is the first report of F. pseudograminearum causing root rot on soybean in China. Considering that soybean is a major crop in China covering 7.8 million ha in 2017, root rot caused by F. pseudograminearum could develop into a disease with major economic impacts.

Monitoring growth condition of spring maize in Northeast China using a process-based model

Early and accurate assessment of the growth condition of spring maize, a major crop in China, is important for the national food security. This study used a process-based Remote-Sensing-Photosynthesis-Yield Estimation for Crops (RS-P-YEC) model, driven by satellite-derived leaf area index and ground-based meteorological observations, to simulate net primary productivity (NPP) of spring maize in Northeast China from the first ten-day (FTD) of May to the second ten-day (STD) of August during 2001–2014. The growth condition of spring maize in 2014 in Northeast China was monitored and evaluated spatially and temporally by comparison with 5- and 13-year averages, as well as 2009 and 2013. Results showed that NPP simulated by the RS-P-YEC model, with consideration of multi-scattered radiation inside the crop canopy, could reveal the growth condition of spring maize more reasonably than the Boreal Ecosystem Productivity Simulator. Moreover, NPP outperformed other commonly used vegetation indices (e.g., Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI)) for monitoring and evaluating the growth condition of spring maize. Compared with the 5- and 13-year averages, the growth condition of spring maize in 2014 was worse before the STD of June and after the FTD of August, and it was better from the third ten-day (TTD) of June to the TTD of July across Northeast China. Spatially, regions with slightly worse and worse growth conditions in the STD of August 2014 were concentrated mainly in central Northeast China, and they accounted for about half of the production area of spring maize in Northeast China. This study confirms that NPP is a good indicator for monitoring and evaluating growth condition because of its capacity to reflect the physiological characteristics of crops. Meanwhile, the RS-P-YEC model, driven by remote sensing and ground-based meteorological data, is effective for monitoring crop growth condition over large areas in a near real time.

Spatial and temporal changes in vapor pressure deficit and their impacts on crop yields in China during 1980–2008

Vapor pressure deficit (VPD) is a widely used measure of atmospheric water demand. It is closely related to crop evapotranspiration and consequently has major impacts on crop growth and yields. Most previous studies have focused on the impacts of temperature, precipitation, and solar radiation on crop yields, but the impact of VPD is poorly understood. Here, we investigated the spatial and temporal changes in VPD and their impacts on yields of major crops in China from 1980 to 2008. The results showed that VPD during the growing period of rice, maize, and soybean increased by more than 0.10 kPa (10 yr)–1 in northeastern and southeastern China, although it increased the least during the wheat growing period. Increases in VPD had different impacts on yields for different crops and in different regions. Crop yields generally decreased due to increased VPD, except for wheat in southeastern China. Maize yield was sensitive to VPD in more counties than other crops. Soybean was the most sensitive and rice was the least sensitive to VPD among the major crops. In the past three decades, due to the rising trend in VPD, wheat, maize, and soybean yields declined by more than 10.0% in parts of northeastern China and the North China Plain, while rice yields were little affected. For China as a whole, the trend in VPD during 1980–2008 increased rice yields by 1.32%, but reduced wheat, maize, and soybean yields by 6.02%, 3.19%, and 7.07%, respectively. Maize and soybean in the arid and semi-arid regions in northern China were more sensitive to the increase in VPD. These findings highlight that climate change can affect crop growth and yield through increasing VPD, and water-saving technologies and agronomic management need to be strongly encouraged to adapt to ongoing climate change.

The Impact of Climate Change on Yield Potential of Maize across China

Maize is one of the major crops in China and its yield potential has been changedsignificantly by climate change induction during last five decades. The national policy of maizeproduction sufficiency emphasizes the necessity for a more accurate estimation of yieldpotential of maize at a national level. In this paper yield potential of maize was calculated usingthe Global Agro-Ecological Zones (GAEZ) model and key meteorological factors impact onyield potential across China was also analyzed. The results shows that, total yield potential ofmaize increased by 0.15 million tons/year during the past five decades due to an increase incultivated area as a result of climate change impact. The partial correlation analysis betweenmain meteorological factors and yield potential of maize at a county level showed that 47% ofthe counties of China were predominately influenced by changes in solar radiation while 16% ofcounties were predominately affected by temperature changes. In addition, each agriculturalzone showed clear spatial difference in the distribution of key impact factors. These researchfindings will not only provide scientific basis for making good use of meteorological resourcesunder climate change, but also play a vital role for the management of national maizeproduction for food security.

