The study was aimed to breed new varieties of fresh-eating sweet potato with high yield and high quality to meet the market demand of fresh-eating varieties. A new fresh-eating variety Guishu No. 15 was successfully bred with Yuzishu No. 7 as the mother and Guiziweishu No. 1 as the father. The variety is spindle-shaped with purple skin and white heart. Guishu No. 15 is centralized and neat, with an average number of 5.10 storage roots per plant. The proportion of commodity sweet potato is high, with a medium and large storage roots rate of 94.20%. The cooked has excellent quality, with β-carotene 27.70 µg/100 g, anthocyanin 67.40 mg/100 g, soluble sugar 5.39%, reducing sugar 1.90 g/100 g, and protein 0.94 g/100 g. The average fresh storage roots yield, dry storage roots yield, and starch yield in the two-year regional trial was 30 303.00 kg/hm² 8187.90 kg/hm² and 5195.99 kg/hm², respectively, significantly increased by 11.95%, 23.10% and 27.81% compared to CK. Guishu No. 15 has good high and stable yield, excellent cooked food quality, and moderate resistance to Fusarium wilt, bactrium wilt, stem nematode, and root rot disease, which is suitable for planting in Guangxi and its similar ecological areas.

Rice (Oryza sativa L.) is one of the most critical staple crops worldwide, and enhancing its yield is fundamental to ensuring global food security. Shanlan rice, a prominent upland rice variety in the southern regions of China, particularly in the mountainous areas of central Hainan province, is highly valued by farmers for its strong adaptability, drought resistance, and superior stress tolerance. However, traditional Shanlan rice varieties often suffer from challenges such as excessive plant height, vulnerability to lodging, and yield instability, which restrict the broader application in modern agriculture. This study focused on four local Shanlan rice varieties: Wuzhishan Nandui Village Shanlan rice, Huangke Shanlan Nuo, Shanlan Nuo and Shanlan Hong. The varieties were subjected to mutagenic treatment using ethyl methanesulfonate (EMS). After treatment, superior mutants were selected through screening across M₁ to M₃ generations based on significantly reduced plant height and either stable or enhanced single-plant yield. The results revealed the successful induction of multiple dwarf, high-yield mutants in all four varieties via EMS mutagenesis. For instance, in Wuzhishan Nandui Village Shanlan rice (WZSNDCSLD2), plant height was reduced by 9.6%, while single-plant yield increased by 52.8%; in Huangke Shanlan Nuo (HKSLN31), plant height decreased by 11.5%, and single-plant yield rose by 46.0%; in Shanlan Nuo (SLN8), plant height was reduced by 15.4%, with a 37.0% increase in single-plant yield; and in Shanlan Hong (SLH6 and SLH9), plant height was reduced by 22.2% and 15.5%, respectively, while single-plant yield increased by 49.6% and 36.8%. The superior mutants also exhibited significant improvements in agronomic traits, including total grain number, spikelet number per panicle, filled grain number per panicle, thousand-grain weight and seed setting rate. The findings of this study demonstrate that EMS mutagenesis is an effective approach for improving both plant height and yield-related traits in Shanlan rice. This research would provide new genetic lines and a solid theoretical foundation for the genetic improvement and molecular breeding of Shanlan rice.

ITS molecular identification and mycelial antagonism experiments on 11 strains collected in the early stage, then screened and studied the biological characteristics of suitable strains for cultivation in tropical regions based on germplasm evaluation to promote the rapid development of Phallus rubrovolvatus industry in tropical regions. The strains collected were all P. rubrovolvatus, of which two strains were synonyms, resulting in a total of 10 different P. rubrovolvatus strains. In mycelial evaluation experience, the mycelia of strains 147, 160, H29 and L70 showed good growth and high degradability on brown sugar medium and rubber sawdust medium, and the mycelia were able to recover growth after stress at 10 ℃ and 35 ℃, making them suitable for off-season cultivation in tropical regions. In rubber forests, four strains were able to produce mushrooms, and H29 produced mushrooms neatly, good shape, storage resistance and high yield (750 kg/667 m²), making it suitable for on-site growing indusium. L70 strain produced more mushroom-eggs, short growth period and high yield (800 kg/667 m²), making it suitable for concentrated growing indusium of mushroom-eggs after harvesting. In the single factor experiment, the nutritional requirements of H29 and L70 mycelia were basically the same, the most suitable carbon sources were trehalose and starch, the most suitable nitrogen source was malt extract, the most suitable temperature was 25-28 ℃, and the most suitable pH was 4-5. In the orthogonal experiment, both strains showed the best growth in formula 4 (soluble starch, malt extract, 25 ℃, pH=4), demonstrating the results of the single factor experiment. Especially, in formula 6, the mycelia of both strains were whiter and denser, making it suitable for the preservation of P. rubrovolvatus. SPSS analysis showed that the influence degree of various factors on mycelial growth was as follows: nitrogen source>pH>carbon source>temperature (H29), nitrogen source>pH>temperature>carbon source (L70), with nitrogen source and pH having a greater impact. The study could provide reference for breeding, large-scale cultivation of P. rubrovolvatus, and the development of mushroom industry in tropical regions.

