Peanut and soybean are important oilseeds and cash crops in China, however they are also vulnerable to aflatoxin contamination, which seriously threatens food safety and restricts industrial development. The prevention and control of aflatoxin occurrence in food is currently an intense research challenge globally. We first put forward the research idea of coupling the aflatoxin green control with the promotion of root nodule nitrogen fixation, based on the research idea, the microbial agent ARC-BBBE was invented. In this study, the effect of on-the-field application of microbial agent ARC-BBBE in the control of Aspergillus flavus and its toxin on peanut was reported. The research was carried out by investigating the effects of ARC-BBBE on biological and economic traits of peanut, and identifying the effects of ARC-BBBE on nodulation and nitrogen fixation of peanut and soybean, to provide theoretical basis and scientific guidance for controlling aflatoxin contamination and reducing the fertilizer and pesticide use from the source in the field. In field control trials, ARC-BBBE was applied to the soil at a dosage of 30 kg/hm2 with base fertilizer during planting in the peanut-producing provinces of China for 2 consecutive years. At the same time, peanut and soybean pot experiments were also conducted. The level of aflatoxin in the soil was investigated by the spread plate method. And the aflatoxin content in peanut samples was determined using high performance liquid chromatography （HPLC）. Measurement of the nitrogen fixation activity of root nodules was performed using acetylene reduction assay. Finally, the number and weight of root nodules were calculated using a 5-point sampling survey. Results showed that ARC-BBBE significantly reduced the abundance of aflatoxin-producing fungi in soil and the level of aflatoxin in peanut, with an average reduction of 66.5% in the abundance of toxin-producing fungi and decrease of 83.5% in aflatoxin content. The application of ARC-BBBE resulted in a general super nodulation phenomenon in peanut roots, and its nitrogenase activity was also verified in this work. The average number of nodules increased more than 10 folds （50 folds in poor soil areas）, the nodule weight increased more than 8.8 folds, and the nodule nitrogenase activity per gram increased more than 5 folds. The fruit filling rate and yield were significantly increased and the leaf color was dense green. In addition, the results of peanut pot experiment in greenhouse showed that the number of nodules was 2.2 folds higher, nitrogen fixing enzyme activity was 4 folds higher and chlorophyll content was 21.3% higher in the ARC-BBBE treated group compared to the control group. The results of soybean potted planting experiment in greenhouse revealed that ARC-BBBE also promoted nodulation and nitrogen fixation in soybean, with a 13.5-fold increase in the number of nodules and a 19.8-fold increase in nodule weight in the ARC-BBBE-treated group compared to the control group. At 26 days after sowing, the root nodules in the treatment group had nitrogen fixation activity while those in the control group had no activity, and biological indices such as root length, root weight, fresh weight and chlorophyll level were significantly enhanced in the treatment group. The effect of ARC-BBBE on the control of Aspergillus flavus and its toxin in peanut is extremely obvious. ARC-BBBE does not only effectively inhibit peanut aflatoxin-producing fungi and reduce the risk of aflatoxin contamination from the source of production, but also significantly improves the amount of peanut root nodules and nitrogen-fixing enzyme activity, which is of remarkable growth-promoting, yield-increasing, disease-control, safety-preserving properties, and economic, social and ecological benefits. Thus, it is of great significance in minimizing the application of pesticides and fertilizers, protecting farmland ecology, and promoting the high-quality environment-friendly development of the peanut industry, which is prospective for application in the production of peanut, soybean and other leguminous crops in the future.