A multi-model analysis of change in potential yield of major crops in China under climate change

Abstract. Climate change may affect crop growth and yield, which consequently casts a shadow of doubt over China's food self-sufficiency efforts. In this study, we used the projections derived from four global gridded crop models (GGCropMs) to assess the effects of future climate change on the yields of the major crops (i.e., maize, rice, soybean and wheat) in China. The GGCropMs were forced with the bias-corrected climate data from five global climate models (GCMs) under Representative Concentration Pathway (RCP) 8.5, which were made available through the Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP). The results show that the potential yields of the crops would decrease in the 21st century without carbon dioxide (CO2) fertilization effect. With the CO2 effect, the potential yields of rice and soybean would increase, while the potential yields of maize and wheat would decrease. The uncertainty in yields resulting from the GGCropMs is larger than the uncertainty derived from GCMs in the greater part of China. Climate change may benefit rice and soybean yields in high-altitude and cold regions which are not in the current main agricultural area. However, the potential yields of maize, soybean and wheat may decrease in the major food production area. Development of new agronomic management strategies may be useful for coping with climate change in the areas with a high risk of yield reduction.

Determination of virtual water content of rice and spatial characteristics analysis in China

Abstract. China is a water-stressed country, and agriculture consumes the bulk of its water resources. Assessing the virtual water content (VWC) of crops is one important way to develop efficient water management measures to alleviate water resource conflicts among different sectors. In this research, the VWC of rice, a major crop in China, is taken as the research object. China covers a vast land area, and the VWC of rice varies widely between different regions. The VWC of rice in China is assessed and the spatial characteristics are also analysed. The total VWC is the total volume of freshwater both consumed and affected by pollution during the crop production process, including both direct and indirect water use. Prior calculation frameworks of the VWC of crops did not contain all of the virtual water content of crops. In addition to the calculation of green, blue and grey water – the direct water in VWC – the indirect water use of rice was also calculated, using an input–output model. The percentages of direct green, blue, grey and indirect water in the total VWC of rice in China were found to be 43.8, 28.2, 27.6, and 0.4%. The total VWC of rice generally showed a roughly three-tiered distribution, and decreased from southeast to northwest. The higher values of direct green water usage were mainly concentrated in Southeast and Southwest China, while the values were relatively low in Northwest China and Inner Mongolia. The higher direct blue water values were mainly concentrated in the eastern and southern coastal regions and Northwest China, and low values were mainly concentrated in Southwest China. Grey water values were relatively high in Shanxi and Guangxi provinces and low in Northeast and Northwest China. The regions with high values for indirect water were randomly distributed but the regions with low values were mainly concentrated in Northwest and Southwest China. For the regions with relatively high total VWC the high values of blue water made the largest contribution, although for the country as a whole the direct green water is the most important contributor.

Chinese Food Security and Climate Change: Agriculture Futures

Abstract Climate change is now affecting agriculture and food production in every country of the world. Here the authors present the IMPACT model results on yield, production, and net trade of major crops in China, and on daily calorie availability as an overall indicator of food security under climate change scenarios and socio-economic pathways in 2050. The obtained results show a relatively optimistic outlook on yield, production and trade toward 2050. The outcomes of calorie availability suggest that China will be able to maintain a level of at least 3,000 kilocalories per day through 2010 to 2050. Overall, Chinese agriculture is relatively resilient to climate change. It is unlikely that Chinese food security by 2050 will be compromised in the context of climate change. The major challenge to food security, however, will rise from increasing demand coupled with regional disparities in adaptive capacity to climate change.

