Triticum Aestivum Research Articles

Source-sink relationships during grain filling in wheat in response to various temperature, water deficit and nitrogen deficit regimes.

Grain filling is a critical process for improving crop production under adverse conditions caused by climate change. Here, using a quantitative method, we quantified post-anthesis source-sink relationships of a large data set to assess the contribution of remobilized pre-anthesis assimilates to grain growth for both biomass and nitrogen. The data set came from 13 years' semi-controlled field experimentation, in which six bread wheat genotypes were grown at plot scale under contrasting temperature, water, and nitrogen regimes. On average, grain biomass was ~10% higher than post-anthesis aboveground biomass accumulation across regimes and genotypes. Overall, the estimated relative contribution (%) of remobilized assimilates to grain biomass became increasingly significant with increasing stress intensity, ranging from virtually nil to 100%. This percentage was altered more by water and nitrogen regimes than by temperature, indicating the greater impact of water or nitrogen regimes relative to high temperatures under our experimental conditions. Relationships between grain nitrogen demand and post-anthesis nitrogen uptake were generally insensitive to environmental conditions, as there was always significant remobilization of nitrogen from vegetative organs, which helped to stabilize the amount of grain nitrogen. Moreover, variations in the relative contribution of remobilized assimilates with environmental variables were genotype-dependent. Our analysis provides an overall picture of post-anthesis source-sink relationships and pre-anthesis assimilate contributions to grain filling across (non-)environmental factors, and highlights that designing wheat adaption to climate change should account for complex multi-factor interactions.

Nitrogen deficiency tolerance conferred by introgression of a QTL derived from wild emmer into bread wheat

Key messageGenetic dissection of a QTL from wild emmer wheat, QGpc.huj.uh-5B.2, introgressed into bread wheat, identified candidate genes associated with tolerance to nitrogen deficiency, and potentially useful for improving nitrogen-use efficiency.Nitrogen (N) is an important macronutrient critical to wheat growth and development; its deficiency is one of the main factors causing reductions in grain yield and quality. N availability is significantly affected by drought or flooding, that are dependent on additional factors including soil type or duration and severity of stress. In a previous study, we identified a high grain protein content QTL (QGpc.huj.uh-5B.2) derived from the 5B chromosome of wild emmer wheat, that showed a higher proportion of explained variation under water-stress conditions. We hypothesized that this QTL is associated with tolerance to N deficiency as a possible mechanism underlying the higher effect under stress. To validate this hypothesis, we introgressed the QTL into the elite bread wheat var. Ruta, and showed that under N-deficient field conditions the introgression IL99 had a 33% increase in GPC (p < 0.05) compared to the recipient parent. Furthermore, evaluation of IL99 response to severe N deficiency (10% N) for 14 days, applied using a semi-hydroponic system under controlled conditions, confirmed its tolerance to N deficiency. Fine-mapping of the QTL resulted in 26 homozygous near-isogenic lines (BC4F5) segregating to N-deficiency tolerance. The QTL was delimited from − 28.28 to − 1.29 Mb and included 13 candidate genes, most associated with N-stress response, N transport, and abiotic stress responses. These genes may improve N-use efficiency under severely N-deficient environments. Our study demonstrates the importance of WEW as a source of novel candidate genes for sustainable improvement in tolerance to N deficiency in wheat.

First report of two Pantoea species causing bacterial leaf blight on wheat in the United States.

