Abstract:Plant branching （tillering） is a complex and strictly regulated developmental process that significantly affects plant morphogenesis and yield， making it one of the focal points in the study of ideal plant architecture. The formation of plant branches requires at least two critical steps： the formation of axillary meristems and the formation and development of axillary buds into branches. In recent years， it has been confirmed that various factors regulate these processes， ultimately affect the number of plant branches. This article briefly describes the molecular regulatory mechanisms of plant branching， including the regulatory networks of key genes involved in the formation of axillary meristems and the formation and growth of axillary buds. It reviews the effects of various endogenous hormones， including auxins， cytokinins， gibberellins， brassinosteroids， and strigolactones， as well as the nutrient sucrose and environmental factors such as light on branch formation. The aim is to lay the foundation for breeding high-yield new varieties with ideal plant architecture. Additionally， the article discusses the regulatory effects of interactions between hormones on branch formation and analyzes the current state and future directions of research on the branching of oil crops， with the hope of providing a theoretical basis for shaping ideal plant types.

Abstract:Iron is one of the essential trace elements in the life process of plant cells， which is involved in respiration， chlorophyll biosynthesis， photosynthesis and other life processes. The soil contains a large amount of iron， but the use of available iron is limited， which leads to iron deficiency in plants. Iron deficiency in plants is directly related to their growth and development， pollen viability and quality formation， resulting in yield loss. An important measure to solve this problem is to improve the absorption and efficient utilization of iron in soybeans. Therefore， mastering the law of soybean iron absorption and utilization and clarifying the molecular genetic mechanism behind it are important prerequisites for achieving efficient utilization of iron in soybean. The high efficiency of iron nutrition is a quantitative trait controlled by multiple genes. Research and cultivation of “high-iron soybean” based on its related functional genes is one of the future hotspots. In addition， iron deficiency chlorosis in soybeans can be effectively improved through cycle selection and targeted selection. Based on this， this study focuses on the role， absorption， distribution， and transportation of iron in soybean， as well as the toxic phenomena caused by excess. It also discusses the involvement of iron in soybean nitrogen fixation， and the effects of iron deficiency and high iron on soybean growth and development. The progress and important scientific problems of iron absorption， transport mechanism and molecular regulation mechanism in soybean at home and abroad are reviewed in order to provide theoretical information for the efficient utilization of iron nutrition in soybean.

Abstract:Lodging not only reduces the yield， but also is the most important factor affecting mechanized harvesting. Improving the strength of stalk is an important target for lodging-resistant breeding.In this study， a doubled haploid （DH） population （GZ-DH population） developed via microspore culture from a cross F₁ between the G922 and Zhongshuang 11 （ZS11） was used as material， quantitative trait loci （QTL） mapping for stalk strength and its related traits were performed. The main results are as follows： （1） The F₁ progeny crossed by ZS11 and G922 had significant mid-parent heterosis in three traits， stalk diameter （SD）， stalk rind thickness （SRT） and stalk bending strength （SBS）. The correlation between the SBS and four traits， SD， SRT， stalk xylem thickness （SXT）， rind penetrometer resistance （RPR）， as well as between the RPR and SXT， were all positively significant correlation. （2） A genetic linkage map was constructed with 1984 SNP markers， and the total length was 2592.64 cM. 90 QTLs for stalk strength and its related traits were detected in four environments， in which 17 QTLs were identified in more than two environments， including 6 QTLs for SD， 5 QTLs for stalk strength （SS）， 2 QTLs for SRT and 4 QTLs for SBS. The major QTL of SD， cqSD.C8-1 could be detected repeatedly in all four environments， and explained 14.67% of phenotypic variation. Two QTL clusters were found on chromosome A2 and C6， respectively， cqSD.A2 consisting of four SD QTLs and cqSS.C6 consisting of four SS QTLs. （3） Stem diameter QTL cluster cqSD.A2 and its three linked molecular markers （Bn-A02-p7893901， Bn-A02-p10176749， Bn-A02-p10668400）， QTL cqSD.C8-1 and its two linked molecular markers （Bn scaff_25981_1-p90999， Bn scaff_16287_1-p366585） can be used for molecular marker assisted breeding. This study further enriches the genetic mechanism of stem lodging resistance in Brassica napus， laying the foundation for fine mapping of stem diameter traits and molecular marker assisted breeding.

