Sugarcane is an important sugar crop and energy crop. Evaluating the nutritional quality of sugarcane germplasm resources can systematically understand the nutritional value of sugarcane germplasm resources, and provide scientific basis for the development and utilization of sugarcane germplasm resources and breeding of new varieties. We carried out a study using 100 sugarcane germplasms, analyzed 14 nutritional indexes such as sucrose, reducing sugar, total free amino acid, polyphenol, mineral and protein in sugarcane juice, SPSS software was used for Principal Component Analysis (PCA) and Systematic Cluster Analysis (SCA) of nutritional quality traits. Results showed that there were differences in nutritional components among the 100 sugarcane germplasms and some nutrients had a significant correlation with each other. Sucrose content was negatively correlated with reducing sugar, protein, total free amino acid, fructose and glucose content, while protein content was positively correlated with total free amino acid and total polyphenol content. The content of fructose, glucose and sucrose was positively correlated with the content of P. Among mineral elements, Ca content and Fe content, Fe content and Cu content were positively correlated. The main factors affecting the nutritional quality of sugarcane germplasm were reducing sugar factor, protein factor, sucrose factor, Ca content factor and K content factor. The cumulative variance contribution rate of the common factors to comprehensive evaluation of sugarcane nutritional quality was 69.62%. SCA showed that the nutritional quality of the 100 sugarcane germplasms could be divided into 5 groups (European distance D=18.5). Group Ⅰcontained 77 resources, which had the highest sucrose content. Group Ⅱ contained 6 resources with higher Ca and Fe content. Group Ⅲ contained 2 resources, the average content of reducing sugar, protein, total free amino acid, total polyphenol, fructose, glucose, P, Na was high, and the average sucrose content and Fe content were low. Group Ⅳ contained 4 resources, which had the highest average total free amino acid content, higher average protein and total polyphenol content. Group Ⅴcontained 11 resources, with the highest average K content. The comprehensive evaluation of nutritional quality of the 100 sugarcane germplasms showed that the top 5 sugarcane varieties were 'Hetang 1', 'Dezhe 0978', 'Funong 40-95', 'Zhongzhe 45' and 'Yunzhe 06-193'.

In this study, 27 phenotypic traits of the floral organs of 135 Phalaenopsis varieties were observed and analyzed to provide a theoretical basis for the utilization of Phalaenopsis germplasm resources and the directional breeding of new varieties. 135 Phalaenopsis germplasm resources collected and preserved in the Fuzhou Branch of the New Plant Variety Testing Center of the Ministry of Agriculture and Rural Affairs were used as the test materials to collect data on 27 phenotypic traits of Phalaenopsis orchid organs and analyze the flower phenotypic traits. The distribution frequency, coefficient of variation, Simpson index and Shannon-Wiener index, and correlation, principal component and cluster analysis of quantitative traits were studied. The majority of butterfly orchid organs were violet petals, racemes, separated petals and no fragrance, which accounted for 31.85%, 60.74%, 79.26% and 84.44% of the corresponding description distribution frequencies respectively. The Simpson index and Shannon-Wiener index of the lobes in the lip were the highest, 0.992 and 7.047, respectively, and the diversity was the most abundant. The variation coefficient of quantitative traits ranged from 19.79% to 52.72%, of which the coefficient of variation of the number of inflorescences was the largest, which was 52.72%. Most of the main quantitative traits had extremely significant positive correlations. Principal component analysis extracted 3 quantitative traits as the representative traits for evaluating Phalaenopsis phenotypic traits, and calculated comprehensive scores. The top 3 were 'JB2312', 'Wanhuayanhuo' and 'Dongfanghong' respectively. The R-type cluster analysis showed that the 16 quantitative traits of Phalaenopsis could be divided into 4 categories, and the Q-type cluster analysis showed that the 135 Phalaenopsis varieties were divided into 5 major species groups. Our research indicates that the flower phenotypes of 135 Phalaenopsis varieties have rich genetic diversity.

