Post-anthesis Stage Research Articles

Understanding nitrogen allocation dynamics in Indian mustard: Insights from enzyme activity and ideotype analysis

The study explores the effect of varying levels of nitrogen (N) application on N allocation in Indian mustard (Brassica juncea) genotypes from vegetative to the generative phases. The use of a heat map and PCA biplot analysis identifies two distinct sets of ideotypes. The first set is represented by genotype IC212031 having “Stay-green” phenotype with effective N regulating enzymes, high N uptake (NUpt) and better root development. The second set of ideotype is represented by HB9902 having delayed flowering phenology phases. The study highlights the relevance of Nitrate reductase (NR) in the final oil buildup in seeds (r = 0.5, p = 0.09). The considerable rise in NR activity from pre-anthesis to post-anthesis stages translates to higher seed storage compounds such as oil (r=−0.65, p = 0.03). And the developed prediction models confirmed the significance of these stages (pre-anthesis and post-anthesis) in the accumulation of seed storage components with emphasis on oil content. Similarly, this prediction model helps us to study the cause and effect relationship between various factors and oil content. The notable rise in Nitrite reductase (NiR) activity during the post-anthesis phase suggests its role in assimilating N for the storage of seed components, most likely proteins. Further, the inverse relationship between seed N (−0.53,p= 0.09) and oil content (−0.65, p= 0.03) confirmed that at the post anthesis stage the allocation of N towards precursor carbon compounds happens, which in turn forms either proteins or lipids. This becomes a critical factor in determining the final composition of the seed. Irrespective of N treatment and genotype, the N allocation follows the pattern: seed > siliquae husk > stover > root. However, higher N application rates primarily result in increased NUpt, but not necessarily improve utilisation. Overall, the study highlights the roles of root characteristics, N metabolising enzymes, and flowering phenology in enhancing N allocation and seed production in Indian mustard offering valuable insights for breeding strategies to enhance seed yield, oil content and nutrient efficiency in oilseed crops.

Characterization and Transcriptomic Analysis of Sorghum EIN/EIL Family and Identification of Their Roles in Internode Maturation.

Ethylene-insensitive 3/Ethylene-insensitive3-like proteins (EIN3/EIL) represent a group of transcription factors critical for the ethylene signaling transduction that manipulate downstream ethylene-responsive genes, thereby regulating plant growth, development, and stress responses. However, the identification, evolution, and divergence of the EIL family remain to be studied in Sorghum bicolor. Here, we identified eight SbEILs, which were expanded due to whole-genome-duplication (WGD) events. Characterization of the protein sequences and expression atlas demonstrates that the WGD-duplicated SbEILs could become divergent due to the differential expression patterns, rather than domain and motif architectures. Comparative expression analysis was performed between the RNA-seq data sets of internodes from several sorghum cultivars to understand the potential roles of SbEIL members in internode elongation and maturation. Our results identified SbEIL3 and 7 (the latter as a homolog of OsEIL7/OsEIL1) to be the highly expressed SbEIL genes in sorghum internodes and revealed a potential functional link between SbEIL7 and internode maturation. The co-expression analysis and comparative expression analysis with ethylene-regulated gene sets found that SbEIL7 was co-regulated with a set of ubiquitin-related protein degradation genes, suggesting possible involvement of SbEIL7 in protein degradation and processing during the post-anthesis stages. Altogether, our findings lay a foundation for future functional studies of ethylene signaling-mediated gene regulation and improvement of sorghum internode development.

Potential Roles of the GRF Transcription Factors in Sorghum Internodes during Post-Reproductive Stages.

