Booting Stage Research Articles

Effects of Nitrogen on Photosynthetic Productivity and Yield Quality of Wheat (Triticum aestivum L.)

This study aims to understand the influence of chlorophyll fluorescence parameters on the yield of winter wheat in some areas of China. Nitrogen (N) application is believed to improve photosynthesis in flag leaf, which ultimately increases the final yield. The experiment was conducted in the wheat experimental base of Shanxi Agricultural University in Taigu, Shanxi Province, China; before sowing, four N application rates were set—N0, N120, N150, and N210 kg ha–1 of the Yunhan-20410 variety from 2019 to 2022. The results from different parameters of research showed that the organic manure partial substitution for chemical fertilizer increased post-anthesis N uptake by 16.4 and 81.4%, thus increasing the post-anthesis photosynthetic capacity and delaying leaf senescence. N150 treatment can improve dry matter (DM) accumulation, thus promoting the increase of the yield. The maximum net photosynthesis PN value of the booting stage and flowering stage indicated that nitrogen application could significantly improve the photosynthetic rate of wheat leaves, among which medium nitrogen treatment had the most significant promoting effect. The single-photon avalanche diode (SPAD) value of the leaf of wheat in each treatment increased rapidly in a small range from the jointing stage to the booting stage, respectively. The grain yield under N fertilizer partial substitution for N fertilizer treatment increased by 23%. According to the different significance test, the effects of nitrogen application rate on net photosynthesis PN of winter wheat were extremely significant at all growth stages, indicating that changing the population distribution mode and nitrogen level could effectively improve leaf photosynthetic performance and that N150 level was the best.

Alternative Furrow Irrigation Combined with Topdressing Nitrogen at Jointing Help Yield Formation and Water Use of Winter Wheat under No-Till Ridge Furrow Planting System in Semi-Humid Drought-Prone Areas of China

Benefiting from the high–farmland construction program in China, one–off irrigation can be guaranteed in most fields in semi–humid drought–prone areas in China. However, little information is available on water and nitrogen (N) management in wheat production under this condition. This study aimed to explore the effects of alternative furrow irrigation (AFI) and topdressing N fertilizer (TN) on wheat productivity under a no–till ridge–furrow planting system in semi–humid drought–prone areas. The experimental design was as follows: two furrow irrigation (FI) methods, namely, EFI (every furrow irrigation) and AFI (alternative furrow irrigation) with 75 mm at the jointing stage were set as the main treatments. Two topdressing N (TN) patterns, namely, NTN (0 kg ha−1 of N) and TN (60 kg ha−1 of N) along with irrigation were set as the secondary treatments. Moreover, a traditional planting practice with no irrigation and no topdressing N (NINTN) was set as control. In 2018–2020, a field experiment was carried out to investigate the effects on soil water, leaf chlorophyll relative content (SPAD) and net photosynthetic rate (Pn), aboveground dry matter assimilates, grain yield, water use efficiency (WUE) and economic benefit. We found that both FI methods and TN patterns significantly influenced soil water content. Compared with NINTN, the soil water content in each combination of the FI method and TN pattern was effectively improved at the booting and anthesis stages, leading to the significant increase in SPAD and Pn in leaves, post–anthesis dry matter accumulation (POA), grain yield, WUE and economic benefit of winter wheat. Compared with the EFI, averaged across years and TN patterns, the AFI technique increased the soil water storage at booting and anthesis stages and significantly improved the Pn at early milk (4.9%) and early dough (7.5%) stages, POA (40.6%) and its contribution to grain (CRPOA, 27.6%), the grain yield (10.2%), WUE (9.1%) and economic benefit (9.1%). In addition, compared with the NTN, the TN pattern significantly increased the water computation by wheat from booting to maturity, enhanced leaf Pn after anthesis and POA, and finally resulted in the increase in grain yield (14.7–21.9%) and WUE (9.6–21.1%). Thus, the greatest improvement in the leaf photosynthetic characteristics, aboveground dry matter assimilates, grain yield, WUE and economic benefit was achieved under AFITN treatment. Above all, it can be concluded that the AFITN with AFI of 75 mm and TN of 60 kg ha−1 at jointing was an alternative management strategy for optimizing yield formation and water use of winter wheat. This study provided new insights into improving wheat productivity in drought–prone areas where one–off irrigation can be guaranteed.