Analysis of Factors Influencing Yield Variability of Major Crops in China

The objective of this research was to analyze the characteristics and major factors influencing yield variability of a number of major crops in China from 1981 to 2010. Based on data for yield and sown area of a crop,four methods were used to separate crop trend yield and meteorological yield from actual yield. There was an association between total yield and per unit area yield for all major crops over the past 30 years in China. The per unit area yields of fruits increased more rapidly than other crops,and was about 7. 09% for citrus fruit annually. The trend yield for different crops also increased year by year. However,meteorological yield fluctuated greatly with greatest fluctuations occurring for fruits ( 17. 76% for citrus and 15. 83% for apple) . The contributions of sown area and per unit area yield to variability of total yield varied among the major crops. For grains and fruits,the contribution of per unit area yield had the dominant effect,while the opposite was the case for sugar crops and cotton. For oil crops both factors contributed almost equally. The variability in per unit area yield of all crops could be largely attributed to var-iability of meteorological factors. Social factors,such as agricultural policy and improved technology,played rela- tively lesser roles. The four methods used in the analysis showed no significant differences. The contributions of the above factors to yield variability were species dependent. To ensure agricultural production security,more attention should be paid to enhance the per unit area yield of crops together with the impact of climate change on yields.

First Report of Bacterial Soft Rot of Potato Caused by Pectobacterium carotovorum subsp. carotovorum in Guangdong Province of China.

Potato (Solanum tuberosum L.) is a major crop in China, with 80.0 million tons being produced in 2010 on 3.3 million ha. Pectobacterium carotovorum subsp. carotovorum Jones 1901; Hauben et al. 1999 causes soft rot worldwide on a wide range of hosts including potato, carrot, and cabbage. During spring 2010, a soft rot with a foul smell was noted in stored potato tubers of different cultivars in the Guangdong Province. Symptoms on tubers appeared as tan, water-soaked areas with watery ooze. The rotted tissues were white to cream colored. Stems of infected plants with typical inky black symptoms could also be found in the fields prior to harvest. Three different potato fields were surveyed, and 13% of the plants had the symptoms. Twenty-seven samples (three symptomatic tubers per sample) were collected. Bacteria were successfully isolated from all diseased tissues on nutrient agar media supplemented with 5% sucrose and incubated at 26 ± 1°C for 36 h. After purification on tripticase soy agar media, four typical strains (7-3-1, 7-3-2, 8-3-1, and 8-3-2) were identified using the following deterministic tests: gram-negative rods, oxidase negative, facultatively anaerobic, able to degrade pectate, sensitive to erythromycin, negative for phosphatase, unable to produce acid from α-methyl-glucoside, and produced acid from trehalose. Biolog analysis (Ver 4.20.05, Hayward, CA) identified the strains as P. carotovorum subsp. carotovorum (SIM 0.808, 0.774, 0.782, and 0.786, respectively). The identity of strains 7-3-1 (GenBank Accession No. JX258132), 7-3-2 (JX258133), and 8-3-1 (JX196705) was confirmed by 16S rRNA gene sequencing (4), since they had 99% sequence identity with other P. carotovorum subsp. carotovorum strains (GenBank Accession Nos. JF926744 and JF926758) using BLASTn. Further genetic analysis of strain 8-3-1 was performed targeting informative housekeeping genes, i.e., acnA (GenBank Accession No. JX196704), gabA (JX196706), icdA (JX196707), mdh (JX196708), mtlD (JX196709), pgi (JX196710), and proA (JX196711) (2). These sequences from strain 8-3-1 were 99 to 100%, homologous to sequences of multiple strains of P. carotovorum subsp. carotovorum. Therefore, strain 8-3-1 grouped with P. carotovorum subsp. carotovorum on the phylogenetic trees (neighbor-joining method, 1,000 bootstrap values) of seven concatenated housekeeping genes when compared with 60 other strains, including Pectobacterium spp. and Dickeya spp. (3). Pathogenicity of four strains (7-3-1, 7-3-2, 8-3-1, and 8-3-2) was evaluated by depositing a bacterial suspension (106 CFU/ml) on the potato slices of cultivar 'Favorita' and incubating at 30 ± 1°C. Slices inoculated with just water served as non-inoculated checks. The strains caused soft rot within 72 h and the checks had no rot. Bacteria were reisolated from the slices and were shown to be identical to the original strains based on morphological, cultural, and biochemical tests. Although this pathogen has already been reported in northern China (1), to our knowledge, this is the first report of P. carotovorum subsp. carotovorum causing bacterial soft rot of potato in Guangdong Province of China.

First Report of Soybean Neocosmospora Stem Rot Caused by Neocosmospora vasinfecta var. vasinfecta in China.

