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The paper purpose was to assess the impact of climate change on wheat, maize and sunflower yield in the period 2017-2021, using statistical data from National Institute of Statistics (NIS) and National Administration of Meteorology (NAM) and other sources. Comparison method was used to evaluate the deviations between the registered air temperatures and precipitations and the 1981-2010 climatological norm. Graphic method reflected the dynamics of monthly air temperatures and rainfalls in each year. Descriptive statistics for mean, standard deviation and coefficient of variation reflected an more comprehensive image upon air temperature, precipitations and yield. Correlations and regression equations were used to establish the intensity of the kinks between climate factors and yield. The highest average air temperature In Romania was 12.130C in 2019. In the period 2017-2020, the average annual temperatures exceeded the climatological norm 1981-2010 accounting for 9.10C. The lowest rainfalls, 614.2 mm, were recorded in 2019, being below of 633.1 mm the norm for the period 1981-2010. The high temperatures associated with drought and low precipitations have deeply affected yield of many agricultural crops, including maize, wheat and sunflower. The highest wheat yield 4,888 kg/ha was achieved in 2017, and the lowest one, 2,966 kg/ha in 2020. Maize registered the highest performance of 7,644 kg/ha in 2018, and the lowest one, 3,977 kg/ha in 2020. Sunflower carried out the high performance 3,041 kg/ha in 2018, and the lowest one, 1,858 kg/ha in 2020. The worst agricultural years for these three crops was 2020, but 2017 favored wheat, while 2018 favored maize and sunflower. The correlation coefficient had in general small values between average temperature and yield, but a higher link with precipitations level. The multiple correlation between yield, air temperatures and precipitations was: r= 0.817 for wheat, r = 0.116 for maize and r = 0.504 for sunflower. In the South Eastern Dobrogea, the driest area in Romania, the rainfalls declined by 65% in the period 2018-2020 having a deep negative impact on sunflower seeds yield, which decreased from 4,282 kg/ha in 2018, to 1,503 kg/ha in 2020. The correlation between precipitations and sunflower yield positive and very strong (r = 0.737). As a conclusion, the climate conditions should be analyzed in each farm and farmers have to take measure to adapt the technologies for sustaining production. [ABSTRACT FROM AUTHOR]

Maize (Zea mays L.) is one of the main agricultural crops grown worldwide under very diverse climate and soil conditions. For maize cultivation in a conventional tillage system, autumn plowing is a mandatory condition. Minimum soil tillage or no tillage has been applied in recent years, both in research and in production, for reasons relating to soil conservation and fuel economy. This paper presents the results of the research executed under pedoclimatic conditions at the Agricultural Research and Development Station Turda (ARDS Turda, Romania; chernozem soil) regarding the behavior of the maize hybrid Turda 332 cultivated in four tillage systems and two levels of fertilization during the period of 2016–2022. The following soil tillage systems were applied: a conventional tillage system (CT) and unconventional tillage systems in three variants—a minimum tillage system with a chisel (MTC), a minimum tillage system with a disk (MTD), and a no-tillage system (NT). They were applied with two levels of fertilization: basic fertilization (350 kg ha−1 NPK 16:16:16, applied at sowing) and optimized fertilization (350 kg ha−1 NPK 16:16:16 applied at sowing + 150 kg ha−1 calcium ammonium nitrate with additional fertilization in the phenophase of the maize with 6–7 leaves). The results highlight the fact that under the conditions of chernozem soils with a high clay content (41% clay content), maize does not lend itself to cultivation in MTD and NT, requiring deeper mobilization, with the yield data confirming this fact. This is because under the agrotechnical conditions for sowing carried out in MTD and NT, the seeder used (Maschio Gaspardo MT 6R) does not allow for the high-quality sowing of maize, especially under dry soil conditions. Instead, the MTC system could be an alternative to the conventional tillage system, with the yield difference being below 100 kg ha−1. [ABSTRACT FROM AUTHOR]

The article examines the prospects of Ukraine on the world grain market and ways to increase the efficiency of maize cultivation using environmentally safe technologies in the conditions of the negative impact of climate change and other stress factors. The methodological approach takes into account the peculiarities of agrarian production based on the use of data of the Food and Agriculture Organization of the United Nations, United States Department of Agriculture, United Nations, Ministry of Agrarian Policy and Food of Ukraine and State Statistics Service of Ukraine. The dynamics of world production and export of maize grain, sown areas, production and yield of maize in Ukraine are demonstrated, which directly focuses attention on the competitiveness of Ukrainian maize on the world grain market. These arguments are confirmed by analytical results, which show that in 2022, among the world leaders of maize grain producers, Ukraine took fifth place, and among exporters - fourth. In order to mitigate the impact of climate change and other stress factors on the effective production and export of Ukrainian maize, adaptation measures are proposed, which consist in the application of modern technologies, which include: optimization of the structure of sown areas and scientifically based crop rotations with the effective use of competitive varieties and hybrids of agricultural crops, the introduction of organic and mineral fertilizers and plant protection products, the use of soil protective tillage, sideration and mulching, irrigation systems, and also the productive use of plant residues with the application of modern biodestructors. Their comprehensive implementation will contribute to the development of maize yield, grain quality, preservation of biodiversity and the solution of the grain-food problem in the world. [ABSTRACT FROM AUTHOR]

Although, morphologically, maize is one of the most vigorous species, with a well-developed root system and stem, lately it has become sensitive to one particular species of weeds, namely Ambrosia artemisiifolia. With devastating effects on agriculture, on the environment and on human health, Ambrosia artemisiifolia, comonly named ragweed, is one of the most harmful invasive species. Currently, it belongs to the category of dominant weeds in some agricultural crops, which causes significant damage in production and from observations made in the maize crop, its frequency exceeds 50 individuals on a square meter. This paper presents the results of herbicides efficacy tests regarding the control of this invasive species in maize crop. The research was carried out in the Timiş Plain, on a eutricambosoil soil type, poorly glayed, with high fertility, due to good physical and chemical properties. Of the four herbicides applied post-emergence in maize crop, the best efficacy was obtained by Glyfos Ultra herbicide, applied in doses of 3.5 l / ha, which ensured a significant reduction in coverage, of over 90% 15 days after application, while Kideka herbicide has been situated at the opposite pole, with an efficacy of about 82%. Also, the results of the same set of herbicides applied indicate very high efficacy of Glyfos Ultra herbicide, which exceeds a percent of 98% 30 days after application, while the lowest results were obtained by the herbicide named Dicash 480 SL of approximately 67%. [ABSTRACT FROM AUTHOR]

Agricultural practices of smallholder farming systems of Latin America can play an important role in reducing their exposure to the risks associated with climate extremes. To date, however, there is no systematic analysis of scientific evidence for the extent to which these practices can provide the multiple benefits needed for smallholders to adapt to climate extremes. In this paper, we searched scientific databases to review scientific evidence of the benefit provided by twenty-six practices in crops commonly farmed by smallholders in the region and highly relevant for their food and nutrition security; namely, coffee, maize and beans. We reviewed scientific documents (n = 304) published in the period 1953–2021 to register evidence of the practices' effects on fifty-five benefits. Our analysis of these documents found measurement records (n = 924) largely based on field experiments (85%). Our results show strong evidence of the multiple benefits that some ecosystem-based practices (e.g., tree-based practices for coffee and no tillage for maize) can provide to support the adaptation to climate extremes of smallholder farming systems and enhance a farm's natural assets (e.g., biodiversity, water, soil). We also found that the majority of research on practices in the region focused more on the socioeconomic dimension (54%) rather than on the capacity of practices to improve the natural assets of a smallholder farmers or reduce the impact of climate extremes. Given these knowledge gaps, we discuss the importance of a renovated investment in research to address existing knowledge gaps. Our concluding suggestions for future research include the need for systematizing existing knowledge from different sources (e.g., peer-reviewed, gray literature, farmers, extension agencies, etc.), and to assess the extent to which these practices can provide multiple benefits for smallholder farming systems by improving their wellbeing, reducing their vulnerability to different hydroclimatic extremes while also contributing to ecosystem services provision at the landscape level. [ABSTRACT FROM AUTHOR]