Rice developmental stages modulate rhizosphere bacteria and archaea co-occurrence and sensitivity to long-term inorganic fertilization in a West African Sahelian agro-ecosystem

BackgroundRhizosphere microbial communities are important components of the soil-plant continuum in paddy field ecosystems. These rhizosphere communities contribute to nutrient cycling and rice productivity. The use of fertilizers is a common agricultural practice in rice paddy fields. However, the long-term impact of the fertilizers usage on the rhizosphere microbial communities at different rice developmental stages remains poorly investigated. Here, we examined the effects of long-term (27 years) N and NPK-fertilization on bacterial and archaeal community inhabiting the rice rhizosphere at three developmental stages (tillering, panicle initiation and booting) in the Senegal River Delta.ResultsWe found that the effect of long-term inorganic fertilization on rhizosphere microbial communities varied with the rice developmental stage, and between microbial communities in their response to N and NPK-fertilization. The microbial communities inhabiting the rice rhizosphere at panicle initiation appear to be more sensitive to long-term inorganic fertilization than those at tillering and booting stages. However, the effect of developmental stage on microbial sensitivity to long-term inorganic fertilization was more pronounced for bacterial than archaeal community. Furthermore, our data reveal dynamics of bacteria and archaea co-occurrence patterns in the rice rhizosphere, with differentiated bacterial and archaeal pivotal roles in the microbial inter-kingdom networks across developmental stages.ConclusionsOur study brings new insights on rhizosphere bacteria and archaea co-occurrence and the long-term inorganic fertilization impact on these communities across developmental stages in field-grown rice. It would help in developing strategies for the successful manipulation of microbial communities to improve rice yields.

Enhancing Rice Yield and Nitrogen Utilization Efficiency through Optimal Planting Density and Reduced Nitrogen Rates

Rice yields can only be achieved by selecting a high-quality population. Nitrogen rates and transplanting density play a significant role in determining population quality and yield. Field experiments were conducted in Heshan District, Hunan Province, China, to explore suitable nitrogen rates and appropriate transplanting densities for rice production in 2021 and 2022. In this study, three levels of nitrogen, e.g., N1, N2, and N3 (0, 150, and 210) kg ha−1, and three transplanting densities, e.g., B1, B2, and B3 (1, 2, and 3) seedlings per hill were used to study their individual or combined effects on rice (Taiyou 390) population quality, yield, and yield components, nitrogen-related enzyme activities, and nitrogen absorption and utilization efficiency. The results showed that N2B3 had the highest yield, with an average yield of 9.30 t ha−1 in two years, which was 3.7~49.6% higher than other treatments. This increase was attributed to higher dry matter accumulation (1538.22 g m−2) and effective panicle number (435.2 × 104 ha−1), influenced by increased nitrate reductase activity at the booting stage and glutamine synthase at the heading stage, along with maintenance of higher SPAD value and leaf area index. Nitrogen rates and transplanting densities significantly affected nitrogen use efficiency, with the contribution rate of nitrogen fertilizer to yield decreasing as nitrogen rates increased. However, N2B3 improved nitrogen use efficiency and stabilized rice yield by reducing nitrogen fertilizer application. This study suggested that N2B3 treatment could enhance rice yield by improving plant nitrogen use efficiency under low nitrogen supplementation.

Clipping Height and Frequency Effects on Japanese Brome Seed Production and Viability

Japanese brome (Bromus japonicus Thunb.) is an invasive annual grass that is common in the Great Plains. Grazing or clipping in the spring has been shown to decrease Japanese brome biomass, but the effect on seed viability is not as clearly understood. We tested two clipping height and two clipping frequency combinations against nonclipped controls to determine effects on productivity and seeds of Japanese brome in greenhouse conditions. Pots containing two Japanese brome plants each were the experimental unit, with six per treatment, and the experiment was repeated a second yr. Plants were clipped to a 75-mm or 150-mm stubble height on a 7-d or 14-d interval starting at the boot stage, or no clipping occurred. Brome biomass was reduced 35% by clipping to 150 mm and 54% with clipping to 75 mm. No biomass differences were detected between clipping frequencies at either clipping height. Cumulative seed production was reduced at least 54% by clipping and reductions increased with shorter clipping and greater clipping frequency. At the end of the experiment, clipped plants had 7−310 seeds per pot, compared with a mean of 2 585 seeds per pot for nonclipped. Mean seed weight for all clipped treatments was 73% less than that of nonclipped plants. Only 15 seeds germinated from the 150-mm treatment clipped every 14 d. Plants clipped at 75 mm, regardless of frequency, and plants clipped to 150 mm weekly did not produce any viable seeds. Defoliation, across clipped heights and frequencies, drastically reduced the number and viability of Japanese brome seed. Targeted defoliation by mowing or grazing can contribute to Japanese brome control through seed limitation.