To find out elite restorer lines during high yield hybrid breeding, 3 Polima cytoplasmic male sterile （Pol CMS） lines of spring Brassica napus L. were used to formulate stronger hybrid combination in spring rapeseed area. SLAF-seq was used to develop SNP markers for the 3 sterile lines and also 118 restorer lines. All 121 materials were clustered based on SNP markers. According to clustering results and their flowering times, 40 restorer lines were selected from each categories to the 3 sterile lines respectively. Under the adopted NCⅡ design, 120 hybrid combinations were prepareed and analysed on their combining ability, heterosis and correlation of parental genetic distance, combined cluster and high-yield combinations. Results showed that genetic clustering divided 121 B. napus resources into 5 categories. The 3 sterile lines were grouped into category V. General combining ability （GCA） of the 43 parents varied from -20.78 to 30.42. Three restorer lines （R83, R107 and R13） and one sterile line S3 （105A） had larger GCA. In the combinations, S3×R13, S1×R48, S3×R11, and S2×R89 had higher special combining abilities. The combination S3×R13 had the largest yield over-standard heterosis and over-parent heterosis （37.12% and 42.52% respectively）. Genetic distance and individual yield were extremely positively correlated, with correlation coefficient of 0.390. Among the hybrid combinations, most of the restorers with top 20 yields were from Type I group, which had large genetic distance with the sterile lines. Meanwhile, some varieties popularized in spring rape areas, including restorer lines of Qingza 2, Qingza 7, Qingza 9 and Qingza 12 were all derived from hybrids of Type I and sterile line S3 （105A）. Therefore, it was considered that sterile lines crossed Type Ⅰ restoring lines could be strong hybrid combination in spring B. napus.
In order to broaden the genetic background of Brassica napus, 54 new lines of B. napus were created by interspecific hybridization between B. juncea and B. napus, and their phenotypic diversity was analyzed. The results showed that， （1） the variation coefficient of 22 quantitative traits ranged from 1.64 to 2.04. The genetic diversity index of 22 morphological traits ranged from 0 to 1.86. Among them, the diversity level of silique length, siliques per plant, seeds weight per plant, growth duration, branch height, protein content and oil content were higher than those of other B. napus reported at home and abroad, which indicated that interspecific hybridization between B. juncea and B. napus could create rich genetic variation and broaden the genetic background of B. napus. （2） Principal component analysis transformed 44 phenotypic traits into 10 comprehensive indexes. The yield and quality related traits such as silique number of the main inflorescence, siliques per plant, seeds per silique, erucic acid , linoleic acid, oleic acid, protein, oil content and other yield and quality related traits were the main indicators reflecting the phenotypic characteristics of new type B. napus. The target line might be obtained by selecting. (3) Affected by the directional breeding of B. napus, the materials tested in this experiment have the phenotypic characteristics biased to B. napus. Cluster analysis integrated 44 phenotypic characteristics, and divided 54 lines into 3 groups, of which 29 lines and parents of B. napus were clustered into one group, representing the parent group of B. napus. The 18 lines were clustered into one group, which was far away from the parent of B. napus group, having less advantage in vegetative growth, and poor comprehensive characteristics with low yield. The 7 lines were clustered into the same group, which was close to B. napus parent, having strong nutritional growth advantage with high yield. For the 7 lines had excellent comprehensive characteristics, they might be used as further breeding objects in this area.
