"Seven Major Crops Breeding" project is the sole special project in the field of biological seed industry during the “13th Five-Year Plan”. It is of great significance for consolidating and leading the development direction of breeding technology and safety ensuring of China's crop seed industry. Rapeseed is one of the important objects in the project. Based on the layout and implementation of rapeseed genetic breeding, this paper summarized the main research progress, major achievements, organization and implementation management experience of rapeseed genetic breeding during the period from 5 aspects, including elite germplasm exploring, genes cloning and mechanism analysis of important agronomic traits, innovation on breeding technologies for new materials and varieties, and seed multiplication and processing technology. In addition, 3 countermeasures and suggestions are put forward for future research in this field: 1st, strengthen top-level design and systematic layout of major projects; 2nd, optimize the management system and improve the regulatory framework for biotechnology breeding; 3rd, innovate the breeding industry chain and build a seed industry innovation system with close division of labor and cooperation between science and enterprise.
Aflatoxins are a group of toxic secondary metabolites produced by fungi such as Aspergillus flavus and A. parasiticus, which are widely found in agricultural products and feedstuffs and pose a great health risk to animals and humans. Their control and quantification in agricultural products is therefore extremely important. Biosensors are a rapid detection technology with high sensitivity, high selectivity, simple operation and easy miniaturisation, and play an important role in aflatoxin detection. This paper describes the principles, types and progress of research on the application of biosensors to aflatoxin detection, and its future perspectives.
The structural lipids known as medium and long-chain triacylglycerols （MLCT） have unique physical-chemical characteristics and nutritional functions. Due to the increasing demand for MLCT in the food, pharmaceutical, healthcare, human milk fat substitutes, and other industries, the study of enzymatic MLCT preparation has steadily grown into a research hotspot. The enzymatic synthesis approach of MLCTs, comprising the synthesis process, lipase types, catalytic reaction system, and product purification, is summarized, analyzed, and discussed in this work. This document is intended to serve as a reference for the production and application of enzymatic MLCT.
Peanut is widely grown in more than 100 countries in the world and can be processed for oil, peanut butter, confectionary, or direct consumption （fresh, baked or roasted）. It is an important source of edible vegetable oil and protein. High yield, high quality, pest and disease resistance are the main objectives of peanut breeding. The majority of released peanut varieties were developed by conventional breeding methods with high cost, lengthy selection processes and low efficiency. Marker-assisted selection can greatly improve the precision and breeding efficiency. High-density genotypic data is prerequisite for QTL mapping and identification of molecular markers for yield, quality and disease resistance traits in peanut. The release of the whole genomic sequences of three peanut cultivars in 2019, including two elite Chinese founder varieties Shitouqi and Fuhuasheng, and a popular U.S. peanut variety Tifrunner, greatly promoted the identification and application of molecular markers for peanut breeding. In recent years, molecular markers for oleic acid content, oil content, root-knot nematode resistance, rust resistance, leaf spots resistance, and yield-related traits have been developed. Peanut varieties or breeding lines combining high oleic acid with high oil content, high oleic acid with resistance to diseases such as rust, bacterial wilt, or root-knot nematode were successfully developed through marker-assisted selection. Utilization of wild relatives in peanut germplasm, development of high-throughput genotyping and phenotyping platforms, and application of genomic selection would be of high priority in peanut breeding in the future.
To support the decision making for peanut production sustainability, based on the statistical data from 2001 to 2020, we use mathematical statistical approach and spatial exploring method to analyze the changes of peanut distribution and clarify the influence indicators for the changes. The results showed that during this two decades, the peanut harvested area and production decreased by 33.00% and 22.34%, respectively, while the yield increased by 15.93%. The spatial patterns of peanut concentrated to the northwest, including Linyi and east region, such as Yantai, Weihai and Qingdao. There are four years that the contribution for peanut production of harvested area is higher than that of yield, and 16 years on contrast. Through the spatial exploring method, the cropland decreased and the proportion of harvested area of the economic crops decreased, and the proportion of peanut production declined consequently. The net profits of peanut production in Shandong were lower than that in other regions and dropped in recent years, and then the harvested area and production declined regularly. In addition, the democratic and global market of peanut and its processed products was not stable, restricting the development of the peanut industry.