Efficacy of quinone outside inhibitors and demethylation inhibitors fungicides against false smut of rice (Oryza sativa)

The present study was carried out at research farm of Bihar Agricultural University, Bhagalpur, Bihar during rainy (kharif) season of 2018–19 and 2019–20 to study the efficacy of four quinone outside inhibitors, demethylation inhibitors and benzimidazole group of fungicides, viz. trifloxystrobin 25% + tebuconazole 50% wg, flusilazole 25% + carbendazim 12.5% se, azoxystrobin 18.2% + difenoconazole 11.4% sc and azoxystrobin 11% + tebuconazole 18.3% W/W at different growth stage of rice (Oryza sativa L.), i.e. booting stage (BS), 50% flowering stage (FS) and 100% flowering stage. Among them, trifloxystrobin 25% + tebuconazole 50% wg @1 g/litre at 50% flowering stage was found superior in minimizing the per cent of disease infection. The number of infected tillers/m2 (18.33 and 13.33), number of smut balls/panicle (1.96 and 1.80), smut balls per panicle (0.48% and 0.51%), disease incidence (5.22%and 3.71%) and disease severity (2.86% and 1.78%) respectively were observed in trifloxystrobin 25% + tebuconazole 50% wg @1 g/litre at 50% flowering stage as compared to control. Out of the tested fungicides, trifloxystrobin 25% + tebuconazole 50% wg was found significantly superior in terms of reducing the infection with highest grain yield (90.58 q/ha) and thereby the grain yield upto 43.05% when it was sprayed at 50% flowering stage of crop @1 ml/litre under the field condition in both years. Hence, it is concluded that, trifloxystrobin 25% + tebuconazole 50% wg belonging to two different chemical family group with broad mode of action fungicide significantly (P<0.05%) reduced the infection at 50% flowering stage of crop against false smut disease.

Synthetic nano-hydroxyapatite as an alternative phosphorus source for wheat grown under field conditions

The aim of this study was to investigate the effects of nano-hydroxyapatite (nHAP) over conventional phosphorus fertilizer in terms of phosphorus nutrition and other nutrients through which it enhances the growth of wheat plants. The experiment was carried out with wheat plants under real field conditions for two consecutive years. Under laboratory conditions, nHAP was synthesized and characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopes (SEM), and elemental dispersive X-rays (EDX). The substance we synthesized according to the characterization tests mentioned here is nano-hydroxyapatite. The application of nHAP was carried out at decreasing rates (80, 60, 40 kg P2O5 ha−1) before sowing, and their effects were compared with 80 kg P2O5 ha−1 diammonium phosphate (DAP) as a reference treatment. Phosphorus and other mineral element concentrations were determined in all plant samples taken at the beginning of the booting stage. In addition, grain samples were taken at harvest. In the nHAP treatment, the plants’ phosphorus, nitrogen and potassium concentrations increased by approximately 25%, 17% and 10%, respectively. This was compared to the DAP treatment. The concentrations of iron and zinc in grain also increased by 46% and 15%, respectively. These increases in grains are particularly noteworthy for biofortification studies. In conclusion, nHAP can be an alternative to conventional fertilizers by reducing phosphorus consumption. However, more studies are required on different plants and long-term field studies regarding the uptake, translocation and interactions of nHAP with other elements.

Effects of elevated CO2 concentration on cell structure and stress resistance physiology of Setaria italica under drought stress.