Wheat (Triticum aestivum) is an important crop worldwide, contributing to about one third of the global caloric intake. In June 2021, leaves with bacterial blight symptoms, including yellow and necrotic lesions running parallel to veins, were found in several fields across five counties in eastern Colorado (Weld, Morgan, Sedgwick, Baca, and Kit Carson). Plants exhibiting these symptoms were scattered throughout fields, but symptoms appeared consistent across counties. To determine the causal agent and complete Koch's postulates, a 1 cm2 symptomatic leaf area was excised and macerated in 0.5 mL of sterilized water from four field samples. The lysate was spread on yeast extract dextrose calcium carbonate medium (YDC agar, 1% yeast extract, 2% dextrose, 2% calcium carbonate, 1.5% agar) to isolate bacteria. Single colonies of yellow, mucoid morphology were selected and streaked on new YDC plates. Isolate genomic DNA was extracted (Zymo Research Quick-DNA Fungal/Bacterial Miniprep Kit, #D6005), and ~30 ng of gDNA was used to amplify the 16S rRNA, gyrB, and rpoB genes of all four isolates (Barret et al., 2015; Delétoile et al., 2009; Krawczyk et al., 2020; Ogier et al., 2019). Amplified PCR products were cleaned (Zymo DNA Clean & Concentrator kit, #D4033) and Sanger sequenced, and all sequences have been deposited in NCBI (16S rRNA: OR707336, OR707337, OR707338, OR707339), (gyrB: PP407951, PP407952, PP407953, PP407954), (rpoB: PP407955, PP407956, PP407957, PP407958). A BLAST search against whole genomes identified one isolate from Kit Carson county (CO314) and two isolates from Baca county (CO316 and CO317) as Pantoea agglomerans with 100% identity for the 16S rRNA, gyrB, and rpoB genes, and one isolate from Weld county (CO315) was 100% identical to Pantoea allii for all three genes. To complete Koch's postulates and confirm Pantoea sp. as the causal disease agents, isolates were grown as lawns on DifcoTM Nutrient Agar (NA) medium (48h, 28℃), suspended in 10 mM MgCl2 using a final optical density of 0.1 (~109 colony forming units per milliliter (CFU/mL)), and syringe-infiltrated into the entire leaf area of 10-day-old wheat seedling leaves (var. Hatcher). Treatments of 10mM MgCl2 and a field isolate that does not cause symptoms, identified as Pseudomonas synxantha by 16S rRNA and gyrB sequencing, were negative controls. Inoculated wheat plants were transferred to a growth chamber (22℃, 90% relative humidity). Symptoms developed 14 days post inoculation (dpi), with the most severe appearing 21 dpi. Each of the four Pantoea isolates were re-isolated from symptomatic leaves by grinding them in a Tissue Lyser II (Qiagen) with two metal beads and diluting with 0.4 mL of sterile water. A 20 µL sample of each isolate was plated on NA (24h, 28℃). The colonies appeared phenotypically identical to the original isolates, and Sanger sequencing confirmed the identities of the isolates. To our knowledge, this is the first report of P. agglomerans causing disease in wheat in the United States, and the first report of P. allii as a wheat disease-causing agent. This report is consistent with previous communications showing P. agglomerans causing wheat disease in China (Gao et al., 2023), and P. ananatis in Poland (Krawczyk et al., 2020). The growing numbers of reports of Pantoea spp. as pathogens in recent years suggests increasing novel disease emergence on cereals worldwide.

Occurrence of Fusarium Crown Rot Caused by Fusarium culmorum on Winter Wheat in Xinjiang Uygur Autonomous Region, China.

Wheat (Triticum aestivum L.) is the predominant grain crop and plays a pivotal role in grain production in Xinjiang Uygur Autonomous Region (XUAR), China. Its cultivated area constitutes approximately half of the total sown area of grain crops in XUAR, with 1.14 million hectares in 2021. Fusarium crown rot (FCR) of wheat, caused by Fusarium culmorum (W.G. Smith) Sacc., is one of the most devastating soil-borne diseases known to seriously reduce grain yield (Ma et al. 2024; Saad et al. 2023). In 2016, FCR of wheat, caused by F. culmorum, was firstly identified in Henan Province, China (Li et al. 2016). In June 2023, during the investigation of FCR of wheat in Aksu Prefecture, XUAR, FCR on winter wheat (cv. Xindong 20) was found (82.761349°E, 41.612202°N). The grain-filling period for winter wheat in early June coincided with a period of high temperatures and water demand in Aksu Prefecture. Approximately 8% of the Xindong 20 wheat plants exhibited symptoms of white heads and browning at the stem base, with the disease present in 82% of the wheat fields surveyed. To identify the pathogens, 20 samples of diseased stem basal tissue, each 0.5 cm in length, were collected and sterilized with 75% alcohol for 30s and 5% NaOCl solution for 2 min, followed by three rinses with sterile water. These samples were then plated onto potato dextrose agar (PDA) medium at 25°C for 5 days. A total of 17 isolates with consistent morphological characteristics were obtained using single-spore technique, with an isolation rate of 85%. The isolated strains exhibited rapid growth on PDA, producing fluffy, pale-yellow hyphae, and accumulating a pale-yellow to dark red pigment on the bottom of the medium. On carnation leaf agar (CLA), these strains formed orange colonies due to the aggregation of a large number of macroconidia. The macroconidia were short and thick, with three to four septa and rounded apical cell, averaging 31.94 to 40.96 × 5.62 to 6.71 μm (Magnification of ×400). Microconidia were not observed. These morphological characters were consistent with those of F. culmorum (Leslie and Summerell. 2006). Two isolates (D-9 and D-11) were selected for molecular identification. The EF-1α gene fragment was amplified using primers EF1/EF2 (5'-ATGGGTAAGGARGACAAGAC-3'/5'-GGARGTACCAGTSATCATG-3') as previously described by O'Donnell et al. (1998). The two 665 bp PCR products were sequenced and submitted to GenBank (GenBank Accession No: PP763247 and PP763248) with 99. 7% identity to the published F. culmorum sequences (e.g., OP985478, OP985477, MG195126, KX702638). The molecular identification was further confirmed by F. culmorum species-specific PCR primers FcOIF/FcOIR (Nicholson et al. 1998). The expected PCR products of 553 bp were produced only in F. culmorum. Strains D-9 and D-11 were used to conduct the pathogenicity experiment on 7-day-old winter wheat (cv. Xindong 20) using drip in the lower stem inoculation method with a 10-μl of 106 macroconidia ml-1 suspension, and the control 7-day-old winter wheat were treated with sterile water (Xu et al. 2017). The experiments were replicated five times in a greenhouse at temperatures ranging from 20℃ to 25℃. After 4 weeks, all inoculated wheat seedlings showed stem base browning or even death. No symptoms were observed on the control plants. The fungus was reisolated from all inoculated wheat plants by the method described above and identified by morphological and PCR amplification using F. culmorum species-specific primers FcOIF/FcOIR. No F. culmorum was isolated from the control wheat plants, fulfilling Koch's postulates. To the best of our knowledge, this is the first report of F.culmorum causing FCR on winter wheat in XUAR, China. Considering wheat is the predominant grain crop and plays a pivotal role in grain production in China, necessary measures should be taken to prevent the spread of F. culmorum to other regions.