This study aimed to identify the plant type factors that affect grain yield per plant of Brassica napus and to develop an ideal plant type for high-yield rapeseed per plant. Three different fertility treatments were carried out on three representative varieties of B. napus in Hunan. Eleven plant type indexes including leaf area, pod area, and rapeseed yield of 81 plants at four growth stages （seedling, initial flowering, full-blooming, and pod-filling stages） were obtained by non-destructive measurement. Based on an analysis of the relevant plant type indicators at different growth stages, the basic growth laws of the relevant plant type indicators were explored. The plant type indexes related to rapeseed yield were analyzed, and it was found that several plant type indexes at different growth stages were significantly correlated with them. Among them, rapeseed yield, pod number, branch length, and pod area of each branch at the pod stage were significantly positively correlated with rapeseed yield per plant, and the correlation coefficients of the corresponding plant type indexes of each branch showed similar variation trends. Branch number, leaf area, green leaf number, root-neck thickness, and plant height were significantly positively correlated with rapeseed yield per plant, and the correlation coefficient showed a corresponding trend according to the different growth stages. Branch height and relative height of the branch were significantly negatively correlated with rapeseed yield per plant, and the relative length of the branch segment was significantly positively correlated with rapeseed yield per plant. The related characteristics and growth rules of the first 10% and 20% rapeseed yields per plant were analyzed. Except that the branch height and the relative height of the branches were significantly reduced, the other plant type indexes were increased to different degrees compared with the corresponding indexes of the overall samples. The first 10 % of the yield samples and the first 20 % of the yield samples showed similar trends, but the corresponding values increased or decreased more. Ideal plant type characteristics of B. napus at different growth stages were qualitatively and quantitatively described. The ideal plant type has the characteristics of a “large surface area of photosynthetic organs （leaves and pods）, strong root-neck, low branch position, strong lodging resistance, secondary branches, and the increased corresponding pod number”. The formation principle of the ideal plant type of B. napus was analyzed from three aspects: photosynthetic efficiency, morphological structure, and source-sink-flow principles. The construction strategy, application method, and research shortcomings of the ideal plant type of B. napus were discussed.
Colored rape has oil and ornamental value, which has attracted more and more attention due to its easy planting, bright petal color and long flowering time, etc. However, it has been reported that colored rape is mainly high in erucic acid and glucosinolate, which is not suitable for ornamental and oil application. Therefore, it is one of the breeding goals of ornamental rape to breed new colored rape germplasm with good quality and suitable plant type. In this study, DW871 that has special inflorescence characteristics and great ornamental value was used as the base material. After crossing with common colored high stalk rape, F1 generation was used to create new colored rape which has DW871 specific inflorescence traits and excellent quality. The results showed that the embryo yield rate was up to 312-507 embryos/bud by using microspore culture technology in the early stage, and finally a total of 14 colored rape germplasms were obtained, including 5 plants of white color flower, 4 plants of orange color flower and 5 plants of kumquat color flower. Through character investigation and quality analysis, we selected all DH plants and found that Y57 is an excellent new germplasm that has dwarf stalk, kumquat color petal and “double low” quality, being familiar with special inflorescence of DW871. The plant height of Y57 is 88 cm, which has 18 primary branches, 39% of oil content, 25.96% of protein content, 0.95% of erucic acid and 28.15 μmol/g·pie of glucosinolate. Y57 is a new colored germplasm of
In this study, the dwarf mutant DW871 and high-stem rapeseed homologous HW871 were used to investigate the type of dwarf mutation by light and dark morphological analysis,hormone sensitivity analysis and determination of endogenous hormonal content. The results showed that DW871 had a normal light-dark phenotype, and hypocotyles and stems were sensitive to exogenous strigolactone, gibberellin, and brassinolide, insensitive to exogenous auxin,and the dwarf phenotype of DW871 could not be restored after bolting during external hormone administration.The determination of the endogenous hormones content showed that the auxin and gibberellin content in DW871 was higher than in HW871, and the content of strigolactones was lower than that in HW871, the brassinolide content was no different from that in HW871. In conclusion, we speculated that the dwarf of Brassica napus DW871 could not be related to hormone defects.
The beneficial fatty acids such as nervonic acid play an important role in human health. As a potential source of nervonic acid, Brassica juncea is a functional oil crop with high quality. In order to investigate the genetic laws of important fatty acids such as nervonic acid in B. juncea, we created genetic analysis generations (P1, P2, F1/RF1, B1/RB1, B2/RB2, F2/RF2) with high nervonic acid germplasm JH1 and low nervonic acid germplasm JL4 of B. juncea as parents, and determined the contents of fatty acids in seeds of each generation. Correlation analysis and genetic analysis were carried out for the contents of nervonic acid, erucic acid and oleic acid. The results showed that oleic acid was significantly negatively correlated with erucic acid and nervonic acid (P<0.01), and nervonic acid was significantly positively correlated with erucic acid (P<0.01). The contents of nervonic acid, erucic acid and oleic acid in JH1 and JL4 were (2.998±0.274)% and (0.000±0.000)%, (47.644±2.343)% and (0.000±0.000)%, (8.853±1.963)% and (48.649±3.395)%, respectively, with significant differences between the parents. The contents of three fatty acids of F1 and RF1 were between those of the two parents and the phenotypes of isolated generations were widely distributed. Genetic analysis showed that the contents of the three acids had strong additive effect, and their best genetic model was MX2-ADI-ADI (two pairs of additive-dominant-epistatic major genes + additive-dominant-epistatic polygenes). The heredity of the three fatty acids in B2/ RB2 and F2/ RF2 was mainly regulated by the major genes, and the heritability was higher, with little environmental influence. Nervonic acid and erucic acid of B1 and RB1 were mainly inherited by major genes or polygenes, with little environmental influence, while oleic acid was more affected by environmental influence. The results of this study provided a theoretical basis for quality breeding of B. juncea with high nervonic acid.