The analysis of the genetic diversity of aromatic rice varieties and clarification of the genetic relationship of aromatic rice varieties can provide references for breeding high-quality aromatic rice varieties. 24 conventional aromatic rice varieties approved in Guangxi was used in the study. The genetic diversity of the varieties was analyzed by SSR fluorescence labeled capillary electrophoresis in this study. The results showed that a total of 170 alleles were detected by 48 SSR primers. The number of alleles (Na) varied from 1 to 9, with an average of 3.54. The range of effective allele number (Ne) ranged from 1 to 4.5534, with an average of 2.0736. The highest effective allele number was RM21, followed by RM481, RM493 and RM258. Four pairs of primers had high detection efficiency. Shannon's index (I) ranged from 0 to 1.7942 with an average of 0.7726. The variation range of polymorphic information content (PIC) ranged from 0 to 0.7541 with an average value of 0.3732, indicating that the 24 varieties had certain genetic variation. The genetic similarity coefficient of the 24 varieties ranged from 0.3299 to 0.9600, among which the genetic similarity coefficient of 'Sanxiang 628' and 'Nongxiang 32' was the lowest, indicating that the genetic basis difference of the two varieties was the greatest and the genetic relationship was the furthest. The genetic similarity coefficient of 'Wanxiang 696' and 'Guangliangxiang 2' was the greatest, indicating that the genetic basis difference of the two varieties was small and the genetic relationship was close. Cluster analysis showed that the 24 cultivars could be divided into three large groups and four subgroups at the similarity coefficient of 0.504. There were two varieties in theⅠcategory, 19 varieties in theⅡcategory and 3 varieties in theⅢcategory. CategoryⅡcould be divided into 4 subclasses at the similarity coefficient of 0.624, including 1 variety in Subclassⅰ, 14 varieties in subclass ⅱ, 3 varieties in subclass ⅲ, and 1 variety in subclass ⅳ. The results showed that there was a certain genetic diversity in the 24 varieties, but it was not rich enough. The DNA fingerprints of the 24 varieties were constructed in the form of digital coding. The results could provide references for breeding and identification of conventional aromatic rice varieties in Guangxi.

To gain insight into the genetic diversity and relationship of the tropic bioenergy plant physic nut (Jatropha curcas L.) in Yunnan, China, joint analysis of agronomic and molecular characters was performed in the present study, using different accessions collected from nine sources/geographical provenances in Yunnan. To investigate the population polymorphism, eight pairs of SSR molecular markers were developed by MISA program, and four of them with higher polymorphism were selected for PCR amplification using 95 DNA samples collected from nine populations. The results indicated that JC01 exhibited the best polymorphism (0.711). UPGMA clustering analysis suggested that Baoshan and Xishuangbanna might serve as the parents or origins of physic nut in Yunnan, which was partially related to the geographical origin of populations. Comprehensive investigations revealed among all examined biological traits of seeds or seedlings, the underground fresh weight (UFW) exhibited the highest coefficient of variation, with obvious separation among populations. Two individual seedlings with extreme variance in UFW (BNMH and CXYM) were selected for RAD-based genomic sequencing, while 2783 and 3033 contigs were assembled. Analysis of genome assembly data using GenomeScope revealed that both materials were diploid, and a total 22 756 valid SNPs were detected at the whole genome level using genome-wide association study (GWAS). High frequency-SNPs associated with UFW preferably located on LG9, and three candidate proteins were linked to the UFW trait. The results indicated that the physic nut germplasm collected from different regions of Yunnan exhibited a high level of genetic diversity and uniqueness, which should facilitate further studies on its molecular breeding.

