Exploring the characteristics of dry-wet climate change and its impacts on crop yield can provide scientific basis for agricultural production planning and meteorological disaster prevention under climate change. Based on the daily ground observation data of meteorological stations in Zhanjiang area from 1960 to 2020 and the statistical data of rice, sugarcane and peanut yields from 1990 to 2020, the aridity index calculated by reference crop evapotranspiration (ET₀) and precipitation were used as drought index to analyze the characteristics of dry-wet climate change, and the impact of dry-wet climate change on crop yield was analyzed. The results showed that the interannual variation of precipitation in Zhanjiang area fluctuated greatly, and the annual average precipitation was 1534.41 mm, showing an insignificant rising trend. The temperature rised significantly at the rate of 0.18 ℃/10 a, and the annual average ET₀ and aridity index was 1242.72 mm/a and 0.87 respectively, showing an insignificant upward trend. According to the annual variation of the dryness index, from January to April and from October to December were the drought prone periods in Zhanjiang. The yield of rice, sugarcane and peanut showed a significant growth trend in the past 31 years, the increase of aridity index in April would reduce the yield of the three crops. The increase of aridity index in May would significantly increase the yield of peanut, but had no significant impact on the yield of the other two crops. The increase of temperature and the decrease of precipitation in June were conducive to the significant increase of rice and peanut yield. Sugarcane yield was not significantly affected by the change of temperature and precipitation, while the increase of dryness index in December significantly increased sugarcane yield. The results are of great significance for Zhanjiang and its surrounding areas agriculture to cope with climate change and improve the crop potential productivity.

In this experiment, seven different camellia plants were used as rootstocks and four different camellia scions to form 28 combinations, to screen the stocks-scion combination and study the grafting affinity, and to measure and analyze grafting experiment indicator that is the survival rate, preservation rate and growth traits of grafted seedlings, to investigate the growth status of grafted seedlings after 18 months. The relationship between grafting anvil, soluble sugar content and graft compatibility was evaluated. The result showed that the grafted survival rate and preservation rate of Camellia gigantocarpa Hu grafted with C. rosmannii and C. achrysantha scion were more than 90%, and the grafting survival rate and survival rate of scions reached more than 80% when C. gigantocarpa Hu grafted with C. chrysantha,, it is proved that C. gigantocarpa Hu is the best rootstock for grafting affinity. The grafting seedlings of C. japonica Heimudan and C. rosmannii had a preservation rate was 6.67%, the preservation rate of C. japonica Heimudan and other 3 kinds of scion was 0, it is proved that C. japonica Heimudan had the worst affinity as rootstock. The scions of C. achrysantha and C. rosmannii had better affinity with different rootstocks. The grafting survival reached more than 90%when C. achrysantha was grafted with C. semiserrata, C. hirsuta, C. japonica Heimudan, C. gigantocarpa. The grafting survival reached more than 90% when C. rosmannii grafted with C. gigantocarpa and C. amplexicaulis. The grafting survival reached more than 80% when C. rosmannii grafted with C. semiserrata and C. polyodonta. Grafting affinity is related to the soluble sugar content of stocks-scion. Closer sugar content of stocks-scion leads to the ratio is closer 1 and the higher grafting survival rate will be. C. gigantocarpa/C. achrysantha, C. hirsuta/C. achrysantha, C. amplexicaulis/C. rosmannii, C. gigantocarpa/C. rosmannii, C. gigantocarpa/C. chrysantha were found to be the excellent combinations by principal component analysis.

