Six mango varieties (Guiqi Mang, Tainong Mang, Guifei Mang, Jinhuang Mang, Ivory Mang, and Jade Mang) mainly planted in Baise were selected as the research objects, and 22 quality indicators (including appearance quality, internal quality.) were analyzed. The results indicated that the coefficient of variation for indexes such as single fruit weight and fruit shape index exceeded 10% among different varieties in appearance quality. For intrinsic quality, Guiqi mango performed optimally in sweetness-related indexes (TSS, total sugar, soluble sugar) and flavor coordination (solid-acid ratio, sugar-acid ratio), with the highest Vc content reaching 36.6 mg/100 g, while Tainong mango had the lowest Vc content at 28.7 mg/100 g. Yumang mango had the highest contents of phenolic substances (4.33 mg/100 g) and flavonoids (1.12 mg/100 g). Guifei mango and Yumang mango had relatively high protein contents, both at 1.0 g/100 g. Further analysis indicated that there existed both relative independence and close correlation among multiple quality index variables of mango. The 5 principal components extracted by principal component analysis accounted for 100% of the information of the above indexes, and the comprehensive quality ranking was as follows: Yumang mango>Guiqi mango>Tainong mango>Xiangya mango>Guifei mango>Jinhuang mango. Systematic clustering classified the 22 quality indexes into 3 categories: bioactive components (e.g., vitamins, flavonoids), fruit flavor characteristics (e.g., sugar-acid related indexes), and mineral elements (e.g., potassium, calcium). The results revealed the characteristic differences in fruit quality among the main mango varieties in Baise, and suggested that principal component analysis and systematic clustering analysis could be applied to simplify the evaluation of mango fruit quality.

10 inflorescence traits of 200 domestic and international Macadamia germplasms in the Jinghong Macadamia Germplasm Repository of the Ministry of Agriculture and Rural Affairs were evaluated using QGA Station combined with different genetic distance metrics, clustering methods, sampling strategies, and sampling proportions to conduct a core macadamia collection construction. The optimal methodology for core collection development was identified as “Mahalanobis distance+multi-clustering deviation sampling+centroid clustering method+15% sampling proportion”, resulting in a core collection comprising 30 accessions. The mean difference percentage, variance difference percentage, range coincidence rate and variation coefficient change of core collection and original collection was 0.00%, 90.00%, 99.31% and 150.08%, respectively. No significant differences in trait means were detected between the core and original collections (T-test). The variances of all traits in the core collection exceeded those of the original collection, with 9 traits showing statistically significant differences. While genetic diversity indices slightly decreased, the conformity rate for all traits remained above 80%. Principal component analysis (PCA) demonstrated that the cumulative variance contribution rate of the first three principal components was 74.118% and 84.350% for the original and core collections, respectively, with congruent geometric structures in their PCA scatterplots. Correlation analysis further confirmed that trait relationships in the core collection closely mirrored those of the original collection. The core collection comprised 8 Australian accessions, 10 Hawaiian accessions, 9 China Yunnan accessions, and 3 accessions of special types, exhibiting a degree of geographic representativeness. Analyses using both cluster analysis and PCA on the core collection revealed that domestic and foreign accessions were distinguishable to a certain extent based on the inflorescence phenotypes. The Macadamia core collection developed in this study, based on inflorescence phenotypic traits, effectively represents the genetic diversity of the original collection and would provide a robust foundation for future research on Macadamia genetic resources.

It aimed to establish and optimize an efficient tissue culture rapid propagation system for Dendrobium Reke Xiamo to address the inefficiency and high cost associated with its traditional propagation methods. By systematically screening the concentration ratios of cytokinin (6-BA) and auxin (NAA), the addition of potato powder, and rooting medium formulations, an efficient and stable tissue culture rapid propagation system was successfully developed. The experimental results showed that the combination of 6-BA at 3 mg/L and NAA at 0.5 mg/L in MS medium was the optimal shoot induction medium, with the highest shoot induction rate achieved when 80 g/L of potato powder was added. The proliferation medium consisting of 6-BA at 2 mg/L and NAA at 0.5 mg/L resulted in an average proliferation coefficient of 5.63. During the rooting stage, the combination of NAA at 0.5 mg/L and IBA at 0 mg/L yielded the most significant results. By establishing a stage-specific precise hormonal regulation system (induction-proliferation-rooting), the propagation bottleneck was successfully overcome, and the proliferation coefficient increased by over 30%. This technical system would provide reliable technical support for the scaled production and commercialization of Dendrobium Reke Xiamo.

