Abstract:Maize is an important food crop that is primarily used as feed to provide necessary metabolizable energy and nutrients for livestock and poultry. The nutritional value of feed is closely associated with the proportion of protein and amino acid composition.However，maize protein exhibits an imbalanced amino acid content，adding soybean meal supplements the lysine and tryptophan lacking in maize. However，sulphur-containing amino acids （cysteine and methionine） are also limiting amino acids in soybean. Methionine has a direct effect on the rate of protein synthesis in the bodies of livestock and poultry，which in turn affects the production of meat，eggs，and milk. Consequently，it is of great importance that there be a significant enhancement of the sulphur-containing amino acid content，particularly that of methionine，in maize，with a view to facilitating the development of animal husbandry. One limitation of China's maize germplasm resources is the lack of high methionine varieties. Additionally，the breeding process is relatively slow. In recent years，extensive research has been conducted on the absorption and transport mechanism of sulfur elements in plants，leading to the initial construction of a metabolic regulatory network for sulfur-containing amino acids. In this study，we summarized the research results of improving the metabolic mechanism of sulfur-containing amino acids in crops，proposed a new strategy of combining population genetics，comparative genomics and molecular biology to mine candidate genes，and used modern biological breeding to improve the methionine content of maize，so as to provide a reference for genetic improvement of high-quality protein maize.

Abstract:Black and red rice varieties are special resources that exhibit black （purple） or red seed coat， respectively， due to pigment deposition， which is rich in nutrients， with more protein， minerals and dietary fiber than white rice. They are also rich in physiological activator such as anthocyanins （procyanidins）， flavonoids， and terpenes. Their nutrient substance and value are significantly higher than those of white rice varieties. Therefore， they are favored by more and more rice consumers. Our country is rich in black and red rice resources， rational utilization of nutrient-rich black and red rice resources， and creation of elite new germplasm and breeding of new black and/or red rice varieties are of great significance to promote the development of special rice industry. In this study， the research history of black and red rice were summarized in four stages and the resource distribution of black and red rice were introduced； the research progress in quality， yield， resistance， and development and utilization of black and red rice were summarized， especially for the latest research progress on quality specificity and formation mechanism. Finally， the weaknesses of current research on black and red rice were summarized， and prospects for future research directions on black and red rice were proposed， so as to provide a reference for the cultivation of new varieties of black and red rice and the further development and utilization of black and red rice.

Abstract:Tomato， being one of the important vegetable crops， holds great significance in evaluating the drought resistance of tomato germplasm resources and selecting drought-resistant varieties for tomato breeding. In this study， we subjected 92 tomato germplasm resources to drought stress treatment using a 12.5% PEG-6000 solution. Six drought-related indexes， including germination potential， germination rate， germination index， vigor index， root length and shoot length， were measured， and the drought resistance of tomato at germination stage was evaluated and screened by correlation analysis， principal component analysis， membership function method and cluster analysis.The results showed a significant reduction in all six indicators under drought stress， with the vigor index and germination potential being the most affected. Through principal component analysis， we transformed the six indicators into two new indicators， which contributed to a cumulative contribution rate of 86.657%. Based on correlation and principal component analysis， we identified germination potential， germination rate， germination index， and vigor index as the main indicators for evaluating drought resistance during the germination period. By using the subordination function method combined with cluster analysis， we classified the tomato germplasm resources into four types，including 19 drought-resistant types， 41 relatively drought-resistant types， 18 relatively sensitive types， and 14 sensitive types. By adjusting the concentration of PEG-6000 solution， further screening of the drought-resistant varieties Mizhihong Tomato and Jinnongaiyang， as well as the sensitive varieties Beijingzaohong and Dahongpao can be conducted.These findings provide a theoretical basis for the study of drought resistance in tomato germplasm resources.