Growth-regulating factor (GRF) is a plant-specific family of transcription factors crucial for meristem development and plant growth. Sorghum (Sorghum bicolor L. Moench) is a cereal species widely used for food, feed and fuel. While sorghum stems are important biomass components, the regulation of stem development and the carbohydrate composition of the stem tissues remain largely unknown. Here, we identified 11 SbGRF-encoding genes and found the SbGRF expansion driven by whole-genome duplication events. By comparative analyses of GRFs between rice and sorghum, we demonstrated the divergence of whole-genome duplication (WGD)-derived OsGRFs and SbGRFs. A comparison of SbGRFs' expression profiles supports that the WGD-duplicated OsGRFs and SbGRFs experienced distinct evolutionary trajectories, possibly leading to diverged functions. RNA-seq analysis of the internode tissues identified several SbGRFs involved in internode elongation, maturation and cell wall metabolism. We constructed co-expression networks with the RNA-seq data of sorghum internodes. Network analysis discovered that SbGRF1, 5 and 7 could be involved in the down-regulation of the biosynthesis of cell wall components, while SbGRF4, 6, 8 and 9 could be associated with the regulation of cell wall loosening, reassembly and/or starch biosynthesis. In summary, our genome-wide analysis of SbGRFs reveals the distinct evolutionary trajectories of WGD-derived SbGRF pairs. Importantly, expression analyses highlight previously unknown functions of several SbGRFs in internode elongation, maturation and the potential involvement in the metabolism of the cell wall and starch during post-anthesis stages.

Sustainable experimental cultivation of the Greek endemic Helichrysum amorginum Boiss. and Orph.: Assessment of the total phenolic content at different flower harvest stages

Helichrysum amorginum Boiss. and Orph. constitutes a range-restricted, endemic species of Greece with known pharmaceutical potency. The current work presents the results of a targeted evaluation of the total phenolic content (TPC) of methanolic extracts of H. amorginum flower heads under cultivation conditions at three consecutive harvest stages in two separate cultivation locations across a period of two years (2018 and 2019). The harvested inflorescence tissue was assessed for TPC via the Folin–Ciocalteu method in three and four-year old H. amorginum individuals. Older plants, during the second evaluation year, generally showed higher flower TPC content throughout. The pooled analysis of the results indicated significant differences in TPC among samples of extracts prepared with plant material from different harvest stages with the early flowering stage (A) presenting higher TPC in both experimental cultivation locations (142.6-156 mg GAE g-1 extract on average among the two cultivation locations) followed by the full bloom stage (B) (139-145.7 mg GAE g-1 extract on average) and the late bloom or early post-anthesis stage (C) which showed the lowest TPC in all cases (130.3-131 mg GAE g-1 extract on average). The current results provide for the first-time basic information on the optimum inflorescence harvest stage during the prolonged flowering period of cultivated H. amorginum in terms of TPC. The proposed work can be incorporated into the establishment of a sustainable cultivation protocol for achieving polyphenol-rich extracts and ultimately contributes to the utilization of H. amorginum in the pharmaceutical/cosmetic sectors.

Indexing heat stress-induced changes in Indian mustard germplasm using biochemical traits, stress tolerance indices and seed morphological features

Heat stress in Brassica is a great threat to its productivity and it is a major abiotic challenge in the current scenario of changing global climatic conditions. Oil production from Brassica is the second largest production after soybean, globally. In this study, 32 Indian mustard accessions were evaluated (post-anthesis stage) under heat stress in field conditions during the rabi season of 2019-20, by being exposed to 3 different growing conditions i.e., early, optimum and late sowing. Biochemical assays were performed at the post-anthesis stage to analyze the best-performing accessions under heat stress during the rabi season of 2021-22. Seed morphological parameters and stress indices (MDA, proline content) were used to find high-performing accessions. The results showed a significant correlation between yield under stress and STI (stress tolerance index), YI (yield index), SSPI (stress susceptibility percent index) and MP (mean productivity), indicating the utility of these indices in the selection of heat-tolerant and high-yielding lines. Based on the morphological, seed yield and quality parameters, accessions IC280920, IC401575, IC426400, IC491509 and IC570301 were found tolerant to heat stress as compared to other accessions. Therefore, the selected accessions can be utilized to improve crop Brassica, especially under heat stress.

Volatile Organic Compounds Mediate Host Selection of Wheat Midge, Sitodiplosis Mosellana (Géhin) (Diptera: Cecidomyiidae) between Preanthesis and Postanthesis Stages of Wheat.

