The germination vigor of wheat seeds is an important indicator of wheat quality, which is directly related to the seed germination and spike germination of wheat. To identify the genetic loci that regulate wheat seed vigor-related traits and explore candidate genes, a natural population consisting of 163 wheat varieties (lines) from the Huang-Huai wheat region was used as experimental materials to investigate three seed vigor-related traits of germination rate, germination potential, and germination index. A genome-wide association study was conducted using a 90K SNP array. The results showed that the seed germination rate, germination potential and germination index of the tested materials showed a rich variation, and the coefficient of variation ranged from 11.81% to 25.58. A total of 196 significant SNPs were identified that were associated with the three seed vigor-related traits using the 90K SNP array. Among them, 67 SNPs can be detected simultaneously for all the three traits. Through gene expression pattern and haplotype analyses, it was speculated that TraesCS4B02G359600 and TraesCS4A02G494700 may be important genes regulating wheat seed vigor.

To reveal the characteristics changes during the in vitro regeneration of wheat immature embryos, this study used immature embryos from eight wheat varieties, including Zhoumai 18 and Zhengmai 004, as materials to induce callus formation and conduct redifferentiation culture. The structural and morphological changes during the formation of embryogenic callus, somatic embryogenesis, and organogenesis in the in vitro culture of wheat immature embryos were observed and analyzed. The results showed that the redifferentiation of embryogenic callus can be divided into three types: direct bud formation, leaf-before-bud, and mixed bud-leaf growth. The organogenesis of these three differentiation types manifested as follows: in the direct bud formation type, young leaves gradually unfolded as the buds grew; For the leaf-before-bud type, new leaves, adventitious buds, and adventitious roots emerged from the edges of young leaves or the tissue between leaves; the mixed bud-leaf type exhibited characteristics of both the former types, with multiple organs developing simultaneously. Somatic embryogenesis was divided into three stages: early embryonic development, differentiation into buds, and differentiation into organs, with somatic embryos at all three developmental stages coexisting in the same tissue. In the later growth stages, the direct bud formation type showed more uniform and consistent seedling growth compared to the other two types, and both the direct bud formation and mixed bud-leaf types were positively correlated with the differentiation rate.

An investigation on wheat disease in Jiangsu Province was carried out and the samples showed that the tip of the flag leaf expanded to the leaf base and became yellow, and the yellowing accounted for about 1/3 to 1/2 of the whole leaf, which was very similar with the symptoms induced by barley yellow dwarf viruses (BYDV). In order to detect and identify the possible virus associated with the disease, the samples were collected from eight locations in Jiangsu province. A total of 261 samples were detected with various wheat viruses using RT-PCR and 182 samples were found positive when a pair of degenerate primers for BYDV was used. The result of sequence analysis revealed that the virus shared the highest sequence identities with BYDV-PAV. The positive samples were further detected using specific primers for BYDV-PAV coat protein gene (CP) and the results showed that all samples were positive. Further phylogenetic analysis based on the sequence of BYDV-PAV CP gene revealed that the virus detected shared the highest sequence identities with the isolates from Korea. This is the first report of barley yellow dwarf virus-PAV in Wheat grown in Jiangsu province, China.

To explore the influencing factors of wheat grain nitrogen content, two wheat varieties with high grain nitrogen content (HGNC) and two wheat varieties with low grain nitrogen content (LGNC) were used as test materials. The changes in grain nitrogen content of the two types of wheats during the grain filling stage were compared, and the characteristics of nitrogen transport and distribution, as well as the differences in physiological traits such as Rubisco content and protein hydrolysis related enzyme activity in flag leaves were analyzed. The results showed that from late grain filling stage to maturity stage, the grain nitrogen content of HGNC wheat was higher than that of LGNC wheat. The nitrogen accumulation and distribution ratio of leaves and stem & sheaths of HGNC wheat were lower than those of LGNC wheat, and the nitrogen transport intensity of HGNC wheat was higher than that of LGNC wheat. At late grain filling stage, the degradation rate of Rubisco and soluble proteins in HGNC wheat was faster, and the activity of proteolytic enzymes was also more active than that in LGNC wheat. Overall, there was a significant difference in grain nitrogen content between HGNC and LGNC wheat from the late grain filling stage to maturity stage, which was influenced by nitrogen allocation and transport. At middle and late grain filling stages, the degradation intensity of Rubisco and soluble proteins in flag leaves has a negative effect on nitrogen content during wheat maturation, while enzyme activity related to protein hydrolysis has a positive effect.

