Wheat Anthesis Research Articles

Spatial Variations of Vegetation Index from Remote Sensing Linked to Soil Colloidal Status

Recent decades have seen a progressive degradation of soils owing to an intensification of farming practices (weeding and high trafficking), increasing use of pesticides and fertilizers, mainly nitrogen, resulting in a steady decline in soil organic matter, a key component to maintain soil fertility. The work has coupled the normalized difference vegetation index (NDVI) of wheat cultivation in Central Italy to soil properties where the wheat was grown to identify the properties linked to within-field variability in productivity. NDVI was assessed through Copernicus Sentinel-2 (S-2) data during the wheat anthesis phase. The main outcome showed a significant correlation of NDVI variability to soil colloidal status and to the relative quantity in the exchange complex of the Ca2+ ions. No relationship emerged between NDVI and soil macronutrients (nitrogen, phosphorus, and potassium) concentration. The work suggested that such elements (nitrogen, especially) should not be provided solely considering the vegetation index spatial variations. Rational and sustainable management of soil fertility requires the integration of the NDVI data with the whole complex of soil physical/chemical status. In this way, the identification of the real key factors of fertility will avoid the negative impact of overfertilization. As an example, a fertilization plan was simulated for the sunflower–wheat sequence. The results showed that in the study area additional supplies of N and K would be unnecessary.

Impact of neem coated urea on phenological development and yield of wheat

In order to study the effects of different nitrogen levels and sources on wheat phenology and productivity, an experiment was conducted during rabi season of 2017-18 at Agronomy Research Area of CCS Haryana Agricultural University, Hisar. The experiment was laid out in a split plot design with four nitrogen sources [Ordinary Urea (½ Basal and ½ at first irrigation), Ordinary Urea (½ Basal + ¼ first irrigation + ¼ heading), Neem Coated Urea (½ Basal + ½ first irrigation) and Neem Coated Urea (½ Basal + ¼ first irrigation + ¼ heading)] in main plots and four nitrogen levels (80%, 90%, 100% and 110% RDN) in sub plots replicated thrice. The experimental site is situated in the sub tropical region at 29º 10´ N latitude and 75º 46´ E longitude with an elevation of 215.2 meter above mean sea level in Haryana State of India.Overall results depicted that application of neem coated urea produced significantly higher yield attributing characters (except test weight) and grain yield of wheat as compared to ordinary urea. However the difference in two and three split application of neem coated urea is not significant. Application of 110 % RDN in wheat resulted in significantly higher growth, yield attributers and yield of wheat than rest two N levels. Days taken to all the phenological stages (except emergence) of wheat were significantly higher with the application of neem coated urea (2-split and 3 split). Days taken to booting, anthesis, milk and dough stage of wheat were significantly less with the application of 80% RDN as compared to 90,100 and 110 % RDN.

Impacts of multi-timescale SPEI and SMDI variations on winter wheat yields

Drought is one of the main factors that impacts crop yields. However, determining how different drought types affect winter wheat yields is difficult due to the lack of observation data. This work aimed to investigate the impacts of multi-timescale droughts on winter wheat yields. The winter wheat yields during 1981–2015 were simulated by the DSSAT-CERES-Wheat model. We analyzed the drought characteristics based on the standardized precipitation evapotranspiration index (SPEI) and soil moisture deficit index (SMDI) at timescales of 1 to 9 months at 108 sites in China. The modified Mann-Kendall (MMK) method was used to test the tendency of 1-, 3- and 6-month SPEI, SMDI and winter wheat yields. Pearson correlation analysis was used to explore the relationship between winter wheat yields and SPEI/SMDI at different timescales. The results showed that, DSSAT-CERES-Wheat generally performed well in simulating winter wheat anthesis date, maturity date and yields (0.64 < R2 < 0.97, where R2 is determination of coefficient). The dry or wet status for the 1- to 9-month timescales of SPEI and SMDI were generally consistent in the three subregions. Seasonal drought occurred more frequently in the Huang-Huai-Hai Plain than in the other two subregions. The 4-month SPEI and 1-month SMDI at the 0–10 cm depth affected the winter wheat yield more during the jointing to milk stages. For yields vs. 4-month SPEI, the number of stations with Pearson correlation coefficient r > 0.4 in March, April and May was 29, 35 and 23, respectively. For yields vs. 1-month SMDI, the number of stations with r > 0.4 in March, April and May was 16, 23 and 33, respectively. SMDI and SPEI explained more than 14% and less than 2% of the yield variability, respectively. Closer relations between SMDI and winter wheat yields were observed. This study provides useful references for preventing agricultural drought.