Mango is known as the "king of tropical fruits" for its unique flavor and rich nutrition. However, mango is extremely perishable during postharvest ripening, and the decay loss caused by anthracnose is the most serious. Therefore, how to prevent and control mango anthracnose after harvest has become a bottleneck problem restricting the healthy development of mango industry. In this paper, Tainong No.1 mango was used as the experimental material, and the green cinnamon essential oil composite chitosan lotion was used as the treatment means to study its control effect and mechanism on postharvest mango anthracnose, which would provide theoretical basis and practical reference for the development of postharvest mango storage, transportation and preservation industry in China. The results showed that the treatment of 0.5% cinnamon essential oil+0.3% chitosan had the best control effect on mango anthracnose, the treatment of 0.03% cinnamon essential oil could completely inhibit the growth and spore production of mango anthracnose in vitro, and the treatment of 0.01% and 0.02% cinnamon essential oil had obvious destructive effect on mango anthracnose mycelium. The complex treatment significantly inhibited the expansion of mango anthracnose disease spot, increased the content of disease resistance related substances lignin, total phenol (TP) and hydrogen peroxide (H₂O₂), and increased the content of disease resistance related enzymes phenylalanine ammonia lyase (PAL), peroxidase (POD),β-1,3 glucanase (β-1,3-GA) and chitinase (CHI). It can be seen that cinnamon essential oil composite chitosan lotion has a good control effect on mango anthracnose by inhibiting or destroying the growth and spore production of mango anthracnose mycelium, and inducing mango fruit to improve disease resistance. Therefore, the proper concentration of cinnamon essential oil combined with chitosan lotion treatment would provide a new green way to control mango anthracnose after harvest.

Dendrobium sinense is a tropical plant endemic to Hainan Island with great ornamental and medicinal values. However, unascertained reference genes restrict the quantitative analysis of gene expression in the species. In this study, using our previous transcriptome data of D. sinense, the 164 candidate genes were identified with low variance (CV≤0.2) and moderate expressions (TPM between 10-300). By GO clustering, 24 candidate genes were selected from different functional groups to avoid the effect of co-expression on further stability analysis. In order to avoid the false positive of genomic DNA that may remain in the template during RT-qPCR amplification, primers across introns were designed in this study, and amplification primers that met the requirements of 15 candidate reference genes were screened by electrophoresis. To ensure the specificity of RT-qPCR amplification, LightCycler 96 was used for melting curve analysis. According to the RT-qPCR data of 15 candidate genes, four tools were used to evaluate the expression stability. The results of multiple algorithm analysis showed that CLP1 & SEC23, SEC23 & CPY71, CLP1 & SEC23 and RNG1L & PECT were the best reference genes under drought stress. After comprehensive sorting, SEC23 and CLP1 were selected as the most stable reference genes under drought stress. In different tissues of D.sinense, ADF11 & IBR5, PRP19 & CLP1, ADF11 & CLP1, ACBP2 & IBR5 were identified as the best reference genes, respectively. After comprehensive analysis, ADF11 and ACBP2 were identified as the most stable reference genes in different tissues. Combined with the above drought stress and different tissue analysis data, IBR5 and CPY71 were finally determined as stable reference genes under comprehensive conditions. The validation of internal reference genes showed that compared with the traditional Actin internal reference, the internal reference genes screened in this study could obtain more accurate RT-qPCR calibration results, indicating that the generated internal reference genes had extremely high stability. In summary, this study provides ideas for identifying stable reference genes using transcriptome data. For the first time, stable reference genes were identified in the whole genome of D.sinense, which laid a foundation for further study of gene expression and function.