The experimental zone of the Transylvanian Plain is characterized by some particular problems for the maize crop due to an oscillating thermal regime; relatively shorter frost-free interval; climatic diversity; mixed relief; and soils with different peculiarities, even from one plot to another. This paper presents the results of research conducted during 2016–2021 regarding the influence of four soil tillage system and two fertilizer doses on emergences and maize yield, in the pedoclimatic conditions of the hilly area of the Transylvanian Plain. In all experimental years, a faster maize emergence was observed in the conventional-plow and minimum tillage—chisel compared to minimum tillage-disk and no-tillage. In a conventional system (control), the yield achieved (7603 kg ha−1) was close to the minimum tillage—chisel system (7529 kg ha−1), and higher than the minimum tillage-disk (6391 kg ha−1) and no-tillage (5178 kg ha−1). The beneficial effect of additional fertilization with CAN 27 (granular nitrogen fertilizer containing magnesium and calcium from dolomite) is found in a better development of plants and on the increase of yield with 356 kg ha−1 compared to the variant with basic fertilization. The yield difference between the two hybrids included in the experiment is insignificant (under 100 kg ha−1). [ABSTRACT FROM AUTHOR]

The water footprint (WF), based on irrigation water quality, is important as a decision-making tool for crop selection based on the comparative advantage of water consumption and yield to maximize agricultural water productivity and sustainably improve water use efficiency. This paper presents a generic link between climate variability and water footprint. To support this link, a case study is presented for wheat and maize in different agro-climate zones in Egypt. In this study, the three agro-ecological zones, Nile Delta, Middle Egypt, and Upper Egypt, were selected to represent three different microclimates. The climate data were analyzed to estimate reference evapotranspiration (ETo) and calculate crop water use (CWU) for wheat and maize from 2015 through 2019. Cultivated area and yield data were analyzed during the study period. Water footprint (WF) was calculated for old land (clay soils) and new lands (sandy soils) in three climate regions based on blue and grey water. Green water was excluded due to negligible rainfall depths in Egypt. The results showed that the mean values of WF for maize were 1067, 1395, 1655 m3/ton in old land and 1395, 1634, 2232 m3/ton in new land under the three climate regions, respectively, while it was 923, 982, 1117 m3/ton in old land and 1180, 1258, 1452 m3/ton for wheat in new land for the three regions, respectively. The results show that the crop water use fluctuated over regions due to climate variability where the CWU values were 6211, 7335, 8007 m3/ha for maize and 4348, 4825, 5774 m3/ha for wheat in the three regions, respectively. The results show an 11% and 33% increase in maize and an 18% and 29% increase in wheat CWU in Middle and Upper Egypt regions comparing to what was observed in Nile Delta due to an increase in solar radiation, temperature, and wind speed. The Egypt mean value of wheat water footprint was 1152 m3/ton and mean value of maize water footprint was 1563 m3/ton. The data clearly show the effect of microclimate variability on WF and irrigation requirements between regions. The methodology and results from this study provide a pathway to help the policy makers to mitigate climate change impacts on crop yield and to enhance water resources management in major crop production regions by redistribution of the cropping patterns based on the comparative advantages of each crop within each region. The crop choices relative to the soil water retention characteristics could also contribute to the moderation of microclimate, which affects ETo and ETc and the water footprint. [ABSTRACT FROM AUTHOR]

Maize is one of the most sensitive industrial crops of zinc supply. Questions about fertilisation methods and the type of fertilisers used are the subject of serious scientific discussion. The key objective of this paper was to evaluate the possibilities to recover the yielding potential of Zn-deficient young maize plants by application of nanosized Zn-containing foliar fertilisers. The agronomic response of Zn-deficient maize plants to foliar fertilisation with nanoscale zinc-containing foliar fertilisers was investigated. The study was conducted in two stages: i) planting and growing the plants under controlled conditions in a zinc-deficient environment for three months; and ii) moving the plants and continuing the experiment in field conditions. A single spray with two nanosized zinc-containing foliar fertilisers was carried out. The physiological status of the plants and the dynamic of zinc and micro- and macroelements concentration in plant organs were monitored. The influence of foliar zinc fertilisation on yield and grain structural components has been determined. Our results indicated that zinc fertilisation throughout the initial growth stages plays a decisive role in the formation of the reproductive organs of maize plants. Foliar zinc fertilisers can entirely recover the physiological performance of plants grown under conditions of zinc deficiency. [ABSTRACT FROM AUTHOR]

Field experiments were conducted for two seasons in Ile-Ife, Nigeria to evaluate the performance of the AquaCrop model in simulating the effects of soil fertility management on the canopy cover (CC), soil water storages (SWS), cumulative aboveground biomass (BM), evapotranspiration (ETa), grain yields, and water productivity (WP) of rainfed maize. Six levels of soil fertility management and two cultivars of maize, SUWAN 1-SR and PVA led to a 2 by 6 factorial experimental treatment and arranged in a randomized complete block design. Agronomic and environmental parameters were measured for two consecutive seasons. The AquaCrop model was calibrated using data from the wetter year. The AquaCrop model captured well the variances in the CC, R2 ≥ 0.88, RMSE ≤ 14.2, and d-index ≥ 0.97 under full and stressed soil fertility. Although the AquaCrop model over and underestimated SWS, it is still within acceptable limits. The model simulated SWS well, R2 ≥ 0.71, EF ≥ 0.97, and d-index ≥ 0.97. AquaCrop tends to underestimate ETa under rainfall and NPK variabilities. The AquaCrop model simulated grain yields excellently, R2 = 0.99, b = 1.00. The 150% of the recommended NPK application is suitable for the desired improvement in land and water productivity of the crop. The AquaCrop model predicted and captured the trends in the yields and water productivity of maize adequately under varying NPK applications. Further research is required on other cultivars of the crop and locations in the area in order to generalize the adequacy of the model. [ABSTRACT FROM AUTHOR]

Zea mays (maize) is a staple food, feed, and industrial crop. Heat stress is one of the major stresses affecting maize production and is usually accompanied by other stresses, such as drought. Our previous study identified a heterotrimer complex, ZmNF-YA1-YB16-YC17, in maize. ZmNF-YA1 and ZmNF-YB16 were positive regulators of the drought stress response and were involved in maize root development. In this study, we investigated whether ZmNF-YA1 confers heat stress tolerance in maize. The nf-ya1 mutant and overexpression lines were used to test the role of ZmNF-YA1 in maize thermotolerance. The nf-ya1 mutant was more temperature-sensitive than the wild-type (WT), while the ZmNF-YA1 overexpression lines showed a thermotolerant phenotype. Higher malondialdehyde (MDA) content and reactive oxygen species (ROS) accumulation were observed in the mutant, followed by WT and overexpression lines after heat stress treatment, while an opposite trend was observed for chlorophyll content. RNA-seq was used to analyze transcriptome changes in nf-ya1 and its wild-type control W22 in response to heat stress. Based on their expression profiles, the heat stress response-related differentially expressed genes (DEGs) in nf-ya1 compared to WT were grouped into seven clusters via k-means clustering. Gene Ontology (GO) enrichment analysis of the DEGs in different clades was performed to elucidate the roles of ZmNF-YA1-mediated transcriptional regulation and their contribution to maize thermotolerance. The loss function of ZmNF-YA1 led to the failure induction of DEGs in GO terms of protein refolding, protein stabilization, and GO terms for various stress responses. Thus, the contribution of ZmNF-YA1 to protein stabilization, refolding, and regulation of abscisic acid (ABA), ROS, and heat/temperature signaling may be the major reason why ZmNF-YA1 overexpression enhanced heat tolerance, and the mutant showed a heat-sensitive phenotype. [ABSTRACT FROM AUTHOR]

The purpose of the study was to trace the after-effect of soil and leaf herbicides applied in maize on the next crop in rotation - wheat. In a 4-year period were carried out field experiments. The efficacy and selectivity of herbicides in maize were traced. Visual observations of plants of wheat were conducted during various phenological phases of the crop: germination, first leaf displayed (BBCH-11), two leaves displayed (BBCH-12), tillering (BBCH-20), lactic maturity (BBCH-77). Manifestations of phytotoxicity on the wheat plants were not established. After-effect of the herbicides was traced and the formation of major quantitative traits: plant height, length of classes, number of classes, number of grains in the class and weight of grain in the class. By variance analysis of pooled data were analyzed signs and evidenced the differences compared to the untreated control. The differences between the variatns with treatment and the control are essential. This confirms the visual assessments about the lack of negative after-effect of Laudis OD, Lumax 538 SC, Elumis, Gardoprim plus Gold 500 SC, Wing P, Stellar, Casper 55 VG and Merlin flex, applied in maize, on the next crop in rotation. [ABSTRACT FROM AUTHOR]