Abstract:Kernel moisture content （KMC） at maturity is a crucial factor affecting the mechanical harvesting of maize. By utilizing multi-locus genome-wide association study （ML-GWAS），this study aims to explore significant genetic loci associated with KMC and provide insights into the genetic basis，which can contribute to the breeding and genetic improvement of maize varieties for appropriate harvesting. In this research，205 maize inbred lines were used to measure the moisture content of kernels，husks，and cobs at maturity in four different environments. Six ML-GWAS methods，including mrMLM，FASTmrMLM，FASTmrEMMA，pLARmEB，pKWmEB，and ISIS EM-BLASSO，were applied in combination with 76492 single nucleotide polymorphisms （SNPs） distributed throughout the genome for association analysis. Candidate genes were identified and gene annotation was performed. Phenotypic analysis showed that the coefficient of variation for KMC-related traits ranged from 10.47% to 33.90%，with a broad-sense heritability ranging from 67.39% to 81.24%. A total of 26，15，and 23 SNP loci were significantly associated with kernel moisture content，husk moisture content，and cob moisture content，respectively. Among them，14 significant SNP loci were identified by three or more methods，with a phenotypic contribution ranging from 1.13% to 17.21%. pLARmEB detected the most significant loci，while FASTmrEMMA detected the fewest. Based on the detection by three or more methods with an average PVE （Proportion of variance explained）≥5%，significant SNP loci Chr1_9232728，Chr4_176596174，Chr8_57716249，and Chr5_191021635 were identified. Around these loci，within a 220kb upstream and downstream range，a total of 17 candidate genes were excavated. These genes were predominantly enriched in cellular anatomical entities，metabolic processes，and cellular processes with catalytic activity. It is hypothesized that these genes may influence the moisture content of maize kernels，husks，and cobs by modulating cellular metabolism and catalytic activity.

Abstract:Genetic stable female sterile line is the key to realize heterosis utilization， and it is also a essential pathway to achieve simplified hybrid seed production by using female sterile gene. A female sterile line in genetics， named FS2106， was first discovered during our investigation of germplasm resource. The phenotypic traits， pollen viability and chromosome numbers were tested in the plants， while two hybrid combinations and their segregation populations were built with FS2106 and other two normal female parent， thus traits separation of female sterile， stigma color， shenth color and involurce texture were observed in F₁ and F₂ generation populations， and inheritance modes and regulations of four traits were revealed by χ² test. The results showed that plant height， stem diameter， tillers， leaf length and leaf width were 86.9 cm， 4.9 mm， 33.4 per plant， 34.3 cm and 2.2 cm in average， respectively. In flowering stage， its pistillate spikelet grows without development， but tassels are proper growth and produce viability pollens， exhibiting stable female sterile characteristics. Chromosome number was a normal type of 2n=20. Moreover， the female sterile trait in FS2106 is a recessive nuclear inheritance controlled by a single gene， while its purple leaf sheath and stigma and involurce texture are the dominant heredity of single gene， and alleles were heterozygous in involurce texture loci. In conclusion， the discovery of FS2106 and the mining of female sterility gene could provide the basic materials for the heterosis utilization and seed production of adlay， and traits of leaf sheath color， stigma color and involurce texture can be acted as macroscopic flags in breeding procedure.

Abstract:To investigate the genetic diversity of aroma components in grape germplasm resources， 62 grape germplasm resources were used as experimental materials. Headspace solid-phase microextraction combined with gas chromatography-mass spectrometry was used to detect volatile compounds， and significance analysis of aroma compounds was conducted. 8 agronomic traits were identified， such as color of the upper side， sheen on upper side， anthocyanin colouration of young leaves， articular flavor of mature berries， and so on. Correlation analysis was carried between volatile compounds and 8 agronomic traits. The characteristic volatile substances compounds was screened out by non-metric multidimensional scale analysis （NMDS， stress<0.2） and orthogonal partial least squares discriminant analysis （OPLS-DA）. The results showed that a total of 99 volatile substances in 7 categories were detected in 62 grape germplasm resources， mainly alcohols， esters and terpenes， with the contents of 13.83 mg/L， 13.53 mg/L and 8.99 mg/L， respectively. There are significant differences among various volatile substances. The results of correlation analysis between 8 agronomic traits and aroma substances showed that the color of the upper side，sheen on upper side， anthocyanin colouration of young leaves， color of skin and articular flavor of mature berries were significantly correlated with terpenes， esters and ketones. Non-metric multidimensional scaling analysis can clearly distinguish the germplasms with very weak anthocyanin coloring of young leaves and the germplasms with middle anthocyanin coloring of young leaves. Based on the variable importance in projection （VIP）>1， P<0.05 as the standard， 17 main volatile substances were screened， among which the VIP value of ethyl caproate was the highest （4.07）， and the VIP value of nerol in terpenes was the highest （2.07）. This study provides a theoretical reference for improving the aroma quality of berries and the innovation of grape germplasm resources.