In order to objectively select new rubber tree clones suitable for China's rubber planting environment, the yield and secondary characters of four introduced clones 'Reshi 09-5' 'Reshi 09-6' 'Reshi 09-7' and 'Reshi 09-10' were systematically identified and evaluated. The results showed that among the four clones, just 'Reshi 09-7' showed fast-growing, not yet in yield. Only 'Reshi 09-5' was close to the control in the first taping year and was lower in other years. The results of latex physiological characteristics showed that, according to good latex stability, fast latex discharge and high sugar utilization rate, 'Reshi 09-5' showed good rubber production potential, had higher thiol content and lower sucrose content than that of 'RRIM600', and there was no significant difference in dry rubber yield and initial speed of latex discharge between them. 'Reshi 09-6' had higher dry rubber content and plugging index, thicker original bark and more latex tubes number than 'RRIM600', and there was no significantly differences in initial flow rate and sucrose content between them. It was considered that the variety had good rubber production potential, but the metabolic intensity of latex was low. It had better potential in latex production, but a low metabolic intensity, so the production could be increased by stimulated tapping. The results of raw rubber properties, physical and mechanical properties, molecular weight and molecular weight distribution of vulcanizates of different varieties showed that there were some differences among the four clones. 'Reshi 09-5' showed the lowest in plastic initial value and Mooney viscosity, but the highest plastic retention rate. 'Reshi 09-6' showed the highest Mooney viscosity. According to larger weight-average molecular weight, 'Reshi 09-7' showed good physical and mechanical properties. In terms of stress resistance performance, 'Reshi 09-5' had the lowest wind damage collapse rate and 'Reshi 09-10' had the highest. The results of cold-resistant outpost data showed that under the condition of no cold injury in the control clone '93-114', the cold injury grade of 'Reshi 09-5' was 1.00, and that of 'Reshi 09-7' was 0.17. The comprehensive analysis results showed that the fast-growing traits of the four introduced clones were obvious. 'Reshi 09-6' had good rubber production potential. 'Reshi 09-5' had better wind resistance than 'RRIM600', 'Reshi 09-7' had good adaptability in cold damage. Among the four clones, 'Reshi 09-6' showed better performance in yield, girth growth, latex physiological characteristics and latex quality, and suitable to popularize and cultivate in same condition.

As one of the characteristic spice crops in tropical areas of China, the content of aroma components is the key index to identify the quality of Pandanus amaryllifolius Roxb. (Pa). Pa is suitable for planting under shade of Hevea brasiliensisr (Hb) forest in Hainan Island, China. However, the effect of Hb and Pa intercropping on the aroma component of the leaves of Pa has not been explored. Pot experiments were set up to compare the differences of soil physical and chemical properties and the types and content of aromatic composition in Pa leaves under intercropping and monoculture treatments. The intercropping mode significantly increased the soil bulk density by 13.63%, the content of soil alkali hydrolyzed nitrogen by 59.71%, the content of soil available phosphorus by 193.03%, the content of soil available potassium by 9.78% and the soil pH reduced by 1.00 (P<0.05). A total of 10 categories and 68 aroma components were detected in the intercropping and monocropping treatments. Compared with monocropping treatment, intercropping significantly decreased the number of ketones by 56.52%, furans by 14.29%, furanones by 33.33%, hydrocarbons by 20.00% and phenols by 28.57% (P<0.05). Although furans significantly reduced the content of aroma components by 65.28%, hydrocarbons by 20.88% and ketones by 69.00%, they significantly increased the content of alcohol by 31.50%, pyrrole by 597.56%, esters by 122.78% and furanone by 96.89% (P<0.05). The decrease of soil pH was the main reason for the reduction of ketones, furans, furanones, hydrocarbons and phenols. Intercropping indirectly increased the content of alcohols, pyrroles and esters and reduced the content of furans and hydrocarbons by reducing pH, while increasing soil available phosphorus and alkali hydrolyzable nitrogen. Pyrrole compounds were the main aroma components of Pa, thus the intercropping mode could significantly promote the quality of Pa. The results of this study would have a positive effect on the optimization and promotion of the Hb intercropping Pa mode, and also conducive to promoting the income increase of farmers and the sustainable development of related industries.