Comprehensive analysis of Alfin-like transcription factors associated with drought and salt stresses in wheat (Triticum aestivum L.)

BackgroundAlfin-like proteins are a kind of plant-specific transcription factors, and play vital roles in plant growth, development and stress responses.ResultsIn this study, a total of 27 Alfin-like transcription factors were identified in wheat. TaAL genes were unevenly distributed on chromosome. Phylogenetic analysis showed TaAL genes were divided into AL-B and AL-C subfamilies, and TaALs with closer evolutionary relationships generally shared more similar exon-intron structures and conserved motifs. The cis-acting element analysis showed MBS, ABRE and CGTCA-motif were the most common in TaAL promoters. The interacting proteins and downstream target genes of TaAL genes were also investigated in wheat. The transcriptome data and real-time PCR results indicated TaAL genes were differentially expressed under drought and salt stresses, and TaAL1-B was significantly up-regulated in response to drought stress. In addition, association analysis revealed that TaAL1-B-Hap-I allelic variation had significantly higher survival rate compared to TaAL1-B-Hap-II under drought stress.ConclusionsThese results will provide vital information to increase our understanding of the Alfin-like gene family in wheat, and help us in breeding better wheat varieties in the future.

Identification of effector genes of &lt;i&gt;Parastagonospora nodorum&lt;/i&gt;, &lt;i&gt;P. pseudonodorum&lt;/i&gt; in Tambov populations and sensitivity genes to NEs in varieties and hybrid lines of spring soft wheat

BACKGROUND: Parastagonospora nodorum and P. pseudonodorum are known for their ability to produce necrotrophic effectors that play an important role in micromycete pathogenicity. Fungal strains characterized by the presence of effector genes will be used to create artificial infectious backgrounds to identify sources and donors of resistance to fungal diseases. Selected varieties and lines that are donors of recessive alleles snn1 and snn3, which control plant resistance to fungal toxins PtrTox1 and PtrTox3, are recommended for inclusion in programs for breeding wheat for resistance to septoriosis pathogens. AIM: The aim of the work is to assess the populations of the fungi Parastagonospora nodorum and P. pseudonodorum in 2023 based on the presence of effector genes, as well as to identify alleles of Snn1/snn1, Snn3/snn3 genes that control the sensitivity or resistance of wheat to PtrTox1 and PtrTox3 toxins. MATERIALS AND METHODS: Infectious samples were collected in 2023 from spring wheat leaves. In addition, the material for the study was 2 varieties and 23 lines of spring soft wheat of local selection. Using the molecular markers Xfcp624 and Xcfd20, the presence of the Snn1 and Snn3-B1 alleles, which control sensitivity to the fungal toxins PtrTox1 and PtrTox3, was detected. RESULTS: Using molecular screening, ToxA and Tox1 genes were identified in genotypes of P. pseudonodorum isolates; Tox3 and Tox267 in P. nodorum isolates. 2 varieties of spring soft wheat and 11 hybrid lines carry a recessive allele snn1, which protects against the phytopathogen toxin PtrTox1; wheat variety Tambovchanka and 2 hybrid lines carry the recessive allele snn3 on chromosome B1, which confers resistance to the fungal toxin PtrTox3. CONCLUSIONS: The ToxA gene was found only among monoconidial isolates of P. pseudonodorum species obtained from leaves of spring soft wheat of Lebedushka variety. As a result of molecular screening, the Tox1 gene was identified among 70 P. pseudonodorum isolates (43,21% of those studied). The presence of the Tox3 and Tox267 genes was established in 30 isolates of P. nodorum species obtained from plant samples of spring durum wheat Donskaya Elegiya. Using the PCR method, donors of the snn1 and snn3 genes were identified.