The plant-specific transcription factor family, shi-related sequence (SRS), plays crucial roles in plant growth, development, hormone signaling, and stress response. To explore the potential functions of the SRS gene family in Brassica napus and its evolutionary history, a comparative genomics approach identified 38, 16, and 20 SRS genes in B. napus, B. rapa, and B. oleracea, respectively. Analysis of physicochemical properties, phylogenetic relationships, gene structure, collinearity, cis-regulatory elements, and expression patterns revealed that all SRS proteins were grouped into nine subgroups, with intron/exon loss events occurring during B. napus SRS gene family evolution. Ka/Ks analysis showed purifying selection following gene duplication events. Most SRS gene promoters contained cis-regulatory elements related to light response, anaerobic induction, and abscisic acid response, with B. napusSRS gene promoters having more endosperm expression and light response elements than their diploid progenitors. Transcriptome analysis demonstrated diverse expression patterns for B. napusSRS genes under various treatments, with preferential expression in roots. This study offers a foundation for understanding the functions and roles of the B. napus SRS gene family, serving as a reference for gene evolution between B. napus and its diploid progenitors.
Peanut pod expansion process directly determines the pod size, and in-depth study of this process is helpful to clarify the regulation mechanism of pod size. In this study, peanut varieties with different pod sizes were used to analyze the changes of transcription level in the early stage of pod development, weighted gene co-expression network analysis (WGCNA) was used to identify the key genes related to pod development. The results showed that DEGs of different materials were significantly enriched in transmembrane receptor protein kinase activity, UDP-glucosyltransferase activity, plant-type cell wall, anchored component of membrane and cell wall biogenesis; MAPK signaling pathway-plant, plant hormone signal transduction, plant-pathogen interaction, phenylpropanoid biosynthesis and starch and sucrose metabolism were the main significant enrichment pathways. A total of 29 modules were identified by WGCNA, of which Antiquewhite4 and Darkolivegreen modules were significantly correlated with pod length and width. Hub gene analysis of 200 gene pairs with the highest weights in two key modules showed that gene-LOC112797233, gene-LOC112743864, gene-LOC112701973, gene-LOC112764826 and gene-LOC112710700 were found to play an important role in pod development. GO enrichment analysis of genes in key modules showed that Antiquewhite4 and Darkolivegreen modules may be related to the formation of secondary cell wall and the regulation of cell cycle, respectively. The results will be helpful for further understanding the molecular mechanism of peanut pod development.
To explore the sequence and expression pattern of COP1 gene in peanut, two COP1 genes were cloned from peanut, named as AhyCOP1a and AhyCOP1b, and the related analysis were conducted in this study. The results showed that AhyCOP1a and AhyCOP1b were 2103 bp and 2049 bp in length, respectively, and both of them contained 13 exons and 12 introns. The phylogenetic results showed that AhyCOP1a and AhyCOP1b grouped with COP1 genes in dicotyledon crops, and were closely related to AduCOP1 and AipCOP1, respectively. The results indicated that the evolution of AhyCOP1a and AhyCOP1b originated from peanut wild accessions Arachis duranensis and A. ipaensis, respectively. In addition, AhyCOP1a and AhyCOP1b had 6 and 7 WD40 repeat motifs, respectively. The similarity of COP1 gene in N-terminus is low, and the homology of WD40 domain in C-terminus is high, indicating that WD40 domain is the main core functional region of COP1 gene. The tissue expression results showed that the expression pattern of AhyCOP1a and AhyCOP1b in the aboveground part was significantly higher than that in the underground part, and the highest expression was found in flowers, followed by leaves and stems. However, the expression level of AhyCOP1a in underground tissues is significantly higher than that of AhyCOP1b, suggesting that AhyCOP1a plays a more important role in the development of underground tissues. In addition, it was also found that light can promote the expression of COP1 gene in peanut, indicating that the expression of COP1 gene in peanut is significantly affected by light. In conclusion, the results of this study preliminarily clarified the sequence and expression pattern of COP1 gene in peanut, which laid a foundation for further exploration of the molecular function of COP1 gene.