Abstract:The content of mineral elements is a crucial indicator for evaluating forage quality and breeding. In recent years， rapeseed has become a valuable high-yield forage source， playing a key role in alleviating the shortage of feed resources in China. This study aimed to reveal the genetic variation of major mineral nutrients in the core germplasm of Brassica napus and to support the breeding of mineral-rich rapeseed. We evaluated the phenotypic variation in the contents of K， Ca， Na， Mg， Fe， Zn， and Cu in 272 core germplasms of B. napus using ICP-OES after hydroponic treatment. Through GWAS， we identified molecular markers significantly associated with the content of these minerals and predicted related candidate genes. The results showed significant variation in mineral content among different germplasms， and principal component analysis transformed the seven mineral indicators into three new indicators， with a cumulative contribution rate of 68.479%. Some significant positive and negative correlations were found between different minerals； some germplasms exhibited extreme values for multiple minerals. A total of 134 SNPs related to mineral content were identified， and 14 candidate genes were predicted. This study provides important insights for the breeding and creation of new germplasm rich in mineral nutrients.

Abstract:Brassica napus is the main source of edible vegetable oil in China， which plays an important role in the security of edible oil supply， and drought has seriously constrained the production of B. napus in China. Mining drought tolerance loci and candidate genes in B. napus germination will provide theoretical basis and technical support for breeding new drought-tolerant B. napus varieties. In this study， 145 B. napus germplasm resources were used for seed germination under normal and 15% PEG6000 conditions， respectively. The data of germination potential， seedling formation rate and germination index of different materials were investigated. The drought tolerance indicators were screened during germination and genome-wide association analysis （GWAS） was performed. The results showed that germination index could be used as an indicator of drought tolerance during the germination stage of B. napus. Total of 17 extreme drought-resistant and 9 extreme drought-sensitive germplasm were screened on the basis of germination index. A total of 2 major effect loci significantly associated with drought tolerance were detected by GWAS analysis of germination index using MLM （Mixed linear model） in B. napus， which were distributed on two chromosomes， C07 and C09， with 11 SNP on chromosome C07 and 3 SNP on chromosome C09. Combing with the functional annotation of the candidate genes in the significantly associated SNP intervals and their expression data under different stresses， BnaC07G0290100ZS，BnaC07G0290500ZS and BnaC07G0290700ZS were significantly induced by drought stress， and it was hypothesized that BnaC07G0290100ZS，BnaC07G0290500ZS and BnaC07G0290700ZS are the key genes regulating drought tolerance in B. napus during germination stage.

Abstract:In order to identify effects of the cross-resistance and the function of resistant genes BnAHAS1-3R in germplasm M196， this study examined the resistance effect of rapeseed M196 and N131 （wild type） by spraying sulfonylurea， sulfonlyaminocarbonyl-triazolinone， imidazolinone， triazolopyrimidine， and pyrimidyl-benzoate with different concentration gradients （0， 1/4， 1/2， 1， 2 and 4 times the recommended concentration of herbicides in the field）， respectively， at 3-5 leaf stage. Based on the greenhouse and field results， the cross-resistance of SU and SCT was observed simultaneously to be the strongest， while IMI， TP and PB were lower. Results of qRT-PCR and in vitro enzyme inhibition experiments in transgenic Arabidopsis indicated that the cross-resistance of ALS herbicides was caused by the elevated expression of the mutated allele of BnAHAS1-3R and the decrease on enzyme sensitivity to herbicides. The study provides a theoretical basis for preventing and resolving the potential problems about weed resistance and drift of resistance gene that may arise from the widespread promotion of resistant varieties.