Abstract:This study aimed to investigate the genetic diversity of fruit phenotypic traits in wild Camellia oleifera from various seed sources， as well as to provide a theoretical basis for selecting superior C. oleifera cultivars and improving genetic germplasm resources. Eight fruit phenotypic traits of C. oleifera were quantified and analyzed using various statistical methods， including analysis of variance， nested analysis of variance， correlation analysis， principal component analysis， and cluster analysis. This study investigated 218 well-developed C. oleifera specimens from 16 provenances across nine provinces（autonomous region）， including Guangdong， Guangxi， Jiangxi， Anhui， Sichuan， Hubei， Hunan， Shaanxi， and Guizhou. The results demonstrated that the mean values of the coefficients of variation for eight fruit phenotypic traits of 16 provenances ranged from 12.03% to 35.08%. Notably， the mean value of the coefficients of variation between provenances （42.83%） was found to be greater than the mean value of the coefficients of variation within provenances （23.99%）. The mean value of the coefficients of variation of the phenotypic differentiation coefficient was 88.63%， indicating that there were abundant variation in phenotypic traits of different germplasm resources of wild C. oleifera fruits. The results of the correlation analysis indicated that there were significant positive correlations between fresh fruit weight， fruit height， fruit diameter， peel thickness， fresh seed weight， and the number of seeds per fruit. Conversely， there were significant negative correlations between peel thickness and fresh seed yield. The results of principal component analysis indicated that the cumulative contribution rate of the first three principal components was 90.773%， suggesting that the majority of the phenotypic traits of wild C. oleifera fruits could be adequately represented by the first three principal components. The first principal component primarily reflected the characteristics of fruit size， the second mainly reflected the characteristics of fruit seeding rate， and the third mainly reflected the characteristics of fruit shape. Cluster analysis revealed that the 16 provenances were divided into Ⅰ and Ⅱ classes at Euclidean distance 10， with further subdivision into subclasses at Euclidean distance 5. Class I is more convenient in terms of production and processing， while Class II is more advantageous in terms of yield and profitability. The phenotypic traits of wild C. oleifera fruits exhibited considerable diversity， and different groups of provenances could be selected as breeding materials according to breeding objectives.

Abstract:Sterculia monosperma Vent.， also known as phoenix-eye fruit， nine-layer-skin fruit， etc.， is a dual-purpose nut plant for medicine and food.In an effort to effectively conserve and exploit the germplasm resources of Sterculia monosperma Vent.， a comprehensive assessment and diversity analysis was conducted on 70 germplasms of this species. This study employed a robust set of statistical methodologies including diversity， cluster， correlation， principal component， and stepwise regression analyses. Variability in thirteen fruit traits was examined， with the coefficient of variation ranging from 7.80% to 42.94%. Notable variability was observed particularly in traits such as single fruit weight， single fruit seed weight， starch content， soluble sugar content， and soluble protein content. The genetic diversity index across these traits spanned from 1.57 to 2.04， with the seed-form index（2.04）， starch content（2.02）， seed longitudinal diameter（2.01）， and fruit seed number （2.00）displaying higher diversity indices， indicative of a substantial genetic variation. Through cluster analysis， the germplasms were segregated into four groups， with Group II consisting of 15 resources identified as larger fruit-bearing and aesthetically superior， aligning with market preferences and breeding objectives. Correlation analysis showed that seed weight was highly significantly and positively correlated with fruit longitudinal diameter， single fruit weight， single fruit seeds weight， seed longitudinal diameter， and seed transverse diameter， respectively；kernel rate was highly significantly and negatively correlated with fruit transverse diameter； and soluble protein content was highly significantly and positively correlated with soluble sugar content.Principal component analysis elucidated that the primary four components accounted for 74.46% of the total variance in the 13 assessed fruit traits. A comprehensive evaluation yielded a score （F） range from -2.95 to 3.35 for the fruit traits， with germplasms S009， S021， S011， S036， and S028 demonstrating superior comprehensive attributes. Furthermore， stepwise regression analysis delineated four pivotal trait indicators—single fruit seed weight， seed weight， soluble sugar content， and seed transverse diameter—as essential for the holistic assessment of the Sterculia monosperma Vent. fruit traits. These indicators are proposed to guide future conservation strategies and breeding programs for this species. Finally，Through identification and evaluation， six excellent germplasm resources with large fruit， high starch content and rich soluble sugar and soluble protein content were selected.