To investigate the genetic mechanism of soybean plant height, genome wide association study （GWAS） was carried out to detect the SNP significantly associated with plant height in natural population containing 264 soybean germplasm resources in 2019 and 2020. There is extremely genetic variation in the plant height of soybean population, showing continuously distribution, and the broad sense heritability was 67.38%. It was found that 91 SNPs were detected to be significantly associated with soybean plant height, which were located on chromosomes 3, 4, 6 and 19, respectively. Among them, the significant correlation signal on Chr.19 is a major QTL controlling soybean plant height, which was detected in both 2019 and 2020, which explained 12.19% of the phenotypic variance. At the same time, five candidate genes for regulating soybean plant height were obtained in this locus, of which Glyma.19G194300 （GmDt1） maybe is the causal gene for this major QTL. In addition, three candidate genes for regulating soybean plant height were identified on chromosome 3 and 6. The results of this study provide new genetic resources and important reference for the genetic improvement of soybean plant height.
Backbone parent is the important germplasm materials in soybean breeding. Zhongdou 41 （one of the target backbone parent） and 9 other cultivars were selected to make 30 crosses by incomplete diallel crossing design. Ten yields and quality related traits in F1 were evaluated to assess combining ability and genetic parameters. Results indicated that Zhongdou 41 had the highest general combination ability （GCA） effects for main agronomic traits except for protein content. Zhongdou 41 showed higher specific combining abilities （SCA）. Three combinations （as Zhongdou 41 × Zheng 196, Zhongdou 41 × Xin silihuang, and Zhongdou 41 × Zhonghuang 319） had higher SCA for yield related traits among the 30 combinations. Genetic parameters analysis showed that 9 traits were dominated mainly by additive effect, including plant height, number of main stem nodes, number of effective branches, number of pods per plant, number of seeds per plant, 100-seeds weight, yield per plant, protein content and oil content. However, bottom pod height was controlled by additive and non-additive effects. These results were expected to provide a theoretical basis for efficient utilization of Zhongdou 41 in soybean breeding.
To clarify the effects of potassium (K) supply and light intensity on leaf growth and photosynthetic characteristics of oilseed rape, a two-factor experimental design with K supply and light intensity was performed in this study, in which three levels of K supply were designed: severe K deficiency (0.03 mmol·L-1 KCl), mild K deficiency (0.09 mmol·L-1 KCl) and sufficient K supply (2.00 mmol·L-1 KCl), and two levels of light intensity were set: low light intensity (LL, ~200 μmol·m-2·s-1) and high light intensity (HL, ~400 μmol·m-2·s-1). The growth, gas exchange parameters, chlorophyll fluorescence characteristics and mesophyll cell ultrastructure characteristics of oilseed rape leaves under different K supply and light intensity under hydroponic conditions, in order to provide a theoretical basis for the rational application of K fertilizer under changing environmental conditions. The results showed that K supply and light intensity significantly affected the growth of oilseed rape leaves. Under the same K supply, the leaf thickness and leaf dry mass per area of oilseed rape increased by 19.6%~24.3% and 57.1%~73.6%, respectively, under high light intensity treatment compared with low light intensity, while the net photosynthetic rate decreased by 63.8% under severe potassium deficiency stress compared with low light intensity conditions. Severely K-deficient stressed leaves were photoinhibited under high light intensity conditions, and the actual photochemical efficiency, maximum carboxylation rate, maximum electron transfer rate and other key photosynthetic parameters were significantly reduced, and chloroplasts were poorly developed. While K deficiency led to a reduction in the proportion of intercellular spaces between mesophyll cells, and a decrease in mesophyll conductance, which in turn led to a significant decline in photosynthetic capacity of leaves. To sum up, K supply and light intensity jointly regulate leaf morphology and structure, affecting photosynthetic capacity. Insufficient K supply under high light intensity will seriously affect the growth of oilseed rape. Reasonable application of K fertilizer is conducive to improving the adaptability of rape to changes in light intensity and maintaining the stability of photosynthetic capacity.