Abstract:Salt stress severely inhibits the growth of plants， resulting in a decrease in crop yield. The germination period is the most sensitive phase for plants to salt damage. Therefore， establishing an accurate and convenient salt tolerance identification and evaluation system， as well as screening for salt-tolerant germplasm in Brassica napus， is crucial for enhancing the salt resistance of rapeseed varieties. In this study， the optimal concentration for salt tolerance identification during the germination period was determined to be 1.25% based on the salt damage index of 15 Brassica napus germplasms. At this concentration， the germination potential， germination rate， root length， hypocotyl length， fresh weight， and dry weight of 186 Brassica napus germplasm resources were measured， and their salt tolerance indices were calculated. Conducting comprehensive salt tolerance assessment of rapeseed germplasm resources using analysis methods such as principal component analysis and membership functions. A salt tolerance comprehensive evaluation model was established， and suitable evaluation indicators were selected. The results showed that under 1.25% NaCl stress， there was a highly significantly positive correlation among the salt tolerance index of germination potential， salt tolerance index of germination ratio， salt tolerance index of root length， salt tolerance index of hypocotyl length， salt tolerance index of fresh weight， salt tolerance index of dry weight of Brassica napus. By employing principal component analysis， these six indicators were condensed into three principal components， which collectively account for a cumulative variance of 92.809%. Based on the weights of these three principal components， D values were calculated for various germplasms， resulting in the classification of 186 germplasms into four levels and the identification of five salt-tolerant materials. Furthermore， a mathematical evaluation model for salt tolerance identification in Brassica napus was established as D=0.111+0.201X₁+0.165X₂+0.381X₅. The salt tolerance identification criteria and salt-tolerant materials chosen in this study provide valuable support for the development of salt-tolerant rapeseed breeding.

Abstract:Nitrogen is essential for the growth and development of plants. In rapeseed， higher nitrogen input increases the accumulation of biomass at vegetative growth stage， and results in elevation on seed yield and protein content，but decrease on oil content at maturity stage. Oil is the target product of rapeseed. Thus， it is of great significance to explore nitrogen-efficient varieties with higher oil production when reducing nitrogen application. In this study， biomass and oil yield were used as indicators to evaluate the nitrogen efficiency of overwintering and mature stages， followed by analyzing the relationship between traits in different periods. The comprehensive evaluation model of nitrogen efficiency at overwintering stage was established through the variation analysis， principal component analysis and membership function analysis of each biomass index under different nitrogen level at overwintering stage. The plant biomass and the fresh biomass were extracted as the comprehensive evaluation indices of nitrogen efficiency at overwintering stage. Three high-efficiency germplasms under high nitrogen condition， seven low-efficiency germplasms under both nitrogen conditions， two high-efficiency germplasms under low nitrogen condition and six high-efficiency germplasms under both nitrogen conditions were identified. At the mature stage， four high-efficiency germplasms under high nitrogen condition， six low-efficiency germplasms under both nitrogen conditions， three high-efficiency germplasms under low nitrogen condition and four high-efficiency germplasms under both nitrogen conditions were identified by oil yield as nitrogen efficiency index. Gained from the results of the two periods， two high-efficiency germplasms （Jie 65 and Zhongshuang 11） under high nitrogen condition in the two periods， one high-efficiency germplasm （6024-1） under both nitrogen conditions， one high-efficiency germplasm （Soviet rapeseed） under low nitrogen condition， three low-efficiency germplasms （Xingxuan 2， Reaina Ⅱ and Gisora） under both nitrogen conditions were identified. No correlation was detected for the traits between overwintering and maturity stage under different nitrogen treatments. These results provide insights to understand nitrogen use efficiency and further identify the key regulatory genes in rapeseed.