Discovering novel genomic regions explaining adaptation of bread wheat to conservation agriculture through GWAS

To sustainably increase wheat yield to meet the growing world population’s food demand in the face of climate change, Conservation Agriculture (CA) is a promising approach. Still, there is a lack of genomic studies investigating the genetic basis of crop adaptation to CA. To dissect the genetic architecture of 19 morpho-physiological traits that could be involved in the enhanced adaptation and performance of genotypes under CA, we performed GWAS to identify MTAs under four contrasting production regimes viz., conventional tillage timely sown (CTTS), conservation agriculture timely sown (CATS), conventional tillage late sown (CTLS) and conservation agriculture late sown (CALS) using an association panel of 183 advanced wheat breeding lines along with 5 checks. Traits like Phi2 (Quantum yield of photosystem II; CATS:0.37, CALS: 0.31), RC (Relative chlorophyll content; CATS:55.51, CALS: 54.47) and PS1 (Active photosystem I centers; CATS:2.45, CALS: 2.23) have higher mean values in CA compared to CT under both sowing times. GWAS identified 80 MTAs for the studied traits across four production environments. The phenotypic variation explained (PVE) by these QTNs ranged from 2.15 to 40.22%. Gene annotation provided highly informative SNPs associated with Phi2, NPQ (Quantum yield of non-photochemical quenching), PS1, and RC which were linked with genes that play crucial roles in the physiological adaptation under both CA and CT. A highly significant SNP AX94651261 (9.43% PVE) was identified to be associated with Phi2, while two SNP markers AX94730536 (30.90% PVE) and AX94683305 (16.99% PVE) were associated with NPQ. Identified QTNs upon validation can be used in marker-assisted breeding programs to develop CA adaptive genotypes.

Induced genetic diversity through mutagenesis in wheat gene pool and significant use of SCoT markers to underpin key agronomic traits

BackgroundThis research explores the efficacy of mutagenesis, specifically using sodium azide (SA) and hydrazine hydrate (HZ) treatments, to introduce genetic diversity and enhance traits in three wheat (Triticum aestivum L.) genotypes. The experiment entails subjecting the seeds to different doses of SA and HZ and cultivating them in the field for two consecutive generations: M1 (first generation) and M2 (second generation). We then employed selective breeding techniques with Start Codon Targeted (SCoT) markers to select traits within the wheat gene pool. Also, the correlation between SCoT markers and specific agronomic traits provides insights into the genetic mechanisms underlying mutagenesis-induced changes in wheat.ResultsIn the study, eleven genotypes were derived from parent varieties Sids1, Sids12, and Giza 168, and eight mutant genotypes were selected from the M1 generation and further cultivated to establish the M2 generation. The results revealed that various morphological and agronomical characteristics, such as plant height, spikes per plant, spike length, spikelet per spike, grains per spikelet, and 100-grain weight, showed increases in different genotypes from M1 to M2. SCoT markers were employed to assess genetic diversity among the eleven genotypes. The bioinformatics analysis identified a correlation between SCoT markers and the transcription factors ABSCISIC ACID INSENSITIVE3 (ABI3) and VIVIPAROUS1 (VP1), crucial for plant development, growth, and stress adaptation. A comprehensive examination of genetic distance and the function identification of gene-associated SCoT markers may provide valuable insights into the mechanisms by which SA and HZ act as mutagens, enhancing wheat agronomic qualities.ConclusionsThis study demonstrates the effective use of SA and HZ treatments to induce gene diversity through mutagenesis in the wheat gene pool, resulting in the enhancement of agronomic traits, as revealed by SCoT markers. The significant improvements in morphological and agronomical characteristics highlight the potential of mutagenesis techniques for crop improvement. These findings offer valuable information for breeders to develop effective breeding programs to enhance wheat quality and resilience through increased genetic diversity.

Once in Three-Year Deep-Banding and Annual Shallow-Banding of P, K and Cu Fertilizer Effects on Crops and Soil Nutrients

Deep-banding of the immobile nutrients (P, K, and Cu) is considered one technique that may improve crop production under temperate dryland systems, where moister soil conditions prevail at seeding followed by relatively drier soil during the growing period. The objectives were to compare growth and yield of canola (Brassica napus L.), field pea&amp;rsquo;s (Pisum sativum L.) and wheat (Triticum aestivum L.); and nutrient concentrations in crops and soil from once in three-year deep-banding (12.5-15 cm) and annual shallow-banding (3.75 to 5 cm diagonally deeper than seeding depth) of P, K and Cu under direct seeding systems. Small plot trials were conducted at the three sites; representing Brown (Dark Brown Chernozem), Black (Black Chernozem), and Grey (Dark Grey Luvisol) soil zones in Alberta, Canada; which represent crop growing conditions for most areas of western Canada. The nine treatments were annual shallow-banding and once in three year deep-banding of P, K, Cu and PKCU nutrients plus a control (no P, K, or Cu fertilizer). Applied thrice the recommended rate for deep-banding (in 2018) treatments and the recommended rate for the annual shallow-banding treatments in 2018, 2019 and 2020. All three phases of pea&amp;rsquo;s-wheat-canola rotation were grown at each site to generate nine years of data for each crop. The density, height, NDVI (normalized difference vegetation index) and biomass of plants, yield for crops and nutrient concentrations in seed and biomass of crops and soil showed significantly positive responses to P, K, and PKCu additions in some cases; generally not linked to the deep or shallow placement of tested nutrients. Changes in nutrient concentrations in seed and biomass of crops in response to nutrient additions were not consistent. Treatments with P showed response more often than with the K and Cu. The soil P and Cu concentrations increased in response to their additions in some cases, but no change was observed from the K addition. Once in three-year deep-banding or annual shallow-banding methods were equally effective. The findings provide another option (once in three year deep-banding) for applying the P, K and Cu fertilizers.