Planting winter rapeseed after double cropping rice, ratooning rice or/and late-maturing japonica rice, might encounter problems of delayed sowing, lower temperature, and delayed growth in late autumn and winter, resulting in decrease yields. In order to select rapeseed varieties that tolerant to late sowing, 48 breeding lines of Brassica napus with different maturity periods were selected, and outdoor nutrient solution hydroponics and field direct seeding were designed under late sowing (Nov. 11). Biomass and field yield in autumn and winter were measured, and their growth ability to tolerate late sowing was compared. Results of outdoor nutrient solution hydroponic cultivation showed that there were rich genetic variations in their low-temperature growth, and biomass accumulation at 30, 60, and 90 days after transplantation was significantly positively correlated with yield per plant at maturity. The biomass of early and middle maturing types at 30 and 90 days was significantly less than that of late maturing type. The 60-day biomass of early maturing type was significantly less than that of late maturing type. The SPAD value of leaves of late maturing type was significantly higher than those of early and middle maturing type at 30 days. In order to select rapeseed varieties tolerant to late sowing, the 30-day biomass accumulation capacity of plants could be an index in the early stage of rapeseed breeding to improve breeding efficiency. Results of field direct seeding showed that yield per plant of the early maturing type was significantly lower than that of middle maturing type. By comparing the biomass accumulation rules of different ecological types of rapeseed at seedling stage under the late sowing, it provides theoretical guidance for the late sowing and high yield cultivation of rapeseed and variety selection.
To explore the optimal bandwidth and row ratios of maize/soybean by relay strip intercropping, a field experiment was conducted. Five bandwidth and row ratios treatments were set up with monocropping maize （MM） and soybean （MS） as the control. There were 2 m bandwidth with maize/soybean row ratio 2∶2 （treatment 1）, 2.4 m bandwidth with maize/soybean row ratio of 2∶3 （treatment 2） and 2∶4 （treatment 3）, 2.8 m bandwidth with maize/soybean row ratio of 2∶3 （treatment 4） and 2∶4 （treatment 5）. The effects of these treatments on yield and nitrogen use efficiency of maize and soybean were studied. The results showed that the grain yield of maize decreased gradually with the increase of bandwidth, and the grain yield of soybean increased gradually with the increase of bandwidth. Under the same bandwidth condition, the grain yield of maize was declined with the increase of maize/soybean row ratio, and the grain yield of soybean showed an increasing trend. The changes of nitrogen uptake and use efficiencies of maize and soybean were consistent with changes of grain yields. The harvest index of maize and soybean at the treatment 2 were increased, accompanied by increased nitrogen allocation ratio to grains and decreased nitrogen allocation ratio to stems. Considering the characteristics of grain yields, economic benefits and the nitrogen uptake, allocation and use efficiency, its suggested that the optimal maize/soybean relay strip planting pattern with 2 rows of maize and 3 rows of soybean under 2.4 m bandwidth was the optimal intercropping mode for maize/soybean in the mountainous area of southwest Hubei Province.
Lead （Pb） and arsenic （As） often coexist in agricultural soils polluted by heavy metals in China. The study on the effect of the interactions between them on their transfer within crop plants has important guiding significance for the safe utilization of heavy metals contaminated farmland. A pot experiment was conducted to examine the enrichment and transfer characteristics of Pb and As in peanut under different Pb （70, 120 mg·kg-1） and As （40, 100 mg·kg-1） concentration gradient pairwise treatments （CK, Pb70, Pb120, As40, As100, Pb70+As40, Pb70+As100, Pb120+As40, Pb120+As100）. The results showed that compared with the single pollution, the co-existence of low concentration of As （As40） had no significant effect on Pb content in different parts of peanut under the low concentration of Pb （Pb70） treatment, and decreased seed Pb content by 17.6% while total Pb accumulation amount had no significant change under the high concentration of Pb （Pb120） treatment. The co-existence of high concentration of As （As100） significantly decreased the content of Pb in different plant parts and the total Pb accumulation amount under the two Pb concentrations, and the translocation factors of Pb from roots, shoots and shells to seeds decreased under the combined pollution. The co-presence of Pb70 increased the content of As in peanut shoots by 18.2%, having no significant effects on other parts, and the total As accumulation amount by 18.8% under the As40 treatment, while significantly increased the content of As in all plant parts as well as the total As accumulation amount under the As100 treatment. The co-existence of Pb120 significantly increased the contents of As in different plant parts and the total As accumulation amount under both the As concentrations. The translocation factors of As from roots, shoots and shells to seeds were enhanced under combined pollution. Generally speaking, the risk of As exceeding food safety standard was increased and the risk of Pb exceeding food safety standard in peanut seeds was decreased under combined pollution. Soil total Pb and As contents and available Pb and As contents were significantly positively correlated with Pb and As contents and total accumulation amount in peanut plants. Soil total As and available As contents were significantly negatively correlated with seed Pb content, and there was no significant relationship between soil total Pb or available Pb content and seed As content.