The orange wheat blossom midge, Sitodiplosis mosellana (Géhin) (Diptera: Cecidomyiidae), is a significant wheat pest in the Prairie Provinces of Canada and northern regions of the USA. Wheat phenology plays a critical role in wheat midge oviposition. We hypothesized that S. mosellana oviposition behaviour is influenced by volatile organic compounds (VOCs) emitted by wheat at two adjacent wheat growth stages: preanthesis and postanthesis. A higher number of S. mosellana eggs laid on preanthesis than postanthesis spikes in an oviposition choice experiment using the susceptible spring wheat cultivar 'Roblin'. In preanthesis, wheat emitted higher amounts of Z-3-hexenyl acetate (Z3-06:OAc) than at the postanthesis stage. Higher amounts of methyl ketones such as 2-tridecanone, 2-pentadecanone, and 2-undecanone were emitted by wheat in the postanthesis stage and these VOCs were sensitive to S. mosellana antennae used in the Gas Chromatography-Electroantennographic Detection. Females were attracted to synthetic Z3-06:OAc but were deterred by 2-tridecanone relative to the solvent control in the vertical Y-tube olfactometer. 2-Undecanone and 2-pentadecanone did not show any attractiveness or deterrence. In a no-choice oviposition experiment, fewer eggs were laid in preanthesis wheat exposed to a synthetic VOC blend of Z3-06:OAc, 2-undecanone, 2-tridecanone, and 2-pentadecanone at the concentrations released by postanthesis spikes. This study shows that the reduction of Z3-06:OAc, in the VOC mix, and possibly the increase in 2-tridecanone, are likely responsible for the reduction in oviposition on postanthesis wheat. These results elucidate for the first time the role of specific VOCs mediating S. mosellana oviposition in preanthesis and postanthesis wheat.

ONION SEED PRODUCTION AS INFLUENCED BY FOLIAR APPLICATION OF THIOUREA AND PGPRS AT POST-ANTHESIS STAGE

The onion (Allium cepa L.) is a biennial vegetable with regard to seed production. Seed yield is influenced by high temperature at the time of anthesis and seed setting in Punjab. Thiourea (TU) and PGPRS have been used in different crops to induce stress tolerance and to increase the yield. Two experiments were conducted to study the effect of different concentrations of thiourea (0, 5, 10, 15 and 20mM) and different PGPRS (Control, PsJN and FD17) on onion seed production. Thiourea and PGPRS were applied as foliar spray at post-anthesis stage in onion seed crop. Three replications were used under RCBD. In first experiment, maximum values of scape height was 30.367cm in 15mM TU, number of scapes (10.33), thousand seed weight (4.20mg), umbel diameter (5.29mm), weight of seed per umbel (0.34g), seed yield per plant (3.21g), plumule length (7.70cm), radicle length (4.17cm), germination percentage (85.66%), yield of seed per plot (369.85g/ft-2), dry weight (70.70mg) and fresh weight (431.64mg) of seedling in 5mM TU and seed germination duration as 16 days in 15mM of TU. Most of the results were higher in 5mM application of TU. While in second experiment, scape height (29.8cm), umbel diameter (5.29mm) and number of scapes per plant (10.3) were not significantly affected by different treatments yet FD17 showed the best results. Seed yield per plant (3.31g/plant) and yield of seed per plot (296.5g/ft2) were significantly (P<0.00) affected by FD17 treatment. Almost all the results of FD17 were superior to PsJN. In conclusion of this research, overall, the performance of thiourea (especially 5mM) was better as compared to others.

Selection of heat tolerant donor lines in indian mustard (Brassica Juncea L.)

Heat stress during the post anthesis (seed filling) stage negatively influences the movement of photosynthates to the developing sinks and, thus lowering the seed yield in Indian mustard [Brassica juncea (L.) Czern & Coss]. The present studywas conducted with the objective to unravel the variability for terminal heat stress (THS) in a fixed diversitygenetic stock of 500 lines of Indian mustard. Germplasm stock exhibited huge variability for seed yield and its contributing traits with variable levels of yield reduction under late sown conditions. The per se yield based computed heat stress susceptibility index (HSI) ranged from 32.3 (highly THS susceptible) to -1.15 (THS tolerant). Based on yield reduction due to THS, 500 test genotypes were grouped into 10 classes and genotypes from each class wererandomly takento constitute a diverse panel of 96 lines. This panel was evaluated under THS by raising crop underpoly-tunnels during reproductive phase along with same set of 96 genotypes raised under normal field conditions (served as control). Based on agronomic advantage and HSI for economic traits, 23 heat tolerant donor lines were selected for utilization in commercial breeding programme. Bangladesh J. Bot. 52(4): 1007-1013, 2023 (December)