The identification and evaluation of superior germplasm are the foundation for the research on germplasm resources and breeding utilization. 45 citronella grass resources from Hainan, Fujian, Guizhou, Yunnan and other regions were assayed to evaluate the essential oil content. The agronomic traits, essential oil content and main components of essential oil of the resources at different cutting stages were analyzed in Kunming. The results showed that there were significant differences in total grass length, leaf length, leaf width, biological yield and essential oil content among different cutting periods and different materials. Correlation analysis between characteristic traits and essential oil content revealed that the essential oil content was significantly negatively correlated with leaf length and significantly positively correlated with leaf width. Systematic cluster analysis based on agronomic traits and essential oil content divided the resources into 5 groups. The Ⅰ group contained 36 materials, and all materials were identified as Cymbopogon citra=tus, The Ⅱ group had 4 materials, all in Cymbopogon winterianus. Cymbopogon caesius and Cymbopogon hamatulus were individually clustered into the Ⅳ and Ⅴ groups, respectively. A standard for identifying and grading superior germplasm oriented towards essential oil yield was established, and the 45 resources were divided into three grades, including 6 in the first grade, 18 in the second grade and 21 in the third grade. In addition, the analysis of essential oil content and main components of 16 germplasm in Yuanmou test region at 6 different periods showed that the accumulation of essential oil did not increase with the extension of planting time, and the contents of main components in essential oil also varied in different periods. Geraniol reached the highest value in January; Linalool had the highest content in March; Geranyl acetate peaked in September; Citronellyl acetate had the highest content in January, and β-myrcene was the highest in May. This study would provide a scientific basis for the identification and evaluation of superior citronella grass germplasm, breeding utilization, and the production and utilization of high-quality and high-yield raw materials.

The study developed a new fresh-eating sweet potato variety Guishu No. 13 and established its virus-free seedling breeding technology system to meet the market demand for fresh-eating sweet potato varieties and healthy seedlings. Guishu No. 13 was bred from seeds by open pollinated using Guizhu No. 10 as mother. The variety has purple red skin, orange yellow flesh, and a high rate of medium to large storage roots. The content of β-carotene, protein and reducing sugar was 1790 mg/100 g, 1860 mg/100 g and 1200 mg/100 g, respectively. In the production experiment, the starch storage roots yield was 29 786.40 kg/hm² and starch yield was 4675.10 kg/hm², which increased by 5.52% and 17.52% respectively compared to Guishu No. 2 (CK). Guishu No. 13 has moderate resistance to Fusarium wilt, black rot, and stem nematode. The best culture medium for callus differentiation and germination rate of Guishu No. 13 was MS+0.10 mg/L NAA+1 mg/L 6-BA and MS+0.20 mg/L NAA+2 mg/L 6-BA, respectively. Guishu No. 13 has good yield and stability, high fresh storage root yield, and the establishment of a virus-free breeding system would lay the foundation for the development and application of the Guishu No. 13.

The study determined quality indexes including single fruit mass, longitudinal and transverse fruit diameter, peel thickness, edible rate, soluble solids and titratable acid of 51 pomelo accessions to analyze the fruit quality characteristics of different pomelo germplasm resources and establish a comprehensive evaluation system. Correlation analysis and principal component analysis were employed to comprehensively evaluate the fruit quality. The fruit longitudinal diameter ranged from 64.00 to 191.00 mm, with transverse diameter measured between 76.00 and 170.90 mm. Fruit shape index values varied from 0.82 to 1.35, while single fruit mass spanned 220.00 to 1750.00 g. Peel mass was recorded between 50.00 and 996.00 g, with edible rates from 19% to 81%. Peel thickness measurements showed variation from 4.00 to 39.67 mm. Segment number per fruit was 10-20, soluble solids content ranged 4.50%-10.90%, and titratable acid level was 0.13%-2.96%. The solid-acid ratio varied between 2.70 and 41.70, with number of seeds ranging from 0 to 224. It indicated that the phenotypic diversity of pomelo germplasm resources in Hekou, Yunnan was rich. Pearson correlation analysis revealed that longitudinal diameter exhibited significant positive correlations with fruit shape index and single fruit mass. Transverse diameter showed extremely significant positive correlations with single fruit mass and peel mass. Significant negative correlations were observed between edible rate and peel thickness, titratable acid and solid acid ratio. Cluster analysis grouped the resources into approximately four categories, with each group displaying substantial difference in both external appearance and internal quality. By principal component analysis (PCA), the 13 traits were integrated into 4 principal components, and the contribution rate of the first principal component was 31.614%. The longitudinal diameter, transverse diameter, single fruit mass and peel mass contributed more. The contribution rate of the second principal component was 16.842%, which was based on edible percentage, number of segments and soluble solid. The contribution rate of the third principal component was 15.397%, and the contribution rate of titratable acid was larger. The contribution rate of the fourth principal component was 14.686%, which was based on the number of seeds. After fruit quality analysis and comprehensive evaluation, Yunqing 1, Green peel and red flesh Pomelo, Huangjin pomelo, Guanxi red flesh pomelo, Dongshizao Pomelo, and Wanbai Pomelo demonstrated superior comprehensive quality and were recommended as candidate materials for main cultivars or breeding parents in Hekou, Yunnan.