Salt stress and drought stress can decrease the growth and productivity of agricultural crops. Plant growth-promoting bacteria (PGPB) may protect and promote plant growth at abiotic stress. The aim of this study was to search for bacterial strains that can help crops resist rises in drought and salt stresses, to improve crop seed resistance under drought and salt stresses, and to investigate the effect of bacterial strains that can help crop resist external stresses under different stress conditions. Pseudomonas DY1-3, a strain from the soil under the glacier moss community of Tien Shan No. 1, was selected to investigate its growth-promoting effects. Previous studies have shown that this strain is capable of producing ACC (1-aminocyclopropane-1-carboxylic acid) deaminase. In this experiment, multifunctional biochemical test assays were evaluated to determine their potential as PGPB and their bacterial growth-promoting properties and stress-resistant effects on maize plants were verified through seed germination experiments and pot experiments. The results showed that strain DY1-3 has good salt and drought tolerance, as well as the ability to melt phosphorus, fix nitrogen, and produce iron carriers, IAA, EPS, and other pro-biomasses. This study on the growth-promoting effects of the DY1-3 bacterial strain on maize seeds revealed that the germination rate, primary root length, germ length, number of root meristems, and vigor index of the maize seeds were increased after soaking them in bacterial solution under no-stress, drought-stress, and salt-stress environments. In the potting experiments, seedlings in the experimental group inoculated with DY1-3 showed increased stem thicknesses, primary root length, numbers of root meristems, and plant height compared to control seedlings using sterile water. In the study on the physiological properties of the plants related to resistance to stress, the SOD, POD, CAT, and chlorophyll contents of the seedlings in the experimental group, to which the DY1-3 strain was applied, were higher than those of the control group of seedlings to which the bacterial solution was not applied. The addition of the bacterial solution reduced the content of MDA in the experimental group seedlings, which indicated that DY1-3 could positively affect the promotion of maize seedlings and seeds against abiotic stress. In this study, it was concluded that strain DY1-3 is a valuable strain for application, which can produce a variety of pro-biotic substances to promote plant growth in stress-free environments or to help plants resist abiotic stresses. In addition to this, the strain itself has good salt and drought tolerance, making it an option to help crops grown in saline soils to withstand abiotic stresses, and a promising candidate for future application in agricultural biofertilizers. [ABSTRACT FROM AUTHOR]

One of the modern crop breeding techniques uses doubled haploid plants that contain an identical pair of chromosomes in order to accelerate the breeding process. Rapid haploid identification method is critical for large-scale selections of double haploids. The conventional methods based on the color of the endosperm and embryo seeds are slow, manual and prone to error. On the other hand, there exists a significant difference between diploid and haploid seeds generated by high oil inducer, which makes it possible to use oil content to identify the haploid. This paper describes a fully-automated high-throughput NMR screening system for maize haploid kernel identification. The system is comprised of a sampler unit to select a single kernel to feed for measurement of NMR and weight, and a kernel sorter to distribute the kernel according to the measurement result. Tests of the system show a consistent accuracy of 94% with an average screening time of 4 seconds per kernel. Field test result is described and the directions for future improvement are discussed. [ABSTRACT FROM AUTHOR]

This paper provides recommendations on how large-scale household surveys should be conducted to generate the data needed to train models for satellite-based crop type mapping in smallholder farming systems. The analysis focuses on maize cultivation in Malawi and Ethiopia, and leverages rich, georeferenced plot-level data from national household surveys that were conducted in 2018–20 and integrated with Sentinel-2 satellite imagery and complementary geospatial data. To identify the approach to survey data collection that yields optimal data for training remote sensing models, 26,250 in silico experiments are simulated within a machine learning framework. The best model is then applied to map seasonal maize cultivation from 2016 to 2019 at 10-m resolution in both countries. The analysis reveals that smallholder plots with maize cultivation can be identified with up to 75% accuracy. Collecting full plot boundaries or complete plot corner points provides the best quality of information for model training. Classification performance peaks with slightly less than 60% of the training data. Seemingly little erosion in accuracy under less preferable approaches to georeferencing plots results in the total area under maize cultivation being overestimated by 0.16–0.47 million hectares (8–24%) in Malawi. [ABSTRACT FROM AUTHOR]

Microsatellite or simple sequence repeat (SSR) markers have wide applicability for genetic analysis in crop plant improvement strategies. Marker-assisted selection is an important tool for plant breeders to increase the efficiency of a breeding process, especially for multigenic traits, highly influenced by the environment. In this paper, the relationships between SSR markers and 26 quantitative traits of hybrid maize varieties (Zea mays L.) were analyzed. Association analyses were performed based on 30 SSR primers in a set of thirteen hybrid maize varieties. A total of 112 SSR markers were detected in these genotypes. The number of alleles per locus ranged from 1 to 17, with the average number of alleles per locus equal to 3.7. The number of molecular markers associated with observed traits ranged from 1 (for the number of kernels in row, ears weight and fresh weight of one plant) to 14 (for damage of maize caused by P. nubilalis) in 2016 as well as from 1 (for soil plant analysis development—SPAD, the number of grains in ear and fresh weight of one plant) to 12 (for carotenoids content) in 2017. The sum of statistically significant associations between SSR markers and at least one trait was equal to one hundred sixty in 2016 as well as one hundred twenty-five in 2017. Marker trait associations (MTAs) were found on the basis of regression analysis. The proportion of the total phenotypic variances of individual traits explained by the marker ranged from 24.4% to 77.7% in the first year of study and from 24.3% to 77.9% in 2017. Twenty-two SSR markers performed a significant effect on at least one tested trait in both years of experiment. The three markers (phi021/4, phi036/3, and phi061/2) can be a good tool in marker-assisted selection because they allow simultaneous selection for multiple traits in both years of study, such as the number of kernels in row and the number of grains in ear (phi021/4), the number of plant after germination, the number of plants before harvest, and the number of ears (phi036/3), as well as moisture of grain and length of ears (phi061/2). [ABSTRACT FROM AUTHOR]

The vegetation index (VI) has been successfully used to monitor the growth and to predict the yield of agricultural crops. In this paper, a long-term observation was conducted for the yield prediction of maize using an unmanned aerial vehicle (UAV) and estimations of chlorophyll contents using SPAD-502. A new vegetation index termed as modified red blue VI (MRBVI) was developed to monitor the growth and to predict the yields of maize by establishing relationships between MRBVI- and SPAD-502-based chlorophyll contents. The coefficients of determination (R2s) were 0.462 and 0.570 in chlorophyll contents' estimations and yield predictions using MRBVI, and the results were relatively better than the results from the seven other commonly used VI approaches. All VIs during the different growth stages of maize were calculated and compared with the measured values of chlorophyll contents directly, and the relative error (RE) of MRBVI is the lowest at 0.355. Further, machine learning (ML) methods such as the backpropagation neural network model (BP), support vector machine (SVM), random forest (RF), and extreme learning machine (ELM) were adopted for predicting the yields of maize. All VIs calculated for each image captured during important phenological stages of maize were set as independent variables and the corresponding yields of each plot were defined as dependent variables. The ML models used the leave one out method (LOO), where the root mean square errors (RMSEs) were 2.157, 1.099, 1.146, and 1.698 (g/hundred grain weight) for BP, SVM, RF, and ELM. The mean absolute errors (MAEs) were 1.739, 0.886, 0.925, and 1.356 (g/hundred grain weight) for BP, SVM, RF, and ELM, respectively. Thus, the SVM method performed better in predicting the yields of maize than the other ML methods. Therefore, it is strongly suggested that the MRBVI calculated from images acquired at different growth stages integrated with advanced ML methods should be used for agricultural- and ecological-related chlorophyll estimation and yield predictions. [ABSTRACT FROM AUTHOR]