Foliar topdressing is a common field management technique for crop high-yield cultivation in modern agriculture. In order to investigate the effects of times and concentration of leaf nitrogen application on nitrogen uptake, accumulation, distribution and utilization of plant, and reveal the nutritional mechanism of foliar topdressing nitrogen on the establishment and function maintenance of different organs in peanut. the experiment was conducted with 5 treatments: T0 was the control; T1 urea concentration was 1%, with one-time topdressing of 35 days before harvesting; T2 urea concentration was 3%, with the same topdressing time as T1; T3 urea concentration was 1%, with three-time topdressing of 50d, 35d and 20d before harvest; T4 urea concentration was 3%, with the same topdressing time as T3. The 15N-labeled urea and common urea were used in this experiment. The dry matter mass, nitrogen content, nitrogen accumulation amount and 15N abundance of each plant organ were determined after harvesting. The results showed that:(1) The nitrogen content of foliar nitrogen application increased by 0-0.22 percentage points, and T4>T3>T2>T1, in which the content of nutrients (roots, stems, leaves) increased by 0.17-0.45 percentage points compared with the control, while the content of reproductive bodies (fruit needles, fruit shells, seeds) increased less. The nitrogen accumulation of plants increased by an average of 19.8% under nitrogen application treatment， with an average increase of 42.1% in nutrient bodies and 12.7% in reproductive bodies. (2) The distribution ratio of nitrogen through foliar application in different organs were quite different, with an order of kernel > leaf > stem > shell > needle > root, among which kernel and leaf accounted for about 60% and 30%, respectively. The proportion of other organs was less. Topdressing time had a certain effect on nitrogen distribution. Application 35d before harvest was more favorable for the distribution of reproductive bodies, which was 7.9% on average higher than that of 50d and 20d before harvest. (3) The plant nitrogen efficiency decreased with the increase of the amount of foliar nitrogen application. Fewer nitrogen application times or low nitrogen fertilizer concentration had high fertilizer utilization rate. The average nitrogen fertilizer utilization rate with one time topdressing was 70.6%, which was 37.7 percentage points higher than that of three time topdressing, and was the highest in treatment of application 35d before harvest, which was 1.8 and 3.9 percentage points higher than that in treatments of application 50d and 20d before harvest, respectively. In conclusion, leaf nitrogen source can significantly improve the level of plant nitrogen metabolism, promote nitrogen absorption and accumulation, especially in nutritive bodies, which is the physiological mechanism of "root and leaf protection" and the technical measure that root nitrogen source is difficult to replace in late growth stage of peanut. Nitrogen from leaf topdressing was mainly distributed in pod and leaves, which was the physiological mechanism of peanut to increase yield and leaf photosynthesis. The utilization rate of leaf nitrogen fertilizer was significantly higher than that of root fertilizer, which was an effective way of economic fertilization for peanut. The plant N efficiency decreased with the increase of leaf N application amount, and the fertilizer utilization rate was higher with less application times or lower nitrogen concentration. This study could provide theoretical basis and technical support for peanut foliar fertilization.
In order to explore the root physiology and rhizosphere soil nutrients under the sugarcane peanut intercropping, three cropping modes were set up for sugarcane monocropping, peanut monocropping, and intercropping of sugarcane and peanut. The changes of root exudates, root extracts and rhizosphere soil nutrients under different cropping modes and their correlations were systematically analyzed. The results showed that the total amino acid in intercropping sugarcane root exudates and the total sugar in intercropping sugarcane root extract were significantly higher than that of monocropping sugarcane, while only the total sugar in intercropping peanut root extract was significantly higher than that in monocropping peanut. The alkali-hydrolyzed nitrogen, available phosphorus, available potassium, and soil organic matter in the rhizosphere soil of intercropping sugarcane were significantly higher than those of monocropping sugarcane, while the available phosphorus and available potassium and pH in the rhizosphere soil of intercropping peanut were significantly lower than those of monocropping peanut. There was no significant different in acid phosphatase, catalase, urease, and saccharase between intercropping and monocropping sugarcane, while the catalase of rhizosphere soil in intercropping peanut was significantly higher than monocropping peanut. There was a significant negative correlation between phenolic acids in root exudates and soil organic matter, while a significant positive correlation between total sugar content and sucrase, and a significant positive correlation between amino acids and urease. Organic acids in root extracts were positively correlated with pH, while amino acids were negatively correlated with soil organic matter while highly negatively correlated with available potassium. Urease was negatively correlated with AK, and sucrase was highly negatively correlated with soil organic matter. In conclusion, sugarcane/peanut intercropping system mainly affected the metabolic activity of root secreted amino acids, total sugars, and phenolic acids. And intercropping can significantly increase the soil available nutrients of intercropping sugarcane.
