To investigate the mechanism of the coupled effects of precipitation, nitrogen (N) fertilizer, and straw mulching on dryland spring wheat yield under different precipitation year types, the APSIM model was calibrated using spring wheat yield, soil, and meteorological data under no-tillage and no-tillage with straw mulching from 2013 to 2018. Combined with historical data from 1970 to 2022 to drive the calibrated model, yields were simulated under 5×5×5 combinations of precipitation changes (±20%, ±10% and 0%), nitrogen application rates (0.0, 52.5, 105.0, 157.5, and 210.0 kg/ha), and straw mulching rates (0, 1125, 2250, 3375, and 4500 kg/ha). The coefficient of variation of yield under single-factor was analyzed for each year type, and quadratic orthogonal polynomial stepwise regression, single-factor analysis, and interaction effects were employed to study the impacts of various factors on yield. The results showed that the APSIM model performed well, with R² > 0.8, NRMSE < 10%, and M_E > 0.8 for both tillage practices. In dry, normal, and wet years, the individual and interactive effects of the three factors all positively influenced yield, with the order of effect intensity being: precipitation change > nitrogen application rate > straw mulching rate. Based on the natural precipitation of the current year, the optimal yields and cultivation measures for each year type were as follows: in dry years, an optimal yield of 2203.65 kg/ha was achieved by increasing precipitation by 20%, applying 153.13 kg/ha of nitrogen, and mulching with 4500 kg/ha of straw; in normal years, an optimal yield of 2838.77 kg/ha required a 20% increase in precipitation, 170.76 kg/ha of nitrogen, and 4500 kg/ha of straw mulching; in wet years, an optimal yield of 3447.11 kg/ha required a 20% increase in precipitation, 188.58 kg/ha of nitrogen, and 4500 kg/ha of straw mulching. In conclusion, within the simulated experimental range, increasing precipitation, nitrogen application rate, and straw mulching amount under no-tillage conditions can enhance the simulated yield of spring wheat, but the degree of impact varies with precipitation year types. For local spring wheat, water, fertilizer, and mulching strategies should be formulated according to the specific year type to achieve high and stable yields.

The main agronomic traits of 513 faba bean germplasm resources at home and abroad were analyzed. The results showed that the coefficient of variation of 15 agronomic traits ranged from 13.09% to 53.58%, indicating that there was a large genetic variation. The coefficient of variation for the number of pods per plant reached the highest value of 53.58%, with a variation range of 1.00 to 42.00, whereas pod width exhibited the lowest coefficient of variation at 13.09%, varying from 0.80 to 2.23 cm. Correlations among traits highlighted that the number of branches, number of effective branches, number of pods per plant, number of grains per plant, plant height, and height of the last pod are key for developing high-yielding faba bean varieties. The principal component analysis extracted five principal components, with the cumulative contribution rate reaching 72.098%, effectively representing the phenotypic characteristics of these germplasm resources. By calculating the membership function values, a comprehensive score (F-value) was derived, and the top 30 germplasm resources with the best comprehensive traits were identified. The cluster analysis subsequently divided the 513 faba bean germplasm resources into three group: Cluster I included 160 resources (31.19% of the total), characterized by high plant height and yield; Cluster II comprised 221 resources (43.08% of the total), suitable as parental selection and screening of excellent genes; and Cluster III contained 132 resources (25.73% of the total), representing specific germplasm.

In order to accurately simulate the initiation process of tobacco leaves and provided reference for precise management and control of tobacco production, field comparison experiments of different transplanting date treatments were carried out for two consecutive years from 2022 to 2023 to establish dynamic models of tobacco leaf changes based on different scales, and the simulation accuracy of different models was analyzed. The results showed that the rate of leaf initiation accelerated with the delay of the transplanting date, and the time to reach the maximum number of leaves was shortened. The final number of leaves (A value) in different transplanting dates was basically the same. The leaf initiation models of tobacco was an atypical “S” type growth curve with no stable growth period. The accuracy of the growing degree days model was higher than that of the growing day model, which had better practicality when the temperature changed in the appropriate range. The accuracy of the thermal-photo effectiveness model was higher than the growing degree days model, however, the prediction accuracy fluctuated across different years. The accuracy of the physiological development time model was higher than other models. The time for the tobacco leaves number to reach the maximum value was 37.63- 46.62, the growing degree days was 440.06-483.04, the thermal-photo effectiveness value was 30.17-34.36, and the physiological development time was 29.13-31.80, in the transplanting date from late April to late May in Shandong tobacco area. The simulation model of tobacco leaf initiation based on physiological development time had higher reliability and universality, which could accurately characterize the process of plant development and provide support for the precise management of tobacco production.