Abstract:Grain traits have a direct impact on the yield and quality of rice. Therefore， understanding the genetic mechanism underlying these traits is crucial for improving rice yield and quality. In this study， Ludao and Guangbaixiangzhan （GBXZ）， which exhibit significant differences in grain traits， were used as parent plants to create a segregating population. Using the 1 K mGPS rice SNP chip， the targeted population was genotyped and a high-density genetic map containing 770 Bin markers was constructed. Through QTL mapping analysis， a total of 17 QTLs related grain traits were detected， including 4 QTLs for grain length， 3 QTLs for grain width， 3 QTLs for grain thickness， 2 QTLs for length-to-width ratio of grain， and 5 QTLs for 1000-grain weight. The phenotypic variation explained by these QTLs ranged from 4.73% to 29.63% with the LOD values ranging from 2.55 to 42.44. Of these 17 QTLs， 9 QTLs were known loci related to grain size， and 8 QTLs might be newly identified. Among the 8 new QTLs， qGL6 was related to grain length， qGW5， qGW10 and qGW12 were related to grain width， qGT10 was related to grain thickness， qGLWR5-2 was related to length-to-width ratio of grain， qTGW10 and qTGW11 were related to 1000-grain weight. Based on the gene annotation， Arabidopsis homologous gene comparison， spatiotemporal expression analysis， hormone response analysis， and sequence analysis of the candidate genes in the definite qGW5 region， a candidate gene Os05g0195101 encoding a CCCH-like zinc-finger protein for regulating rice grain width was finally screened. This study lays the foundation for further cloning of rice grain trait genes and analyzing the genetic regulation of grain traits.

Abstract:The amylose and amylopectin contents of 100 broomcorn millet germplasm resources were measured， and they were genotyped by molecular markers targeting the Waxy gene， the key factor modulating amylose synthesis. Some representative resources showing different amylose content were sequenced by Sanger approach. The amylose content in the collection ranged from 0 to 22.78%， with an average of 6.07%. 36% of germplasm resources were detected with amylase content less than 3.7%， including 24% detected without amylase. The amylopectin content ranged from 4.55% to 56.73%， with an average of 15.30%. The functional marker M5/R11 was able to effectively distinguish S₀， S_-15 and S₀S_-15 genotypes， and PCR products of markers int5Lf/R3 and M12/R12 were digested by endonucleases Acc I and EcoN I， enabling the identification of L_C， L_Y and L_F alleles. Nine genotypes at the Waxy locus were found in the collection. The genotype S₀/Lc accounted for 33%， and S_-15/L_F accounted for 25%. The genotypes remained heterozygous （S₀S_-15/L_F， S₀S_-15/L_C and S₀S_-15/L_YL_F）， and each of them accounted for 2%. A large number of new SNPs were found among landraces such as Gangu Heichanbei， Black millet， Qingyang Esiniu， as well as the varieties Jinshu 9 and Chimi 2. These SNPs serve a potential in future gene function analysis and innovative breeding in broomcorn millet. Collectively， this study provided theoretical basis for molecular breeding and quality improvement in broomcorn millet.