Banana (Musa spp.) is one of the most popular fruits in the world and is widely loved for its sweet taste and nutritious value, it is usually eaten after ripened. Bananas are rich in more than 90% resistant starch before they are unripe, and the effective use of resistant starch in green bananas can significantly increase the added value of the banana planting industry. In addition, green bananas are prone to producing a large number of defective fruits during the harvesting process, resulting in a serious waste of starch resources. In order to study the effect of autoclaving treatment on the digestion and structure properties of flour, three different banana cultivars: Dajiao, Fenjiao, and Gongjiao were chosen. By using scanning electron microscopy, dynamic light scattering, rapid paste viscometer, differential scanning calorimetry, Fourier transform near infrared spectroscopy, and X-ray diffraction analysis. To investigate the relationship between the structural changes and digestion properties of the three green banana flours before and after an autoclaving treatment was applied to them. The content of resistant starch in green banana flour decreased from 91.50%-93.33%(RS2 type) to 39.17%-44.63% (RS3 type) after autoclaving treatment. The scanning electron microscope results showed that powder granules were completely pasted and disintegrated, with variable particle size distribution and irregular shape. The amylose starch content increased from 23.3%-28.3% to 32.7%-37.0%, so that the thermal stability and gel enthalpy of green banana flour were significantly decreased (P<0.05) while the peak viscosity and breakdown was increased. The relative crystallinity of the green banana flour decreased from 28.98%-32.56% to 20.66%-22.26% after the autoclaving treatment. Despite this, the B-type crystalline structure was still preserved after the treatment. The new chemical bonds or functional groups were not found after the autoclaving treatment compared with green banana flour, and the short-range order R_1047/1022 was decreased from 1.031-1.166 to 1.016-1.122. The findings revealed that although the content of the resistant starch was reduced after autoclaving treatment, the type of resistant starch was changed from RS2 to RS3. This suggests that the stability of the resistant starch is greatly enhanced after autoclaving treatment. This research could offer a theoretical foundation for the production of heat-stable banana resistant starch, support the development of naturally starch-based materials, and is crucial for resolving the disparity between banana industry production and sales.

Chinese cabbage Sclerotinia rot is caused by Sclerotinia sclerotiorum, which seriously endangers the yield and quality of Chinese cabbage. In this study, the transcription level of resistance genes to the infection of S. sclerotiorum were explored at the molecular level and provided candidate genes for further study of disease resistance mechanism. The leaves of resistant inbred line H72 and susceptible strain Y26 were inoculated for transcriptome sequencing analysis. The results show that a total of 121.77 Gb clean reads were obtained by transcriptome sequencing analysis. Filtering the raw sequencing data, the clean reads of each sample were over 6 Gb, Q₂₀ ranged from 97.21% to 97.99%, and the average percentage was 97.61%, Q₃₀ ranged from 92.59% to 93.98%%, and the average percentage was 93.20%, indicating that the sequencing quality could be used for subsequent analysis. The number of common differentially expressed genes were 13 and 11 after inoculation for 36 h and 48 h, respectively. After removing the common differentially expressed genes at each time point, we obtained 18 differentially expressed genes. Combined with gene function annotation, 11 genes involved in defense response. MYB34 transcription factor was up-regulated, while ERF003 was down-regulated, which might negatively regulate the infection of S. sclerotiorum. Gretchen hagen 3.3 (GH3.3), PR proteins (TLP1), F-box, amino acid transporter (ANT1), caffeoyl-CoA O-methyltransferase (Cco AOMT), aspartyl protease (AED3), chaperone protein (DnaJ 11) were up-regulated, which were proposed to response to Chinese cabbage pathogen. The expression of epithiospecifier protein (ESP) and calcineurin B-like protein gene (CBL1) were down-regulated, and the disease resistance function in Chinese cabbage needs further analysis and verification. A further qPCR analysis was used to verify the transcriptome, The expression trends of differentially expressed genes ERF003, CBL1, GH3.3, MYB34, ANT1, TLP1 were consistent with that of transcriptome sequencing. These results will be helpful for further research the resistance mechanism to S. sclerotiorum.