The frequency of drought will increase under further warming. The increase in atmospheric CO2 concentration, along with more frequent drought, will affect crop growth. We examined the changes of cell structure, photosynthetic physiology, antioxidant enzymes, osmotic regulatory substances, and yield of foxtail millet (Setaria ita-lica) leaves under different CO2 concentrations (ambient air CO2 concentration and ambient atmospheric CO2 concentration + 200 μmol·mol-1) and water treatment (soil moisture content maintained at 45%-55%, and 70%-80% of field capacity, representing mild drought and normal water condition, respectively). The results showed that elevated CO2 concentration increased the number of starch grains, the area of single starch grains, and the total area of starch grains in the chloroplast of millet mesophyll cells. Under mild drought condition, elevated CO2 concentration increased net photosynthetic rate of millet leaves at the booting stage by 37.9%, but did not affect water use efficiency at this stage. Elevated CO2 concentration increased net photosynthetic rate and water use efficiency of millet leaves under mild drought condition at the filling stage by 15.0% and 44.2%, respectively. Under mild drought condition, elevated CO2 concentration increased the content of peroxidase (POD) and soluble sugar in millet leaves at the booting stage by 39.3% and 8.0%, respectively, but decreased proline content by 31.5%. It increased the content of POD in millet leaves at the filling stage by 26.5% but decreased the content of MDA and proline by 37.2% and 39.3%, respectively. Under mild drought condition, elevated CO2 concentration significantly increased the number of grain spikes by 44.7% and yield by 52.3% in both years compared with normal water condition. The effect of elevated CO2 concentration on grain yield under mild drought conditions was higher than that under normal water condition. Under mild drought conditions, elevated CO2 concentration increased leaf thickness, vascular bundle sheath cross-sectional area, net photosynthetic rate, and water use efficiency of millet, improved the antioxidant oxidase activity, and changed the concentration of osmotic regulatory substances, alleviated the nega-tive effect of drought on foxtail millet, and finally increased the number of grains per ear and yield of foxtail millet. This study would provide a theoretical basis for millet production and sustainable agricultural development in arid areas under future climate change.

Kinetic characteristics of and critical stages for mercury accumulation in rice (Oryza sativa L.)

By studying the dynamic characteristics of and key growth stages for mercury (Hg) enrichment in rice, the Hg migration and translocation processes in this species can be better understood. In this study, a pot experiment was conducted, wherein two rice cultivars, Tianyouhuazhan (TYHZ, indica) and Zhendao 18 (ZD18, japonica), were selected and planted for analysing the Hg accumulation kinetic characteristics in rice plants. The plants were sampled at each growth stage, and the biomass and total Hg (THg) and methylmercury (MeHg) concentrations of each tissue were measured. The relative Hg contribution rates (CRs) in whole rice plants and rice grains were calculated, and the growth stage with the highest relative contribution was identified as the key growth stage for Hg accumulation. The results indicated that in rice, the MeHg translocation capability was stronger than the THg translocation capability. Significant differences in the kinetic characteristics of Hg accumulation were found between the two rice cultivars, and the TYHZ rice grains had a stronger Hg accumulation ability than the ZD18 rice grains. The key growth stages for THg accumulation in whole rice plants of both cultivars were the tillering and booting stages, while that for MeHg accumulation was the tillering stage. The key period for Hg accumulation in rice grains was the grain filling stage for both cultivars. The insights from this study could provide scientific guidance for the safe production of rice in Hg-contaminated soil.

Detection of combined frost and drought stress in wheat using hyperspectral and chlorophyll fluorescence imaging

Immediate detection and prediction tools for interactive stresses are essential to avoid yield losses. This study investigated the capability of hyperspectral (HSI) and chlorophyll fluorescence imaging (CFI) to characterize individual and interactive frost (−4 °C) and drought (40% soil moisture content) stress responses at the booting stage of wheat under controlled environmental conditions. HSI full range reflectance (280–2500 nm), CFI, and traditional responses (leaf water content, photosynthesis, and enzymatic activity) were measured from flag leaves. The potentiality of HSI to detect cellular damage in terms of enzymatic activity was explored by developing partial least square regression (PLSR) models, and spectral indices were calculated to characterize the responses to individual and combined stresses. Reflectance in 360, 700, 1400, 1900, and 2460 nm wavebands showed the most important variables in developing PLSR models for enzymes. Superoxide dismutase, peroxidase, and ascorbate peroxidase showed the highest R2c (0.99, 0.95, and 0.98), R2v (0.94, 0.90, 0.93), and the ratio of prediction to deviation (4.04, 3.06, and 3.85). CFI decreased under individual frost and combined frost and drought stresses. Ratio vegetation stress index (RVSI), green difference vegetation index (GDVI), difference vegetation index (DVI), and normalized difference water index (NDWI) were the most important variables and could be used to detect combined frost and drought by determining enzymatic activity and reactive oxygen species (ROS), verified by PLSR models. Spectral indices and enzyme activities showed a strong correlation in determining yield losses. Hence, HSI and CFI techniques successfully detected combined frost and drought stresses for rapid quantification.