Skipping irrigation at pre- and post-anthesis stages influences grain yield and starch contents of bread wheat derived from synthetic or landraces

This study aims to evaluate the role of genetic diversity originated from three-way crosses of landraces and synthetic bread wheat derivatives attempted with elite cultivars to identify the genotypes having better grain yield as well as better starch contents under flowering stage drought stress. In total, 50 genotypes comprised of 47 derivatives of landraces and synthetics, and three standard varieties were grown in the fields of CIMMYT, Obregon following alpha lattice design with two replications. Drought stress was imposed by stopping the irrigation before anthesis and post-anthesis stages. Different traits related to physiological adaptations, earliness, grain yield and starch contents were decreased under drought stress except amylose which increased significantly. Canopy temperature depression was not significantly affected by drought stress. Further, we identified strong correlation of grain yield with plant height, normalized difference in vegetation index, plant maturity, spike length, grain number and thousand grain weight but negative with canopy temperature depression. Non-significant correlation of amylose and amylopectin was recorded with grain yield. Results revealed that genetic diversity derived from landraces and synthetic bread wheat can improve grain yield and starch contents but simultaneous improvement of both is elusive.

Ethylene sensitivity underscores the yield advantage of high-grain numbers in cylinder-shaped rice panicles

Panicle-wise grain-filling of individual spikelets is location-specific in rice; apical spikelets dominate over their basal counterparts. This pattern of grain filling changes with panicle architecture among cultivars, but the underlying mechanisms are not understood. The newly introduced rice cultivars with cylinder-shaped panicles, although suited for high yield, exhibit several instances of poor filling. In this study shoot apical meristem gene expressions in the ontogeny stage and their influence on spikelet survival at the post-anthesis stage were elucidated by screening two types of rice Recombinant Inbreed Lines (RIL) having similar spikelet density in the cylinder-shaped panicles, such as SR-157 (low-sterile) and SR-159 (high-sterile) and their parents NPT-V12 (low-sterile) and SPS-1–6–1 (high-sterile). Between cultivars, SR-157 versus SR-159, and spikelets located apically versus basally, grain filling was more vulnerable in the latter than the former owing to a more remarkable evolution of ethylene at anthesis. Combined genome analyses revealed that branching genes like DEP2, SPL-14, PTR, and FZP over-expressed in high-sterile compared to low-sterile cultivars during the ontogeny stage. But this over-expression had no matching improvement in grain-setting in the post-anthesis stage. Grain starch synthesis was higher, and expression of ethylene receptors and signal transducer genes was lower in the low- compared to high-sterile cultivars. Thus, the quantum of grain set in the post-anthesis stage determining actual panicle yield was not dependent on the expression of genetic factors in the pre-anthesis stage defining potential grain yield. It was concluded that the default expression of ethylene synthesis and transducer genes at anthesis cause spikelet degeneration and deride the yield advantage of a high spikelet number in some cylinder-shaped rice panicles. The genomic studies controlling ethylene evolution and action in rice panicles must be an inalienable part of any constructive contribution to the yield potential.

Nitrogen uptake and remobilization from pre- and post-anthesis stages contribute towards grain yield and grain protein concentration in wheat grown in limited nitrogen conditions