Can discrepancies between Fusarium graminearum trichothecene genotype and chemotype be explained by the influence of temperature in the relative production of 3-ADON and 15-ADON?

Wheat is one of the most important crops in Argentina and worldwide. One of the major diseases affecting the crop is the Fusarium Head Blight (FHB). It is an endemic disease caused mainly by Fusarium graminearum, the most common agent of FHB around the world. The infection is strongly influenced by environmental parameters and occurs mostly when there are favourable conditions of moisture and temperature during wheat anthesis or flowering. This destructive disease affects wheat, barley and other small grains and has the capability of destroying crops, causing great economic losses due to reduced grain quality, and the accumulation of significant levels of mycotoxins such as trichothecenes. The aim of this study was to evaluate the influence of temperature on mycotoxin biosynthesis, on three strains of F. graminearum of 15-ADON genotype and one of 3-ADON genotype, with different capacity of synthesizing DON, 3-ADON and 15-ADON. Trichothecene production of the strains at different temperatures (5, 10, 15, 20, 25, 30 and 35 °C) was evaluated after 7, 14, 21, 28 and 35 d of incubation. The optimum temperature to produce DON and 3-ADON was between 25 and 30 °C, but the maximum production of 15-ADON occurred at a lower temperature (10 °C) for all the strains. Conversely, the minimum production of DON and 3-ADON was recorded between 5 and 10 °C and of 15-ADON between 30 and 35 °C. A possible explanation for the similar accumulation of both acetyl derivatives by strains of different chemotype and genotypes could be that the acetyl derivatives biosynthesis is regulated by temperature.

Monitoring of Nitrogen and Grain Protein Content in Winter Wheat Based on Sentinel-2A Data

Grain protein content (GPC) is an important indicator of wheat quality. Earlier estimation of wheat GPC based on remote sensing provided effective decision to adapt optimized strategies for grain harvest, which is of great significance for agricultural production. The objectives of this field study are: (i) To assess the ability of spectral vegetation indices (VIs) of Sentinel 2 data to detect the wheat nitrogen (N) attributes related to the grain quality of winter wheat production, and (ii) to examine the accuracy of wheat N status and GPC estimation models based on different VIs and wheat nitrogen parameters across Analytical Spectra Devices (ASD) and Unmanned Aerial Vehicle (UAV) hyper-spectral data-simulated sentinel data and the real Sentinel-2 data. In this study, four nitrogen parameters at the wheat anthesis stage, including plant nitrogen accumulation (PNA), plant nitrogen content (PNC), leaf nitrogen accumulation (LNA), and leaf nitrogen content (LNC), were evaluated for their relationship between spectral parameters and GPC. Then, a multivariate linear regression method was used to establish the wheat nitrogen and GPC estimation model through simulated Sentinel-2A VIs. The coefficients of determination ( R 2 ) of four nitrogen parameter models were all greater than 0.7. The minimum R 2 of the prediction model of wheat GPC constructed by four nitrogen parameters combined with VIs was 0.428 and the highest R 2 was 0.467. The normalized root mean square error (nRMSE) of the four nitrogen estimation models ranged from 26.333% to 29.530% when verified by the ground-measured data collected from the Beijing suburbs, and the corresponding nRMSE for the GPC-predicted models ranged from 17.457% to 52.518%. The accuracy of the estimated model was verified by UAV hyper-spectral data which had resized to different spatial resolution collected from the National Experimental Station for Precision Agriculture. The normalized root mean square error (nRMSE) of the four nitrogen estimation models ranged from 16.9% to 37.8%, and the corresponding nRMSE for the GPC-predicted models ranged from 12.3% to 13.2%. The relevant models were also verified by Sentinel-2A data collected in 2018 while the minimum nRMSE for GPC invert model based on PNA was 7.89% and the maximum nRMSE of the GPC model based on LNC was 12.46% in Renqiu district, Hebei province. The nRMSE for the wheat nitrogen estimation model ranged from 23.200% to 42.790% for LNC and PNC. These data demonstrate that freely available Sentinel-2 imagery can be used as an important data source for wheat nutrition and grain quality monitoring.