Clubroot has caused serious harms to rapeseed and other cruciferous vegetables in China. The risk levels of clubroot in a field can be evaluated by detecting the concentration of Plasmodiophora brassicae spores which causes rapeseed clubroot. In this study, a real-time quantitative PCR (qPCR) method for P. brassicae quantitative detection was established. The method was validated by diseased rapeseed plants and rhizosphere soils of diseased plants from different areas in Hunan Province, and the results showed that the method has high sensitivity and specificity. This qPCR method determines that the threshold concentration of P. brassicae spores in soil for the occurrence of clubroot is 1.34×103/g of soil. When the concentration of spores in the soil is higher than the threshold concentration, the risk of the occurrence of clubroot in rapeseed is higher. A field investigation was carried out in rapeseed planting areas of Changde, and 481 soil samples were randomly collected. The qPCR method was used to detect the concentration of P. brassicae spores in soil samples. On the basis of concentration of rhizome spores detected and the field clubroot investigation, it was found that rapeseed clubroot has developed at many points in Changde and has the trend of accelerating the spread. If effective control measures are not taken in time, the clubroot will break out in a large area in Changde, which pose a severe danger to rapeseed production in Changde. For the rapeseed planting areas in Changde, the probability of occurrence of clubroot in fileds is low when no spores of P. brassicae or the spore concentration less than 1.34×103/g of soil have been detected, and non-resistant rapeseed varieties can be planted in these fields, but the disease in these fields should be monitored closely. Fields with spore concentration higher than1.34×103/g of soil need chemical prevention and control or planting of rapeseed varieties with resistance to clubroot.
In order to explore the effect of combined application of nitrogen and calcium on nitrogen utilization and calcium accumulation of peanut, a field experiment was conducted using Huayu 25 with two calcium （Ca） rates （0 and 600 kg·hm-2）, and five nitrogen （N） rates （0, 75, 150, 225, and 300 kg·hm-2） were set up in Jiyang and Yinmaquan experimental bases, respectively, to study the effects of nitrogen and calcium interaction on nitrogen metabolism enzyme, nitrogen utilization and calcium accumulation of peanut in different plots. The results showed that the interaction of nitrogen and calcium significantly increased the chlorophyll content of peanut in the early growth stage, at full fruit stage, under the condition of Ca0，the SPAD value of peanut with nitrogen application was 3.8%-14.8% higher than that without nitrogen application, while higher 3.9%-15.2% under the condition of Ca600. Nitrogen fertilizer could increase the activity of nitrogen metabolizing enzyme in peanut. In the mature stage, the glutamine synthetase （GS） activity of Ca0 treatment under N300 condition was 57.8% higher than that of N0 condition, while that of Ca600 treatment was 87.3% higher. With the increase of nitrogen application rate, nitrogen use efficiency decreased gradually, while calcium fertilizer could improve peanut nitrogen use efficiency. Under the same nitrogen application conditions, nitrogen agronomic use efficiency and nitrogen use efficiency of Ca600 increased by 10.1%-24.6%、7.1%-48.7% and 2.1%-16.6%, respectively, compared with Ca0. The interaction of nitrogen and calcium increased the calcitonin distribution rate in mature pods. Under the same nitrogen application, the calcitonin distribution rate in Ca600 treatment increased by 2.5-15.0 percentage points compared with Ca0 treatment, and the calcitonin distribution rate of N225 treatment was the highest. In summary, The interaction between nitrogen and calcium is beneficial to increase the content of chlorophyll in the early growth stage of peanut, increase the activity of nitrogen metabolic enzymes, improve nitrogen use efficiency and promote the distribution of calcitonin to pods, and the comprehensive performance of Ca600 and N225 treatments was the best.
Cylindrocladium black rot and Neocosmospora foot rot are important diseases that seriously threaten healthy peanuts production. It is difficult to distinguish these two diseases due to their similar symptoms in the fields. In this study, duplex PCR detection was developed for the differential diagnosis of Cylindrocladium parasiticum and Neocosmospora vasinfecta based on calmodulin (cmdA) sequences. Two specific target bands (274 bp and 409 bp) were successfully amplified under the optimum conditions: reaction concentration of 1.8 ×, primer concentration of 0.2 μmol/L, annealing temperature of 62°C, and number of reaction cycles of 37. The detection limit of the duplex PCR system was 100 pg/μL The established duplex PCR assay was specific and efficient, could be used to distinguish accurately and control timely of the two confusing peanut diseases.