BackgroundIn wheat, nitrogen (N) remobilization from vegetative tissues to developing grains largely depends on genetic and environmental factors. The evaluation of genetic potential of crops under limited resource inputs such as limited N supply would provide an opportunity to identify N-efficient lines with improved N utilisation efficiency and yield potential. We assessed the genetic variation in wheat recombinant inbred lines (RILs) for uptake, partitioning, and remobilization of N towards grain, its association with grain protein concentration (GPC) and grain yield.MethodsWe used the nested association mapping (NAM) population (195 lines) derived by crossing Paragon (P) with CIMMYT core germplasm (P × Cim), Baj (P × Baj), Watkins (P × Wat), and Wyalkatchem (P × Wya). These lines were evaluated in the field for two seasons under limited N supply. The plant sampling was done at anthesis and physiological maturity stages. Various physiological traits were recorded and total N uptake and other N related indices were calculated. The grain protein deviation (GPD) was calculated from the regression of grain yield on GPC. These lines were grouped into different clusters by hierarchical cluster analysis based on grain yield and N-remobilization efficiency (NRE).ResultsThe genetic variation in accumulation of biomass at both pre- and post-anthesis stages were correlated with grain-yield. The NRE significantly correlated with aboveground N uptake at anthesis (AGNa) and grain yield but negatively associated with AGN at post-anthesis (AGNpa) suggesting higher N uptake till anthesis favours high N remobilization during grain filling. Hierarchical cluster analysis of these RILs based on NRE and yield resulted in four clusters, efficient (31), moderately efficient (59), moderately inefficient (58), and inefficient (47). In the N-efficient lines, AGNa contributed to 77% of total N accumulated in grains, while it was 63% in N-inefficient lines. Several N-efficient lines also exhibited positive grain protein deviation (GPD), combining high grain yield and GPC. Among crosses, the P × Cim were superior and N-efficient, while P × Wya responded poorly to low N input.ConclusionsWe propose that traits favouring pre- or post-anthesis biomass accumulation and pre-anthesis N uptake may be targeted for breeding to improve grain-yield under limited N. The lines with positive GPD, a first report of genotype-dependent GPD associated with both AGNpa and AGNa in wheat, may be used as varieties or genetic resources to improve grain yield with high GPC for sustainable development under limited N conditions.

Responses of maize hybrids to water stress conditions at different developmental stages: accumulation of reactive oxygen species, activity of enzymatic antioxidants and degradation in kernel quality traits.

Sustainable maize production under changing climatic conditions, especially heat and water stress conditions is one of the key challenges that need to be addressed immediately. The current field study was designed to evaluate the impact of water stress on morpho-physiological, biochemical, reactive oxygen species, antioxidant activity and kernel quality traits at different plant growth stages in maize hybrids. Four indigenous i.e., YH-5427, YH-5482, YH-5395, JPL-1908, and one multinational maize hybrid i.e., NK-8441 (Syngenta Seeds) were used for the study. Four stress treatments (i) Control (ii) 3-week water stress at pre-flowering stage (iii) 3-week water stress at anthesis stage (iv) 3-week water stress at grain filling/post-anthesis stage. The presence of significant oxidative stress was revealed by the overproduction of reactive oxygen species (ROXs) i.e., H2O2 (1.9 to 5.8 µmole g-1 FW) and malondialdehyde (120.5 to 169.0 nmole g-1 FW) leading to severe negative impacts on kernel yield. Moreover, a severe reduction in photosynthetic ability (50.6%, from 34.0 to 16.8 µmole m-2 s-1), lower transpirational rate (31.3%, from 3.2 to 2.2 mmol m-2 s-1), alterations in plant anatomy, reduced pigments stability, and deterioration of kernel quality was attributed to water stress. Water stress affected all the three studied growth stages, the pre-flowering stage being the most vulnerable while the post-anthesis stage was the least affected stage to drought stress. Antioxidant activity was observed to increase under all stress conditions in all maize hybrids, however, the highest antioxidant activity was recorded at the anthesis stage and in maize hybrids YH-5427 i.e., T-SOD activity was increased by 61.3% from 37.5 U mg-1 pro to 60.5 U mg-1 pro while CAT activity was maximum under water stress conditions 8.3 U mg-1 pro as compared to 10.3 U mg-1 pro under control (19.3%). The overall performance of maize hybrid YH-5427 was much more promising than other hybrids, attributed to its higher photosynthetic activity, and better antioxidant defense mechanism. Therefore, this hybrid could be recommended for cultivation in drought-prone areas.