Double benefits of mechanical wounding in enhancing chilling tolerance and lodging resistance in wheat plants.

Chilling and lodging are major threats to wheat production. However, strategies that can be used to effectively mitigate the adverse effects of these threats are still far from clear. Mechanical wounding is a traditional agronomic measure, whereas information about the role it plays in wheat chilling and lodging is scant. The aim of the present study was to investigate mechanisms underlying the protective roles of mechanical wounding in alleviating damage from chilling at jointing stage and enhancing lodging resistance after anthesis of winter wheat (Triticum aestivum L.). Our data show that net photosynthesis rate, maximum photochemical efficiency of photosystem II, activity of the antioxidant enzymes and osmolytes were significantly increased in the latest fully expanded leaves of wounded plants under chilling. Wounding also reduced hydrogen peroxide accumulation, electrolyte leakage and water loss in wounded plants. Moreover, mechanical wounding significantly reduced the length but increased the diameter and wall thickness of the basal second internode of the main stem. Quantitative and histochemical analysis further indicated that wounding increased lignin accumulation and activity of enzymes involved in lignin synthesis, which resulted in increased mechanical strength and the lodging resistance index in the main stem. We conclude from our data that mechanical wounding confers both cold tolerance by alleviating the damage caused by chilling at jointing stage and lodging resistance after anthesis of wheat plants.

Photoperiod-sensitivity genes shape floret development in wheat.

Lengthening the pre-anthesis period of stem elongation (or late-reproductive phase, LRP) through altering photoperiod sensitivity has been suggested as a potential means to increase the number of fertile florets at anthesis (NFF) in wheat. However, little is known about the effects that the Ppd-1 genes modulating plant response to photoperiod may have on reproductive development. Here, five genotypes with either sensitive (b) or insensitive (a) alleles were grown in chambers under contrasting photoperiods (12 h or 16 h) to assess their effects. The genotypes consisted of the control cultivar Paragon (three Ppd-1b) and four near-isogenic lines of Paragon with Ppd-1a alleles introgressed from: Chinese Spring (Ppd-B1a), GS-100 (Ppd-A1a), Sonora 64 (Ppd-D1a), and Triple Insensitive (three Ppd-1a). Under a 12-h photoperiod, NFF in the genotypes followed the order three Ppd-1b > Ppd-B1a > Ppd-A1a > Ppd-D1a > three Ppd-1a. Under a 16-h photoperiod the differences were milder, but three Ppd-1b still had a greater NFF than the rest. As Ppd-1a alleles shortened the LRP, spikes were lighter and the NFF decreased. The results demonstrated for the first time that Ppd-1a decreases the maximum number of florets initiated through shortening the floret initiation phase, and this partially explained the variations in NFF. The most important impact of Ppd-1a alleles, however, was related to a reduction in survival of floret primordia, which resulted in the lower NFF. These findings reinforce the idea that an increased duration of the LRP, achieved through photoperiod sensitivity, would be useful for increasing wheat yield potential.