1-year-old and 5-year-old Alpinia galanga intercropped under rubber forests was used to understand the photosynthetic physiological characteristics of Alpinia galanga in rainy and dry season, explore its growth adaptability and growth habits, and provide a theoretical basis for its popularization under rubber forests. There were significant differences in photosynthetic parameters between 1-year-old and 5-year-old plants. The net photosynthetic rate (P_n) and transpiration rate (T_r) of 1-year-old plants were higher than those of 5-year-old ones, and T_r was higher in rainy season than in dry season, indicating drought tolerance and stronger photosynthetic capacity in seedlings. There existed differences in light response curve parameters. Light saturation point (LSP) and light compensation point (LCP) of both age groups were between those of heliophytes and sciophytes, confirming shade tolerance. LSP and apparent quantum efficiency (AQE) were higher, while LCP was lower in the dry season, further indicating drought tolerance. The maximum photochemical efficiency (F_v/F_m) was slightly higher in the dry season, suggesting stronger photosynthetic capacity. Contents of chlorophyll a, chlorophyll b, total chlorophyll, and Chl a/b ratio were higher in the dry season, indicating more favorable growth conditions. The 5-year-old plants had thicker upper epidermis and higher palisade-spongy ratio, adapting to shade and drought under rubber forests. The spongy tissue thickness exceeded that of palisade tissue in both age groups, confirming shade tolerance. In conclusion, Alpinia galanga is shade/drought-tolerant with high weak-light utilization. This indicates that dry season conditions and appropriate shading (shading degree of 40%-80%) are more conducive to the growth of Alpinia galanga.

A field split plot experiment of pineapple was carried out from 2023 to 2024 to explore the effects of nitrogen fertilizer postponing and magnesium fertilizer coupling on the growth and development, yield and quality of pineapple and to provide practical reference for scientific fertilization management of pineapple. The main area was magnesium application rate, namely MgO 0 kg/hm² (M₀), MgO 37.5 kg/hm² (M₁) and MgO 75 kg/hm² (M₂). The sub-area was conventional nitrogen application treatment (N₁) and nitrogen fertilizer postponing treatment (30% of nitrogen fertilizer in slow growth period and flowering period was postponed to rapid growth period and fruit enlargement period, respectively) (N₂). The leaf number, leaf area index, chlorophyll content, dry matter accumulation, yield and quality indexes of pineapple were measured during the key growth period of pineapple. The results showed that compared with N₁, N₂ could significantly increase the contents of chlorophyll a and chlorophyll b in pineapple leaves at mature stage, and increase the number of leaves and leaf area index of pineapple at red stage. Compared with N₁, the dry matter quality and yield at maturity stage increased by 9.40% and 7.65%, respectively, and the vitamin C content and soluble sugar content of fruit were also significantly higher than those of N₁ (P<0.05), while the difference in yield was not significant. Similarly, compared with M₀ and M₂ treatments, M₁ treatment could significantly increase the contents of chlorophyll a, chlorophyll b and carotenoids in leaves, and the leaf number and leaf area index of pineapple at the red stage of flowering increased significantly, thereby improving the dry matter quality and yield at the mature stage, and the difference was significant (P<0.05). The fruit dry matter distribution rate, soluble sugar content, soluble protein content, vitamin C content and sugar-acid ratio under M₁ treatment were significantly higher than those under M₀ and M₁ treatments (P<0.05). Interaction effect analysis revealed that N₂M₁ treatment could increase the content of chlorophyll a, chlorophyll b and carotenoid in pineapple compared with other treatments, and then the number of leaves, leaf area index and dry matter quality increased significantly. Yield increased significantly by 19.43%, 17.39%, 10.07% and 24.96% compared with those of N₂M₀ (P<0.05), N₁M₂, N₁M₁ and N₁M₀, respectively, but not significantly different from that of N₂M₂. The fruit shape index, vitamin C, soluble sugar, soluble protein content and sugar-acid ratio of pineapple fruit treated with N₂M₁ were higher than those of other treatments, and there was a significant difference between N₂M₁ and N₁M₀ (P<0.05). Correlation analysis showed that pineapple yield was significantly positively correlated with leaf number, leaf area index, dry matter accumulation, chlorophyll b content, vitamin C, soluble sugar and soluble protein. There was a significant negative correlation with titratable acid content. N₂M₁ treatment can significantly increase the number of leaves, leaf area index and photosynthetic pigment content of pineapple plants, increase fruit dry matter distribution, thereby increasing pineapple yield and effectively improving fruit quality. Therefore, N₂M₁ could be recommended as the best model for fertilization management of pineapple in tropical regions.