Abscisic-Acid-Modulated Stomatal Conductance Governs High-Temperature Stress Tolerance in Rice Accessions

Rising air temperature is a major constraint for crop productivity under the current climate change scenario. Rice crops are known to be sensitive to high-temperature (HT) stress at anthesis and post-anthesis stages. Photosynthesis is an important metabolic process and is affected by HT stress. A pot study was planned to screen a set of seventy-three Indian rice accessions based upon changes in the rate of photosynthesis (Pn) and related gas exchange traits under HT, and to characterize the contrasting rice accessions for component traits of HT stress tolerance. All accessions were raised under ambient temperature (AT) until the booting stage and exposed to HT using controlled chambers at anthesis and post-anthesis. HT exposure led to a large reduction (up to 50%) in Pn, but stomatal conductance (gs) and the rate of transpiration (E) increased significantly across the rice accessions. Based on the photosynthetic response under HT, two contrasting rice accessions (IRGC 135883, tolerant, and IRGC 127222, sensitive) were selected and characterized for HT tolerance, along with an NL-44 check. Among them, Pn decreased marginally but gs and E showed significant increases under HT in the tolerant accession, while sensitive accession showed an up to 50% reduction in Pn and marginal increase in gs and E. No significant changes were recorded for chlorophyll fluorescence (Fv/Fm) in both the genotypes, but tissue temperature depression (TTD) was higher in IRGC 135883 accession under HT. Endogenous abscisic acid (ABA) content increased under HT in the flag leaf of both the accessions, and the highest increase was observed in the sensitive accession. Similarly, spikelet fertility and grain yield showed large reductions in sensitive rice accession under HT. A large increase in ABA concentration in the leaves of the sensitive rice accession might be affecting its gs and cooling capacity under an HT environment. Finally, the study concludes that tolerant rice accessions can be recommended as donors and exploited in future rice breeding programs for developing climate-resilient rice genotypes.

Management of spot blotch of barley through different dates of sowing and chemical and organic amendments

Spot blotch caused by Bipolaris sorokiniana is one of the most serious diseases of barley in tropical areas where barley and wheat are grown. A field experiment was conducted at Regional Research Station Masodha, ANDUA&T, Kumarganj, Ayodhya, Uttar Pradesh during Rabi season. To evaluate the effect of different dates of sowing and chemical and organic amendments on spot blotch and consequently on seed quality of barley. The experiment was conducted during the Rabi season 2016-17 under hotspot area of spot blotch. RD-2794 was sown in a split plot manner with two dates of sowing.The experiment was performed in split plot design with three replications comprising two different dates of sowing, i.e. mid- November (D1 ) and mid-December (D2 ) in the main plot and chemical and organic amendments viz., RDF (60N:30P:20K kg/ hectare) -T1 , FYM @ 5 t/h-T2 , T1 + Mulch@ 6 t/h-T3 , T1 + FYM @ 5t/hec + Mulch @ 6t/ hec.-T4 , T4 + 2 spray of zinc sulphate @ 0.5 %-T5 , T4 + 2 spray of KCl @0.5%-T6 and T5 + 2 spray of KCl @ 0.5 %-T7 in the sub plot. Results revealed that minimum disease severity (46.9%) with maximum disease control (39.98%) and per cent seed infection (5.5%) were recorded in D1 × T7 . The interpretation of data revealed that there was highly positive and significant correlation (r=0.95) between disease severity and per cent seed infection. The maximum 1000-seed weight (43.41g) and yield (38.67 q/ha) with maximum yield gain (57.25%) was also recorded in D1 × T7 . The same treatment combination was also useful in maximizing the seed quality in terms of seed viability (98%), Germination (97%), seedling length (27.30cm) and vigour index-I (2648.153) when the freshly harvested seeds were tested in seed testing laboratory. Spot blotch is a serious disease of barley spreads primarily through infected seeds and reduced the yield up to 30%. The disease can be minimized by sowing the crop timely i.e. mid-November with recommended dose of fertilizers + FYM @ 5 t/ha+ Mulch@ 6 t/ha+ 2 spray of zinc sulphate @ 0.5 % + 2 spray of KCl @ 0.5 % at flag leaf and post anthesis stage which improves the seed quality.

