A field experiment was conducted to investigate the effects of planting densities and nitrogen application levels on the growth, biomass allocation and yields of Salvia prionitis Hance. Three planting density levels, high density (666 666 plant/ha), medium density (200 000 plant/ha), and low density (95 238 plant/ha); and three fertilization levels [no nitrogen application, low nitrogen (22.5 g/m²) and high nitrogen (45 g/m²)] were set. The results showed that both the density and nitrogen level significantly affected plant size, biomass allocation and yield of S.prionitis. However, the interaction effect only extremely significantly affected the parameters related to biomass allocation. In general, nitrogen application increased the plant height, number of flower stalks, and number of primary branches flower stalks of S.prionitis under all planting densities, and leaf length, leaf width, and plant height of the two low density treatment were greater than those of the high density treatment under all nitrogen levels. Nitrogen level did not significantly affect the root biomass ratio and root- shoot ratio of S.prionitis at medium density treatment, while the root biomass ratio and root-shoot ratio at low and high densities were significantly reduced with the increasing of nitrogen application. Under each densities, the root biomass, supporting structure biomass, total biomass, whole plant yield and root yield of S.prionitis were the greatest in the low nitrogen treatment, then followed by the high nitrogen treatment. under every nitrogen application levels, the root biomass, supporting structure biomass and total biomass of S.prionitis increased significantly with the decreasing of density, However, the whole plant yield and root yield increased significantly with the decreasing of density. In all treatments, whole plant yield and root yield of S.prionitis were the greatest at high density (666 666 plant/ha) with low nitrogen level (22.5 g/m² pure nitrogen, urea).

Using Wanzhi 21 sesame as the experimental material, four harvesting periods of sesame leaf vegetable were set as follows: starting from the 40th day (P40), the 50th day (P50), the 60th day (P60), and the 70th day (P70) after the emergence of sesame, with the without harvesting sesame leaf vegetable as control (PCK). Through the two year continuous experiment, the effects of different harvesting periods on the main economic traits and yield of sesame leaf vegetable were studied, and a comprehensive benefit analysis was conducted. The results showed that the effects of the harvesting period of sesame leaf vegetable on the plant height, capsule axis length, effective node number, number of capsules per plant, number of seeds per capsule, and 1000-seed weight reached a significant level. The later the harvesting period of leaf vegetable, the slower the decline in the economic traits, which was specifically reflected as PCK > P70 > P60 > P50 > P40. The later the harvesting period of leaf vegetable, the higher the yield of sesame seeds, and the lower the reduction rate of seed yield. On the contrary, the earlier the sesame leaf vegetable harvesting, the higher the yield and net benefit of sesame leaf vegetables, but the lower the dry-fresh ratio of leaf vegetable. Specifically, the dry-fresh ratio showed an order of P40 < P50 < P60 < P70. The benefit from sesame seeds was just the opposite, and the later the sesame leaf vegetable harvesting, the higher the benefit from sesame seeds. The comprehensive benefit of harvesting leaf vegetable was the highest at P70 treatment, which increased by 39.06%-58.22% compared with PCK treatment. Therefore, the 70th day is the best harvesting period for sesame leaf vegetable, which can achieve the greatest comprehensive benefit of sesame cultivation.

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 analyze the genetic diversity of rice germplasm resources in the border areas of Yunnan Province and identify SSR markers closely related to major agronomic traits, a total of 376 newly collected rice germplasm resources from Yunnan (China), and its adjacent Myanmar and Laos were used as experimental materials. These resources were divided into three analysis units, and 11 phenotypic traits were investigated. Genetic diversity and association with phenotypic traits were analyzed using 27 pairs of SSR markers. Results showed that a total of 142 allelic variation loci were detected, including 100 rare allelic variation loci and nine peculiar allelic variation loci. Based on the comprehensive evaluation of six genetic diversity parameters, the scoring order of rice germplasm resources from the three analysis units was: Yunnan, China analysis unit > Myanmar analysis unit > Laos analysis unit. Among the 27 pairs of SSR markers, RM214, RM1086, RM5481, RM6089, RM1509, and RM7479 were closely associated with phenotypic traits, could explain more than 10.0% of the variation in panicle length, panicle exsertion, filled grains per panicle, unfilled grains per panicle, grains per panicle, and 1000-grain weight. Principal component analysis of phenotypic traits extracted four principal components with a cumulative contribution rate of 77.218%. A total of 36 excellent germplasm resources (comprehensive score ≥1.000) were selected. Among these, Huake, Nalei 5, and Haonuolang had a score greater than 2.000. They demonstrated potential as parents for multiple-tillering and large-panicle type, large-panicle type, and glutinous type, respectively.

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.

To clarify the production status and limiting factors of intercropping systems in the Hetao Irrigation District, Hanggin Rear Banner, a representative area for crop cultivation in the Hetao Irrigation District, was selected as the research site for the survey. Based on 503 valid questionnaires from 24 administrative villages across eight townships of Hanggin Rear Banner, the results showed that the intercropping systems were widely applied in Hanggin Rear Banner. There were wheat/maize, wheat/sunflower, watermelon/sunflower and maize||soybean (mainly food and cash crops). The wheat/maize and wheat/sunflower relay were cropping the most prevalent, accounting for 42.5% and 23.5%, respectively. Both systems significantly improved land use efficiency, with land equivalent ratios of wheat/maize and wheat/sunflower were 1.48 and 1.29, respectively. There were two main limitations of applying intercropping in this region. On the one hand, field managements were more complex in intercropping than monocultures, with the average number of irrigations and weeding times were higher, with an average of 1.0 and 0.9 times higher than in monocropping, respectively; on the other hand, the average amount of nitrogen application in intercropping systems was 70.7% higher than in monocropping. Overall, it is necessary to further explore field management practices and fertilization strategies suitable for intercropping in the area to reduce water and fertilizer inputs. Meanwhile, the research and development of intercropping machinery, herbicides and other related production materials should be strengthened, and technical training should be carried out to enhance farmersʼ understanding of intercropping.

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.

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.

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.