Effect of Potassium Fertilizer on Yield and Yield Components of HomWarin Rice Variety in Low Fertility Sandy Soil

The objective of this research was to study the effect of potassium (K) fertilizer rate on growth, yield and yield components of HomWarin rice variety grown in low fertile sandy soils. The experiment was laid out in randomized complete block design (RCBD) with three replications and five rate of K treatments comprising 0, 6, 12, 18 and 24 kg K2O per rai. Each treatment was applied with nitrogen and phosphorus fertilizers at 12 (N) and 8 (P2O5) kg per rai, respectively. Split fertilizers were established in three application timings. The first application was applied 15 days after transplanting with 40 percent of total fertilizer established in treatments. The second and third applications were applied at tillering (40%) and booting stages (20%), respectively. The results revealed that the potassium application at the rate of 18 kg K2O per rai significantly caused the longest panicle length, number of seeds per panicle and the 1,000 grain weight of HomWarin rice variety (p<0.05). Different rates of the potassium application displayed no significant effects on height, number of tillers per culm, number of panicles per culm, shoot dry weight, filled grain percentage, unfilled grain percentage and grain yield. Nevertheless, potassium fertilizer at 18 kg K2O per rai tended to produce the highest grain yield of HomWarin (927.56 kg per rai).

节水灌溉与调理剂结合对旱直播稻产量、养分吸收及品质影响

Dry direct seeding cultivation technology of rice is an important aspect of rice production and management. Six treatments were designed in this paper, and that is, T1 (conventional irrigation), T2 (conventional irrigation + conditioner), T3 (30% water-saving irrigation), T4 (30% water-saving irrigation + conditioner), T5 (50% water-saving irrigation), T6 (50% water-saving irrigation + conditioner). The results showed that in the three separate irrigation treatments, 30% water-saving irrigation was conducive to the growth of dry direct seeding rice at the tillering stage, jointing and booting stage, and 50% water-saving irrigation was more conducive to the growth of rice at grain filling stage. Compared with no application of amendments, all kinds of treatments could significantly promote the growth of dry direct seeding rice. Under the condition of water-saving irrigation of 30%, higher dry matter quality, yield and nutrient absorption can be obtained. The total dry matter quality and rice yield of T4 treatment with 30% water-saving irrigation and conditioner were the highest, which were 99.90 g/pot and 37.76 g/pot respectively, compared with conventional treatment (T1) was 37.60% and 45.96% higher, and this treatment had obvious effect on nitrogen and potassium absorption. In terms of quality impact, water saving was 30% Irrigation conditions are conducive to the improvement of rice processing quality, appearance quality and nutritional quality, especially after the application of conditioner, the overall rice quality is improved. This study has a certain reference value for water-saving irrigation, promoting nutrient utilization, stable yield and high quality of dry direct seeding rice.

Multi-Model Rice Canopy Chlorophyll Content Inversion Based on UAV Hyperspectral Images