Using SAR Data to Detect Wheat Irrigation Supply in an Irrigated Semi-arid Area

The objective of this study was to use SAR (sensitivity of Synthetic Aperture Radar) data to detect the supply of irrigation water during the anthesis and grain-filling phenological stages of wheat in the irrigated Tadla perimeter of Morocco. Backscattering coefficients were derived from four ERS-1 (European Remote-Sensing Satellite-1) images acquired between 31 March and 12 April 2011 and were compared with the irrigation water invoices database. The analysis showed that there were significant changes in backscattering values caused by irrigation, with average values ranging between 0.11 and 3.11 dB. A reference level of 0.52 dB was established for differentiating between (recently; up to 4 days) irrigated and non-irrigated plots. We also set an interval of 5 days for the acquisition of SAR images in order to ensure continuous monitoring of the irrigated wheat plots over time. The study showed that radar data contain important information for the assessment of irrigation supplies during the cropping season, which could help regional decision-support systems to monitor and control irrigation supplies over large areas.

Effects of exogenously applied plant growth regulators on the physiology and anti-oxidant activity of wheat under water deficit condition

An experiment was conducted to know the effect of plant growth regulators, Thidiazuron; 0.01 µL L−1, Paclobutrazol; 30 µL L−1, Ascorbic acid; 100 µL L−1, on wheat genotypes under osmotic stress imposed with PEG 6000 and water-deficit stress in pots. Under osmotic stress with PEG6000, the total chlorophyll content and ethylene evolution were estimated from wheat seedling, and in pot experiment, detailed physiological studies were performed at different growth stages (pre-anthesis, anthesis and post anthesis) of wheat under water deficit stress and irrigated condition. Study revealed that the level of ethylene increased while the content of chlorophyll decreased under osmotic stress condition. Moreover, the higher level of ethylene and chlorophyll content were observed in C306 followed by in HD2987 as compared to HD2888 and HD2733 under control as well as in osmotic stress conditions. However, application of plant growth regulators (PGRs) led to the down-regulation of ethylene evolution from osmotic stressed wheat seedling while the chlorophyll content was improved across the wheat genotypes. Further, in pot experiment, PGRs application on water deficit stressed plants led to the improvement in ascorbic acid content and ascorbate peroxidase (APX) activity while the abscisic acid and thiobarbituric acid reactive substances (TBARS) content goes down in comparison to water deficit stress plants without PGRs application. Findings of the study indicated that due to simultaneous application of PGRs plant developed a sense of lower stress level thus lesser ethylene evolution and lipid peroxidation (TBARS content) was observed. Further PGRs application helped in maintenance of chlorophyll and ascorbic acid content with higher APX activity under water deficit condition indicating better tolerance level. The results of this study provide a synergetic effect of PGRs for abiotic stress tolerance.

Physiological determinants of fertile floret survival in wheat as affected by earliness per se genes under field conditions

Abstract Variations in wheat yield are largely explained by changes in grain number per m2 which is linked to the number of fertile florets at anthesis. This, in turn is the outcome of developmental processes which control floret initiation and mortality. Earliness ‘per se’ (Eps) genes are involved in fine-tuning time to anthesis in wheat (and other cereals) but their effect on development prior to anthesis is less well studied. We aimed to determine effects of Eps genes on spike fertility, quantifying aspects of floret developmental which influence this trait. Field experiments were carried out to record floret primordia generation/degeneration dynamics in near isogenic lines (NILs) with contrasting Eps alleles (late flowering vs early flowering alleles; Eps-late and Eps-early, respectively) derived from the Avalon x Cadenza (AxC) cross with the Eps gene on either chromosome 1D or 3 A and from the Spark x Rialto (SxR) cross with the Eps gene on chromosome 1D. Eps NILs varied in spike fertility: Eps-late alleles increased fertility. Although the effect was in general slight, the magnitude was affected by the particular alleles and the cross used to produce the NILs. Differences in the number of fertile florets were explained by differences in the dynamics of floret development. NILs with Eps-late alleles improved the development of a small number of labile florets allowing them to complete their development to become fertile florets instead of dying, as in lines carrying early alleles. Thus, these alleles improved floret fertility mainly through reducing the rate of floret mortality with no influence on the dynamics of floret primordia initiation or in maximum number of floret primordia. Therefore, Eps genes could be exploited in wheat breeding not only to fine-tune time to anthesis but also to improve spike fertility.