The Psathyrostachys juncea DWARF27 gene encodes an all-trans-/9-cis-beta-carotene isomerase in the control of plant branches in Arabidopsis thaliana by strigolactones.

Strigolactones(SLs), carotenoid-derived plant hormones, govern the growth and development of both monocotyledonous and dicotyledonous plants. DWARF27 (D27), a plastid-targeted protein located at the initiation site of the core pathway in SL synthesis, plays a crucial role in regulating plant tillering (branching). In rice (Oryza sativa) and wheat (Triticum aestivum), OsD27 and TaD27-B proteins modulate the number of plant tillers by participating in SL biosynthesis. Similarly, AtD27 in Arabidopsis thaliana is required for SL production and has a significant impact on phenotypic changes related to branching. At the same time, TaD27 in wheat has been confirmed as a functional ortholog of AtD27 in Arabidopsis, and both P. juncea and wheat belong to the Triticeae, so we speculate that PjD27 gene may also have the same function as AtD27 in Arabidopsis. In this study, we initially screened the PjD27 gene significantly associated with tillering regulation through transcriptome data analysis and subsequently validated its expression levels using qRT-PCR analysis. Furthermore, we conducted phylogenetic analysis using amino acid sequences from 41 species, including P. juncea, to identify closely related species of P. juncea. Here, we analyze the conservation of D27 protein among P. juncea, rice, wheat, and Arabidopsis and provide preliminary evidence suggesting that PjD27 protein is an ortholog of D27 protein in Arabidopsis. Through reverse genetics, we demonstrate the crucial role of PjD27 in regulating plant branching, establishing it as a functional ortholog of D27 in Arabidopsis. Furthermore, following transient expression in tobacco (Nicotiana tabacum), we demonstrate that the subcellular location of the PjD27 protein is consistent with the cellular location of TaD27-B in wheat. Quantitative analysis of SLs shows that PjD27 is a key gene regulating tillering (branching) by participating in SLs biosynthesis. By elucidating the function of the PjD27 gene, our findings provide valuable genetic resources for new germplasm creation and improving grain yield in P. juncea.

Winter wheat source‐sink relationships under various planting modes, complementary irrigation, and planting densities

AbstractVarious agronomic practices can affect the processes of aboveground dry matter accumulation (source) and grain filling (sink), resulting in yield differences. Improved source‐sink relationships can facilitate the production and accumulation of assimilates to increase the productivity of winter wheat (Triticum aestivum L.). A two‐season field experiment was undertaken on winter wheat during 2020–2021 and 2021–2022. In a split‐split‐plot design with three replicates (randomized blocks), we compared two planting modes (ridge‐furrow planting with plastic mulching [RFPM]; traditional flat planting [TF]), two complementary irrigation levels (I30+30: 30+30 mm; I0: no irrigation), and three planting densities (D1, D2, and D3: 240, 360, and 480 plants m−2). The results showed that RFPMI30+30 significantly increased maximum yield by 28.5% compared with TFI0. Although D3 increased the number of effective spikes per unit area and duration of grain filling compared to D2, it reduced the number of grains per spike, 1000‐grain weight, and average filling rate. Compared to TF and I0, RFPM and I30+30 improved the sink/source ratio by 5.3% and 6.5%, respectively. Grain yield peaked at D2 in the RFPM and at D3 in the TF. Medium planting density (D2) and complementary irrigation (I30+30) during the wintering and reviving periods under RFPM can achieve better source‐sink balance relationships and the maximum grain yield of winter wheat. Overall, we believe that in most cases, wheat yields are source‐limited and can be improved by ridge‐furrow planting with plastic mulching, complementary irrigation, and planting density regulation.