Rice is China’s main crop and its output accounts for 30% of the world’s total annual rice production. Rice growth status is closely related to chlorophyll content (called Soil and Plant Analyzer Development (SPAD) values). The determination of a SPAD value is of great significance to the health status of rice, agricultural irrigation and regulated fertilization. The traditional SPAD value measurement method is not only time-consuming, laborious and expensive but also causes irreparable damage to vegetation. The main aim of the present study is to obtain a SPAD value through the inversion of hyperspectral remote sensing images. In order to achieve this purpose, the hyperspectral image of rice at different growth stages at the canopy scale was first acquired using a hyperspectral imaging instrument equipped with a drone; the spectral characteristics of the rice canopy at different growth stages were analyzed and combined with a ground-level measured SPAD value, the bands with high correlation between the SPAD values and the spectra of the rice canopy at different fertility stages were selected. Subsequently, we combined the spectral characteristics with the continuous projection algorithm to extract the characteristic band and used the PLS method in MATLAB software to analyze and calculate the weight of each type of spectral value and the corresponding canopy SPAD value; we then used the wavelength corresponding to the spectral value with the highest weight as the used band. Secondly, the four methods of univariate regression, partial least squares (PLS) regression, support vector machine (SVM) regression and back propagation (BP) neural network regression are integrated to establish the estimation model of the SPAD value of rice canopy. Finally, the models are used to map the SPAD values of the rice canopy. Research shows that the model with the highest decision coefficient among the four booting stage models is “booting stage-SVR” (R2 = 0.6258), and the model with the highest decision coefficient among the four dairy maturity models is “milk-ripe stage-BP” (R2 = 0.6716), all of which can meet the requirement of accurately retrieving the SPAD value of rice canopy. The above results can provide a technical reference for the accurate, rapid and non-destructive monitoring of chlorophyll content in rice leaves and provide a core band selection basis for large-scale hyperspectral remote sensing monitoring of rice.

Rice Yield Prediction in Different Growth Environments Using Unmanned Aerial Vehicle-Based Hyperspectral Imaging

There are certain growth stages and spectral regions that are optimal for obtaining a high accuracy in rice yield prediction by remote sensing. However, there is insufficient knowledge to establish a yield prediction model widely applicable for growth environments with different meteorological factors. In this study, high temporal resolution remote sensing using unmanned aerial vehicle-based hyperspectral imaging was performed to improve the yield prediction accuracy of paddy rice cultivated in different environments. The normalized difference spectral index, an index derived from canopy reflectance at any two spectral bands, was used for a simple linear regression analysis to estimate the optimum stage and spectral region for yield prediction. Although the highest prediction accuracy was obtained from the red-edge and near-infrared regions at the booting stage, the generalization performance for different growth environments was slightly higher at the heading stage than at the booting stage. The coefficient of determination and the root mean squared percentage error for the heading stage were R2 = 0.858 and RMSPE = 7.52%, and they were R2 = 0.853 and RMSPE = 9.22% for the booting stage, respectively. In addition, a correction by solar radiation was ineffective at improving the prediction accuracy. The results demonstrate the possibility of establishing regression models with a high prediction accuracy from a single remote sensing measurement at the heading stage without using meteorological data correction.

Impacts of Partial Substitution of Chemical Fertilizer with Organic Manure on the Kinetic and Thermodynamic Characteristics of Soil β–Glucosidase

To study the characteristics of the β–glucosidase enzymatic reaction in wheat field soil under the condition of reducing the application of chemical fertilizer, five fertilization treatments were established, including no fertilizer (CK), chemical fertilizer (F), organic fertilizer (OF), 25% organic fertilizer plus 75% chemical fertilizer (25% OF), and 50% organic fertilizer plus 50% chemical fertilizer (50% OF). The activity of β–glucosidase and its kinetic and thermodynamic characteristics were analyzed by using microplate p–nitrophenol colorimetry. The results showed that the Vmax values of soil β–glucosidase in the organic substitution of chemical fertilizer treatment were higher than those in the chemical fertilizer and no fertilizer treatments, and the Km values were lower than those in the chemical fertilizer and no fertilizer treatments at the different growth stages. The Vmax value in the 25% OF treatment was the highest at the jointing stage and that of the OF treatment was the highest at the booting stage; the Km value in the 50% OF treatment was the lowest at the different growth stages. Compared with the chemical fertilizer and no fertilizer treatments, the application of organic fertilizer effectively reduced thermodynamic parameters such as Ea, Q10, ∆H, ∆G, and ∆S at the jointing and booting stages of wheat. The thermodynamic parameters in the 25% OF treatment were the lowest at the jointing stage and those in the OF treatment were the lowest at the booting stage. A reasonable amount of organic fertilizer is more beneficial to enzymatic reactions and improves the soil quality and the ability to supply nutrients to wheat cultivation.

