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.

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.

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.

Using SSR molecular markers, genetic diversity and population structure analysis were conducted on 104 local tartary buckwheat germplasm resources in China. The results showed that nine pairs of highly polymorphic SSR primers amplified a total of 22 alleles in the 104 tartary buckwheat germplasm resources. The number of alleles amplified per primer pair ranged from two to four, with an average of 2.444 alleles per locus. The average values for effective allele number (N_e), Shannon’s diversity index (I), observed heterozygosity (H_o), and expected heterozygosity (H_e) were 1.820, 0.629, 0.058, and 0.401, respectively. The polymorphic information content (PIC) ranged from 0.0096 to 0.6115, with an average of 0.3312. UPGMA clustering analysis divided the 104 tartary buckwheat germplasm resources into four groups. The tartary buckwheat from Inner Mongolia, Yunnan, Guizhou, and Sichuan showed similar distributions, primarily clustered in group III and IV. Materials from other provinces were more evenly distributed, demonstrating rich genetic diversity. Population structure analysis and two-dimensional principal coordinate analysis (PCoA) further confirmed that the grouping results were largely consistent with the cluster analysis. This study further clarified the genetic diversity and phylogenetic relationships among local germplasms of tartary buckwheat, and screened 17 genetically pure germplasm materials. This provides a theoretical basis for the effective utilization of tartary buckwheat germplasm resources and the breeding of new varieties.

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.

To identify the distribution of disease resistance functional genes in Xinjiang spring wheat materials and provide materials for genetic improvement of wheat disease resistance breeding, KASP technology was employed to detect genes associated with resistance to stripe rust, leaf rust, powdery mildew, and Fusarium head blight in 549 Xinjiang spring wheat materials. The results showed that 121 materials carried five stripe rust resistance alleles with relatively high frequencies (QYrqin.nwafu-2AL, Yr29, QYrsn.nwafu-1BL, QYrqin.nwafu- 6BS, Yr78); 352 materials carried two leaf rust resistance alleles with relatively high frequencies (Lr67, Lr46); and 142 materials carried three Fusarium head blight resistance alleles with relatively high frequencies (QFhb.Hbaas-5AS, QFhb.hbaas-5AL, QFhb.caas-5AL). No presence of the five powdery mildew resistance genes (Pm12, Pm21, Pm2a, Pm5e, PmV) was detected in any of the materials. In summary, Xinjiang spring wheat varieties exhibited high frequencies of resistance genes for stripe rust, leaf rust, and Fusarium head blight, but a notable lack of resistance sources for powdery mildew. Therefore, it is crucial to focus on introducing and utilizing new powdery mildew resistant materials to improve the disease resistance breeding capacity of Xinjiang spring wheat.

In order to clarify the pathogenicity and the potential risk of major corn pathogens to soybean root rot in corn-soybean inter planting, this study artificially inoculated non-co-occurring pathogens onto soybean roots and observed the symptoms in pots, and identified the infection grades of pathogens on soybean root rot. The results showed that Curvularia lunata causing corn curvularia leaf spot, Bipolaris maydis causing southern corn leaf blight, and Exserohilum turcicum causing northern corn leaf blight were non-co-occurring pathogens and could cause soybean root rot. Isolation and identification confirmed that the isolated strains were identical to the inoculated pathogens; C.lunata could cause soybean root rot up to Grade 5, B.maydis and E.turcicum could lead to soybean root rot up to Grade 3. The above results indicated that all three pathogens were causal agents of soybean root rot, and there was a potential risk of causing soybean root rot.

The effects of nitrogen (N) application on maize yield, root distribution, and N metabolism were analyzed under high-density planting by using the maize cultivar Xianyu 335 as material, setting up a conventional density treatment of 6.75×10⁴ plants/ha (D1) and a high-density treatment of 8.25×10⁴ plants/ha (D2), and applying N at five rates (0, 160, 220, 280, and 340 kg N/ha) per density treatment. The results indicated that with the increasing of N application rate, the maize yield showed a trend of increasing and then decreasing. The yield of D2 treatment was significantly higher than that of D1 treatment and the combination of high-density planting and optimized N application (160-220 kg N/ha) increased the yield by 39.1%-51.8% compared to conventional management. The optimized combination of N rates and planting densities increased root length, root length density, root surface area, root volume, specific root length, as well as the activities of glutamate synthase and glutamine synthetase in roots. The two enzyme activities were positively correlated with root growth distribution. In conclusion, an application of 160-220 kg/ha of N at a planting density of 8.25×10⁴ plants/ha is recommended. This combination enhances nitrogen metabolism enzyme activities, promotes root growth, and increases soil nutrient uptake, thereby improving maize yield. This can serve as a high-yield maize planting model for the Guanzhong region of Shaanxi.

The combining ability and heterosis of sorghum sterile line and restorer line in spring-sown early maturing regions were studied to provide theoretical basis for the parent selection of sorghum hybrid combinations in the future. Using 31 sorghum as parent materials, 206 hybrid combinations were prepared by incomplete diallel cross design, and 13 main traits including plant height, panicle length and combining ability and heterosis of parents and their hybrid F₁ were analyzed. The results showed that there were significant differences in various traits between the sterile and restorer lines of sorghum, and the combining ability of different materials was significantly different. Among the 31 materials, Ji 64A, SX44A, Ji 5535A, Ji 5575A, HLS×125×2999, HLS Zao and Ji R4334 had more advantages in plant height, panicle length, grain weight per panicle, yield, penultimate leaf angle, penultimate width, and antepenultimate leaf angle, etc. The general combining ability of other traits was also excellent, so the six materials were ideal parents. There was a large heterosis utilization potential in the hybrid combination, but the mid-parent heterosis was not prominent. Meanwhile, the yield of the hybrid combination was affected by both additive and non-additive effects. To select excellent parents attention should be paid to the comprehensive traits and general combining ability of the parents, as well as the special combining ability and the complementary effect of the parents.

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.