During October 2009, the occurrence of a disease on soybean (Glycine max) was observed in several fields in Boluo County and Zengcheng City, Guangdong Province. Top leaves of infected plants initially turned yellow and plants eventually were defoliated, while stems and roots became black and rotted. The stem lesions sometimes extended 10 to 15 cm upward from the soil surface. Orange-to-brown spherical fruiting bodies, which were very similar with those of the soybean red crown rot pathogen, scattered or congregated on the stem lesions. Plants with symptoms were sampled from fields. Fruiting bodies were excised from diseased tissues. Microscopic examination revealed that they were perithecia, globose to pyriform, ostiolate with a short neck, and measured 160 to 298 × 151 to 235 μm. Under gentle pressure, asci and ascospores were exuded from these perithecia. Asci were eight spored, narrowly cylindrical to clavate, thin walled, with a short stalk, and measured 58 to 124 μm long and 8 to 15 μm in diameter. Ascospores were uniseriately arranged, globose to ellipsoid, thick walled, one celled, hyaline to pale, and measured 14 to 17 × 8 to 12 μm. Isolation was made from stem tissues at the edge of disease lesions on potato dextrose agar (PDA) amended with streptomycin sulfate and incubated at 25°C. Mycelia were white and floccose. Conidia were cylindrical to oblong-ellipsoidal, hyaline, one celled, and measured 6 to 22 × 2 to 5 μm, aggregating in a slimy mass on the apex of the conidiogenous cell. Abundant orange-to-brown spherical perithecia were produced on the colony. Ascospores had walls with a rugose ornamentation that could be clearly seen under a scanning electron microscope. The fungus was identified as Neocosmospora vasinfecta var. vasinfecta (anamorph Acremonium sp.) (1). The internal transcribed spacer (ITS) region of rDNA of two isolates were amplified with universal primers ITS1/ITS4 and sequenced (GenBank Accession No. JF705861 and JF705862), and comparisons with GenBank accessions showed 99% similarity with N. vasinfecta strain Pec070 (Accession No. FJ940902) and strain NRRL22497 (Accession No. AY381142). Pathogenicity tests were conducted. Five, 3-week-old seedlings of soybean cv. Huaxia No. 3 planted in plastic pots (20 cm in diameter) were wounded with a needle at the base of the stem below the soil line and near the root system, and then inoculated by drenching the soil with a conidial suspension (105 per ml). Control plants were inoculated with sterile water. There were six replicates for each treatment. The treated plants were incubated at 25 ± 2°C in a greenhouse. All inoculated plants exhibited symptoms of leaf yellowing and black rot of stems and roots 3 weeks after inoculation. N. vasinfecta var. vasinfecta was reisolated from the diseased plants. All control plants remained healthy. To our knowledge, this is the first observation of Neocosmospora stem rot of soybean in China. The pathogen could pose a threat to soybean, which is a major crop in China. This disease has been previously reported in the United States though the anamorph of the pathogen has either not been identified or has been identified as a Cylindrocarpon sp. (2,4). This fungus is also associated with human infections (3).

Synthesis and herbicidal activity of 2-cyano-3-substituted-pyridinemethylaminoacrylates.

Two series of 2-cyano-3-substituted-pyridinemethylaminoacrylates, namely 12 new (Z)-2-cyano-3-methylthio-3-substituted-pyridinemethaneaminoacrylates and 10 new (Z)-2-cyano-3-alkyl-3-substituted-pyridinemethaneaminoacrylates, were synthesized as herbicidal inhibitors of photosystem II (PSII) electron transport. All of these compounds were confirmed by (1)H NMR, elemental, IR, and mass spectrum analyses. Their herbicidal activities were evaluated. Some compounds exhibited excellent herbicidal activities, even at a dose of 75 g/ha. A suitable substituent at the 2-position of the pyridine ring and the well-fit group at the 3-position of acrylate were essential for high herbicidal activity. 2-Cyanoacrylates containing a substituted pyridine ring provide higher herbicidal activities than parent compounds containing phenyl. These PSII inhibitor herbicides are safe to corn, which is a major crop in China.

A Literature review ofPhaseolus angularis— the adsuki bean

Phaseolus angularis (Willd.) W. F. Wight is a major crop in China and Japan, but its production is small elsewhere. Although it is the sixth largest crop in Japan, and a frequent subject in Japanese publications, its appearance in Western botanical literature does not reflect this importance. The last literature review in a Western language was published in 1914 (40). In view of the economic importance of this bean, it seems worthwhile to provide an up-todate review, accessible to the Western reader.