In order to identify high nitrogen efficiency winter rapeseed for both paddy-dryland rotation and dryland rotation planting in yellow soil in Guizhou Province, field experiment was conducted on growth, nutrient absorption and utilization efficiency of different rapeseed varieties under 4 nitrogen application rates （0, 45, 135 and 180 kg/hm2, named as N0, N45, N135 and N180 respectively） using 26 varieties.Results showed that yield of all tested varieties increased with nitrogen application rates. Under N180 treatment, Deyouza 11 had the highest yield, output value and economic benefit under dryland rotalion. Its yield, output value and economic benefit reached 3130 kg/hm2, 15 650 yuan/hm2 and 9998 yuan/hm2. And Deyouza 11 also had the highset yield, output value and economic benifit under paddy-dryland rotation, reached 2767 kg/hm2, 13 835 yuan/hm2 and 8183 yuan/hm2, respectively. Deyouza 11 also had the largest biomass in both dryland rotation and paddy-dryland rotation. Nitrogen agronomic efficiency in dry field planting increased firstly, and then decreased with nitrogen application rate, and reached the peak value in N135 treatment. Partial nitrogen productivity and uptake efficiency of all tested varieties decreased with nitrogen application rate. Compare to paddy-dryland rotation, rapeseed yield, nutrient uptake and nitrogen use efficiency in dryland rotation were much higher. The nitrogen agronomic efficient of winter rapeseed in dry field planting increased firstly, and then decreased with the increase of nitrogen application rate, and reached the maximum value in N135 treatment. Under different nitrogen application conditions, partial nitrogen productivity and nitrogen absorption rate of all tested winter rapeseed varieties decreased with the increase of nitrogen application rate. The yield, nutrient uptake and nitrogen use efficiency of winter rapeseed planted in dryland rotation were better than those in paddy-dryland rotation. Considering the yield, economic benefit and nutrientnitogen uptake and utilization, 8 varieties were recommended for dryland rotation, including Deyouza 11, Qianyouzao 2, Longting 1, Qingyou 1, Jinyou 8, Qingyou 3, Jinnongyou 1 and Qianyouzao 1. And 8 varieties were recommended for paddy-dryland rotation, including Deyouza 11, Qianyou 28, Guangyuan 68, Qingyou 3, Hualongyou 1, Longting 1, Qingyou 1 and Rongyou 28. It was suggested that nitrogen management of winter rapeseed should be adjusted according to rotation patterns.
In order to accurately identify the phenotypic traits of the Northeast soybean germplasm population in Jiamusi, observe the performance of this population and study its potential breeding significance in Jiamusi. Using the Northeast China Soybean Germplasm Population composed of 361 local varieties and bred varieties in the Northeast region of China, the repeated inner grouping design experiment method was used to conduct accurate phenotypic identification of main agronomic traits in Jiamusi from 2012 to 2014. The results showed: 1） The average performance of the soybean germplasm population in Northeast China was 113.5 days （92.5-136.0 days）, protein content 39.8% （35.6%-45.0%）, oil content 21.5% （17.5%-24.2%）, total protein-oil was 61.3% （57.4%-64.3%）, the 100-seed weight was 21.1g （8.2-32.0g）, the plant height was about 101.2cm （54.9-142.6cm）, the nodes No. of main stem was 18.6 （12.4-24.6）, and the branches was 2.5 （0.2-7.4）, lodging 2.1 （1.0-4.0）. 2） The local suitable maturity groups were MG0 and MGI, and the average value of each trait of these two maturity varieties was similar to the total average value of the population. The growth days of MG000-00 are concentrated at 95-110 days, which is about 15-25 days earlier than the local frost-free period; the oil content and total protein-oil was about 1 and 1.5 percentage points higher than MG0-I, respectively; the plant height and node number were about 10-40 cm and 2-8 nodes lower respectively. The growth days of MGII were as long as 150 days, and it can’t be stable and mature. Compared with local varieties, the protein and the total protein-oil were about 2% lower, and the oil is about 0.5% lower. The plant height and the number of nodes were about 10 cm and 2 nodes higher respectively; The degree of lodging is as high as level 3. MGIII could not mature normally in Jiamusi, and its growth and lodging degree increased. 3） According to the estimation of the genetic progress of various agronomic and quality traits in Jiamusi, although the oil and protein content is relatively lower, but they have certain potential to be improved. The Jiamusi region has bred many excellent varieties suitable for the northern part of the Northeast by using the soybean resources of the Northeast China, which reflects the important role of the Northeast germplasm. According to the performance of local varieties, excellent parents for improving different shapes were selected from the Northeast soybean germplasm population for reference by breeders.