To investigate the response of drought-resistant quinoa seedlings to drought stress, the strongly drought-resistant quinoa variety Longli No.1 (LL1) and the new breeding line LQ18 were selected as experimental materials. PEG-6000 solution was used to simulate drought environment. Three treatments were set: normal irrigation (CK), mild drought stress (5% PEG-6000), and severe drought stress (20% PEG-6000). We investigated quinoa seed germination rate, germination potential, germination index; seedling plant height, leaf area, root length, aboveground and underground dry weights; soluble protein and proline contents; superoxide dismutase (SOD) and peroxidase (POD) activities; and malondialdehyde (MDA) content. The results showed that severe drought stress reduced plant height, leaf area, and aboveground dry weight in both varieties (lines), but increased root length, underground dry weight, and root-shoot ratio. Specifically, the reductions in leaf area and aboveground dry weight, as well as the increases in root length, underground dry weight, and root-shoot ratio were all smaller in LQ18 than in LL1. Under drought stress, the soluble protein content of LL1 gradually decreased, while that of LQ18 first increased and then decreased to a level with no significant difference from CK. Under severe drought stress, the proline content of both varieties (lines) significantly increased, and the proline content of LQ18 was significantly higher than that of LL1. Drought stress influenced the activities of SOD and POD and increased MDA content in both varieties (lines). Under severe stress, the SOD activity of LQ18 decreased slightly, whereas its POD activity increased significantly; furthermore, its MDA content remained significantly lower than that of LL1.

To explore the optimal nitrogen application rate for different wheat varieties in various environments and provide a scientific basis for enhancing the mineral element content in wheat grains, this study used 15CA73, Jimai 22, Zhongmai 255, and Zhongmai 578 as experimental materials. Five nitrogen application treatments were established across four environments: Anyang (Henan), Hefei (Anhui), Weifang (Shandong), and Liaocheng (Shandong). These treatments included no nitrogen application (N₀), basal application of 45 kg/ha pure nitrogen + topdressing of 45 kg/ha pure nitrogen at the jointing stage (N₄₅₊₄₅), basal application of 90 kg/ha pure nitrogen + topdressing of 90 kg/ha pure nitrogen at the jointing stage (N₉₀₊₉₀), basal application of 135 kg/ha pure nitrogen + topdressing of 135 kg/ha pure nitrogen at the jointing stage (N_135+135), and basal application of 180 kg/ha pure nitrogen + topdressing of 180 kg/ha pure nitrogen at the jointing stage (N_180+180). The results showed highly and extremely significant correlation coefficients (P < 0.01) between the contents of elements such as K and P (r = 0.72), and Zn and Cu (r = 0.69) in grains. Compared with the N₀ treatment, the N_180+180 treatment resulted in the highest contents of Ca, Cu, Mg, and S in wheat grains at the Weifang site across all environments, with increases of 11.06%, 10.78%, 0.15%, and 7.83%, respectively. The Zn content at the Weifang experimental site was highest under the N_135+135 treatment, showing a 46.01% increase compared to the N₀ treatment. Furthermore, compared with the N₀ treatment, the N_180+180 treatment led to the highest contents of Cu, Fe, Mg, Mn, and S in Zhongmai 255 grains among all tested varieties, with increases of 2.42%, 3.50%, 1.65%, 4.23%, and 16.10%, respectively. The Zn content in Zhongmai 255 grains was the highest under the N_135+135 treatment, increasing by 13.26% compared to N₀ treatment. In summary, increased nitrogen application enhanced the contents of Ca, Cu, Fe, Mn, S, Mg, and Zn in wheat grains. K content was less affected by nitrogen application, while P content showed a declining trend. Concurrently, the P/Mg, P/Fe, and P/Zn ratios decreased, further improving the bioavailability of Mg, Fe, and Zn in the grains. Therefore, the recommended optimal nitrogen fertilizer treatments for wheat cultivation at the experimental sites are N_135+135 for Anyang, N₀ for Hefei, N_180+180 for Liaocheng, and N_180+180 for Weifang. Moreover, N₀ is determined to be the optimal nitrogen fertilizer treatment for 15CA73 and Jimai 22, whereas N_180+180 is optimal for Zhongmai 255 and Zhongmai 578.