Sugarcane plantations are mainly distributed in mountainous areas with high land fragmentation and complex cropping structure in Yunnan Province. Frequent cloud cover reduces the good observations of the land cover by using optical remote sensing. So it is difficult to extract sugarcane plantations with a high accuracy based on satellite optical remote sensing data. Xinping Country, a typical mountainous sugarcane plantation region, was chosen to explore a suitable method for the extraction of sugarcane plantations in mountainous areas. In this study, Landsat-8 and Sentinel-2 optical imagery for Xinping from October 1, 2019 to July 1, 2021 were used as the main data sources, and the DEM data and field survey data were used as the auxiliary data. The synthetic time-series images with high spatial-temporal resolution were constructed on Google Earth Engine (GEE). Firstly, we analyzed the differences among sugarcane and evergreen vegetation, water body, impervious, and other crops in spectral index characteristics, phenological characteristics, and topographic characteristics. Secondly, we determined the optimal thresholds for extracting sugarcane plantations for the four phenological parameters including rise time, fall time, above integral of season and below integral of season, as well as elevation and slope factors based on the training samples. Thirdly, we mapped the sugarcane plantations of 2020 and the mapping accuracy was verified using the validation samples in the study area. Finally, the spatial distribution of sugarcane plantations was analyzed at town scale. The results showed that synthetic time-series images based on the Landsat-8 and Sentinel-2 optical imagery could increase the number of good observations in the study area and improve the spatial resolution of the images, which could solve the problem of low quality of remote sensing images in mountainous areas and could better monitor phenological characteristics and seasonal changes of vegetation. The resultant 2020 sugarcane map had overall, user and producer accuracy of 97.07%, 88.85% and 80.57%, respectively with the Kappa coefficient of 0.83. According to the annual sugarcane map in 2020, there was a total of 7705 hm² sugarcane in Xinping, there were more sugarcane distribution in the southeast than in the northwest, as well as the southeast terrain was lower than that in the northwest. There were significant differences in the area of sugarcane plantations between townships, the township with the largest sugarcane plantation area is Mosha Town (2786 hm²) and the township with the smallest sugarcane plantation area is Gucheng district (0.87 hm²), which is consistent with the actual research. The sensitivity analysis of phenology parameters for sugarcane mapping demonstrated that the four parameters including rise time, fall time, above integral of season, and below integral of season are all important to improve the user accuracy and reduce the commission errors in the sugarcane mapping. The sugarcane plantation mapping algorithm proposed in this study could provide a reference for the extraction of sugarcane plantations in the complex landscapes of mountainous areas in the future.

Leaf color mutants are not only an ideal material for the study of rice functional genomics, but also of great significance for hybrid rice breeding. They can also be used as ornamental rice, committed to building rural leisure agricultural sightseeing spots and promoting rural revitalization. Based on a rice bright green leaf mutant bgl-2 obtained by radiation mutagenesis in the early stage of our research group, this study compared the difference in leaf color between the mutant bgl-2 and the wild-type SIPI, and showed that the mutant bgl-2 showed a bright green color different from the wild-type SIPI. The content of photosynthetic pigments in leaves was determined by 95% ethanol extraction at tillering stage. The results showed that the chlorophyll content of mutant bgl-2 was not significantly different from that of wild-type SIPI. By observing the other plant morphology of mutant bgl-2, it was found that the leaf tips of its flag leaf and the last two leaves were bent, and the flag leaf was significantly shorter than that of wild-type SIPI, and its plant height was also significantly shorter than that of wild-type SIPI. It was found that the 1000 grain weight, grain length and grain width of mutant bgl-2 was significantly smaller than those of wild-type SIPI, but its length width ratio was not significantly different from that of wild-type SIPI. The structure of flag leaf cells of wild-type SIPI and mutant bgl-2 at tillering stage was observed by the transmission electron microscope. The results showed that the cell wall of mutant bgl-2 was significantly thickened, but the thickness of outer membrane of cell membrane was significantly reduced, the inner membrane was almost degraded, and the lamellar structure of thylakoid in chloroplast ultrastructure was looser than that of wild-type SIPI. F₁ plants were obtained by hybridization with mutant bgl-2 as female parent and wild-type SIPI as male parent. The investigation found that its leaves were normal green, and the morphology of flag leaf and inverted two leaves were normal, while the F₂ population after self pollination isolated normal green leaf seedlings and bright green leaf seedlings with obvious leaf color differences. The segregation ratio of normal leaf color plants and bright green leaf plants in the population was counted, which showed that it conformed to the single gene model of 3 : 1. The above results clarify the phenotype and genetic characteristics of the mutant bgl-2, and provide a theoretical basis for the study of the molecular regulation mechanism of the mutant bgl-2 and promoting its application in rice breeding. The location cloning and functional analysis of BLG-2 gene will be carried out later.