Minimization of the possible harmful effects of soil pollution on agricultural production and food safety are the major challenges in modern agriculture. There is great scientific interest in the detailed understanding of the physiology of lead uptake and toxicity in Zea mays, together with the search for approaches to minimizing Pb accumulation in tissues. The aim of the present study was to explore the possibility of reducing Pb accumulation in Z. mays plants cultivated in Pb-contaminated soil, by means of vermicompost amendment. Z. mays plants were cultivated at three soil vermicompost amendment rates (10, 20, and 30%), with the addition of 1000 mg L−1 of Pb in the form of Pb(NO3)2 or an equivalent amount of nitrogen in the form of NH4NO3. Additional nitrogen had a significant stimulatory effect on plant growth and physiology, but only for control plants, and at a low vermicompost amendment rate. Independently, Pb had an insignificant negative effect on plant growth and biomass partitioning, but significantly negatively affected the mineral nutrition of Z. mays plants. At a 10 and 20% soil vermicompost amendment rate, the Pb concentration in plant leaves and roots decreased by 65%, while plant biomass increased four to five times in comparison to soil-grown control plants, together with accelerated flowering. It was concluded that vermicompost is one of the most promising soil amendments for reducing heavy metal uptake and accumulation in crop plants, while also being an efficient organic fertilizer. [ABSTRACT FROM AUTHOR]

Fungal endophytes are not widely known for their role in bioactive metabolite production and salinity stress alleviation in different crop plants. Presently, we investigated the salt stress (NaCl, KCl, and H2SO4) mitigation capabilities of fungal endophyte Candida membranifaciens (FH15) isolated from Euphorbia milii L. The pure culture filtrate (CF) of C. membranifaciens revealed siderophore production and solubilization of phosphate, with high levels of indoleacetic acid (IAA: 35.8µg/mL), phenolics (70 µg/mL), and flavonoids (50 µg/mL) by using a UV spectrophotometer. The LC/MS analysis of the CF showed different phenols and flavonoids that were identified as Salicylic acid, Baicalein, Aconitic acid, Feruloylquinic acid, Coniferyl aldehyde hexoside, Pentose, Chlorogenic acid, Myricetin, Propoxyphene, and Amino-flunitrazepam. Inoculation of maize seedlings with C. membranifaciens significantly (p = 0.05) enhanced the fresh and dry biomass, carotenoid, and chlorophyll contents under 100 mM salt stress conditions. Similarly, the catalase, peroxidase activity, phenols, proline flavonoids and relative water contents (RWC) of the maize plants were enhanced. More interestingly, the inoculation of C. membranifaciens on maize revealed a higher endogenous IAA level as compared to non-inoculated control plants. Endophyte C. membranifaciens inoculation on maize seedlings under salt stress revealed a 20.87% and 16.60% increase in fresh and dry biomass, as well as significantly enhanced root shoot length and allied growth attributes, in addition to an alleviation of the adverse effects of salinity stress. Conclusively, endophytic C. membranifaciens significantly enhanced the growth attributes of maize and mitigated the adverse effects of salinity stress. Such endophytic fungal strain could be used for further field trails to enhance agricultural productivity and facilitate sustainable agricultural practices. [ABSTRACT FROM AUTHOR]

Chilling is a major stress to plants of subtropical and tropical origins, including maize (Zea mays L.). To reveal the molecular mechanisms underlying chilling tolerance and survival in maize, we investigated transcriptomic responses to chilling stress in differentiated leaves and roots as well as in crowns with meristem activity. The application of chilling stress to shoots or roots each contributed to seedling lethality in maize. Comparison of maize lines with different chilling tolerance capacities revealed that chilling survival is highly associated with the up-regulation of abscisic acid biosynthesis and responses as well as transcriptional regulators in leaves and crowns. It was also associated with the down-regulation of translation in leaves and the heat response in crowns. Chilling treatment of all or part of the plants revealed that the response to distal chilling is very distinct from, and sometimes opposite to, the response to local or whole-plant chilling in both leaves and roots, suggesting communication between shoots and roots in the environmental response. This study thus provides information on transcriptomic responses in leaves, roots, and crowns under different chilling stresses in maize, and reveals potential chilling tolerance and survival mechanisms, which lay the ground for improving chilling tolerance in crop plants. [ABSTRACT FROM AUTHOR]

Summary: Due to climate change, drought has become a severe abiotic stress that affects the global production of all crops. Elucidation of the complex physiological mechanisms underlying drought tolerance in crops will support the cultivation of new drought‐tolerant crop varieties. Here, two drought‐tolerant lines, RIL70 and RIL73, and two drought‐sensitive lines, RIL44 and RIL93, from recombinant inbred lines (RIL) generated from maize drought‐tolerant line PH4CV and drought‐sensitive line F9721, were selected for a comparative RNA‐seq study. Through transcriptome analyses, we found that gene expression differences existed between drought‐tolerant and ‐sensitive lines, but also differences between the drought‐tolerant lines, RIL70 and RIL73. ZmbHLH124 in RIL73, named as ZmbHLH124T‐ORG which origins from PH4CV and encodes a bHLH type transcription factor, was specifically up‐regulated during drought stress. In addition, we identified a substitution in ZmbHLH124 that produced an early stop codon in sensitive lines (ZmbHLH124S‐ORG). Overexpression of ZmbHLH124T‐ORG, but not ZmbHLH124S‐ORG, in maize and rice enhanced plant drought tolerance and up‐regulated the expression of drought‐responsive genes. Moreover, we found that ZmbHLH124T‐ORG could directly bind the cis‐acting elements in ZmDREB2A promoter to enhance its expression. Taken together, this work identified a valuable genetic locus and provided a new strategy for breeding drought‐tolerant crops. [ABSTRACT FROM AUTHOR]

Background. Saline-alkali soil is mainly distributed in the northern and coastal areas of China. The Songnen Plain, located in the northeast of China, is a region with a relatively high concentration of saline-alkali soil and is also one of the more at-risk areas in the country. Every year, the increasing spread of saline-alkali soil areas has a serious impact on the growth of agricultural crops. The maize crop is sensitive to saline-alkali stress, which seriously affects its growth and development. Our previous study determined that Klebsiella variicola performs a variety of biological functions, as well as improves the rhizosphere microenvironment and promotes the growth and development of maize seedlings in saline-alkali soil environments. The present study further analyzed the mechanism that enables K. variicola to alleviate saline-alkali stress at the level of the antioxidant system. Methods. The accumulation of O2- was observed directly via histochemical staining. The activities of several antioxidant enzymes were determined using the nitro blue tetrazolium and the guaiacol methods. The contents of non-enzymatic antioxidants were determined using the dithionitrobenzoic acid method. Results. The contents of the superoxide anion and hydrogen peroxide in leaves and roots of maize seedlings increased under saline-alkali stress conditions. The higher level of reactive oxygen species increased the degree of membrane lipid peroxidation. There were differences in the degree of oxidative damage and performance of the antioxidant defence system in maize seedlings under saline-alkali stress. Following the application of increasing concentrations of K. variicola, the activity of antioxidant enzymes increased by 21.22%-215.46%, and the content of non-enzymatic antioxidants increased as well, the ratios of ASA/DHA and GSH/GSSG in leaves increased by 4.97% and 1.87 times, respectively, and those in roots increased by 3.24% and 1.60 times, respectively. The accumulation of reactive oxygen species was reduced, and the content of H2O2 decreased by 26.07%-46.97%. The content of O2- decreased by 20.18%-37.01%, which alleviated the oxidative damage to maize seedlings caused by saline-alkali stress. Conclusion. K. variicola reduced ROS-induced peroxidation to membrane lipids and effectively alleviated the damage caused by saline-alkali stress by increasing the activities of antioxidant enzymes in maize seedlings, thus enhancing their saline-alkali tolerance. A bacterial concentration of 1×108 cfu/mL was optimal in each set of experiments. [ABSTRACT FROM AUTHOR]

Hybrids account for nearly all commercially planted varieties of maize and many other crop plants because crosses between inbred lines of these species produce first-generation [F1] offspring that greatly outperform their parents. The mechanisms underlying this phenomenon, called heterosis or hybrid vigor, are not well understood despite over a century of intensive research. The leading hypotheses--which focus on quantitative genetic mechanisms (dominance, overdominance, and epistasis) and molecular mechanisms (gene dosage and transcriptional regulation)--have been able to explain some but not all of the observed patterns of heterosis. Abiotic stressors are known to impact the expression of heterosis; however, the potential role of microbes in heterosis has largely been ignored. Here, we show that heterosis of root biomass and other traits in maize is strongly dependent on the belowground microbial environment. We found that, in some cases, inbred lines perform as well by these criteria as their F1 offspring under sterile conditions but that heterosis can be restored by inoculation with a simple community of seven bacterial strains. We observed the same pattern for seedlings inoculated with autoclaved versus live soil slurries in a growth chamber and for plants grown in steamed or fumigated versus untreated soil in the field. In a different field site, however, soil steaming increased rather than decreased heterosis, indicating that the direction of the effect depends on community composition, environment, or both. Together, our results demonstrate an ecological phenomenon whereby soil microbes differentially impact the early growth of inbred and hybrid maize. [ABSTRACT FROM AUTHOR]