A Semi-Empirical Model of Winter Wheat Grain Protein Content

Winter wheat grain protein content (GPC) is an important criterion for assessing grain quality. A timely and simple GPC model is urgently required for GPC prediction ahead of maturity. The GPC model included regressional models of dry matter and N accumulation and translocation for anthesis and post-anthesis stages, and incorporated both soil nitrogen (N) supply and meterological factors based on historical as well as current season data, final GPC were calculated as the ratio of N accumulation to dry matter in grain at maturity. This study conducted six field experiments during the 2003–2006 and 2008–2011 growing seasons to establish and validate the model. A three-way factorial arrangement of N fertilization, sowing date, and cultivar was conducted using a split-plot design. Critical growth parameters were determined by field measurements, and historical seasonal meteorological data covering the growing period were collected.

Improving the effects of drought priming against post-anthesis drought stress in wheat (Triticum aestivum L.) using nitrogen.

Water and nitrogen (N) deficiencies are the major limitations to crop production, particularly when they occur simultaneously. By supporting metabolism, even when tissue water capacity is lower, nitrogen and priming may reduce drought pressure on plants. Therefore, the current study investigates the impact of nitrogen and priming on wheat to minimize post-anthesis drought stress. Plant morphology, physiology, and biochemical changes were observed before, during, and after stress at the post-anthesis stage. The plants were exposed to three water levels, i.e., well watering (WW), water deficit (WD), and priming at jointing and water deficit (PJWD) at the post-anthesis stage, and two different nitrogen levels, i.e., N180 (N1) and N300 (N2). Nitrogen was applied in three splits, namely, sowing, jointing, and booting stages. The results showed that the photosynthesis of plants with N1 was significantly reduced under drought stress. Moreover, drought stress affected chlorophyll (Chl) fluorescence and water-related parameters (osmotic potential, leaf water potential, and relative water content), grain filling duration (GFD), and grain yield. In contrast, PJWD couple with high nitrogen treatment (N300 kg ha–1) induced the antioxidant activity of peroxidase (37.5%), superoxide dismutase (29.64%), and catalase (65.66%) in flag leaves, whereas the levels of hydrogen peroxide (H2O2) and superoxide anion radical (O2–) declined by 58.56 and 66.64%, respectively. However, during the drought period, the primed plants under high nitrogen treatment (N300 kg ha–1) maintained higher Chl content, leaf water potential, and lowered lipid peroxidation (61%) (related to higher activities of ascorbate peroxidase and superoxide dismutase). Plants under high nitrogen treatment (N300 kg ha–1) showed deferred senescence, improved GFD, and grain yield. Consequently, the research showed that high nitrogen dose (N300 kg ha–1) played a synergistic role in enhancing the drought tolerance effects of priming under post-anthesis drought stress in wheat.

Post-Anthesis Heat Influences Grain Yield, Physical and Nutritional Quality in Wheat: A Review

Climate change threatens to impact wheat productivity, quality and global food security. Maintaining crop productivity under abiotic stresses such as high temperature is therefore imperative to managing the nutritional needs of a growing global population. The article covers the current knowledge on the impact of post-anthesis heat on grain yield and quality of wheat crops. The objectives of the current article were to review (1) the effect of post-anthesis heat stress events (above 30.0 °C) on wheat grain yield, (2) the effect of heat stress on both the physical and chemical quality of wheat grain during grain development, (3) identify wheat cultivars that display resilience to heat stress and (4) address gaps within the literature and provide a direction for future research. Heat stress events at the post-anthesis stage impacted wheat grain yield mostly at the grain filling stage, whilst the effect on physical and chemical quality was varied. The overall effect of post-anthesis heat on wheat yield and quality was genotype-specific. Additionally, heat tolerance mechanisms were identified that may explain variations in yield and quality data obtained between studies.