To investigate the mechanism behind the synergistic improvement of yield and nitrogen use efficiency in winter wheat under appropriate nitrogen application rate, a strong gluten wheat cultivar Fengdecun 5 was used as the experimental material and three nitrogen fertilization treatments [0 kg·hm^-2 (N0), 180 kg·hm^-2 (N180) and 300 kg·hm^-2 (N300)] were set up. The study analyzed the effects of nitrogen application rate on internode morphological characteristics, vascular bundle structure, dry matter and nitrogen accumulation and translocation, as well as yield and nitrogen use efficiency in winter wheat. The results showed that nitrogen application increased internode diameter, number of big vascular bundles (NBV)(except for the 3rd top internode below the spike), mean area of big vascular bundles (MABV), total area of big vascular bundles (TABV), number of small vascular bundles (NSV), mean area of small vascular bundles (MASV), and total area of small vascular bundles (TASV). Compared with N0, the internode diameter of N180 and N300 treatments increased by 14.80%-29.95% and 10.80%-29.41%, NBV increased by 3.35%-28.39% and 1.05%-17.91%, NSV increased by 17.32%-41.69% and 13.25%-33.31%, MABV increased by 4.49%-20.10% and 3.75%-9.91%, TABV increased by 8.19%-48.87% and 5.10%-27.58%, MASV increased by 1.94%-20.47% and 0.49%-15.53%, TASV increased by 41.50%-59.79% and 19.76%-50.67% respectively. Nitrogen application increased dry matter and nitrogen accumulation in vegetative organs at anthesis, and also increased the pre-anthesis dry matter translocation, post-anthesis dry matter accumulation, pre-anthesis nitrogen translocation and its contribution rate to grain nitrogen, and N180 treatment was the highest. Compared with N0, the grain yield of N180 and N300 treatments increased by 271.95% and 215.81%, spike number increased by 195.29% and 147.38%, and grain number per spike increased by 40.87% and 34.42%, respectively. Compared with N300, nitrogen use efficiency, nitrogen uptake efficiency, agronomic use efficiency of nitrogen fertilizer and partial factor productivity of N180 treatments were increased. Collectively, under the experimental conditions, 180 kg·hm^-2 nitrogen application was conducive to increase the diameter of internode and promote the development of internode vascular, facilitates the post-anthesis translocation of pre-anthesis dry matter and nitrogen to grains, and thereby achieves synergistic improvement in yield and nitrogen use efficiency.

In order to investigate the differences in antioxidant capacity of wheat grains with different grain colors under high and low soil fertility conditions, five black-grained wheat, two blue-grained wheat and one white-grained wheat variety (lines) were selected to determine the contents of anthocyanins, total phenols and flavonoids in grains. The antioxidant capacity of the grains was evaluated by measuring the ferricion reducing antioxidant potential (FRAP value), 1,1-diphenyl-2-trinitrophenylhydrazine (DPPH·) radical scavenging rate, 2,2-azinobis (3-ethyl-benzothiazoline-6-sulfonic acid)(ABTS⁺·) radical scavenging rate, and hydroxyl (·OH) radical scavenging rate. The results showed that low fertility soil was conducive to the accumulation of anthocyanins in grains, and the anthocyanin content were increased by 33.20%-73.57% compared to those in high fertility soil. Among them, blue-grained wheat had a higher content, followed by black-grained wheat, and white-grained wheat had the lowest content; The content of total phenols and flavonoids in grains was decreased by 4.12%-56.46% and 1.14%-25.87%, respectively. Fertility, variety, and fertility×variety had significant effects on the content of anthocyanins, total phenols, and flavonoids. The FRAP value and ABTS⁺· clearance rate of grains in high fertility soils were higher than those in low fertility soils, while the overall DPPH and ·OH clearance rates were higher in low fertility soils than in high fertility soils. The total nitrogen and organic matter content in soil were the main regulatory factors of antioxidant capacity. Fertility, variety, and fertility×variety had significant effects on FRAP values and ABTS⁺·, DPPH, and ·OH clearance rates. The comprehensive score of high and low fertility soil ranked as black-grained wheat>blue-grained wheat>white-grained wheat. The average score of high fertility soil was higher than that of low fertility soil. In summary, wheat grown in high fertility soil has higher antioxidant capacity than that in low fertility soil, with black-grained wheat was higher than blue- and white-grained wheat.