Identifying the physiological traits indirectly selected during the search for high-yielding maize hybrids is useful for guiding further improvements. To investigate such traits, in this study we focused on the critical period of kernel formation because kernel number is the main yield component affected by breeding. Our results show that breeding has increased the number of florets per ear and ear growth rate but not the vegetative shoot growth rate, suggesting localised effects around the ear. Consistent with this possibility, breeding has increased the net CO2 exchange of the ear leaf in field-grown crops grown at high population densities. This response is largely accounted for by increased light interception (which increases photosynthesis) and by reduced rates of respiration of the ear leaf in modern hybrids compared to older ones. Modern hybrids show increased ear-leaf area per unit leaf dry matter (specific leaf area), which accounts for the reduced respiratory load per unit leaf area. These observations are consistent with a model where the improved ear leaf CO2 exchange helps the additional florets produced by modern hybrids to survive the critical period of high susceptibility to stress and hence to produce kernels. [ABSTRACT FROM AUTHOR]

Hydropriming has the potential to ameliorate the stress-induced ill effects on yields of the crop plants and quality of seed produced. In the present study, half of the fresh seeds of maize hybrid, PEHM 5 and its parental lines (Female - CM 150, Male - CM 151) were subjected to accelerated aging test for bringing down the viability and vigour, thereby creating low vigour lots while high vigour lots consisted of fresh seeds, which were hydroprimed (30 h at 25 °C). Half of the hydroprimed seeds were surface dried while the other half were redried back to the original moisture contents. All the seed lots after treatments were evaluated for performance of physiological and biochemical parameters viz.: germination test, vigour index, electrical conductivity of seed leachates, and antioxidant enzyme activities. Results divulged significant improvement of germination and the seedling growth parameters in both the treatments: surface dried and redried after hydropriming over untreated seeds. Significant improvement was observed in root and shoot lengths, dry weight of seedlings, and vigour indices of surface dried maize seeds, and this treatment also resulted in earlier and synchronized germination. A steady increase was also noted in the activities of four key antioxidant enzyme systems: peroxidase (POX), superoxide dismutase (SOD), catalase (CAT), and glutathione reductase (GR) in both high and low vigour seed lots of hybrid and its parental lines upon hydropriming irrespective of surface dried or redried strategies. It is, therefore, suggested that hydro priming could improve the seed vigour by protecting the seed from oxidative damage by reactive oxygen species by the increasing activities of antioxidant enzymes. The surface dried seed showed all the benefits of seed priming in terms of seed quality parameters and enhanced antioxidant defense mechanism as compared to redried seeds. Therefore, surface drying could be promulgated as an effective and simple technique to mitigate the ill effects while sowing maize seeds under unfavorable growing conditions. [ABSTRACT FROM AUTHOR]

The growth and yield response of irrigated maize (Zea mays L.) under varying levels of inorganic fertilizer and poultry manure was evaluated during 2019/2020 dry season at two locations (Teaching and Research Farm of the Department of Crop Science, Kaduna State University, Kafanchan Campus and Kadawa, Irrigation Research Farm of Ahmadu Bello University Zaria, Nigeria) using a complete randomized block design with three replications. The experimental treatments consist of varying quantities of poultry manure: 1.5, 3.0, and 4.5 tonnes per hectare that were incorporated in to the soil along with four levels of inorganic fertilizer 0, 100, 120, and 140 kg N ha-1. The results of the field trials showed that all growth and yield parameters were significantly affected by poultry manure rate in both Kafanchan and Kadawa. However, the effect of poultry manure on maize plant height and cob diameter was not significant in Kafanchan. The application of inorganic fertilizer had a positive and significant influence on all maize growth and yield attributes in both locations. Irrigated maize yield showed significant increase with increasing quantities of inorganic fertilizer and poultry manure in both Kafanchan and Kadawa. The results of the field trial indicated that a combination of 120 kg N ha-1 inorganic fertilizer and 3.0 tha-1 poultry manure is desirable for optimum irrigated maize yield in Kafanchan and Kadawa. [ABSTRACT FROM AUTHOR]

Copyright of Acta Scientiarum Polonorum. Formatio Circumiectus is the property of Wydawnictwo Uniwersytetu Rolniczego im. Hugona Kollataja w Krakowie and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The combination of tillage implements and weeding durations is very important for the improvement in the leaf area index and chlorophyll content of fodder maize along with the environment friendly management of the weeds infesting maize crop. In this connection, two field experiments were conducted at the Research Farm of the University of Agriculture Peshawar during the summer seasons of 2016 and 2017. Two tillage implements including mouldboard plough and cultivator as factor A (allotted to main plots) and 14 different weeding durations as factor B (assigned to subplots) were used in a randomized complete plot design with split plot arrangement. Data were recorded on leaf area, leaf area index, number of leaves plant-1, and the chlorophyll content of maize plants. The results indicated that there was a higher leaf area (294 cm2), leaf area index (2.1), leaves count plant-1 (11.7) and chlorophyll content (50.1 SPAD values) in mouldboard plough treatments than in the cultivator treatments. On the other hand, among the weeding intervals, the highest leaf area (377 cm2), leaf area index (2.7), leaves count plant-1 (13) and chlorophyll content (60.3 SPAD values) were achieved in full season weeding treatments, followed by 12 weeks weeding treatments, 10 weeks, 8, 6, 4 and 2 weeks weeding. Moreover, for the interaction of tillage implements and weeding regimes, the leaf area, leaf area index, leaves count plant-1and chlorophyll content were highest in the interaction of mouldboard plough under full season weeding regimes. In conclusion, the interaction of mouldboard plough with full season weeding has been the most successful combination for achieving the best leaf area index and chlorophyll content of maize crop plants. [ABSTRACT FROM AUTHOR]

Background. Deterioration of the ecological environment in recent years has led to increasing soil salinization, which severely affects the cultivation of agricultural crops. While research has focused on improving soil environment through the application of pollution-free microbial fertilizers, there are relatively few plant growth-promoting bacteria suitable for saline-alkali environments. Although Klebsiella variicola can adapt to saline-alkali environments to successfully colonize rhizosphere microenvironments, only a few studies have investigated its role in promoting crop growth. Its effect on the crop rhizosphere soil microenvironment is especially unclear. Methods. In this study, the biological function of K. variicola and its colonization in maize seedling rhizosphere soil were studied in detail through selective media and ultraviolet spectrophotometry. The effects of K. variicola on the rhizosphere soil microenvironment and the growth of maize seedlings in saline-alkali and neutral soils were systematically analysed using the colorimetric method, the potassium dichromate volumetric method, and the diffusion absorption method. Results. Our results showed that K. variicola played a role in indole acetic acid, acetoin, ammonia, phosphorus, and potassium production, as well as in nitrogen fixation. A high level of colonization was observed in the rhizosphere soil of maize seedlings. Following the application of K. variicola in neutral and saline-alkali soils, the nutrient composition of rhizosphere soil of maize seedlings increased in varying degrees, more notably in saline-alkali soil. The content of organic matter, alkali-hydrolysable nitrogen, available phosphorus, available potassium, alkaline phosphatase, sucrase, urease, and catalase increased by 64.22%, 117.39%, 175.64%, 28.63%, 146.08%, 76.77%, 86.60%, and 45.29%, respectively, insaline-alkalisoil. Conclusion. K.variicola, therefore, performed a variety of biological functions to promote the growth of maize seedlings and effectively improve the level of soil nutrients and enzymes in the rhizosphere of maize seedlings, undersaline-alkali stress conditions. It played an important role in enhancing the rhizosphere microenvironment of maize seedlings under saline-alkali stress. [ABSTRACT FROM AUTHOR]