Soil Microbial Community Structures under Annual and Perennial Crops Treated with Different Nitrogen Fertilization Rates

Perennial bioenergy crops may enhance microbial community structures due to their extensive root system compared to annual crops. However, the long-term effect of perennial bioenergy crops receiving different N fertilization rates on microbial community structures is not well defined. We evaluated the 11-year effect of perennial bioenergy crops with various N fertilization rates as well as an annual crop with the recommended N rate on soil microbial properties in 2019 and 2020 in the US northern Great Plains. Perennial grasses were intermediate wheatgrass, IWG (Thinopyrum intermedium [Host] Barkworth and Dewey), and switchgrass, SG (Panicum virgatum L.), with N fertilization rates of 0, 28, 56, and 84 kg N ha−1, and the annual crop was spring wheat, WH (Triticum aestivum, L.) with 80 kg N ha−1. The total fungal phospholipid fatty acid (PLFA) proportion and fungal/bacterial ratio were significantly lower under annual spring wheat than perennial grass (SG). Increased N fertilization rate linearly increased Gram-positive bacterial PLFA proportions and the Gram-positive/Gram-negative bacterial ratio for IWG in 2020 but decreased the PLFA proportions of arbuscular mycorrhizal fungi (AMF) for both perennial bioenergy crops in all years. The proportions of AMF neutral lipid fatty acid and Gram-negative bacterial PLFA were greater for SG (0.432 and 0.271, respectively) than IWG (0.339 and 0.258, respectively), but actinomycetes and the Gram-positive/Gram-negative bacterial ratio were greater for IWG (0.160 and 1.532, respectively) compared to SG (0.152 and 1.437, respectively). Microbial community structures varied with perennial bioenergy crops, N fertilization rates, and perennial vs. annual crops. This study showed how perennial crops favored fungal growth and how annual crops enhanced bacterial growth impacting soil biological health.

Spring wheat nitrogen-use indicators responses to cropping sequence and nitrogen fertilization

ABSTRACT Spring wheat (Triticum aestivum L.) nitrogen-use efficiency (NUE) and recovery with nitrogen (N) fertilization rates in crop rotations need further exploration. The effect of cropping sequence and N fertilization rate were evaluated on spring wheat N concentration and uptake, N harvest index (NHI), N-use efficiency (NUE), and N recovery index (NRI) from 2012 to 2019 in the northern Great Plains, USA. Cropping sequences were conventional till spring wheat-fallow (CTWF), no-till spring wheat-fallow (NTWF), no-till spring wheat-pea (Pisum sativum L.) (NTWP), and no-till continuous spring wheat (NTCW), and N fertilization rates to spring wheat were 0, 50, 100, and 150 kg N ha−1. Straw N concentration and N uptake were greater for CTWF than NTWP and NTCW in 4 out of 8 years and increased with increased N fertilization rate. Grain N concentration and NHI varied with treatments and years. Grain N uptake was greater for CTWF and NTWF than NTWP and NTCW at most N fertilization rates and years. In contrast, NUE was greater for NTCW than CTWF and NTWF at all N fertilization rates in most years. The NRI was greater for NTWP or NTCW than CTWF or NTWF in most years. Increasing N fertilization rate increased grain N uptake for most cropping sequences in all years but had a variable effect on NUE and NRI. Although spring wheat N concentration and N uptake were superior for CTWF and NTWF, and NUE for NTCW, NTWP with 50 to 100 kg N ha−1 can be used to sustain grain yield, N uptake, NUE, and NRI.

Phenotypic characterization and gene mapping of hybrid necrosis in Triticum durum–Haynaldia villosa amphiploids

Key messagePhenotypical, physiological and genetic characterization was carried out on the hybrid necrosis gene from Haynaldia villosa, and the related gene Ne-V was mapped to chromosome arm 2VL.Introducing genetic variation from wild relatives into common wheat through wide crosses is a vital strategy for enriching genetic diversity and promoting wheat breeding. However, hybrid necrosis, a genetic autoimmunity syndrome, often occurs in the offspring of interspecific or intraspecific crosses, restricting both the selection of hybrid parents and the pyramiding of beneficial genes. To utilize the germplasms of Haynaldia villosa (2n = 2x = 14, VV), we conducted wide hybridization between durum wheat (2n = 4x = 28, AABB) and multiple H. villosa accessions to synthesize the amphiploids (2n = 6x = 42, AABBVV). This study revealed that 61.5% of amphiploids derived from the above crosses exhibited hybrid necrosis, with some amphiploids even dying before reaching maturity. However, the initiation time and severity of necrosis varied dramatically among the progenies, suggesting that there were multiple genetic loci or multiple alleles in the same genetic locus conferring to hybrid necrosis in H. villosa accessions. Genetic analysis was performed on the F2 and derived F2:3 populations, which were constructed between amphiploid STH59-1 with normal leaves and amphiploid STH59-2 with necrotic leaves. A semidominant hybrid necrosis-related gene, Ne-V, was mapped to an 11.8-cM genetic interval on the long arm of chromosome 2V, representing a novel genetic locus identified in Triticum-related species. In addition, the hybrid necrosis was correlated with enhanced H2O2 accumulation and cell death, and it was influenced by the temperature and light. Our findings provide a foundation for cloning the Ne-V gene and exploring its molecular mechanism.