In order to understand the genetic background of flax germplasm resources and breed high-quality flax varieties, genetic diversity analysis, cluster analysis, principal component analysis and population structure were conducted on nine agronomic traits and six quality traits of 387 flax germplasm resources by phenotypic traits and molecular markers (SSR). The genetic diversity index of agronomic traits was between 0.70 and 2.08, and the coefficient of variation was between 5.55% and 129.18%. The genetic diversity index of quality traits ranged from 1.83 to 2.08, and the coefficient of variation ranged between 0.07% and 1.38%. A total of 320 SSR loci were amplified with an average of 11.81 loci per primer pair; the effective allele number was 1.1991-1.8230, PIC of primers varied from 0.2489 to 0.6257; at the genetic similarity coefficient of 0.66, the 387 flax germplasm resources could be divided into five groups, and cluster analysis based on agronomic traits and quality cluster analysis could also be divided the germplasm resources into five groups.

To explore the effects of silicon (Si) on the physiological characteristics of oat leaves infected by Puccinia graminis f. sp. avenae and clarify the physiological mechanism of silicon-induced resistance to stem rust, a pot experiment was conducted using ʻBayou 1ʼ, an oat cultivar highly susceptible to stem rust, as the experimental material. Four treatments were established: CK (no silicon, no stem rust pathogen inoculation), +Si-P (silicon application, no stem rust pathogen inoculation), -Si+P (no silicon, stem rust pathogen inoculation), and +Si+P (silicon application, stem rust pathogen inoculation). This study investigated the effects of 1.5 mmol/L silicon application on the disease progression, reactive oxygen species content, and antioxidant enzyme activities of oat leaves after stem rust pathogen infection. The results showed that silicon application effectively delayed the disease development process of oat stem rust, and significantly alleviated disease symptoms. Stem rust pathogen infection led to a rapid increase in O₂^-. and hydrogen peroxide content in leaves. Simultaneously, the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), malondialdehyde (MDA) content, and relative electrical conductivity of leaves increased rapidly, while ascorbate peroxidase (APX) activity decreased rapidly. Within seven days after stem rust pathogen inoculation, silicon application reduced the reactive oxygen species content in leaves, while increasing the activities of SOD, POD, and CAT, and decreasing APX activity and MDA content. Furthermore, silicon application reduced the relative electrical conductivity of leaves within 11 days after inoculation. Silicon application enhanced the antioxidant defense ability of oat leaves, reduced the degree of membrane lipid peroxidation, and enhanced oat resistance to stem rust.

A total of 24 progenies from Saccharum robustum L. and Nanjian chewing cane through reciprocal crosses were used. Correlation analysis, principal component analysis, cluster analysis, and comprehensive evaluation associated with seven important agronomic traits were performed. The results showed that there were differences in agronomic traits among different germplasm materials in the same planting period experiment, and there were differences in agronomic traits among different planting period experiment in the same germplasm materials. The variation coefficient of agronomic traits ranged from 11.17% to 43.37%. The variation of sugar yield and sugarcane stalk yield was the largest, which was 43.37% and 42.20%, respectively, the variation of plant height was small. The correlation analysis showed that sugarcane stalk yield and sugar yield were significantly positively correlated with single stalk weight and effective stalk number, respectively, and sugarcane stalk yield was significantly positively correlated with sugar yield. The yield-sugar factor, stalk diameter-sugar factor and stalk diameter-quality factor were extracted via principal component analysis, and the cumulative contribution rate was 81.39%. The results of cluster analysis showed that the 24 germplasm materials were divided into three groups at the Euclidean distance of 6.00, which were basically consistent with the results of principal component scores. Among them, the seven agronomic indexes of group III were excellent, with high yield and high sugar. Yunrui 12-38-27, Yunrui 12-38-18, Yunrui 12-9-45, Yunrui 12-9-9 and Yunrui 12-38-29 ranked top five based on their comprehensive evaluation D values.