Grain yield and mineral nutrient concentration in cereal crops are usually inversely correlated, undermining biofortification efforts. Here, sink size, expressed as kernel number per cob, was manipulated by controlling the time when the silks of sweetcorn (Zea mays) cv. Hybrix 5 and var. HiZeax 103146 were exposed to pollen. Twelve other varieties were manually pollinated to achieve the maximum potential kernel number per cob, and kernel Zn concentration was correlated with kernel number and kernel mass. As kernel number increased, kernel Zn concentration decreased, with the decrease occurring to similar extents in the embryo tissue and the rest of the kernel. However, total kernel Zn accumulated per cob increased with increasing kernel number, as the small decreases in individual kernel Zn concentration were more than offset by increases in kernel number. When both kernel number and mass were considered, 90% of the variation in kernel Zn concentration was accounted for. Differential distribution of assimilates and Zn to sweetcorn cobs led to significant decreases in kernel Zn concentration with increasing kernel number. This suggests there will be challenges to achieving high kernel Zn concentrations in modern high-yielding sweetcorn varieties unless genotypes with higher Zn translocation rates into kernels can be identified. [ABSTRACT FROM AUTHOR]

Copyright of Pesticides & Phytomedicine / Pesticidi i Fitomedicina is the property of Institute of Pesticides & Environmental Protection and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Meristems are highly regulated structures ultimately responsible for the formation of branches, lateral organs, and stems, and thus directly affect plant architecture and crop yield. In meristems, genetic networks, hormones, and signaling molecules are tightly integrated to establish robust systems that can adapt growth to continuous inputs from the environment. Here we characterized needle1 (ndl1), a temperature-sensitive maize mutant that displays severe reproductive defects and strong genetic interactions with known mutants affected in the regulation of the plant hormone auxin. NDL1 encodes amitochondria-localized ATP-dependent metalloprotease belonging to the FILAMENTATION TEMPERATURESENSITIVE H (FTSH) family. Together with the hyperaccumulation of reactive oxygen species (ROS), ndl1 inflorescences show upregulation of a plethora of stress-response genes. We provide evidence that these conditions alter endogenous auxin levels and disrupt primordia initiation in meristems. These findings connect meristem redox status and auxin in the control of maize growth. [ABSTRACT FROM AUTHOR]

This study aims to assess the impact of climate change on productivity of maize in Khyber Pakhtunkhwa (KP) province of Pakistan over a period of thirty years from 1986 to 2015. According to the ecological landscape, KP is divided into three climatic regions; the northern climatic region, the central climatic region, and the southern climatic region. The study uses Autoregressive Distributed Lag (ARDL) model for maize crop in KP. This study reveals that the impacts of climatic variables are increasing from the southern climatic region to the northern climatic region. The study also reveals that any negative shock to the crops productivity can be overcome by increasing the area under maize cultivation. It is concluded that the variations in climatic variables have significant effects on maize productivity in the short-run as well as in the long-run in all the climatic regions of KP. [ABSTRACT FROM AUTHOR]

Various models and datasets related to aflatoxins in the maize and dairy production chain have been developed and used but they have not yet been linked with each other. This study aimed to investigate the impacts of climate change on aflatoxin B1 production in maize and its consequences on aflatoxin M1 contamination in dairy cow’s milk, using a full chain modelling approach. To this end, available models and input data were chained together in a modelling framework. As a case study, we focused on maize grown in Eastern Europe and imported to the Netherlands to be fed–as part of dairy cows’ compound feed–to dairy cows in the Netherlands. Three different climate models, one aflatoxin B1 prediction model and five different carryover models were used. For this particular case study of East European maize, most of the calculations suggest an increase (up to 50%) of maximum mean aflatoxin M1 in milk by 2030, except for one climate (DMI) model suggesting a decrease. Results from all combinations of carryover and climate models suggest a similar or slight increase (up to 0.6%) of the chance of finding aflatoxin M1 in milk above the EC limit of 0.05 μg/kg by 2030. Results varied mainly with the climate model data and carryover model considered. The model framework infrastructure is flexible so that forecasting models for other mycotoxins or other food safety hazards as well as other production chains, together with necessary input databases, can easily be included as well. This modelling framework for the first time links datasets and models related to aflatoxin B1 in maize and related aflatoxin M1 the dairy production chain to obtain a unique predictive methodology based on Monte Carlo simulation. Such an integrated approach with scenario analysis provides possibilities for policy makers and risk managers to study the effects of changes in the beginning of the chain on the end product. [ABSTRACT FROM AUTHOR]

Vitellaria paradoxa provides many benefits to farmers within the Shea belt. However, increased threats to it necessitate its conservation, and one common approach is the practice of agroforestry. A number of studies have shown that Shea tree has influence on crop production, and yet, some of these studies were done using single season experiments or bioassays using mature Shea tree components. In this study, the seasonal influence of young and mature Shea trees on Maize and Soybean yields was investigated using field experiments in Otuke district of northern Uganda, where, Shea tree parklands are dominant and Maize and Soybean are used for food security and income. Our results show that there are differential responses of maize and soybean yield to rainy seasons and physiological variations of Vitellaria paradoxa with age. We find yield reduction for maize more pronounced than yield reduction for soybeans under different Shea age (Mature and Young) for two rainy seasons. We attribute the variance to the differential maize and soybean responses to Vitellaria paradoxa shading and its differential allelopathic inhibition of these crops. We recommend that Soybeans should be preferred to maize when planting under Shea canopy. [ABSTRACT FROM AUTHOR]

Water supply deficit requires agro-environmental rationale for the use of alternative water sources to feed agricultural crops, viz.: industrial wastes, municipal drains, farm animal waste, drainage and escape water of rice irrigation systems. We have analyzed the quality of irrigation water from different sources, with regard to the content of cations, anions, water-soluble salts, power of hydrogen (рН), sodium adsorption ratio (SAR), etc. in it. In the course of greenhouse trial, we diagnosed its impact on the indicator crop (maize) (Zea mays L.) with its herbage crop stage of 10 leaves, supplied with water of varied quality. We proved the viability of improved drainage and escape water of rice irrigation systems in irrigated agriculture, owing to which maize herbage had been diminished, at an average, by 5.82 %. We verified the negative impact of irrigation water, which contains effluent disposals of metallurgical production, on croppers – it had contributed to diminishing the watered maize herb, at an average, by 39.27 %. Correlation analysis of the test data proved the closely interrelated feedback between the maize herbage amount and the content of cations, anions and water-soluble salts in irrigation water (coefficient of correlation r varied between 0.88 and 0.98). The worked-out linear regressive model for maize herbage, based on the content of water-soluble salts in irrigation water, together with SAR index (Y=2342.71-1.82×x1+366.78×x2), affirmed the validity of the pattern, discovered by means of correlation analysis. [ABSTRACT FROM AUTHOR]

Plants are associated with a complex microbiota that contributes to nutrient acquisition, plant growth, and plant defense. Nitrogen-fixing microbial associations are efficient and well characterized in legumes but are limited in cereals, including maize. We studied an indigenous landrace of maize grown in nitrogen-depleted soils in the Sierra Mixe region of Oaxaca, Mexico. This landrace is characterized by the extensive development of aerial roots that secrete a carbohydrate-rich mucilage. Analysis of the mucilage microbiota indicated that it was enriched in taxa for which many known species are diazotrophic, was enriched for homologs of genes encoding nitrogenase subunits, and harbored active nitrogenase activity as assessed by acetylene reduction and 15N2 incorporation assays. Field experiments in Sierra Mixe using 15N natural abundance or 15N-enrichment assessments over 5 years indicated that atmospheric nitrogen fixation contributed 29%–82% of the nitrogen nutrition of Sierra Mixe maize. [ABSTRACT FROM AUTHOR]

Plant viruses are mostly transmitted by sucking insects via their piercing behaviors, which may differ due to host plant species and their developmental stages. We characterized the transmission of a fijivirus, southern rice black-streaked dwarf virus (SRBSDV), by the planthopper vector Sogatella furcifera Horváth (Hemiptera: Delphacidae), between rice and corn plants of varying developmental stages. SRBSDV was transmitted from infected rice to uninfected corn plants as efficiently as its transmission between rice plants, while was acquired by S. furcifera nymphs at a much lower rate from infected corn plants than from infected rice plants. We also recorded a high mortality of S. furcifera nymphs on corn plants. It is evident that young stages of both the virus donor and recipient plants added to the transmission efficiency of SRBSDV from rice to corn plants. Feeding behaviors of the vector recorded by electrical penetration graph showed that phloem sap ingestion, the behavioral event that is linked with plant virus acquisition, was impaired on corn plants, which accounts for the high mortality of and low virus acquisition by S. furcifera nymphs on corn plants. Our results reveal an asymmetric spread of SRBSDV between its two host plants and the underlying behavioral mechanism, which is of significance for assessing SRBSDV transmission risks and field epidemiology, and for developing integrated management approaches for SRBSDV disease. [ABSTRACT FROM AUTHOR]