The mini-seedling graft method of Hevea brasiliensis is widely used in the breeding of high-quality rubber tree seedlings due to its advantages such as a short nursery period, low labor intensity, large number of seedlings per unit area, and well-developed main roots of seedlings. However, the seedlings of rubber trees budded in autumn and winter require more time for the scions to germinate after graft survival, and the grafted mini-seedlings grow weakly, which diminishes the advantages of the mini-seedling graft method. Therefore, it is crucial to find appropriate technical measures to improve the germination rate and growth rate of the seedling scions. In this study, the effects of grafting time and topping time on the sprouting and growth of scions in grafted seedlings of rubber tree were investigated, specifically focusing on the seedlings grafted in winter with the variety H. brasiliensis reyan879. Grafting time significantly affected the survival rate, sprouting rate, seedling height, and nursery release rate of the grafted seedlings (P<0.05), with seedlings grafted in November showing significantly higher survival, sprouting, and release rates than those grafted in October, while the seedling height at the two leaf-umbrellas was significantly lower for November-grafted seedlings. Topping time significantly influenced the height of the scions at the stage of two leaf-umbrellas, without significant impact on the survival rate, sprouting rate, withering rate, nursery release rate, or scion stem thickness. The interaction between grafting time and topping time did not significantly affect the survival rate, sprouting rate, withering rate, growth volume, and nursery release rate of the grafted seedlings. It is advisable to adopt a strategy of overwintering with the stalks for mini-rubber seedlings grafted in winter, and to perform topping from February to March after the beginning of spring in the next year, which could significantly shorten the time of budding, reduce the number of times the rootstock debudding, and ensure higher scion growth quality, and this timing aligned well with the planting period of the year, offering significant practical value for production. For seedlings with rootstocks that have reached two leaf-umbrellas, topping just above the first pair of true leaves did not affect the survival rate and could control the withering rate below 4%, demonstrating good technical stability. It is recommended that in practical production, the grafting and topping times for rubber tree seedlings should be strictly controlled to ensure the rootstock reaching an appropriate growth state before topping, and management measures should be adjusted as needed to achieve the best nursery results. The application of the findings would help improve the production efficiency of rubber tree seedling cultivation.

The present work aims to provide references for differentiated nutrient management of litchi cultivars, and enhance the cultivation promotion of the new quality cultivars via clarifying the differences in nutrient content, nutrient transfer capacity and nutrient accumulation in different parts of litchi fruits among the main and the new quality cultivars in South China. A total of 73 litchi fruit samples belonging to 25 main and new quality litchi cultivars were collected from 29 litchi orchards in South China. The contents of 12 nutrients in pericarp, flesh and kernel of litchi fruits were determined to compare the discrepancies in nutrient transfer and accumulation among cultivars. Further, the types of nutrient accumulation in litchi fruit were categorized through cluster analysis. The results show that, most cultivars of litchi had the highest K content in the pericarp and the flesh, whereas the highest N content were observed in the kernel. The average transfer factors of P, S, Fe, Cu and Zn from pericarp to kernel ranged from 1.09 to 1.58, with strong transfer ability. N, K, Mg, B and Mo had medium transfer ability, with the average transfer factors within 0.53-0.99. The average transfer factor of Ca and Mn was only 0.35 and 0.481 respectively, with relative low transfer capability. With regard to the transfer capability from pericarp to flesh, N, K, Mg, S, Fe, Zn, B and Mo were figured by average transfer factors of 0.49-0.87, and Cu and P by high average transfer factors (5.91 and 1.32). However, Ca and Mn were characterized by extremely low average transfer factors of 0.069 and 0.112, respectively. Among the 25 cultivars, the content of Ca, Mg and Mn in Xiantaoli peel was higher than that of all the other cultivars, which was 6.13 g/kg, 3.34 g/kg and 233.52 mg/kg, respectively. Moreover, the ability of the three elements transferring from peel to kernel or flesh was lower than that of all the other cultivars, leading to excess accumulation in the peel. The requirement of N and K in 25 litchi cultivars was categorized into seven types: low N and high K, medium N and low K, medium N and medium K, medium N and high K, high N and low K, high N and medium K, high N and high K. The accumulation of Ca, Mg, B and Mo was divided into three groups including the low-, medium- and high-types, respectively. Ca and Mn were difficult to transfer in litchi fruit, being an obstacle to the development of litchi fruit. Conclusively, the nutrient accumulation of litchi fruit is cultivar dependent, therefore, elaborate nutrient strategy for litchi can be made to meet the nutrient demand for fruit development. The fertilization strategy for the new quality varieties of litchi can be referred to the traditional cultivars belonging to the same nutrient requirement type.