In order to solve the problem of poor photosynthetic performance and low water use efficiency caused by uneven spatial and temporal distribution of water resources in irrigated agricultural areas of Xinjiang, the main spring wheat variety Xinchun 44 in northern Xinjiang was used as the material in this study. Under the condition of reducing irrigation by 20%, a two-factor randomized block design was used to set up four types of water-retaining agents: granular polymer water-absorbing polymer (SAP), potassium polyacrylate drought-resistant water-retaining agent, sodium polyacrylate drought-resistant water-retaining agent and powdered SAP and three dosage levels (D1: 30 kg·hm^-2; D2: 45 kg·hm^-2; D3: 60 kg·hm^-2), with no water-retaining agent as control (CK), the effects of water-retaining agent on photosynthetic performance, yield and water use efficiency of spring wheat were studied. The results showed that compared with CK, the water-retaining agent treatment improved the photosynthetic characteristics of spring wheat at flowering and filling stages, improved the potential light energy conversion efficiency of PSII reaction center in flag leaves and the overall functional activity of electron transport chain, and enhanced the light energy capture and transfer efficiency of plants. The grain yield (5.36%-28.90%) and water use efficiency of spring wheat were increased. Under the same application amount, there was no significant difference in photosynthetic characteristics, comprehensive performance indexs and yield of spring wheat between sodium polyacrylate drought-resistant water-retaining agent and powdered SAP treatment, but it was 5.47%—26.75%, 30.76%—51.80% and 11.39%—20.60% higher than granular SAP treatment. The water use efficiency of sodium polyacrylate drought-resistant water-retaining agent and powdered SAP was significantly higher than that of potassium polyacrylate drought-resistant water-retaining agent and granular SAP. Under the same type of water-retaining agent treatment, the photosynthetic characteristics, fluorescence parameters, yield and water use efficiency of spring wheat basically showed D3>D2>D1, and the yield showed that D2 and D3 significantly increased by 1.02%—3.60% and 2.66%—9.21% compared with D1, and the water use efficiency showed that D2 and D3 significantly increased by 1.16%—6.66% and 2.12%—8.00% compared with D1. Under the conditions of this experiment, the photosynthetic characteristics, yield and water use efficiency of spring wheat in Xinjiang were the highest under the management mode of sodium polyacrylate water retaining agent and 60 kg·hm^-2, it is the best management mode to achieve high yield and high water use efficiency of reduced irrigation wheat in Xinjiang.

To explore the effect of straw returning on the physiological characteristics of wheat seedlings subjected to freezing stress in early spring, a comparative analysis was conducted based on a 15-year long-term field experiment at the Crop Cultivation Science Observation Station of the Ministry of Agriculture and Rural Affairs in East China region. From 2023 to 2024, four different straw-returning modes were evaluated for their effects on the growth and physiological traits of wheat seedlings under freezing stress in early spring: full pulverization and surface coverage of wheat straw (T1), full pulverization and surface coverage of wheat straw and corn straw (T2), full pulverization and subsoil incorporation of corn straw (T3), and no incorporation of either wheat or corn straw (CK). Principal component analysis (PCA) was employed to construct a comprehensive evaluation model for the effect of different straw returning modes on the physiological indices of wheat under the conditions of freezing stress (-3 ℃) in early spring. The results indicated that straw returning had a significant influence on the development of wheat spikes and the accumulation of dry matter in above-ground parts and roots under the freezing stress in early spring. After the freezing injury, compared with CK, the spike length growth rate in T1, T2, and T3 treatments increased by 36.19%, 40.38%, and 60.67%, respectively. The dry matter weight of above-ground parts and roots in wheat treated with T1 and T3 increased, with an increase rate of 15.14% and 19.12% for above-ground parts, and 13.05% and 10.26% for roots, respectively. Compared to no straw returning, straw returning enhanced the antioxidant enzyme activity and the content of osmotic regulatory substances in wheat leaves and roots under freezing stress in early spring, while reducing the content of malondialdehyde (MDA). Specifically, the activities of superoxide dismutase (SOD) and peroxidase (POD) in leaves and roots in T1 treatment increased, with an increase rate of 140.08% and 71.47% for leaves, and 26.69% and 35.60% for roots compared to CK respectively, while the MDA content decreased significantly by 37.87% and 99.57%. The content of soluble protein and proline in leaves and roots in the T1 treatment increased significantly, with an increase rate of 40.55% and 64.44% for leaves, and 55.11% and 83.71% for roots, respectively. PCA revealed that the comprehensive physiological index for different treatments ranked as T1>T3>T2>CK. In summary, straw returning increased the antioxidant enzyme activity and the content of osmotic regulatory substances in wheat at the regreening stage, enhancing its cold resistance, which in turn promoted the development of wheat spikes and the accumulation of plant dry matter under freezing stress in early spring. Moreover, the full pulverization and surface coverage of wheat straw was proved to be the most effective treatment.