Intercropping patterns of soybean is an important model in southern China, the shading stress of high stalk crops is an important factor that affects the yield and quality of intercropped soybean. Therefore, it is particularly important to analyze the shade tolerance of soybean. In this study, a recombinant inbred lines （RILs） established from the shade-tolerant （Aijiaozao） and shade-sensitive （Chippewa）, 30 shade-tolerant and shade-sensitive accessions were selected to construct two DNA hybrid pools, respectively. Progeny hybrid and parent pools were covered for an average depth of 60× and 30×. By calculating the SNP-index of two progeny pools, the differences of SNP-index between shade-tolerant and shade-sensitive chromosomal segments were compared. And the candidate genes of shade tolerance were predicted based on their functional annotations. The results showed that 11 963 077 single nucleotide polymorphisms （SNPs） were obtained from four samples. There were 408 genes were found that they were mainly located on chromosome1 （51 942-505 708 bp）, chr. 4 （50 972 768-51 854 631 bp）, chr. 9 （48 778 767-50 178 743 bp） and chr. 18 （40 858 027-43 909 456 bp）. According to gene annotation and functional analysis, five candidate genes might be related to shade tolerance of soybean, including 1-aminocyclopropane-1-carboxylate oxidase 5-like, auxin-induced protein 5NG4-like, phytochrome-associated serine/threonine protein phosphatase-like, MYBJ6 and MYB128 were identified. They might play an important role in the process of soybean shade tolerance. The results will lay an important foundation for the molecular mechanism of soybean shade tolerance, and laid solid theoretical foundation for map-based cloning of shade-tolerant genes in soybean.
Saline-alkali stress always exists in all stages of crop, and it is of great significance to screen saline-alkali tolerant soybean resources in the whole growth period. The salt species, salt content and pH value of saline-alkali soil in Daqing area were firstly measured, then the salt species and concentration of salt for screening were determined. In culture dish, germination bag and pot screening experiment, the saline-alkali tolerance of soybean was evaluated by the germination rate, the amount of matter at seedling stage and the dry matter weight at maturity stage. The results showed that the soil in Daqing area was sulfate soda saline-alkali soil, and the saline alkali solution is the mixed saline alkali solution of NaCl, Na2CO3, NaHCO3 and Na2SO4 （molar ratio is 1:1:9:9）, and the total salt concentration calculated by Na ion content is 80 mmol · L-1, and the pH value of the solution is 8.9. Therefore, the salt content and pH value of soil in pot experiment were 3.3 ‰ and 8.9, respectively. Among the 887 soybean cultivars identified, the seed coat colors were black, brown, red, green, yellow and double color, and the correlation analysis showed that there was a significant positive correlation between salt tolerance and seed coat color of soybean. 296 tolerance soybean cultivars were selected from 887 soybean resources in germination stage, and 123 cultivars among 296 cultivars were identified as high resistance in germination and seedling stage, furthermore 7 resistant soybeans, including 5 from South China, 2 from Huanghuai, and 62 tolerant soybeans were obtained in the whole growth stage, and the proportion of pot screening was 56.10%. This study established a stepwise screening method from germination stage, seedling stage to the whole growth stage, and 69 salt and alkali resistant resources were selected from 887 soybean germplasm resources, which provided material basis for salt tolerance breeding and utilization of salt tolerant gene resources.
A peanut recombinant inbred population with Huayu 28 and P76 as parents was used to perform genetic mapping for 100-pod and 100-seed weight. Phenotypic data of 100-pod and 100-seed weight were collected in 3 environments. QTL mapping analysis was performed with individual environmental analysis and multi-environmental joint analysis. Multi-environmental joint analysis demonstrated 5 QTLs for 100-pod weight and 10 QTLs for 100-seed weight. Individual environmental analysis yielded 3 QTLs for 100-pod weight (qHPW05.1, qHPW07.1, qHPW19.1) on 3 linkage groups, and 4 QTLs for 100-seed weight (qHSW05.1, qHSW07.1, qHSW19.1, qHSW20.1) on 4 linkage groups. Among these, qHPW07.1, qHPW19.1, qHSW 07.1 and qHSW 19.1 could be detected in two or three environments with phenotypic variation explained (PVE) ranging from 4.610%-8.840%, 9.985%-11.224%, 7.155%-10.464% and 7.239%-13.845%. qHPW07.1 could be detected in 3 environments with phenotypic variation explained (PVE) of 4.610%-8.840%. Comparative analysis of all QTLs revealed two QTL clusters on LG07 (Cluster I) and LG19 (ClusterⅡ). These results provided a theoretical basis for both improvement of peanut yield and cloning of associated genes.