Fungicide application at anthesis of wheat provides effective control of leaf spotting diseases in western Canada

Leaf spotting diseases commonly occur on spring wheat crops grown in Saskatchewan, causing yield losses of up to 15%, although greater losses have been documented during severe epidemics. In the past decade, Fusarium head blight (FHB) has become a major concern for growers resulting in extensive use of fungicide to mitigate the disease. The optimal fungicide timing for leaf spot control is generally at the flag-leaf stage, while the optimal timing for FHB is during anthesis. The objective of this study was to determine whether applying fungicide at anthesis timing can provide adequate control of leaf spots when compared to application at flag-leaf stage. Fungicide treatments applied at flag-leaf, anthesis, and both growth stages were evaluated on the cv. Carberry. Prothioconazole + tebuconazole and tebuconazole (only) applied at anthesis provided adequate control of leaf spots, although the severity of leaf diseases was slightly higher in this treatment than application at flag-leaf stage but yields were similar. Test weight and thousand kernel weight were improved with the application at anthesis relative to that at flag-leaf stage. Two applications of fungicide provided only a small incremental benefit to the anthesis application, and would not be economically justified in western Canada at this time. Anthesis fungicide application provided adequate leaf spot disease control and is the optimum timing for the control of FHB.

Scenario modeling of ammonia emissions from surface applied urea under temperate conditions: application effects and model comparison

The use of emission factors (EF) for ammonia (NH3) after fertilizer application is a central tool for nitrogen management. Ammonia loss measurements after application of urea fertilizer at three research sites in Germany indicated that emissions deviated from European standard EFs. Scenario modelling of emissions based on long term weather data and variable application dates could provide a robust basis for the derivation of EFs. Two model approaches were used to test this approach for urea applied to winter wheat. The two model approaches comprised the dynamic model Volt’Air’ and a statistical model. Scenario calculations were run for 15 years and 4 application dates in each year for the 3 sites. The empirical model performed better at predicting cumulative losses. Both models simulated more than half of relative NH3 emissions (% urea N applied) in a range of 0–10%. The average and median EFs by both models over all application dates were 10.2 and 8.1%, respectively, and were substantially lower than the current European EFs for urea (15–16%). The lowest median and mean EFs were observed at beginning of the vegetation period with 4.3/4.8 and 7.2/6.7% applied N for empirical and Volt’Air model, respectively, and highest at wheat anthesis (15/17.4 and 11/10.2%). Scenario modelling can be considered as a tool for the derivation of robust and representative EFs for NH3 emissions not only for urea but also other emitting fertilizer sources. A much more expanded data set is needed and both model approaches require further development to reach this aim.

Effect of phosphorus and potassium foliage application post-anthesis on grain filling and hormonal changes of wheat

Foliage application of fertilizer is an important supplement for soil application fertilizer. Phosphorus (P) and Potassium (K) are important nutrient elements that significantly affect the grain weight and grain yield of wheat, and foliage application of K and P is mainly used for wheat production in the northern dryland region of China. However, the mechanism underlying the regulation of grain filling by foliage application of K and P is not understood. In the present study, monopotassium phosphate (KH2PO4), monosodium orthophosphate (NaH2PO4) and potassium chloride (KCl) were used for foliage application at the anthesis of wheat, and the changes of IAA, ABA, Z+ZR, GAs and ETH in wheat grain were measured during the grain filling process. The objective of this study was to investigate the effect of P and K foliage application on the grain filling process of wheat and to determine how changes in the endogenous hormones of the developing grains of winter wheat under P and K foliage application are related to the grain filling process. The results indicate that the effect of P and K foliage application on the grain filling of wheat is the difference. The K foliage application significantly increased the Z+ZR and ABA contents and decreased the ETH evolution rate in inferior grains, which promoted sink strength and increased the grain filling rate and the grain weight. In comparison, the P foliage application significantly promoted the activities of SOD, POD, and CAT and decreased the MDA content in the flag leaves and relieved the premature senility of the plant, which increased the active grain-filling period and the grain weight. For the heavy panicle cultivar, foliage P had a reasonable effect on grain filling, and for the light panicle cultivar, foliage K had a reasonable effect on grain filling. The mixture of P and K had an additive effect and prevented P and K deficiencies. Foliage application of KH2PO4 is an effectual measure for promoting the grain weight of wheat.