The phenotypic characters of sugarcane germplasm resources native of domestic were analyzed to study the law of genetic variation, so as to provide a theoretical basis for the selection of sugarcane genetic breeding parents and the construction of core germplasm population. 160 sugarcane varieties/parents from 8 different regions native of domestic were used as materials to evaluate the phenotypic traits with reference to the specification and data standard for sugarcane germplasm resources description. Most traits showed rich genetic diversity. Among them, the diversity index of the 20 quality traits was 0.07-1.40, with a mean of 0.84, which was the highest in bud type and the lowest in stalk shape. Five quantitative traits had 8.74%-38.26% of the coefficient of variation, with a mean of 17.69%, which was the highest in millable stalks (38.26%) and the smallest in stalk lengt (8.74%). The diversity index (H′) of the five traits was 1.46-1.83, with a mean of 1.64, which was the highest in stalk lengt (1.83) and the lowest in millable stalks (1.46). The average coefficient of variation of the tested materials in different regions was 13.56%-22.33%. The coefficient of variation of the variety population from Hainan was the largest (22.33%), and the dispersion of quantitative characters was the largest. The coefficient of variation of variety population from Fujian was the lowest (13.56%). By cluster analysis,160 accessions materials were divided into seven categories based on four traits, among them class 5 accounted for 90.62% of the total germplasm resources. This group resource has the characteristics of high yield and sugar content. The results could provide an important reference for the utilization of sugarcane germplasm resources, parental selection and variety breeding.

Cowpea wilt is a soil-borne fungal disease caused by Fusarium oxysporum f.sp. tracheiphilum (FOT), and is one of the most important diseases of cowpea. In our study, several biocontrol bacteria were isolated and evaluated. One of the bacteria which were found the best antagonistic effect to FOT was identified and studied on its antagonistic mechanism and growth promoting function, while it was evaluated by the control and growth-promoting effects. This study established the foundation for the research and development of excellent biocontrol agents for cowpea Fusarium wilt. 93 strains of bacteria were isolated by plate dilution method, and 11 biocontrol strains, which exhibited good inhibitory effect on the pathogenic bacteria of cowpea wilt, were screened by plate confrontation method, and the antagonistic strain SD13 had the best inhibition rate (the inhibition rate reached 82.0%). SD13 was identified as Bacillus velezensis based on Morphology and 16S rDNA sequence. Liquid medium co-culture method showed that SD13 could break down the cell wall of the hyphae, spores, and germinated spores of the FOT. Assay medium test results indicated that SD13 could secrete cellulase, protease and β-1,3-glucanase, and had the function related to the production of siderophore, nitrogen fixation and solubilise inorganic phosphorus. Plate confrontation method showed that SD13 had antagonistic activity against a wide spectrum of pathogenic fungi, with inhibition rate ranging from 66.7% to 82.3%. Pot experiments indicated that in four treatments in concentration of 10⁴, 10⁶, 10⁸, 10⁹ CFU/mL, there were the best control effect of SD13 in concentration of 10⁶ CFU/mL, reaching 62.0%, and the growth promotion effect was the second, lower than that of the concentration of 10⁸ CFU/mL. This study shows that SD13 has good biocontrol and growth-promoting effects, and is preliminarily clarified the antagonistic mechanism and functions related to growth-promoting ability, which has potential application value for the prevention and control of Fusarium wilt.