The present study was carried out to screen comprehensive feeding evaluation indexes of peanut straw and to identify peanut germplasm resources with highly feeding value. Forty peanut varieties and breeding lines were used for detecting protein, ash, calcium, phosphorus, neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL) and in vitro dry matter digestion (IVDMD) of stalks and leaves by employing near infrared reflectance spectroscopy technology respectively, as well as calcium, phosphorus and protein of seeds. By comparing content of nutrients between peanut leaves and stalks, peanut leaves contained 5% higher content of protein, approximately equal content of ash, calcium and phosphorus, and lower content of NDF, ADF, ADL, reflecting that peanut leaves have higher feeding value than peanut stalks. There were significant and positive correlation between content of calcium and phosphorus in peanut stalks, leaves and seeds respectively, indicating that absolute synergistic absorption existed. Furthermore, both content of calcium and phosphorus were significantly negative with content of protein in stalks and leaves respcetively, while the both content of calcium and phosphorus were significantly positive with content of protein in peanut seeds. Five comprehensive indexs with 91.12% accumulative contribution of 18 indexes of peanut stalks and leaves were extracted by PCA analysis. Based on comprehensive score (namely D) of each peanut variety, 40 peanut varieties and lines were divided into 3 groups by cluster analysis, the first group contained 10 peanut varieties with high comprehensive feeding scores (CFS) , the second group contained 17 peanut varieties with medium CFS, and the third group contained 13 peanut varieties with low CFS. The optimal mathematical model of peanut feeding evaluation was established on account of D scores and 18 indexes of peanut stalks and leaves, namely D=0.014X1+0.012X2-0.003X5+0.009X7-0.023X8+0.009X10+0.011X16-1.582 (R2=0.994, F=764.329, P=0.000), which showed high estimation accuracy above 88%. Hence, 7 indexes were screened out, which consisted of five indexes of stalks (protein, ash, NDF, DM and ADL) and 2 indexes of leaves (protein and DM).
In this study, the oil content, oleic acid, linoleic acid, palmitic acid and stearic acid content variations of the RIL population, that generated from the high oil content sesame cultivar "Zhongzhi 13" (56.31%) and the low oil content sesame material ZZM2748 (48.75%) with 548 lines, were studied in two different environments by near infrared method, and the QTL were mapped using the two softwares WinQTLCart2.5 and ICIMapping3.0 based on a genetic linkage map. It was found that the oil content and fatty acid content of the population had great variation. The RIL oil contents varied from 42.43% to 58.38% in different environments, and it had no significant correlation with oleic acid and linoleic acid content but palmitic acid content. A total of 50 QTLs were mapped and distributed in 11 linkage groups of sesame, with the contribution rate varying from 1.59% to 40.62%. Among them, 21 QTLs were detected by the two software parallelly, and 7 QTL were repeatedly detected in the two environment. The two QTL qSOC_10.3 and qSOC_11.1contributed 34.38% and 40.62% to the phenotype variations respectively, and were the major loci for the oil content variation. Especially, qSOC_11.1 also exhibited pleiotropic for oleic acid, linoleic acid, palmitic acid and stearic acid. In combination with gene annotation and differential expression analysis, 24 candidate genes were found at the two major loci. The genetic variation characteristics of sesame oil content and different fatty acid content, QTL and candidate genes obtained in this study have guiding significance and application value for genetic improvement of related traits.