In order to realize the accurate estimation of winter wheat yield, this study used an unmanned aerial vehicle (UAV) to collect multi-temporal canopy multispectral data from 266 wheat varieties (lines), extracted multiple vegetation indices, and established a single-fertility and multi-fertility combined single-stage and multi-stage based on machine learning algorithms, such as multiple linear regression (PLSR), support vector regression (SVR), random forest (RF), and back-propagation neural network (BP), to set up. wheat grain yield prediction model. At the same time, the coefficient of determination (R²) and root mean square error (RMSE) were used to evaluate the models. It was found that the yield prediction with a single growth stage was best at mid-filling stage, and the optimal model was the RF model with the prediction accuracy of R²=0.655 and RMSE=0.550 kg·m^-2 and the optimal model for the yield prediction model with a combination of multi-growth stages was the RF model based on multi-spectral data from the five development stages (flowering, mid-filling, late-filling, dough and full-maturity), with the prediction accuracy of R²=0.834, RMSE=0.381 kg·m^-2. Meanwhile, the accuracy of the winter wheat yield prediction model was further improved after adding textural features to the modeling features. Based on a single stage, the optimal prediction stage for the vegetation index combined with textural features was the combination of dough and full-maturity stages, and the optimal model was the SVR model, with the prediction accuracy of R²=0.924 and RMSE=0.253 kg·m^-2. Therefore, unmanned canopy spectra can be used to predict winter wheat yield based on vegetation indices plus textural features, with the best prediction accuracy based on SVR models with multiple growth stages (dough and full-maturity).

To investigate the effects of nano-carbon dots on wheat emergence, the morphological and physiological characteristics of seedling and yield, a total of three treatments were set up: seed soaking, seed dressing, foliar spraying after emergence with nano-carbon dots aqueous solution, and no application of nano-carbon dots was used as the control (CK), with a wheat variety Yangmai 25 as the material, Three carbon dots concentrations were applied for seed soaking, seed dressing, and foliar spraying, with concentrations of 0.02, 0.1, and 0.5 mg·mL^-1, respectively. The differences in wheat emergence rate, plant height, biomass, stress resistance physiology, and yield under different treatments were analyzed. The results showed that using carbon dots aqueous solution for seed soaking and seed dressing, the actual emergence rates in the field after 20 days of sowing reached 76.8%-78.0% and 58.4%-60.5%, respectively. Compared with CK, the emergence rates of wheat in the field were increased by 27.0-28.2 percentage points and 8.6-10.7 percentage points, respectively. Compared with CK, after 20 days of wheat sowing, the height of seedlings treated with seed soaking, seed dressing, and foliar spraying increased by 39.8%-52.5%, 25.6%-28.1%, and 23.3%-32.2%, respectively; the fresh weight of aboveground parts increased by 95.3%-100.4%, 46.9%-53.8%, and 45.3%-56.5%, respectively; the maximum root length increased by 58.4%-60.7%, 28.6%-35.4%, and 19.2%-34.7%, and the fresh weight of roots increased by 60.2%-85.8%, 45.5%-48.1%, and 36.2%-39.1%, respectively. After seed soaking, seed dressing, and foliar spraying with nano-carbon dots, wheat seedling’ α-amylase and β-amylase activities, antioxidant enzyme activity, and content of soluble sugar were significantly increased, and the content of malondialdehyde was decreased. The wheat yield increased by 13.8%-16.0%, 9.8%-10.6%, and 5.4%-7.0%, respectively. The above results indicated that using nano-carbon dots for seed soaking, seed dressing, and foliar spraying led to the effectively promoted wheat emergence, early emergence and strong seedling, enhanced its stress resistance, and thus increased yield, and using 0.02-0.5 mg·mL^-1 nano-carbon dots solution to soak seeds can achieve the best effect in wheat production.