In order to promote the application of digital image processing technology in forest nutrition diagnosis and realize real-time monitoring of forest growth status and nutrient content, three prediction models of the total nitrogen content of young Aquilaria sinensis Lignum Resinatum based on image color and shape characteristics were constructed in this study, which provided a theoretical basis for nutrition diagnosis of young forest tree. Firstly, the optimal K value is determined according to the boundary distance and the size of the setting error, and the improved K-Means algorithm is used to extract the foreground image. Then, separate the three channels of R, G, and B of the foreground image and calculate the average value respectively. Then, the R, G, and B three channels of the foreground image are separated and the mean values are calculated respectively. According to the image color space conversion formula, the image is converted to HIS and Lab color space respectively, and the hue (H), saturation (S), brightness (I), brightness (L), red to green channel (a), yellow to blue channel (b), and a total of 9 color features are obtained. Find the minimum circumscribed rectangle of the foreground image, calculate the area (CA) of the foreground image, the area (RA), perimeter (RC), and rectangularity (RD) of the minimum circumscribed rectangle of the foreground image, and obtain four shape features in total. Finally, principal component analysis was performed on the color features, shape features, and color features + shape features, and the obtained three types of principal components were used as independent variables to construct a prediction model for the total nitrogen content of young A. sinensis, and the accuracy of the three models constructed was tested. Finally, the principal component analysis of color feature, shape feature, and color feature +shape feature was carried out respectively, and the three principal components obtained were used as independent variables to construct the prediction model of the total nitrogen content of young A. sinensis, and the accuracy of the three models was teste. The results show that improving the K value selection method can reduce the uncertainty of the K-Means clustering segmentation algorithm, enhance the segmentation efficiency of the algorithm, and achieve accurate segmentation of A. sinensis visible light images. The three models of the total nitrogen content of young agarwood constructed in this study had good prediction ability. The model accuracy based on single image parameters was basically the same, but the model based on shape features used fewer parameters and had higher relative modeling efficiency. The two-image parameter model uses more parameters than the single-image parameter model, but the fitting degree is better and the accuracy is higher. In practical applications, it can be selected according to different needs. In this study, different image features were used to build a total nitrogen model, which better realized the non-destructive estimation of the total nitrogen content of young trees, and provided a certain reference for precision forestry.

Sugarcane is an important sugar crop in the world, but the main sugarcane producing areas in China are hilly and dry slopes, and seasonal droughts occur frequently due to the uneven distribution of rainfall. Droughts do great harm to yield and quality and the sustainable development of sugarcane industry in China. The plant hormone abscisic acid (ABA) not only regulates plant growth and development, but also plays an important role in the physiological and biochemical responses of plants environmental stresses. In this study, we used sugarcane (Saccharum officinarum L.) variety 'Guitang 42' as the material to investigate the effects of exogenous ABA on leaf physiological characteristics and gene expressions under water stress condition in treatments control (normal irrigation), control+ABA, drought (stop irrigation), drought+ABA. The foliar application of 15 μmol/L ABA was sprayed twice in two days before drought stress given. The results showed that the changes of main physiological and biochemical parameters and gene expression in control+ABA treatment were not significantly different from those of the control. The leaf relative water content (RWC) was gradually decreased by drought treatment but it could maintain higher in drought+ABA treatment. The drought treatment could result in an increase in malondialdehyde (MDA) and hydrogen peroxide (H₂O₂) content, but the plants applied with ABA were found to resist the excessive accumulation of MDA. Drought stress significantly reduced the leaf chlorophyll content in sugarcane, but the exogenous ABA application decreased the degradation of chlorophyll, counteracted, at least in part, the decrease in quantum efficiency of PSII (ΦPSII). The expression of gene encoding 9-cis-epoxycarotenoid dioxygenase (NCED) for ABA biosynthesis, the genes encoding Δ1-pyrroline-5-carboxylate synthase (P5CS) for proline biosynthesis, and the antioxidant enzymes catalase (CAT), superoxide dismutase (SOD), ascorbate peroxidase (APX), peroxidase (POD) encoding genes was significantly increased in the leaf under water stress condition, following the significantly higher endogenous ABA content, proline content and CAT, SOD, APX and POD activities in water stress treatment as compared to the control. But exogenous ABA application under water stress could further enhance the expression of the genes, hence further improved the ABA content, proline content and related antioxidant enzyme activity. The results clearly suggests that the foliar ABA application could triggering the over expression of antioxidative defense system, and improve drought tolerance of sugarcane under water stress condition.