Abstract:In order to explore the molecular mechanism of the variation of kiwifruit from dioecious to monoecious， transcriptome sequencing， bioinformatics analysis and qRT-PCR verification on female and male flowers of the monoecious mutant of Mantianhong kiwifruit were carried out. The results of transcriptome differential expression gene identification showed that there were 337 differentially expressed genes （DEGs） between female and male flowers， with 241 genes up-regulated and 96 genes down-regulated in male flowers. The GO and KEGG enrichment of DEGs showed that compared with female flowers， the up-regulated genes in male flowers were mainly involved in the metabolism of amino sugars and nucleotide sugars and the synthesis of secondary metabolites. The down-regulated genes were mainly enriched in secondary metabolite synthesis， carotenoid synthesis and other pathways. Through functional annotation analysis， 30 potential gender-related regulatory genes were identified， five of which were expressed in the secondary metabolite synthesis pathway. Seven DEGs were selected for qRT-PCR， and their expression levels in male and female flowers were in accordant with those in transcriptome data. The results of this study provide a theoretical basis for the creation of kiwifruit monoecious materials.

Abstract:Low temperature stress during storage will greatly reduce the commodity value of sweetpotato. It is of great significance to study the molecular mechanism of cryopreservation tolerance and reduce the influence of low temperature in the storage process of sweetpotato. In this study， ‘Shangshu 19’ （S19）， ‘Yanshu 25’ （Y25） and ‘Sushu 16’ （S16）， three sweetpotato varieties that showed tolerance，intolerance，and moderately tolerant to low temperature storage， were stored at 9 ℃ and 6 ℃ for 35 days， respectively. The total RNA of above tuberous roots were exacted for transcriptome sequencing and comparative analyis，and the results showed that S19 had fewer differentially expressed genes after low temperature storage， while the opposite was observed for Y25， and S16 was intermediate. KEGG and GO analysis of differentially expressed genes showed that the expression level of proteasome related genes was higher in tuberous roots under low temperature stress. Finally， by comparing the transcriptome data of tuberous root of different varieties under different storage temperatures， a candidate gene Ibat.Brg.02F_G010830 that responds to low temperature stress during storage was obtained and it was annotated as cold-responsive protein kinase 1-like. qRT-PCR verified that the expression of this gene was consistent with the transcriptome data. The phylogenetic analysis of this gene and its alleles and orthologs was conducted， as well as the variation of this gene in different varieties. This study will provide support for the resolution of response mechanism under low temperature storage and the selection of varieties with low temperature storage tolerance.

Abstract:The plant growth regulator 5-hydroxy-tryptamine （5-HT） has been used in agricultural production to improve crop drought resistance. The underlying molecular mechanisms of its transcriptional response are largely unknown. In this study， the simulated drought stress-related physiological and molecular mechanisms of exogenous 5-HT on Morella cerifera seedlings were elucidated， including transcriptome sequencing and the evaluation of endogenous hormone levels and antioxidant enzyme activity. The results demonstrated that abscisic acid （ABA） and jasmonic acid （JA） content in Morella cerifera fibrous roots significantly increased following 50 μmol/L 5-HT treatments but decreased in 100 μmol/L treatments. Both the malondialdehyde （MDA） content and superoxide dismutase （SOD） activity were significantly increased but hydrogen peroxide （H₂O₂） content decreased following 50 μmol/L 5-HT treatments. Based on gene set enrichment analysis （GSEA）， two-concentration levels 5-HT treatments were investigated. The differential gene set terms primarily included antioxidant activity， oxidoreductase activity， auxin and gibberellin-mediated signaling， cell wall biosynthetic， phospholipid translocation， xylan biosynthetic， pectin metabolic， secondary metabolite biosynthetic， phenylpropanoid metabolic and galacturonan metabolic process. The differentially expressed genes （DEGs） related to antioxidant enzyme activity and hormone metabolism were mainly PER， LAC， DHAR and PIN. Eight sets of co-expressed gene modules were significantly correlated with 5-HT and drought stress by the weighted gene co-expression network analysis （WGCNA）. The hub genes KAB1218346.1（LOX3）， KAB1219593.1（WRKY53）， KAB1217691.1（CZF1） were primarily associated with hormone metabolism and regulation of transcription. These key genes and their molecular regulatory mechanisms will be important targets for future research.