Abstract:Abscisic acid （ABA） plays a crucial role in plant response to abiotic stress. However， the molecular mechanism by which ABA inhibits the absorption of cadmium （Cd） in Brassica napus seedlings remains to be elucidated. In this study， ‘Youfei 1’ of Brassica napus L. was used as experimental material， and application of 10 μmol/L Cd in Hoagland solution was conducted to simulate cadmium stress. The effects of adding 5 μmol/L ABA under cadmium stress condition， on photosynthetic rate， chlorophyll， carotenoid contents in leaves， cadmium content in above/below ground parts of seedlings and gene expression were analyzed. The results showed that the photosynthetic rate， transpiration rate and stomatal conductance of the leaves were significantly increased， while the contents of chlorophyll and carotenoid were decreased. The contents of cadmium in aboveground and underground tissues were significantly increased under Cd stress condition if compared with that of the control group. The application of ABA could effectively reduce the leaf transpiration rate and stomatal conductance， as well as the contents of cadmium in aboveground and underground parts， and significantly increase the contents of chlorophyll a and carotenoid. Through transcriptome sequencing to identify differentially expressed genes （DEGs）， 514 upregulated and 431 downregulated genes were found. Kyoto Encyclopedia of Genes and Genomes （KEGG） pathway enrichment analysis indicated that DEGs were heavily enriched in pathways such as sucrose and starch metabolism， secondary metabolite biosynthesis， metabolic pathways， and the MAPK signaling pathway， etc. Gene Ontology （GO） functional enrichment revealed that DEGs were enriched in categories such as hemicellulose metabolism， oxidoreductase activity， phenolic compound metabolism， cell wall macromolecule metabolism， and system acquired resistance. The transcriptional trend of selected genes revealed by qRT-PCR is consistent with the transcriptome sequencing results. Further analysis of the differential expression of lignin-related and hemicellulose-related genes （XTH， BXL， PAL， C4H， etc.） in rapeseed leaves under Cd stress revealed that most of these genes were downregulated after abscisic acid treatment. These findings provide a reference for understanding the physiological mechanisms of ABA regulation under Cd stress and contribute to molecular breeding efforts for rapeseed.

Abstract:To analyze the effects of drought treatments on physiological indexes and DNA methylation levels of Brassica Rapa， this study subjected oilseed rape Longyou 7 to three treatments， namely， normal water supply， drought stress， and rehydration after drought， followed by analyzing the physiological indexes and DNA methylation after treatments. In comparison to those under normal water supply treatment， the oilseed rape under drought stress exhibited 167.27%， 254.85%， 103.24%， and 164.64% of increase on malondialdehyde content， SOD， POD and CAT activities， respectively. Osmoregulatory substances Pro and SP were elevated up to 3.21 μg/g and 0.048 μg/mg， respectively； the relative water content of leaves decreased significantly by 53.64%. The physiological indexes decreased partially after rewatering. Compared with normal water supply treatment， the methylation level showed an increasing trend after drought， while the methylation rate after rewatering was even higher than that of drought and control， with the methylation rate reaching 20.56%. Through GO enrichment analysis， differentially methylated genes （DMGs） were enriched in biological processes， nucleus， and molecular functions. KEGG functional enrichment analysis showed that DMGs were mainly involved in the ubiquitin mediated protein hydrolysis， cytotoxicity， ABC transporter proteins， carbon fixation in photosynthetic organisms， and other metabolism-related pathways. A correlation between methylation rate and physiological indicators was observed， and through integration of both GO and KEGG enrichment results， seven DMGs were revealed encoding peroxidases. The results of this study will provide a basis for unrevealing the regulatory mechanism to drought stress in rapeseed and breeding for drought tolerant new varieties.