The effect of gibberellin (GAs) on the fruit size of longan using the F₁ generation of a stable hybrid population, FD 52 (big-size fruit) and FD 114 (small-size fruit), which derived from the cross between ‘Fengliduo’ and ‘Dawuyuan’, were studied. Three concentrations of gibberellin (50 mg/L, 100 mg/L, and 150 mg/L) were applied to the inflorescences of small-fruit longan at four time points: 3 days before anthesis (–3 d), on the day of anthesis (0 d), 3 days after anthesis (3 d), and 6 days after anthesis (6 d). The endogenous GAs contents in the treatments were measured, and fruit quality traits were mature at the ripening stage. Additionally, the endogenous GAs content, cell size, and the number of cell layers in untreated large-fruit and small-fruit longan were compared. Results showed that exogenous gibberellin application significantly increased endogenous GAs levels and promoted fruit enlargement, with the most pronounced effect observed when 100 mg/L gibberellin was applied 3 days after anthesis. Early in fruit development, GA₄ was the predominant active gibberellin in longan fruit, with higher levels of GA₄, larger cell size, and more cell layers observed in big-size varieties compared to small-size ones. The findings suggest that GAs application and the differential accumulation of GA₄ along with cellular factors such as cell size and layer number, contribute to the variation in fruit size. This study would provide valuable insights for improving longan fruit size through the application of gibberellin in cultivation practices.

Melon is an important cash crop in Hainan, and its pollination is mainly hormone pollination, which is easy to cause fruit deformity and accompanied by different degrees of flavor and quality decline, affecting commodity rate and planting efficiency. Melon Jiyoumi 29 was used as the experimental material. Different artificial pollen combinations were used to pollinate to compare with hormone pollination. The growth status of plants and fruits, the internal quality of fruits and the activities of key enzymes for sucrose accumulation, and analyzed the effects of pollination on the growth of plants and fruits were studied. Different pollination methods had great effects on plant height, stem diameter and biomass, fruit weight and hardness, and the stem diameter and biomass and fruit weight treated with T₁ were significantly higher than those of the other treatments. The plant height and fruit hardness treated with CK were significantly higher than those of the other treatments. There were significant differences among different pollination methods on each index of melon fruit internal quality, and T₁ treatment had the best effect, and its soluble solids, soluble sugar, sucrose content, fructose content and glucose content were significantly higher than CK treatment. The activity of sucrose synthase (SS) treated with T₄ was relatively high during fruit growth and development. The sucrose phosphate synthase (SPS) in T₁ treatment maintained a high level during the fruit growth and development, and the acid invertase activity in T₁ and T₂ treatment reached the highest at the 40th day after pollination, which were 93.69 U/g and 88.54 U/g respectively. The treatment of T₁ (strong pollen vitality × high stigma receptivity) has the best effect on the growth and fruit quality of melon plants after artificial pollen pollination.