Mulching and nitrogen are critical drivers of crop production for smallholders of the Loess Plateau in China. The purpose of this study was to investigate the effect of mulching and nitrogen fertilizer on the soil water content, soil nitrate-N content and vertical distribution in maize root-zone. The experiment was conducted over two consecutive years and used randomly assigned field plots with three replicates. The six treatments consisted of no fertilizer without plastic film (CK), plastic film mulching with no basal fertilizer and no top dressing (MN0), basal fertilizer with no top dressing and no mulching (BN1), plastic film mulching and basal fertilizer with no top dressing (MN1), basal fertilizer and top dressing with no mulching (BN2) and plastic film mulching with basal fertilizer and top dressing (MN2). In the top soil layers, the soil water content was a little high in the plastic film mulching than that without mulching. The mean soil water content from 0 to 40 cm without mulching were 3.35% lower than those measured in the corresponding mulching treatments in 31 days after sowing in 2012. The mulching treatment increased the soil nitrate-N content was observed in the 0–40-cm soil layers. The results indicate that high contents of soil nitrate-N were mainly distributed at 0–20-cm at 31 days after sowing in 2012, and the soil nitrate-N concentration in the MN2 treatment was 1.58 times higher than that did not receive fertilizer. The MN2 treatment greatly increased the soil nitrate-N content in the upper layer of soil (0–40-cm), and the mean soil nitrate-N content was increased nearly 50 mg kg−1 at 105 days after sowing compared with CK treatment in 2012. The soil nitrate-N leaching amount in MN1 treatment was 28.61% and 39.14% lower than BN1 treatment, and the mulch effect attained to 42.55% and 65.27% in MN2 lower than BN2 in both years. The yield increased with an increase in the basal fertilizer, top dressing and plastic film mulching, and the grain yield increase ranged from 31.41% to 83.61% in two consecutive years. The MN1 and MN2 treatment is recommended because it increased the grain yield and improved the fertilizer use efficiency, compared with the no-mulching treatment. [ABSTRACT FROM AUTHOR]

Cereal storage proteins are major nitrogen sources for humans and livestock. Prolamins are the most abundant storage protein in most cereals. They are deposited into protein bodies (PBs) in seed endosperm. The inner structure and the storage mechanism for prolamin PBs is poorly understood. Maize opaque10 (o10) is a classic opaque endosperm mutant with misshapen PBs. Through positional cloning, we found that O10 encodes a novel cereal-specific PB protein. Its middle domain contains a seven-repeat sequence that is responsible for its dimerization. Its C terminus contains a transmembrane motif that is required for its ER localization and PB deposition. A cellular fractionation assay indicated that O10 is initially synthesized in the cytoplasm and then anchored to the ER and eventually deposited in the PB. O10 can interact with 19-kD and 22-kD α-zeins and 16-kD and 50-kD γ-zeins through its N-terminal domain. An immunolocalization assay indicated that O10 co-localizes with 16-kD γ-zein and 22-kD α-zein in PBs, forming a ring-shaped structure at the interface between the α-zein-rich core and the γ-zein-rich peripheral region. The loss of O10 function disrupts this ring-shaped distribution of 22-kD and 16-kD zeins, resulting in misshapen PBs. These results showed that O10, as a newly evolved PB protein, is essential for the ring-shaped distribution of 22-kD and 16-kD zeins and controls PB morphology in maize endosperm. [ABSTRACT FROM AUTHOR]

Waxy maize is prevalently grown in China and other countries due to the excellent characters and economic value. However, its low content of lysine can’t meet the nutritional requirements of humans and livestock. In the present study, we introgressed the opaque2 (o2) allele into waxy maize line Zhao OP-6/O2O2 by using marker-assisted selection (MAS) technique and successfully improved the lysine content and quality of waxy maize. Transcript abundance analysis indicated that the wx1 expression levels had no difference between Zhao OP-6/o2o2 and Zhao OP-6/O2O2. However, Zhao OP-6/o2o2 was characterized by a phenotype of hard and vitreous kernels and accumulation of protein bodies at smaller size (one third of that of parents) but in larger numbers. Biochemical analyses showed that Zhao OP-6/o2o2 had 16.7% less free amino acids than Zhao OP-6/O2O2, especially those derived from glycolytic intermediates, but its content of lysine was increased by 51.6% (0.47% vs. 0.31%). The content of amylopectin was 98.5% in Zhao OP-6/o2o2, significantly higher than that in Zhao OP-6/O2O2 (97.7%). Proteomic analyses indicated that o2 introgression not only decreased the accumulation of various zein proteins except for 27-kDa γ-zein, but also affected other endosperm proteins related to amino acid biosynthesis, starch-protein balance, stress response and signal transduction. This study gives us an intriguing insight into the metabolism changes in endosperm of waxy maize introgressed with opaque2. [ABSTRACT FROM AUTHOR]

Zhengdan958 and Anyu5 are two elite maize hybrids of China, which manifest similar paternal lines (Chang7-2) but different maternal lines (Zheng58 and Ye478). Zhengdan958 has a 10–15% yield advantage over Anyu5. In this study, we applied digital gene expression technology to analyze transcriptomes of mature embryos from the two hybrids and their parents, aimed to investigate molecular mechanism of heterosis and genetic effects of maternal lines. Results showed that 71.66% and 49.70% of differentially expressed genes exhibited non-additive expression in Zhengdan958 and Anyu5, respectively. The number of non-additive genes involved in abiotic and biotic stress responses in Zhengdan958 was higher than that in Anyu5, which was in agreement with their phenotypic performance. Furthermore, common over-dominance and under-dominance genes (137 and 162, respectively) between the two hybrids focused on plant development and abiotic stress response. Zhengdan958 contained 97 maternal expression-level dominance (maternal-ELD) genes, and the number was higher than that of Anyu5 (45). Common up-regulated maternal-ELD genes were significantly enriched in meristem and shoot development while common down-regulated maternal-ELD genes were involved in pyruvate metabolic process, negative regulation of catalytic activity and response to stress. Therefore, non-additive genes mainly contribute to heterosis in Zhengdan958, including many genes for plant development, abiotic and biotic stress responses. Maternal effects may play important roles in maize heterosis. [ABSTRACT FROM AUTHOR]

Quality control (QC) of germplasm identity and purity is a critical component of breeding and conservation activities. SNP genotyping technologies and increased availability of markers provide the opportunity to employ genotyping as a low-cost and robust component of this QC. In the public sector available low-cost SNP QC genotyping methods have been developed from a very limited panel of markers of 1,000 to 1,500 markers without broad selection of the most informative SNPs. Selection of optimal SNPs and definition of appropriate germplasm sampling in addition to platform section impact on logistical and resource-use considerations for breeding and conservation applications when mainstreaming QC. In order to address these issues, we evaluated the selection and use of SNPs for QC applications from large DArTSeq data sets generated from CIMMYT maize inbred lines (CMLs). Two QC genotyping strategies were developed, the first is a “rapid QC”, employing a small number of SNPs to identify potential mislabeling of seed packages or plots, the second is a “broad QC”, employing a larger number of SNP, used to identify each germplasm entry and to measure heterogeneity. The optimal marker selection strategies combined the selection of markers with high minor allele frequency, sampling of clustered SNP in proportion to marker cluster distance and selecting markers that maintain a uniform genomic distribution. The rapid and broad QC SNP panels selected using this approach were further validated using blind test assessments of related re-generation samples. The influence of sampling within each line was evaluated. Sampling 192 individuals would result in close to 100% possibility of detecting a 5% contamination in the entry, and approximately a 98% probability to detect a 2% contamination of the line. These results provide a framework for the establishment of QC genotyping. A comparison of financial and time costs for use of these approaches across different platforms is discussed providing a framework for institutions involved in maize conservation and breeding to assess the resource use effectiveness of QC genotyping. Application of these research findings, in combination with existing QC approaches, will ensure the regeneration, distribution and use in breeding of true to type inbred germplasm. These findings also provide an effective approach to optimize SNP selection for QC genotyping in other species. [ABSTRACT FROM AUTHOR]