In‐Season Canopy Reflectance Can Aid Fungicide and Late‐Season Nitrogen Decisions on Winter Wheat

Core Ideas Wheat grain yield response to foliar fungicide is highly dependent on environment. Late‐season N can offset protein dilution from fungicide‐driven yield increase. Foliar N rates necessary to impact grain protein have potential for leaf burn. Controlled‐release N and urea ammonium nitrate both impacted wheat responses similarly. In‐season canopy reflectance can aid in fungicide decision. Winter wheat (Triticum aestivum L) response to foliar fungicide and late‐season N is inconsistent. We evaluated various late‐season N fertilizer‐by‐foliar fungicide combinations to test whether wheat anthesis normalized difference vegetative index (NDVI) could aid fungicide decisions. Six site‐years were conducted with N fertility &gt;120 kg N ha−1 during 2012–2013 and 2013–2014 in Oklahoma, using a three‐way factorial arrangement of a randomized complete block design with four replications. Fungicide treatment (with or without), foliar N source (urea ammonium nitrate [UAN] or controlled‐release N), and N rate (0, 2.8, 5.6, or 28 kg N ha−1) were applied during anthesis. Statistical analyses were performed by site‐year, by yielding environment (low [LY] &lt;3.2 Mg ha−1 and high [HY] &gt;3.2 Mg ha−1), and pooled across site‐years. Grain yield was 0.21 Mg ha−1 greater due to fungicide in the pooled analysis, mostly led by the 0.59 Mg ha−1 yield advantage in HY as opposed to non‐significance in LY. Fungicide increased test weight in 6 to 7 kg m−3 across all analyses, and 28 kg N ha−1 increased grain protein by ∼10 g kg−1 but caused leaf burn. Anthesis NDVI &lt;0.6 occurred when preanthesis abiotic stresses restricted yield potential, not warranting fungicide application. Fungicide can benefit grain yield and test weight and could be considered when anthesis NDVI &gt;0.6, but yield response will depend on grain‐filling conditions. Foliar N rates needed to increase grain protein in a well‐fertilized crop have potential for leaf burn.

Reprint of “An integrated dual strategy to control Fusarium graminearum sensu stricto by the biocontrol agent Streptomyces sp. RC 87B under field conditions”

Fusarium head blight (FHB) caused by species within the Fusarium graminearum complex is a devastating disease that causes extensive yield and quality losses to wheat in humid and semi-humid regions of the world. The disease can cause not only yield losses but also grain contamination with mycotoxins such as deoxynivalenol (DON). Several epidemics have occurred in Argentina, the last in 2012, with yield losses up to 70%. Control of the disease is partially achieved by chemical treatments, crop rotation, breeding for resistance and tillage practices. Biocontrol can be used as part of an integrated pest management. The objetives of this study were: 1- to evaluate the biological control effect of Streptomyces sp. RC 87B on FHB disease incidence, severity and DON accumulation and 2- to evaluate if Streptomyces sp. RC 87B reduces F. graminearum inoculum when applied to wheat stubble. Streptomyces sp. RC 87B was applied at wheat anthesis to determine effects on FHB disease parameters and over wheat stubble left after harvest to evaluate effects on the survival of F. graminearum. FHB incidence and severity were visually estimated and DON content was assessed by HPLC after harvest. On stubble, F. graminearum prevalence was monitored by using TaqMan PCR for 180days. A significant disease severity and DON reduction were observed with the biocontrol treatments during the field trials (29–39% and 69–85%, respectively), but no reduction on disease incidence was achieved. On wheat stubble, Streptomyces sp. 87B reduced F. graminearum inoculum after 45days (82%) and after 90days no inoculum was detected in the first of two trials. In a second trial, a significant reduction (46%) in F. graminearum inoculum was observed after 90days. The biocontrol strain Streptomyces sp. 87B showed high potential for contributing to the reduction of FHB on wheat at different times in the F. graminearum life cycle.