Testing the efficacy of a newly released fungicide, Sphaerex, for control of Fusarium Head Blight in wheat

Fusarium head blight (FHB) is a destructive disease of wheat and other small-grain cereals. FHB causes reduction in crop yield due to pre-mature bleaching of spikes. Additionally, it deteriorates the crop quality due to the production of mycotoxins. An integrated management strategy is needed to effectively manage this disease. One of the most important strategies in the FHB management toolbox is chemical control. Fungicides start losing their efficacy over time due to the development of fungicide resistance in the pathogens. This necessitates the development and testing of new fungicides with multiple active ingredients or modes of action. In this 3-year study, we evaluated the effectiveness of a new fungicide with multiple active ingredients, Sphaerex (a proprietary mix of metconazole and prothioconazole) in an FHB-susceptible soft red winter wheat cultivar, Shirley in the eastern United States. Sphaerex provided significantly better control over untreated plots for FHB Incidence, FHB Severity, and DON content across all three years. The level of control of FHB and DON by Sphaerex was found to be similar to that provided by other standard FHB fungicides. The yield of the fungicide-treated plots was statistically similar to that of the untreated plots.

Association between molecular markers and resistance to bacterial blight using binary logistic analysis

The most effective strategy for managing wheat bacterial blight caused by Pseudomonas syringae pv. syringae is believed to be the use of resistant cultivars. Researching the correlation between molecular markers and stress resistance can expedite the plant breeding process. The current study aims to evaluate the response of 27 bread wheat cultivars to bacterial blight disease in order to identify resistant and susceptible cultivars and to pinpoint ISSR molecular markers associated with bacterial blight resistance genes. ISSR markers are recommended for assessing a plant's disease resistance. This experiment is focused on identifying ISSR molecular markers linked to bacterial blight resistance. After applying the bacterial solution to the leaves, we performed sampling to determine the infection percentage in the leaves at different intervals (7, 14, and 18 days after spraying). In most cultivars, the average leaf infection percentage decreased 18 days after spraying on young leaves. However, in some cultivars such as Niknegad, Darab2, and Zarin, leaf infection increased in older leaves and reached up to 100% necrosis. In our study, 12 ISSR primers generated a total of 170 bands, with 156 being polymorphic. The primers F10 and F5 showed the highest polymorphism, while the F7 primer exhibited the lowest polymorphism. Cluster analysis grouped these cultivars into four categories. The resistant group included Qods, Omid, and Atrak cultivars, while the semi-resistant and susceptible groups comprised the rest of the cultivars. Through binary logistic analysis, we identified three Super oxide dismutase-related genes that contribute to plant resistance to bacterial blight. These genes were linked to the F3, F5, and F12 primers in regions I (1500 bp), T (1000 bp), and G (850 bp), respectively. We also identified seven susceptibility-associated genes. Atrak, Omid, and Qods cultivars exhibited resistance against bacterial blight, and three genes associated with this resistance were linked to the F3, F5, and F12 primers. These markers can be used for screening or transferring tolerance to other wheat cultivars in breeding programs.

Manifestation of the Effect of Growth Heterosis in Intraspecific Hybrids of Soft Wheat

The presented article presents the results of the study of height inheritance in hybrid combinations of the first generation (F1) of bread wheat. The research was conducted in the 2019-2020 growing season at the Apsheron District Experimental Farm under irrigation conditions. In 32 combinations of hybrids of the first generation (F1), obtained as a result of reciprocal crossing of 9 local varieties («Mirbashir-128», «Azeri», «Gobustan», «Fatima», «Gyrmyzy gul-1», «Murov-2», «Askeran», «Matin» and «Onur»). Studied the height of plants in comparison with parental forms and determined the degree of true heterosis and dominance. In the studied hybrid combinations, a variety from high dominance to depression was found in the transmission of heredity. When analyzing hybrids of bread wheat of the first generation (F1) according to the inheritance of plant height, high dominance was determined in 19 combinations (59.4%), depression — in 8 combinations (25.0%), intermediate heredity - in 5 combinations (15.6% ). Positive heterosis was revealed in 19 combinations (59.4%), negative heterosis - in 13 combinations (40.6%). As a result of the research, it is possible to initially conclude that it is possible to obtain low-growing hybrids by involving in the hybridization a variety of the same height.