To evaluate phenotypic characteristics of sunflower germplasm and select core collection in southern China, 11 phenotypic traits from 422 sunflowers were analyzed and evaluated using descriptive statistics, correlation analysis and principal component analysis in 2016 and 2018. A wide variation was found with coefficient of variation ranged from 3.60% to 83.32% including several important characteristics as branching rate (0%-62.5%), seed weight per plant (9.70-232.35 g), hundred-grain weight (4.60-14.92 g), number of leaf (14.40-48.38) and plant height (103.75-260.00 cm). Significant correlations were observed between traits. Principal component analysis showed that 4 main components affecting the traits accounted for 71.72% of the total variance. A total of 72 core collections for candidate populations were constructed by using QGAstation 2.0 software. The best core collection was constructed including 84 materials according to their mean difference percentage, variance difference percentage, range coincidence rate and coefficient of variation percentage. The 84 core resources were divided into 5 categories by cluster. Compared with the original population, mean value of the selected core collection had no significant difference, while the variance was significantly increased, which could represent the preservation and utilization of the original sunflower planting resources.
To improve cold tolerance breeding of rapeseed （Brassica napus L.）, effect of low temperature on rapeseed growth was studied using 8 cultivars. In natural temperature （falling with 2.75℃ mean temperature）, the content of proline and chlorophyll in cold tolerant varieties were higher than those in cold sensitive ones, and the relative conductivity had no significant differences. When the natural temperature rising to the mean temperature of 7.52℃ to 12.39℃, no difference was found of the biomass for the recovery growth in these varieties. Under 10℃/4℃, biomass of all varieties was increased in the first 3 weeks. But from the fourth week, the biomass of cold sensitive varieties decreased with white spots in new leaves. While, the biomass of cold tolerant varieties remained unchanged with white spots appeared in old leaves. Under low temperature, proline continued to increase, and chlorophyll became significantly higher, which resulted in significant growth advantage in cold tolerant rapeseed varieties.
Suitable density and nitrogen fertilizer were studied for efficient peanut physiological characteristics, plant and pod yield characteristic under single seed planting. The field experiment was conducted in the Zhaoyuan, Yantai City, Shandong Province. The field experiment was carried out in the year 2018 and 2019, with a export big-pod variety of peanut Huayu22 as tested material. Three plant densities of 120 000, 200 000 and 280 000 plant/hm2（named as D1, D2 and D3）, and four nitrogen application rates of 0, 50, 115 and 180 kg/hm2 were designed （named as N0, N50, N115, N180, respectively）.The SPAD, plant and pod yield characteristic of peanut were investigated in different bear periods. Both the plant density and nitrogen application rate had significant effected SPAD value, dry matter quality, plant and pod yield characteristic of peanut, and the interaction between them was significant as well. Compared to low plant density （120 000 plant/hm2） and high plant density （280 000 plant/hm2）, the pod yields under plant density of 200 000 plant/hm2 were significantly increased by 24.31%-45.04% and 10.57%-15.13%, respectively. The SPAD value of maturation period were significantly increased by 3.70%-27.82% and 6.10%-18.94%, dry matter quality of maturation period were significantly increased by 7.31%-32.34% and 10.65%-34.59%. Under the plant density of 200 000 plant/hm2,when the nitrogen application rate was increased from 50 to 180 kg/hm2, the pod yield, SPAD value and dry matter quality of peanut were significantly increased and all were significantly higher than that of the N0 treatment, and were in order of N115 > N180> N50>N0, and the pod yield reached the highest in N 115, which was 6.83% and 3.90% higher than those in N50 and N180 treatments. Synergistic improvement of the SPAD value, dry matter quality, plant characteristic were caused. Under this experimental field condition, comprehensively considering the physiological characteristics and pod yield characteristic, the characteristics were increased with the nitrogen application rates in the plant density of 120 000 plant/hm2, the appropriate plant density of single seed planting in peanut is 200 000 plant/hm2 and the nitrogen application rate is 115 kg/hm2.