The present study investigated the ameliorative effects of 5-aminolevulinic acid (5-ALA) on muskmelon seedlings subjected to saline-alkali stress. Using the melon variety Zhongbao No.1 as the test material, under pot cultivation conditions, the study investigated the effects of root application of five different concentrations (25, 50, 100, 150, and 200 mg/L) of 5-ALA on the growth changes, photosynthetic pigments, reactive oxygen species (ROS) accumulation, osmotic adjustment, and antioxidant system of melon seedlings under 150 mg/L mixed salt-alkali stress. The results showed that under saline-alkali stress, exogenous 5-ALA at appropriate concentrations (100, 150 mg/L) significantly increased plant height, stem diameter, leaf length, leaf width, and leaf area of muskmelon seedlings. It also increased the contents of photosynthetic pigments and soluble sugars, proline content was reduced but still remained higher than that of CK, and significantly reducing both MDA content and O^2- generation rate. Furthermore, the activity of antioxidant enzymes, specifically SOD, CAT, APX, and GR, along with GSH content, exhibited elevation. Although POD activity showed a decrease, it maintained significantly higher levels compared to the control treatment (CK). In addition, TOPSIS comprehensive evaluation analysis was conducted on different exogenous 5-ALA treatments based on all the above measurement indicators, and the results showed that SA₁₅₀ treatment ranked first. Therefore, exogenous 5-ALA at a concentration of 150 mg/L exhibits the optimal effect in alleviating saline-alkali stress in muskmelon seedlings, which would provide a theoretical foundation for the cultivation of crops under saline-alkali stress conditions.

Reasonable fertilization is of great significance for increasing the yield of oil-tea Camellia, and the application of bio-organic fertilizers is superior to the current practice of using farm manure as the main fertilizer for oil-tea Camellia in many aspects. In order to develop and value the specialized bio-organic fertilizers suitable for the soil conditions of oil-tea Camellia plantations in tropical regions, the nutrient contents of oil-tea Camellia leaves, the physical and chemical properties, and enzyme activities of oil-tea Camellia forest soil were determined. The results showed that the application of bio-organic fertilizers and conventional compound fertilizer could significantly increase the water content, relative chlorophyll content (SPAD value), and nutrient elements of oil-tea Camellia leaves. The soil moisture contents and field capacities of different fertilization treatments were higher than those without fertilization, but there were no significant differences in soil bulk density and porosity between the treatments and the control group. All four types of bio-organic fertilizers could increase the contents of soil organic matter, alkaline nitrogen, available phosphorus, available potassium, and soil enzyme activity in different soil layers. T₁ and T₄ bio-organic fertilizer improved the chemical properties of oil-tea Camellia soil more, which is of great significance for the targeted improvement of the fertility and available potassium content of Hainan oil-tea Camellia forest land. The results would provide data for screening specialized bio-organic fertilizers suitable for tropical oil-tea Camellia, laying a scientific foundation for the subsequent large-scale application of bio-organic fertilizers for tropical oil-tea Camellia.