Growth and yield performance of selected wheat varieties under water deficit conditions

Effect of water deficit stress on growth and yield of three wheat (Triticum aestivum) varieties, viz. BARI Gom 25, BARI Gom 26 and Sourav was studied. Water deficit lowered the light interception at anthesis in wheat. Under water deficit condition, the highest amount of PAR interception was recorded in BARI Gom 26. The reduction of leaf area index (LAI), crop growth rate (CGR), relative growth rate (RGR) and net assimilation rate (NAR) were less in BARI Gom 26. Water deficit conditions lowered the SPAD values in all the three wheat varieties. BARI Gom 26 showed less reduction, while BARI Gom 25 reflected the highest reduction in SPAD value under water deficit condition. Under water deficit condition the maximum number of spikelets/spike, 1000- grain weight and HI were recorded in BARI Gom 26 and the minimum in BARI Gom 25. Under both control and water deficit conditions BARI Gom 26 gave the highest grain yield, while the lowest grain yield was obtained from BARI Gom 25.Bangladesh J. Sci. Res. 29(2): 163-172, December-2016

Spring phenology of cotton bollworm affects wheat yield.

Climate change has changed numerous species phenologies. Understanding the asynchronous responses between pest insects and host plants to climate change is helpful in improving integrated pest management. It is necessary to use long‐term data to analyze the effects of climate change on cotton bollworm and wheat anthesis. Data for cotton bollworm, wheat yield, and wheat anthesis collected since 1990 were analyzed using linear regression and partial least‐squares regression, as well as the Mann–Kendall test. The results showed that warmer temperatures in the spring advanced the phenologies of cotton bollworm and wheat anthesis, but the phenology changes in overwintering cotton bollworm were faster than those in wheat anthesis, and the eclosion period of overwintering was prolonged, resulting in an increase in overwintering adult abundance. This might lead to more first‐generation larvae and subsequent wheat damage. An early or late first‐appearance date significantly affected the eclosion days. The abrupt changes of phenologies in cotton bollworm, wheat anthesis, and climate were asynchronous, but the abrupt phenology changes occurred after or around the climate abrupt change, especially after or around the abrupt changes of temperature in March and April. The expansion of asynchronous responses in the change rate of wheat anthesis and overwintering cotton bollworm would likely decrease wheat yield due to climate warming in the future. Accumulated temperature was the major affecting factor on the first eclosion date (t 1), adult abundance, and eclosion days. Temperatures in March and April and precipitation in the winter mainly affected the prepeak date (t 2), peak date (t 3), and postpeak date (t 4), respectively, and these factors indirectly affected wheat yield. Thus, the change in the spring phenology of the cotton bollworm and wheat anthesis, and hence wheat yield, was affected by climate warming.

An integrated dual strategy to control Fusarium graminearum sensu stricto by the biocontrol agent Streptomyces sp. RC 87B under field conditions