Taraxacum grypodon Dahlst. is an important medicinal and edible perennial herb. To study the effects of light intensity on the growth and secondary metabolites of T. grypodon can lay a foundation for revealing the formation mechanism of its secondary metabolites, and provide crucial reference for its subsequent comprehensive development and utilization, and also provide guidance for establishing high-quality and high-yield dandelion artificial cultivation system. In this study, four shading gradients (the light transmittance was 100%, 80%, 50%, 30%, respectively) were set up in the greenhouse to cultivate T. grypodon. At the time of harvesting, the growth related indicators were measured, and the sugar, flavonoids, total phenols, and lignin components in the aboveground leaves and underground roots were analyzed. 100% light transmittance was conducive to the growth and photosynthetic efficiency of T. grypodon. Under this light condition, leaf length, root length, aboveground and underground biomass were the highest (P<0.05), and the SPAD value of leaves was the largest. The total sugar and polysaccharide contents of leaves and roots were the highest when the light transmittance was 100%, and the total sugar content in roots was significantly higher than that in leaves (P<0.05), and the polysaccharide content in roots was significantly higher than that in leaves. The content of reducing sugar in leaves and roots both was the highest when the light transmittance was 50%. The content of reducing sugar in leaves and roots both had significant difference under different shading treatment. The flavonoids content in the leaves was significantly higher than that in the roots (P<0.05), and reached to the highest content in 100% light transmittance. The total phenolic content in leaves was significantly higher than that in roots (P<0.05), and reached to the highest at 100% light transmittance, but decreased significantly after shading. The lignin content in roots was significantly higher than that in leaves (P<0.05), and both reduced under shading. In conclusion, the flavonoids and phenols of T. grypodon are mainly accumulated in leaves, while total sugars and polysaccharides were mainly accumulated in roots. Sufficient light is more conducive to the accumulation of the metabolites and plant growth. Proper shading is beneficial to the accumulation of reducing sugar, reduces the content of total phenol and lignin, and increases the taste quality of T. grypodon. In production, both medicinal and edible quanlity should be taken into account, so the cultivation conditions of T. grypodon are suitable for no shaded or slightly shaded habitats.

Bletilla striata var. Alba is a variant of B. striata which possesses high ornamental and medicinal value. However, there have been no reports on its seed germination and propagation to date. In this study, using the seeds of B. Striata var. Alba as the experimental material, indoor seed germination tests and pot tests were carried out to investigate the effects of mycorrhizal fungi from different sources (MB-15, MB-18, MH1-E and YDLXB) on seed germination and seedling growth. The results demonstrated that various mycorrhizal fungi had different effects on promoting the germination of B. striata var. Alba seeds. Among them, the Sebacina fungus MB-18, derived from the roots of B. striata, exhibited an extremely significant promotional effect. Compared with the control treatment, the germination rate and seedling formation rate in the petri dish experiment increased by 10.76% and 20.55% respectively, while in the pot validation test was 36.95% and 355.78%, respectively. Moreover, when sown directly, the seeds of B. striata var. Alba could germinate, but the seedling formation process was hindered. However, compatible mycorrhizal fungi (MB-15, MB-18, MH1-E and YDLXB) effectively promoted the formation of seedlings. The results are of great significance for the germplasm conservation, large-scale seedling breeding and sustainable utilization of B. striata var. Alba.

Hyphal polarized growth in filamentous fungi requires tip-directed secretion of growth-related substances, and previous studies have shown that exocyst complex plays an important role in the processes of fungal secretion and polar growth. However, there are few researches on the hyphal polarized growth and pathogenic mechanism of obligate biotrophic fungi at present. Rubber tree (Hevea brasiliensis) is the most important source of natural rubber. Powdery mildew is one of the most serious diseases of H. brasiliensis, and its pathogen Erysiphe quercicola belongs to obligate parasitic fungi. In this study, EqExo70, a subunit of the exocyst complex, was identified in E. quercicola. The GFP labeled EqExo70 was expressed in the E. quercicola by electrotransformation method, and it was found that the protein showed fluorescence aggregation at the hyphal tip, suggesting that EqExo70 may be related to hyphal polarized growth. In addition, we silenced the EqExo70 by electroporating the reverse complementary sequence of EqExo70 into the E. quercicola, it was found that the pathogenic ability of E. quercicola decreased and the growth of hypha slowed down, suggesting that EqExo70 affects the pathogenicity of E. quercicola. The level of callose deposition and reactive oxygen species burst in H. brasiliensis significantly increased upon infection with the EqExo70-silenced strain, indicating that EqExo70 contributes to suppressing host immune response. The results indicated that EqExo70 is a key factor affecting pathogenicity of E. quercicola, and may be involved in the interaction with H. brasiliensis, as well as the hyphal polarized growth.