Metabolomic approach to investigate Dactylis glomerata L. from the VIR collection.

The perennial grass cocksfoot (Dactylis glomerata L.) is a valuable early highly nutritious crop used as green fodder in agricultural production. The species is widespread across the Eurasian continent; it is characterized by plasticity and high ecological and geographical variability. The article considers the metabolic profiles of 15 accessions of the cocksfoot from the collection of the N.I. Vavilov Institute of Plant Genetic Resources (VIR). The material is represented by varieties and wild forms of various origin: the European part of the Russian Federation, Norway and Finland. The study was carried out using gas-liquid chromatography coupled with mass spectrometry. The study and comparison of groups of metabolites of cocksfoot accessions of various ecological and geographical origin was carried out. Statistical processing included the calculation of the main parameters of variability, factor analysis of the correlation system (Q- and R-technique), cluster analysis by Ward's method and discriminant analysis. The variability of the quantitative and qualitative composition of the substances identified was revealed. Based on statistical processing of the results obtained, five groups of cocksfoot accessions were identified, differing in the profile of metabolites. One of the groups with a similar composition of metabolites consisted of accessions from one ecological and geographical region; another, of accessions of different origin. Significant differences were noted in the metabolomic profiles of a late-maturing wild cocksfoot accession from the Republic of Karelia at the booting stage from early- and mid-maturing accessions at the heading stage; it contained the largest number of free amino acids and the smallest number of identified primary and secondary metabolites. Wild-growing accession k-44020 from Norway surpassed other wild-growing accessions in the content of free amino acids, sugars and phosphates at the heading stage. Wild-growing accessions differed from breeding varieties with a high content of proline and threonine, indicators of high resistance to lack of moisture and high air temperature.

Analysis of metabolic differences in maize in different growth stages under nitrogen stress based on UPLC-QTOF-MS.

Maize has a high demand for nitrogen during the growth period. The study of metabolic changes in maize can provide a theoretical basis for rational nitrogen nutrition regulation. In order to investigate the changes of different metabolites and their metabolic pathways in maize leaves under nitrogen stress, we used ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) for metabolomic analysis of maize leaves under different nitrogen treatments at three critical growth stages (V4, V12 and R1) in a pot experiment under natural conditions. The results showed that nitrogen stress significantly affected sugar metabolism and nitrogen metabolism, and affected carbon and nitrogen balance, and the effects of stress on maize leaves metabolism increased with the growth process. Metabolic pathways such as the TCA cycle and starch and sucrose metabolism were mainly affected at the seeding stage (V4). The stress response to nitrogen deficiency also showed significant upregulation of flavonoids such as luteolin and astragalin during the booting stage (V12) and anthesis-silking stage (R1). During R1 stage, the synthesis of tryptophan and phenylalanine and the degradation of lysine were significantly affected. Compared with nitrogen stress, the metabolic synthesis of key amino acids and jasmonic acid were intensified and the TCA cycle was promoted under nitrogen sufficiency conditions. This study initially revealed that the response mechanism of maize to nitrogen stress at the metabolic level.

Effects of elevated atmospheric ammonia concentration on photosynthetic characteristics and grain yield in wheat under different nitrogen rates.

To evaluate the effects of nitrogen (N) application rates on the growth, photosynthetic traits and yield of winter wheat under elevated atmospheric ammonia (NH3) concentrations could provide guidance for N management under high NH3 environment. We conducted a split-plot experiment for two consecutive years (2020-2021 and 2021-2022) with top-open chambers. The treatments included two NH3 concentrations [elevated ambient NH3 concentration at 0.30-0.60 mg·m-3 (EAM) and air NH3 concentration at 0.01-0.03 mg·m-3 (AM)] and two N application rates [recommended N dose (+N) and no N application (-N)]. We analyzed the effects of aforementioned treatments on net photosynthetic rate (Pn), stomatal conductance (gs), chlorophyll content (SPAD value), plant height, and grain yield. The results showed that averaged across the two years, EAM significantly increased Pn, gs, and SPAD values at the jointing and booting stages at the -N level by 24.6%, 16.3%, 21.9% and 20.9%, 37.1%, 5.7%, respectively, compared with AM. However, EAM significantly decreased Pn, gs, and SPAD values at jointing and booting stages at +N level by 10.8%, 5.9%, 3.6% and 6.8%, 18.9%, 9.3%, respectively, over AM treatment. There was a significant effect of NH3 treatment, N application rates and their interaction on plant height and grain yield. Compared with AM, EAM increased the average plant height and grain yield by 4.5% and 32.1% at -N level and decreased by 1.1% and 8.5% at +N level, respectively. In a nutshell, the eleva-ted ambient NH3 concentration had positive effect on photosynthetic characteristics, plant height, and grain yield under ambient N condition, but a inhibitory effect under N application.