Abstract:This study aimed to identify genetic variations on the whole genome level using genome resequencing data of 13 peanut cultivars， clarify their distribution characteristic， develop and verify InDel markers， and evaluate the efficiency of InDel markers in peanut cultivar identification. A total of 313432 high-quality SNPs and 38777 high-quality InDel were detected， with an average distribution density of 123/Mb and 15.23/Mb， respectively. The InDels and SNPs were mainly distributed in intergenic regions， with a frequency of 52.35% and 60.08% of the total SNP and InDel， respectively. Primers were designed using InDel with insertion or deletion length ≥10 bp， and 3675 InDel could be used to develop InDel markers. These InDel locus were unevenly distributed on the 20 chromosomes of peanut with an average density of 1.48 /Mb. Using electronic PCR， the InDel primers amplified mainly with 1 locus and 2561 effective primers （69.69%） could amplified 3133 effective loci in the peanut reference genome. The physical map of amplification loci was drawn according to the loci position in cultivated peanut genome. Among 100 pairs of random primers， 31 pairs amplified different bands in the 4 varieties with distant relatives. The 31 InDel primer pairs amplified 62 alleles in 47 peanut cultivars （or breeding lines）， the frequency of major genes ranged from 0.51 to 0.98 with an average of 0.77， and the polymorphic information content ranged from 0.04 to 0.37， with an average of 0.24. Both cluster analysis and population structure analysis could divide the 47 peanut cultivars （breeding lines） into two groups， and the 47 materials could be distinguished by at least 7 markers， indicating that the developed InDel markers could be effectively used for the assessment of genetic diversity and variety identification of peanut. The research results enriched the molecular markers of peanut， and was beneficial for the use of InDel markers in genetic studies of peanut resource genetic diversity， variety identification， fingerprint construction.

Abstract:To address the breeding needs of peanuts for higher yield and resistance to late leaf spot disease， 120 representative peanut germplasm resources were selected from the germplasm bank of Nanchong Academy of Agricultural Sciences for identification and evaluation. A phenotypic survey was conducted on 16 traits， and descriptive statistical results showed that the coefficients of variation of traits ranged from 7.40% to 47.65%. The variation coefficient of branch number， full pod number per plant， pod number per plant and yield per plant is larger， while the variation coefficient of the related traits of pod length， pod width， seed length and seed width were is smaller. Correlation analysis showed that stem height and branch length were positively correlated， pod number per plant， full pod number per plant were negatively correlated with hundred pod weight， pod length and pod width ， and late leaf spot grade was negatively correlated with branch length and branch number. Principal component analysis categorized 16 traits into five principal components， with a cumulative contribution rate of 85.013%. The germplasm was divided into four groups by cluster analysis， the large pod group Ⅰ and Ⅱ， and the small and medium pod group Ⅲ and Ⅳ. A comprehensive score is constructed based on the contribution weights of five principal components， the top 10 germplasm resources with the highest comprehensive scores were selected， including ICGV88938 ， which exihibited high yield and resistance to late leaf spot disease， four germplasm resources resistant to late spot disease were screened in a natural disease nursery. This study identified and evaluated 16 traits across 120 germplasm resources， thus providing valuable breeding materials and a theoretical foundation for future peanut variety improvement.

Abstract:In order to understand genetic diversity of phenotypic traits of peanut germplasm resources in high latitude and improve their comprehensive utilization efficiency， 226 accessions were examined for 19 phenotypic traits （eleven agronomic traits and eight quality traits）， followed by coefficient of variation （CV）， Shannon-weaver index（H′）， cluster analysis and so on. The CV ranged from 2.90% （oil content） to 34.07% （saccharose content）， including 13 traits showing CV over 10.00%， indicating abundant genetic variation in these traits. The H′ ranged from 1.237 （linoleic acid content） to 2.077 （pod length）. The variations on diversity were observed from germplasm types ， and abundant diversity was detected at five quality traits in the lines and eight agronomic traits in breeding varieties.The correlation analysis showed that seed length positively correlated with other agronomical traits， while oil content negatively correlated with other quality traits. Three groups were divided by cluster analysis， including group I containing 14 germplasms， which were mainly characterized by high oleic acid， and reducing sugar， soluble sugar， saccharose and total sugar content， with potential in breeding for high oleic acid varieties and fresh peanut varieties. Group Ⅱ contained 30 germplasms， with the average values of 12 phenotypic traits that were the highest among the three groups. That included number of branches with pods， height of main stem and oil content， which could be used for breeding high-oil varieties. Group Ⅲ contained 182 germplasms， showing the highest coefficient of variation at 13 traits among the three groups， such as number of branches with pods and length of first branch， and rich germplasm types， which could provide a wide range of basic germplasms for breeding high-yield varieties. Ten elite germplasms were selected by comprehensive score F-value， with potential serving as parental lines in peanut breeding in high latitude.