Aiming at the issues of poor soil structure, insufficient nutrient supply, and low potato yield in the agro-pastoral ecotone in the Northern piedmont of Yinshan Mountain, Inner Mongolia, a two-year field randomized block experiment was conducted. Taking conventional fertilization as the control (CK), three treatments were set up, including chemical fertilizer reduction combined with sheep manure (NPK+SD), chemical fertilizer reduction combined with biochar (NPK+B), and chemical fertilizer reduction combined with microbial fertilizer (NPK+MF). The dynamic changes of leaf area index (LAI), SPAD value, photosynthetic performance, plant nutrient accumulation and dry matter accumulation of potato plants under different treatments were compared and analyzed. The results showed that during the tuber bulking, NPK+MF treatment significantly improved LAI and leaf photosynthetic performance of potato, with leaf SPAD value significantly increased by 8.04% compared to CK, and no significant difference compared to NPK+SD and NPK+B treatments. The net photosynthetic rate of NPK+MF treatment was significantly increased by an average of 11.31%, 7.66%, and 4.92% compared to CK, NPK+SD, and NPK+B treatments, respectively. Under the NPK+MF treatment, with the growth process of potato, plant nutrients are transported from stems and leaves to tubers, and the accumulation of N, P, and K in potato leaves, stems, roots, and tubers were significantly increased. During the late stage of potato growth, the distribution ratio of nitrogen, phosphorus, and potassium in the tubers increased by 90.58%, 178.78% and 226.06%, respectively. The yield of NPK+MF treatment was the best, with an average of 40 054 kg/ha, which was 25.58% higher than that of CK. This experiment identified that chemical fertilizer reduction combined with microbial fertilizer was an effective fertilization method for soil fertility improvement and efficient utilization of soil and fertilizer resources in the agro-pastoral ecotone of the northern piedmont of Yinshan Mountain.

Drought experiments were carried out in different stages of tuberous root differentiation and formation by potting soil cultivation to analyze the changes of reactive oxygen species metabolism and endogenous hormone content in sweetpotato roots. The results showed that drought stress caused the decrease of sweetpotato fresh tuber weight per plant, and the earlier the drought, the greater the effect. Compared with normal irrigation treatment (CK), the O₂^-. content in sweetpotato roots was significantly decreased and H₂O₂ content was significantly increased under drought stress. The increase of H₂O₂ was effectively inhibited after rehydration. Drought stress at different periods resulted in the decrease of activities of peroxidase (POD) and catalase (CAT) in sweetpotato roots, and ascorbate peroxidase (APX) activity increased significantly in early, middle and late stages of sweetpotato root differentiation and formation under drought stress. The results showed that the root system of sweetpotato mainly relied on APX to remove reactive oxygen species under drought stress, and SOD also made great contribution to the removal of reactive oxygen species during the early and middle stages of drought stress. After rehydration, the APX activity in sweetpotato roots decreased, while POD activity increased, indicating that sweetpotato root recovered the damage caused by drought stress by enhancing POD activity to improve antioxidant capacity after rehydration. In addition, the free proline content in sweetpotato roots increased under drought stress, and as an osmotic regulator to resist drought stress, the proline content in sweetpotato roots decreased after rehydration. Compared with CK, the contents of ABA and JA in sweetpotato roots for the treatments of D_8-14 and D_15-21 were significantly increased, while the contents of GA and IAA were significantly decreased, and the decreasing ranges were smaller than the increasing ranges of ABA and JA. When drought treatment (D_22-28) was carried out at late stage of root differentiation and formation, the contents of these four endogenous hormones in sweetpotato roots did not change significantly. These results indicated that when sweetpotato was subjected to drought stress in early and middle stages of tuberous root differentiation and formation, it responded strongly by increasing the contents of JA and ABA in roots. However, when sweetpotato was subjected to drought stress during tuberous root differentiation and formation stage, only JA had a significant increase.