Artocarpus heterophyllus is popular for its sweet fruit and has a very promising market, but conventional seed propagation makes it difficult to maintain its excellent traits and the grafting method has a very low survival rate. The technique of tissue culture and rapid propagation has been widely used in the propagation of many rare and valuable plants, but there are no reports of its application in the production of A. heterophyllus. In the process of tissue culture, it was found that the stem tip of A. heterophyllus was severely browned, which led to the difficulty of establishing asexual reproduction system. In order to effectively investigate the measures to overcome the browning, this experiment took the stem tips of A. heterophyllus 'Haida 2' as the explants and inoculated them into different concentrations of PVP medium after low-temperature pretreatment at different lengths for primary culture, the browning rate and germination rate were calculated after 15 d, and PPO activity, total phenol and total flavonoid content were determined to explore the inhibition of different concentrations of PVP on browning in stem the tip tissue culture of A. heterophyllus after low-temperature pretreatment. The results showed that the browning rate of A. heterophyllus explants was the lowest and the germination rate was the highest after 12-24 h low-temperature treatment of stem tip and then in 1/2MS medium supplemented with 2.0 g/L PVP. The experimental results showed that this method was beneficial to the proliferation of A. heterophyllus explants. The purpose of this experiment is to promote the establishment of technique of tissue culture and rapid propagation for A. heterophyllus, with a view to providing a theoretical basis for the construction of the A. heterophyllus seedling breeding technology system and its industrial production demonstration.

Eucalyptus urophylla × E. grandis is a hybrid of Eucalyptus grandis (♂) and Eucalyptus urophylla (♀). It has the advantages of rapid growth, straight trunk, high yield, short rotation period, easy to germinate, strong adaptability and so on. So it has become the main cultivated tree species in the key forest areas, important commercial timber forest bases and forest products industrial bases of Yunnan Province. Due to its endogenous plant growth inhibitors, the disposal of wood processing residues has not yet been effectively solved. In this study, urea, manure from chicken and sheep, EM bacteria and enzyme bacteria were added to Eucalyptus bark for decomposing fermentation to promote the degradation of its endogenous inhibitors, making it an organic substrate with similar physical and chemical properties to peat. In order to reveal the effects of three levels of decomposed Eucalyptus bark (raw/40-day/60-day) compounding with three volume ratios (10%, 20% and 30%) of perlite on the enzymatic activity at plant seedling stage, four crops (Lycopersicon esculentum, Brassica oleracea, Lactuca sativa and Moringa oleifera) were cultivated in a greenhouse using the two-factor and three-level experimental design. After 6-8 weeks of growth, the activity of six enzymes associated with carbon and nitrogen metabolism (SS, SPS, Rubisco, GS, GOGAT, NR) in the leaves was determined. The results showed that the decomposition level and the proportion of perlite had the extremely significant interaction on the SPS activities of L. esculentum, B. oleracea and L. sativa (P<0.01). On the whole, the activity of enzymes related to nitrogen metabolism was more affected by the decomposition level than those related to carbon metabolism. The enzymatic activity of the three vegetables in 60-day-decomposed Eucalyptus bark were significantly higher than those in the control peat, raw Eucalyptus bark and 40-day-decomposed Eucalyptus bark (P<0.05). Among them, the enzyme activity of L. sativa in compound 30% perlite was significantly higher (P<0.05). In addition, the enzymatic activity of the three vegetables in 40-day-decomposed Eucalyptus bark compounding with 20% perlite were significantly higher than those in peat (P<0.05). The enzymatic activity of M. oleifera in peat was significantly higher than that in Eucalyptus bark substrate (P<0.05), and that in raw Eucalyptus bark was significantly higher than that in decomposed Eucalyptus bark. Besides, the mechanism of endogenous compounds in Eucalyptus bark influence on the activity of enzymes related to carbon and nitrogen metabolism during plant growth needs to be further studied.