Abstract:To expedite the process of salt-tolerant sesame breeding， this research established a precise and highly efficient method for identifying and evaluating the salt tolerance of sesame seedlings and screened extreme materials by conducting salt tolerance identification on 239 materials at the seedling stage. Through experiments on 28 varieties with considerable differences in salt tolerance， the seedlings were subjected to stress growth in NaCl solutions of different concentrations （0， 70， 140， 210， 280， and 350 mmol/L） from the seedling stage. After three weeks of treatment， growth and physiological indicators were measured to determine the optimal concentration and key indicators， based on which the salt tolerance of 239 core germplasm was identified. The results indicated that the optimal stress concentration for identifying the salt tolerance of sesame seedlings was 210 mmol/L， and the core indicators were relative plant height and relative fresh weight. Regression analysis was conducted on the D value and the salt tolerance coefficients of six traits， and the regression equation was obtained： D = -0.171+1.081X₁+0.253 X₂. Using this regression equation to identify the salt tolerance of 239 sesame core germplasm during the seedling stage， they were classified into five grades： high salt tolerance， salt tolerance， moderate salt tolerance， salt sensitivity， and high salt sensitivity. Among them， 5 germplasm with high salt tolerance and 42 germplasm with salt tolerance were selected. Through conducting a correlation analysis between salt tolerance identification results and germplasm sources， it was discovered that the salt tolerance of sesame varieties is associated with the degree of soil salinization in their source regions. This research provides a methodological and material foundation for the breeding of salt-tolerant sesame varieties.

Abstract:Honesty （Lunaria annua L.） belongs to the Brassicaceae family and is a biennial herb with high nutritional and medicinal value， as it contains nervonic acid， and its seeds are rich in oil. In order to explore the types and contents of fatty acids during the development process of the fruit， as well as the synthesis characteristics of very-long-chain fatty acids， especially nervonic acids， this study used gas chromatography and mass spectrometry to analyze the fatty acid components and content of nervonic acids in Lunaria， Arabidopsis， Borage， and Malania fruit. The results showed that a total of 10 types of fatty acids were involved in fatty acid metabolism during the development process of the Lunaria fruit， seven detected in seeds and eight in pericarps. Most of them are long chain and very-long-chain unsaturated fatty acids. The fatty acids in seeds were mainly composed of palmitic acid， stearic acid， oleic acid， linoleic acid， linolenic acid， erucic acid and nervonic acid. The content of palmitic acid， stearic acid， linoleic acid and linolenic acid gradually decreased along with seed development. The oleic acid， erucic acid and nervonic acid gradually increased along with seed development and accumulated in large quantities in the first 25-35 days after anthesis. The pericarp was free of erucic acid and nervonic acid， but specializes in behenic acid， lignoceric acid and cerotic acid. Lunaria， Borage and Malania seeds all contain erucic acid and nervonic acid. Woody plant Malania seed has the highest content， followed by Lunaria， and Borage that has the lowest content. The content of nervonic acid in seeds of the three plants is significantly positively correlated with the content of erucic acid. This study elucidated the characteristics of fatty acid metabolism and accumulation of nervonic acid during the fruit development process of Lunaria， providing new ideas for fully utilizing the germplasm resources of Lunaria and expanding the pathways for obtaining nervonic acids.