Giving full play to symbiotic nitrogen fixation in soybean production is important in reducing nitrogen fertilizer application, increasing the activity of soil microorganisms, ensuring the health of arable land and agroecosystems, and promoting the sustainable development of green agriculture. In this study, the high-yielding, high-quality, multi-resistant and widely adapted soybean variety Zhongdou 63 was used as the capture host, and soybean rhizobium Y63 was isolated and identified from a high-yielding demonstration field in Honghu City, Hubei Province. The strains with the apparent characteristics of rhizobia were screened by using plate scribing and BTB reaction test, and the 16S rDNA sequences were amplified and a phylogenetic tree was constructed to identify two soybean rhizobia strains, both named Y63-1 and Y63-2, as rhizobia from a single nodule of Zhongdou 63. The antibiotic resistance analysis showed that Y63-1 was resistant to Carbenicillin (Car), Cefotaximesodium (Cef), Ampicillin (Amp) and Rifampin (Rif), and Y63-2 was resistant to kanamycin (kan), Carbenicillin (Car) and Ampicillin (Amp), Rifampin (Rif). Finally, the two rhizobia Y63-1 and Y63-2 were inoculated in pots at certain ratios with the slow-growing rhizobium 113-2 and the fast-growing rhizobium HH103 as controls, and the fresh weight of above-ground parts, the number of nodules and the dry weight of nodules of Zhongdou 63 were statistically analyzed at 42 and 51 days after inoculation. The results showed that Y63-1∶Y63-2=2∶1 had the best nodulation effect when inoculated with Zhongdou 63. The preliminary identification of the proportion of Y63-1 and Y63-2 in the nodules after mixed inoculation showed that Y63-1 was the dominant rhizobium, consistent with the nodulation phenotype. This study enriches the rhizobial resources in China, and the results provide a theoretical basis for the application of mixed rhizobial inoculation techniques in soybean production, as well as a theoretical basis for incising the yield potential of Zhongdou 63 and other varieties through inoculation with highly efficient rhizobia in production.
A strain of Bacillus sp. ate -1 with high atrazine degrading ability was obtained by using SMS medium from the soil of maize field where atrazine had been applied for a long time. The strain was storage with number of CCTCC NO: M2019925. After characterization of the strain, it was found that the strain could tolerate atrazine at least 1000 µg/mL concentration and had the ability to produce IAA. The germination test of sunflower seed was carried out with the fermentation broth of the strain. It was confirmed that the dilution of fermentation broth from 40 to 100 times can significantly promote the root length during seed germination. By measuring the chlorophyll content of sunflower leaves in pot experiment, it was found that the chlorophyll content of sunflower increased in different degrees when the atrazine content was 5 mg/kg, 10 mg/kg, 15 mg/kg and 20 mg/kg soil, and the highest degree of improvement was found in the soil treated with atrazine below 15 mg/kg. The results of the determination of soil Urease and Phosphatase also confirmed that the enzyme activity after adding degrading bacteria was higher than that without adding bacteria. The results provided a new microbial resource for the remediation of atrazine contaminated soil, and provided technical support for alleviating the damage of atrazine to sunflower seedlings.
In order to determine the effects of functional plants planted in peanut field on the occurrence of main predatory natural enemies and thrips, four functional plants were designed into three treatment areas (Veronica persica+Helianthus tuberosus treatment area, Zinnia elegans treatment area, and Cichorium intybus treatment area), to construct peanut-functional plant micro landscape system. The quantility and population dynamics of three families of predatory natural enemies (i.e., Coccinellidae, Anthocoridae, Syrphidae) and thrips in different treatment areas were investigated and analyzed. The results indicated that the total amount of occurrence of syrphids in the V. persica+H. tuberosus treatment area was 1.85 times higher than that of peanut monoculture area. And V. persica exhibited a significant attraction on syrphids at seedling stage of peanut when syrphids eaters peak occurrence period. The attractive effect of H. tuberosus on
In order to provide theoretical data and technical support for the practical application of forage rape, this experiment selected forage rape (Brassica napus L.) and alfalfa (Medicago Sativa L.) during full flowering period as raw materials to explore the effects of mixed silage on its nutrition and fermentation quality. Silage materials were mixed according to the ratio of fresh weight 0∶10, 3∶7, 5∶5, 7∶3 and 10∶0. The silage cans were opened at 5, 10, 20, 40 and 60 days after ensiling to determine the dynamic changes of fermentation index and nutrient content. The results showed that the overall quality of forage rape and alfalfa silage alone was poor. With the increase of alfalfa addition ratio, the sensory quality score of mixed silage gradually improved. The contents of crude protein, soluble carbohydrate and lactic acid of mixed silage increased to varying degrees, while the pH value, NH3-N/TN and butyric acid content decreased to a certain extent. It is better to mix and store forage rape and alfalfa at a ratio of 3∶7. At 60 days of fermentation, the pH value (3.95) and a NH3-N/TN (4.16%) content were significantly lower than those in the control group (P<0.05), and lactic acid (96.46g·kg-1DM) was significantly the highest (P<0.05). The V-score was good (80.07) and the membership function value was the highest (0.7649), which could be used as the appropriate proportion scheme for mixed silage of forage rape and alfalfa.