Fusarium head blight (FHB) caused by species within the Fusarium graminearum complex is a devastating disease that causes extensive yield and quality losses to wheat in humid and semi-humid regions of the world. The disease can cause not only yield losses but also grain contamination with mycotoxins such as deoxynivalenol (DON). Several epidemics have occurred in Argentina, the last in 2012, with yield losses up to 70%. Control of the disease is partially achieved by chemical treatments, crop rotation, breeding for resistance and tillage practices. Biocontrol can be used as part of an integrated pest management. The objetives of this study were: 1- to evaluate the biological control effect of Streptomyces sp. RC 87B on FHB disease incidence, severity and DON accumulation and 2- to evaluate if Streptomyces sp. RC 87B reduces F. graminearum inoculum when applied to wheat stubble. Streptomyces sp. RC 87B was applied at wheat anthesis to determine effects on FHB disease parameters and over wheat stubble left after harvest to evaluate effects on the survival of F. graminearum. FHB incidence and severity were visually estimated and DON content was assessed by HPLC after harvest. On stubble, F. graminearum prevalence was monitored by using TaqMan PCR for 180days. A significant disease severity and DON reduction were observed with the biocontrol treatments during the field trials (29–39% and 69–85%, respectively), but no reduction on disease incidence was achieved. On wheat stubble, Streptomyces sp. 87B reduced F. graminearum inoculum after 45days (82%) and after 90days no inoculum was detected in the first of two trials. In a second trial, a significant reduction (46%) in F. graminearum inoculum was observed after 90days. The biocontrol strain Streptomyces sp. 87B showed high potential for contributing to the reduction of FHB on wheat at different times in the F. graminearum life cycle.

Combined impact of climate change, cultivar shift, and sowing date on spring wheat phenology in Northern China

Distinct climate changes since the end of the 1980s have led to clear responses in crop phenology in many parts of the world. This study investigated the trends in the dates of spring wheat phenology in relation to mean temperature for different growth stages. It also analyzed the impacts of climate change, cultivar shift, and sowing date adjustments on phenological events/phases of spring wheat in northern China (NC). The results showed that significant changes have occurred in spring wheat phenology in NC due to climate warming in the past 30 years. Specifically, the dates of anthesis and maturity of spring wheat advanced on average by 1.8 and 1.7 day (10 yr)−1. Moreover, while the vegetative growth period (VGP) shortened at most stations, the reproductive growth period (RGP) prolonged slightly at half of the investigated stations. As a result, the whole growth period (WGP) of spring wheat shortened at most stations. The findings from the Agricultural Production Systems Simulator (APSIM)-Wheat model simulated results for six representative stations further suggested that temperature rise generally shortened the spring wheat growth period in NC. Although the warming trend shortened the lengths of VGP, RGP, and WGP, the shift of new cultivars with high accumulated temperature requirements, to some extent, mitigated and adapted to the ongoing climate change. Furthermore, shifts in sowing date exerted significant impacts on the phenology of spring wheat. Generally, an advanced sowing date was able to lower the rise in mean temperature during the different growth stages (i.e., VGP, RGP, and WGP) of spring wheat. As a result, the lengths of the growth stages should be prolonged. Both measures (cultivar shift and sowing date adjustments) could be vital adaptation strategies of spring wheat to a warming climate, with potentially beneficial effects in terms of productivity.

Improved tolerance to drought stress after anthesis due to priming before anthesis in wheat (Triticum aestivum L.) var. Vinjett.

Drought stress occurring during the reproductive growth stage leads to considerable reductions in crop production and has become an important limiting factor for food security globally. In order to explore the possible role of drought priming (pre-exposure of the plants to mild drought stress) on the alleviation of a severe drought stress event later in development, wheat plants were subjected to single or double mild drought episodes (soil relative water content around 35-40%) before anthesis and/or to a severe drought stress event (soil relative water content around 20-25%) 15 d after anthesis. Here, single or double drought priming before anthesis resulted in higher grain yield than in non-primed plants under drought stress during grain filling. The photosynthesis rate and ascorbate peroxidase activity were higher while malondialdehyde content was lower in primed plants than in the non-primed plants under drought stress during grain filling. Proteins in flag leaves differently expressed by the priming and drought stress were mainly related to photosynthesis, stress defence, metabolism, molecular chaperone, and cell structure. Furthermore, the protein abundance of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) small subunit, Rubisco activase and ascorbate peroxidase were upregulated in primed plants compared with non-primed plants under drought stress during grain filling. In conclusion, the altered protein expression and upregulated activities of photosynthesis and ascorbate peroxidase in primed plants may indicate their potential roles in alleviating a later-occurring drought stress episode, thereby contributing to higher wheat grain yield under drought stress during grain filling.