The prokaryotic and fungal communities of oat rhizosphere responded contrastingly to different irrigation regimes at pre- and post-anthesis stages

The transition from the vegetative stage to reproductive stage of plants and variations in soil water regimes can alter the community feedbacks of rhizosphere microbiomes by affecting the partitioning of photosynthates to roots. However, little is known about how different rhizosphere microbiota respond to the growth stages of drought-resistant crops under different irrigation regimes. To address these issues, we investigated the effects of irrigation regimes on the rhizosphere prokaryotic and fungal communities at the pre- and post-anthesis stages of oats in a semi-arid region of northeastern China. The prokaryotic and fungal community traits of the oat rhizosphere were characterized by Illumina high-throughput sequencing. The results revealed that the prokaryotic diversity was primarily regulated by oat growth stage, while the fungal diversity was mainly increased by irrigation regimes. Similarly, all prokaryotic phyla responded significantly to oat growth stages rather than irrigation regimes, while the composition of the fungal taxa was largely regulated by irrigation regimes. Approximately 2–3-fold higher proportions of the predominating pathogenic Fusarium genus were identified under dryland farming conditions than under irrigation treatment. In addition, functional predictions suggested that the contrasting responsive traits of prokaryotes and fungi were attributed to their functional guilds, which were related to oat growth stages and soil water conditions. However, the properties of the prokaryotic networks mainly responded to irrigation regimes while the fungal networks were regulated by oat growth, implying distinct determination mechanisms for microbial diversity and community stability. Our results indicate that rhizosphere prokaryotic and fungal communities differentially responded to oat growth stages and soil water history, highlighting the significance of irrigation in manipulating rhizosphere microbes in semi-arid regions.

Effects of wide range sowing on grain yield, quality, and nitrogen use of strong gluten wheat

<p id="C3">It is well known that wide range sowing can simultaneously improve grain yield (GY) and nitrogen use efficiency (NUE). However, the effects of wide range sowing on grain quality have not been investigated while GY and NUE increased. In the present study, four winter wheat cultivars (Gaoyou 5766, Jimai 44, Taishan 27, and Zhouyuan 9369) were used as experimental materials and two sowing patterns (the wide range sowing and conventional drilling sowing) were designed during 2018-2019 and 2019-2020 growing seasons. Also, we investigated the effects of wide range sowing on GY, NUE, and grain quality. Under wide range sowing, grain number on unit land area were increased by an average of 13.16% across cultivars and growth seasons mainly due to the increase of spike number on unit land area, and in turn GY increased by an average of 13.39%. Meanwhile, nitrogen (N) uptake during whole growth season especially at post-anthesis stage were enhanced. The N accumulation during whole growth season increased by an average of 10.29% while that increased by an average of 36.83% at post-anthesis stage. Consequently, N uptake efficiency and NUE increased by 12.73% and 13.39%, respectively. Enhanced N uptake resulted in a sufficient N supply for grain and a significant increase in grain N accumulation on unit land area. A similar increase magnitude was observed between grain N accumulation (on average 13.38%), grain number (13.16%), and GY (13.39%). As a result, total quantity of N per grain and grain protein concentration remained unchanged, which led to a stable grain protein composition and grain quality. Conclusively, wide range sowing can maintain good grain quality with increased GY and NUE by optimizing coupling of GY formation process with the process of N uptake and translocation.

Inter-auricular distance: A morphological biomarker for ethylene production in the boot and coincidental grain loss of rice plant

Inter-auricular distance (IAD) has been often used for physical calibration of defects in panicle emergence of rice plants induced by stress-prone environments or cytoplasmic male sterility genetic factors slackening male gametogenesis. Information is scant on the physiological relationship inherent between IAD, panicle enclosure, and spikelet filling despite the wide phenotypic diversity of rice cultural types. In the present study, IAD extension and grain filling pattern in the panicle of the main shoot of rice cultivars contrasting for spikelet sterility were assessed concerning physiological factors like assimilate homeostasis, ethylene evolution, and expression of ethylene signal transducers genes at the anthesis stage of development. The panicle retention time was longer and the concentration and expression of ethylene and its transducer protein genes respectively, were higher in high sterile cultivars compared to low sterile ones. Spikelets subjected to a high concentration of ethylene for a longer time interval filled poorly because of infringement of starch synthesis in the post-anthesis stage of development. Alternatively, faster release of panicle by enhanced IAD extension shortened the exposure time and marginalized inhibitory effects of ethylene on grain filling. Rapid IAD extension and attenuation of boot ethylene production could be beneficial for male gametogenesis and grain filling.