Impact of Planting Date and Physiological Activator (Appetizer) Application on Quality and Quantity of Wheat Grains (Triticum aestivum.L)

A field experiment was conducted during the winter season 2022-2021 in the field experiments field of the College of Agriculture - Al-Qasim Green University in the south of Babylon province, located at latitude 32.40 north and longitude 44.39 east. In order to study the effect of planting date and stages of spraying with the physiological stimulant Appetizer on the growth and yield of wheat (Triticum aestivum L.)), the experiment was conducted by arranging the split plots according to the Randomized Complete Block Design (RCBD) with three replicates. The planting dates included the main plot T1, a suitable first date on 15/11 and T2 a second late date on 15/12, while the subplot included spraying with the physiological stimulant (Appetizer) according to the stages of wheat growth within the Zadoks classification, which was given the symbols (A0 without spraying and A1 stage, The results showed that the date of 11/15 was significantly superior to the studied traits, where the number of spikelets in spike was 20.1 spikelets. spike -1 The number of grains in the spike is 43.6 grain. spike -1 The number of spikes is 364. The weight of 1000 grains is 36.26 g, and the grain yield is 3.84 tons. ha1-. The biological yield is 11.25 tons. ha-1 and the carbohydrate content is 73.29%, while the date of 15/12 is significantly excelled on trait of the protein content, as the average was 9.43% As for the phases of spraying with the physiological activator (Appetizer), they were significantly excelled at the elongation and booting stage in the studied traits, including the number of spikes of 20.6 spikes. Plant-1 The number of grains is 48.9 grains. spikes -1 and the weight of 1000 grains is 40.7 g. The grain yield is 4.17 tons. hectare 1- and a biological yield of 11.01 tons. ha -1 The protein content is 9.56% and the carbohydrate content is 77.03%. As for the number of spikes, the number of spikes was significantly excelled at the tillering stage g and elongation, where their average values reached 368 spikes.m2. As for the interaction between planting dates and the phases of spraying with the physiological activator (Appetizer) it was significant in all the studied traits, the interaction between the date of 15/11 and the stages of spraying with the physiological activator at the elongation and end stage gave the highest average number of spikelets in the spike of 20.8 spikelets. spike -1 The number of grains in the spike is 52.7 grains. spike 1- and the weight of 1000 grains is 42.42 g. The grain yield is 4.66 tons. ha-1 has a biological yield of 11.46 tons. ha-1 and the carbohydrate content is 77.76%. As for the number of spikes, the interaction was significant between the date of 15/11 and the spraying phase when treating the tillering and elongation, as the average was 381 spikes. It reached 9.65%.

Influence of Planting Date and Kinetin Concentration on Thermal Accumulation and Some Growth Trails in Barley

A field experiment was carried out in Alsufia - Al-Ramadi city - Al-Anbar governorate Republic of Iraq at winter season 2020-2021 on sandy loam soil. The experiment included 12 treatment resulted from the combination of planting date Oct25, Nov10, Nov25 and Dec10 ( main plots) and kinetin concentration 0,30 and 60 mg L-1( sub plots ) using RCBD with split plot arrangement and three replications. The results revealed that the plants of first planting date recorded 91 days until booting stage and reduced gradually to 60 days at fourth date. First planting date score highest thermal accumulation at 1876 C and declined to lowest value at third date (1389) C. Fourth planting date gave the highest CGR (0.127) g day-1 and NAR (0.00028) g cm-2 day-1. The concentration of kinetin 30 mg L-1 surpass in CGR significantly, but kinetin concentration have on significant effect on NAR.