Histone modifications are involved in regulation of chromatin structure. To investigate the relationship between chromatin modification and cell cycle regulation during plant cell proliferation, Okadaic acid (OA), a specific inhibitor of serine/threonine protein phosphatase, was applied in this study. The results showed that OA caused the cell cycle arrest at preprophase, leading to seedling growth inhibition. Western blotting assay revealed that the spatial distribution of phosphorylation of Ser10 histone H3 tails (H3S10ph) signals was altered under OA treatment. Reactive oxygen species (ROS) was found to be at higher levels and TdT-mediated dUTP nick end labeling (TUNEL) assay displayed DNA breaks happened at the chromatin after treatment with OA, companied with an increase in the acetylation of histone H4 at lysine 5 (H4K5ac) level. From these observations, we speculated that the alteration of the spatial distribution of H3S10ph and the level of H4K5ac was involved in the procedure that OA induced DNA breaks and G2-M arrested by the accumulation of ROS, and that the histone H3S10ph and H4K5ac might facilitate DNA repair by their association with the chromatin decondensation. [ABSTRACT FROM AUTHOR]

This study examined ruminal microbial community composition alterations during initial adaption to and following incubation in a rumen simulation system (Rusitec) using grass or corn silage as substrates. Samples were collected from fermenter liquids at 0, 2, 4, 12, 24, and 48 h and from feed residues at 0, 24, and 48 h after initiation of incubation (period 1) and on day 13 (period 2). Microbial DNA was extracted and real-time qPCR was used to quantify differences in the abundance of protozoa, methanogens, total bacteria, Fibrobacter succinogenes, Ruminococcus albus, Ruminobacter amylophilus, Prevotella bryantii, Selenomonas ruminantium, and Clostridium aminophilum. We found that forage source and sampling time significantly influenced the ruminal microbial community. The gene copy numbers of most microbial species (except C. aminophilum) decreased in period 1; however, adaption continued through period 2 for several species. The addition of fresh substrate in period 2 led to increasing copy numbers of all microbial species during the first 2–4 h in the fermenter liquid except protozoa, which showed a postprandial decrease. Corn silage enhanced the growth of R. amylophilus and F. succinogenes, and grass silage enhanced R. albus, P. bryantii, and C. aminophilum. No effect of forage source was detected on total bacteria, protozoa, S. ruminantium, or methanogens or on total gas production, although grass silage enhanced methane production. This study showed that the Rusitec provides a stable system after an adaption phase that should last longer than 48 h, and that the forage source influenced several microbial species. [ABSTRACT FROM AUTHOR]

Competition or facilitation characterises intra- and interspecific interactions within communities of species that utilize the same resources. Temperature is an important factor influencing those interactions and eventual outcomes. The noctuid stemborers, Busseola fusca and Sesamia calamistis and the crambid Chilo partellus attack maize in sub-Saharan Africa. They often occur as a community of interacting species in the same field and plant at all elevations. The influence of temperature on the intra- and interspecific interactions among larvae of these species, was studied using potted maize plants exposed to varying temperatures in a greenhouse and artificial stems kept at different constant temperatures (15°C, 20°C, 25°C and 30°C) in an incubator. The experiments involved single- and multi-species infestation treatments. Survival and relative growth rates of each species were assessed. Both intra- and interspecific competitions were observed among all three species. Interspecific competition was stronger between the noctuids and the crambid than between the two noctuids. Temperature affected both survival and relative growth rates of the three species. Particularly at high temperatures, C. partellus was superior in interspecific interactions shown by higher larval survival and relative growth rates. In contrast, low temperatures favoured survival of B. fusca and S. calamistis but affected the relative growth rates of all three species. Survival and relative growth rates of B. fusca and S. calamistis in interspecific interactions did not differ significantly across temperatures. Temperature increase caused by future climate change is likely to confer an advantage on C. partellus over the noctuids in the utilization of resources (crops). [ABSTRACT FROM AUTHOR]

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Maize streak virus (MSV), which causes maize streak disease (MSD), is the major viral pathogenic constraint on maize production in Africa. Type member of the Mastrevirus genus in the family Geminiviridae, MSV has a 2.7 kb, single-stranded circular DNA genome encoding a coat protein, movement protein, and the two replication-associated proteins Rep and RepA. While we have previously developed MSV-resistant transgenic maize lines constitutively expressing “dominant negative mutant” versions of the MSV Rep, the only transgenes we could use were those that caused no developmental defects during the regeneration of plants in tissue culture. A better transgene expression system would be an inducible one, where resistance-conferring transgenes are expressed only in MSV-infected cells. However, most known inducible transgene expression systems are hampered by background or “leaky” expression in the absence of the inducer. Here we describe an adaptation of the recently developed INPACT system to express MSV-derived resistance genes in cell culture. Split gene cassette constructs (SGCs) were developed containing three different transgenes in combination with three different promoter sequences. In each SGC, the transgene was split such that it would be translatable only in the presence of an infecting MSV’s replication associated protein. We used a quantitative real-time PCR assay to show that one of these SGCs (pSPLITrepIII-Rb-Ubi) inducibly inhibits MSV replication as efficiently as does a constitutively expressed transgene that has previously proven effective in protecting transgenic maize from MSV. In addition, in our cell-culture based assay pSPLITrepIII-Rb-Ubi inhibited replication of diverse MSV strains, and even, albeit to a lesser extent, of a different mastrevirus species. The application of this new technology to MSV resistance in maize could allow a better, more acceptable product. [ABSTRACT FROM AUTHOR]

The overuse of Nitrogen (N) fertilizers on smallholder farms in rapidly developing countries has increased greenhouse gas (GHG) emissions and accelerated global N consumption over the past 20 years. In this study, a regional N management approach was developed based on the cost of the agricultural response to N application rates from 1,726 on-farm experiments to optimize N management across 12 agroecological subregions in the intensive Chinese smallholder maize belt. The grain yield and GHG emission intensity of this regional N management approach was investigated and compared to field-specific N management and farmers' practices. The regional N rate ranged from 150 to 219 kg N ha−1 for the 12 agroecological subregions. Grain yields and GHG emission intensities were consistent with this regional N management approach compared to field-specific N management, which indicated that this regional N rate was close to the economically optimal N application. This regional N management approach, if widely adopted in China, could reduce N fertilizer use by more than 1.4 MT per year, increase maize production by 31.9 MT annually, and reduce annual GHG emissions by 18.6 MT. This regional N management approach can minimize net N losses and reduce GHG emission intensity from over- and underapplications, and therefore can also be used as a reference point for regional agricultural extension employees where soil and/or plant N monitoring is lacking. [ABSTRACT FROM AUTHOR]

Maize (Zea mays) is the most widely grown crop species in the world and a classical model organism for plant research. The completion of a high-quality reference genome sequence and the advent of high-throughput sequencing have greatly empowered re-sequencing studies in maize. In this study, plants of maize inbred line B73 descended from two different sets of seed material grown for several generations either in the field or in the greenhouse were found to show a different growth phenotype and ionome under phosphate starvation conditions and moreover a different responsiveness towards mycorrhizal fungi of the species Glomus intraradices (syn: Rhizophagus irregularis). Whole genome re-sequencing of individuals from both sets and comparison to the B73 reference sequence revealed three cryptic introgressions on chromosomes 1, 5 and 10 in the line grown in the greenhouse summing up to a total of 5,257 single-nucleotide polymorphisms (SNPs). Transcriptome sequencing of three individuals from each set lent further support to the location of the introgression intervals and confirmed them to be fixed in all sequenced individuals. Moreover, we identified >120 genes differentially expressed between the two B73 lines. We thus have found a nearly-isogenic line (NIL) of maize inbred line B73 that is characterized by an altered growth phenotype under phosphate starvation conditions and an improved responsiveness towards symbiosis with mycorrhizal fungi. Through next-generation sequencing of the genomes and transcriptomes we were able to delineate exact introgression intervals. Putative de novo mutations appeared approximately uniformly distributed along the ten maize chromosomes mainly representing G:C -> A:T transitions. The plant material described in this study will be a valuable tool both for functional studies of genes differentially expressed in both B73 lines and for research on growth behavior especially in response to symbiosis between maize and mycorrhizal fungi. [ABSTRACT FROM AUTHOR]