Abstract:The germplasm resources serve as the fundamental foundation for the original innovation of agricultural science and technology， as well as the advancement of the modern seed industry.Screening excellent germplasm provides a material basis for cultivating excellent cotton varieties. In this study， 13 phenotypic traits of 230 cotton germplasm resources were analyzed using genetic diversity， correlation， principal component and clustering methods. The results show that the variation coefficient of 13 characters between 0.90%-22.43%， the variation coefficient of uniformity index minimum， the maximum variation coefficient of boll number per. The genetic diversity index of each phenotypic trait ranged from 1.92-2.07. The genetic diversity index of micronucleus value was the highest， and the genetic diversity index of boll number per plant was the lowest.The results of principal component analysis showed that the cumulative contribution rate of the six principal components reached 74.413%. The first principal component， the fifth principal component and the sixth principal component could be combined into fiber quality factor， the second principal component and the third principal component could be combined into cotton yield factor， and the fourth principal component was plant trait factor.Cluster analysis divided 230 cotton germplasm materials into three categories， including group Ⅱ is yield and fiber quality traits comprehensive performance better. Finally the evaluation on the basis of comprehensive D value， preliminary screening of 29 performance better cotton varieties， can according to the breeding goals in breeding work carries on the corresponding improvement.

Abstract:'Allen Eureka' is a progeny variety of the variety ‘Eureka lemon’ due to bud mutation. This variety showed excellent performance at fruiting traits， while it was susceptible to winter defoliation， eventually resulting in severe leaf shedding and decreasing the yield production in the coming year. The mechanism of leaf shedding remains unknown. Two lemon cultivars （‘Allen Eureka’ and ‘Yunning No. 1’） with degrees of winter defoliation were used to investigate the molecular regulatory mechanisms of leaf abscission. The petiole abscission zones were collected at three stages， namely， the pre-defoliation stage （E24）， mid-defoliation stage （E48）， and post-defoliation stage （E72）， and subjected for transcriptome sequencing. The differentially expressed genes （DEGs） between two lemon varieties were identified， revealing a total of 14002466， and 935 DEGs in pre-defoliation stage， mid-defoliation stage， and post-defoliation stage， respectively. The largest number of DEGs was found in mid-defoliation stage. GO enrichment analysis revealed that these DEGs were mainly enriched in the processes of heme binding， tetrapyrrole binding， oxidoreductase activity， iron ion binding， transcription regulator activity and response to oxidative stress， cellular glucan metabolic process， glucan metabolic process， cell periphery， cell wall in the defoliation stages. KEGG analysis showed that the DEGs were concentrated in mid-defoliation stage and involved in plant hormone signal transduction， phenylpropanoid biosynthesis， plant-pathogen interaction， and MAPK signaling pathway. By analyzing the genes with significant differential expression of the four pathways， 13 genes including xyloglucan endotransglucosylase/hydrolase protein， indoleacetic acid-induced protein， indole-3-acetic acid-amido synthetase， peroxidase， β-glucosidase， pathogenesis-related genes transcriptional activator AP2 and pathogenesis-related protein were selected.They might be associated with the regulation of lemon leaf abscission. qRT-PCR verified that the expression of these genes was consistent with the transcriptomic data. This study raised new insights in deciphering the lemon leaf abscission， as well as provided reliable data to identify lemon defoliation candidate genes and uncover the analysis of leaf shedding pathways.

Abstract:The problem of excessive cadmium in rice grains seriously threatens human health. Disrupting the function of the cadmium transport gene OsNramp5 in rice can effectively reduce cadmium accumulation in rice. To rapidly create new rice germplasm with low cadmium accumulation， this study used CRISPR/Cas9 gene editing technology to knock out the cadmium transport gene OsNramp5 in the high-quality disease-resistant restorer line Chuanhui491 （R491） of three-line hybrid rice. Various edited plants with different mutations were obtained， and two homozygous mutant lines （KO1 and KO2） with single-target mutations without transgenic elements were selected. Compared with wild-type R491， the cadmium content of brown rice in knockout lines KO1 and KO2 were significantly reduced by about 90% when planted in cadmium-polluted soil fields. Agronomic trait investigation revealed no significant difference between the KO1 plants and wild-type R491， whereas the plant height， seed setting rate， and 1000-grain weight of KO2 mutant lines were significantly reduced. Therefore， knocking out the cadmium transporter gene OsNramp5 by CRISPR/Cas9 gene editing technology can quickly create new rice germplasm with low cadmium accumulation. The new germplasm created in this study provides novel genetic resources for accelerating the breeding of safe rice varieties that can be planted in the cadmium-polluted field.