Maximizing wheat (Triticum aestivum) productivity through variable nutrient management practices

Field experiment was conducted during the winter (rabi) seasons of 2017–18 and 2018–19 at Indira Gandhi Krishi Vishwavidyalaya, Raipur to evaluate the effect of foliar NPK application and nutrient management practices on wheat (Triticum aestivum L.) productivity. Selected twelve treatments combinations of three nutrient levels, four timings of N application and 2 foliar sprays were tested in RBD with 3 replications. The soil of experimental field was Vertisol, being neutral (pH 7.04) in reaction, medium (0.45 %) in soil organic carbon, low in N (182 kg/ha), medium in P (16.2 kg/ha) and high in K (312 kg/ha) content. Results revealed that number of effective tillers, dry matter accumulation and yield attributing characters, viz. length of ear (cm), number of grains/ear, ear weight (g), grain yield (3.99 and 4.07 t/ha), harvest index, highest net return (` 50,350 and ` 56,694/ha) and B:C ratio (2.72 and 2.94) were significantly higher under the treatments 150% RDF (25% of N as basal + 25% at CRI + 25% tillering stage + 25% late jointing stage) + foliar spray of NPK (19:19:19) @ 5 g/l of water at 5 days after (DA) tillering and 5 DA late jointing stage as compared to others. It was at par with same fertilizer dose with or without one foliar spray at 5 days after late jointing stage during 2017–18 and 2018–19, respectively. Plots receiving 150% of recommended doses of fertilizers and two foliar sprays adjunct with 4 splits of N have accounted for higher available NPK status in the soil and elevated NPK built-up.

Effect of nano-urea and irrigation regimes on growth parameters of wheat (Triticum aestivum L.)

Wheat (Triticum aestivum L.) is a crucial cereal crop globally, serving as a staple food for a vast population. Its productivity faces challenges such as nutrient imbalance and terminal heat stress exacerbated by climate change, particularly in regions like the North-Eastern Plain Zone of India. To address these issues, a study was conducted during the rabi season of 2021–2022 in Jharkhand, India, aiming to examine the impacts of irrigation regimes and nano-urea-based nitrogen management practices on wheat. Employing a split-plot design with three replications, the experiment assessed three irrigation regimes and five nitrogen management practices. Results revealed that irrigation regimes registered non-significant effects on crop growth parameters like plant height, LAI (leaf area index), root dry weight, flag leaf area and tillers/m2 , which might be due to frequent rain up to the flowering stage during the crop growth period. Higher levels of nitrogen in commercial urea significantly increased plant height, LAI, flag leaf area, recovered root dry weight and dry matter accumulation. However, nano-urea spray at 45 DAS helped crop plants positively to increase all growth parameters more compared to nano-urea spray at 60 DAS. All growth attributes with 50% RDN+2-nano-urea spray were statistically at par with 50% RDN+1 nano-urea spray up to 40 DAS, but after the flowering stage, it was statistically similar with 100% RDN. The maximum tillers/m2 was found under 100% RDN, followed by 75% RDN+ one nano-urea spray and 50% RDN+2 nano-urea spray. Thus, 3- irrigations at CRI, flowering and milk stage and 100% RDN (120 kg N/ha) were found sufficient for enhancing the growth parameters of wheat.

Influence of microbial consortia mediated in-situ rice straw management options on yield, economics and energetics in rice-wheat cropping system

A field experiment was carried out during rainy and winter seasons of 2019–20 and 2020–21 at ICAR-IARI, New Delhi to study the effect of crop establishment methods and microbial consortia (Pusa decomposer) mediated in-situ rice straw management options on yield, economics and energetics of rice (Oryza sativa L) (cv. Pusa Basmati 1509) and wheat (Triticum aestivum L.) (cv. HD 2967). The experiment was laid out in split-plot design with three replications. The main plot consisted of two treatments viz., aerobic rice (AR) and conventional transplanted (CT) rice in wet season and seven sub-plot treatments viz. clean cultivation (removal of paddy straw), paddy straw incorporation (PSI), paddy straw mulching (PSM), PSI + Pusa decomposer (PD), PSM + PD, PSI + urea @ 20 kg/ha, PSI + PD + urea @ 10 kg/ha in dry season. In rice, results showed that grain yield (4.23 and 4.42 t/ha), net return (`69,470 and `71,682/ha) and energy output (157361 and 160950 MJ/ha) were significantly superior in CT rice than AR in main plots during both the years of experiment. However, sub-plot treatments showed a non-significant difference on these parameters. In wheat, among in-situ rice straw management options, paddy straw incorporation+ Pusa decomposer + urea @ 10 kg/ha treatment significantly resulted in higher grain yield (4.86 and 4.92 t/ha), net return (`62697 and `64801 /ha) and energy output (174951 and 176730 MJ/ha) compared to other treatments and control (clean cultivation). However, in main plots, statistically similar results were obtained with AR-wheat and CT-wheat. Thus, conventional rice transplanting resulted in significantly higher productivity and profitability over aerobic rice, however, AR consumed less energy (18.95%) and water (31.73%). Whereas, paddy straw incorporation+ Pusa decomposer + Urea @ 10 kg/ha was found effective in-situ rice management options with higher productivity and energy output compared to control.