In order to provide theoretical basis for selecting soybean varieties suitable for intercropping, sixteen soybean varieties including early maturity （EM）, medium maturity （MM） and late maturity type （LM） were used as experimental materials to compare the agronomic traits and yield components in “maize-soybean” relay strip intercropping with the control of sole cropping of soybean. The results showed that the plant height, average internode length and lodging rate of three types of soybean varieties in intercropping were significantly higher than those of control. The plant height, bottom pod height, node number, average internode length and lodging rate of EM were significantly lower than those of MM and LM. The number of effective branches of LM in intercropping was significantly higher than those of control, whereas EM and MM were not significant. The yields of three types in intercropping were significantly lower than those of control. The pod number per plant, seed number per plant, 100-seed weight and yield of EM were significantly lower than those of MM and LM, but the differences between MM and LM were not significant. In addition, the available pods rate of MM and LM in interplanting were significantly higher than those of control, the available pods rate of LM were significantly higher than those of MM and EM, meanwhile available pods rate of MM are significantly higher than EM. The full grain rate was no significant difference between intercropping and control, but the full grain rate of MM and LM were significantly higher than those of EM. Through correlation analysis, the lodging rate in intercropping condition was significantly positively related to high plant, nod number and average internode length; maturity was significantly positively related to the available pods rate, the yield per plant, full grain rate and yield. The SPMS/M （symbiotic phase of maize and soybean/maturity） was significantly negative related to the available pods rate, full grain rate and yield. These results concluded that the MM and LM soybean varieties have a longer period of light compensation and could obtain higher yields in intercroping than EM varieties, which are suitable soybean varieties for maize-soybean intercropping.
The objective of this study was to explore the potential allelochemicals in sesame root exudates that might cause sesame continuous cropping obstacles. Cultivar Jinhuangma was selected as material during budding, blooming and maturing stages under normal rotation (CK) and continuous cropping (CC). Sesame root exudates showed "low promotion and high inhibition" to seed germination. 18 to 28 organic compounds were identified in sesame root exudates at budding, blooming and maturing stages under CK and CC treatments. Sesame root exudates at budding and blooming stages contained esters, hydrocarbons, acids, phenols, amines, alcohols and ketones. Among them, the relative abundance of trans-(2,3-diphenylcyclopropyl)-methyl phenyl sulfoxide was the highest. Polyethers were found at maturing stage, but not at budding and blooming stages. The relative abundance of octaethyleneglycol monododecylether at maturing stage was the highest. Esters was important part in sesame root exudates, with the total relative abundance to 75.12% (CK) and 52.96% (CC) respectively at budding stage. Compared to CK, the relative abundance of diisooctyl phthalate and octaethyleneglycol monododecylether was 9.48 and 5.73 percentage points higher in root exudates of continuous cropping sesame. As the main source of allelochemicals, acidic substances had the highest content in root exudates at maturing stage. The total relative abundance of acids reached to 17.53% and 42.71% in exudates under CK and CC treatments respectively. Compared to CK, the relative abundances of palmitic acid, linoleic acid and stearic acid were higher by 15.78, 1.33 and 1.15 points respectively. Both oleic acid and myristic acid were detected in root exudates of continuous cropping sesame only, with the relative abundance of 10.66 and 1.62 points respectively. Compared with CK, the relative abundance of erucamide was 21.68 and 11.51 points higher at budding and blooming stages in the continuous cropping sesame root exudate, while the corresponding oleic acid amide was 2.16 and 7.44 points higher respectively. In summary, continuous cropping changed the compounds of sesame root exudates.
Crop yield is closely related to population structure, and rational population structure configuration is one of the effective ways to improve crop light energy utilization rate and increase yield. The effects of different population structures on photosynthetic characteristics and yield in tuber growth stage were studied to provide theoretical basis for further tapping yield potential of Cyperus esculentus in the midwestern of Heilongjiang Province. C. esculentus variety Heiyousha 2 was used as material in 2018. Three factors split-split plot design was used to study the effects of different population structures on photosynthetic characteristics and yield by analyzing canopy apparent photosynthetic （CAP）, Chl（a+b） content, Fv/Fm and qP. The main plots was planting density with 90 000 plants/hm2 （A1）, 110 000 plants/hm2 （A2）, and 130 000 plants/hm2 （A3）; split plot was planting way with 110 cm ridge 3 lines （B1）, 65 cm ridge 2 lines （B2）, and 45 cm ridge 1 line （B3）. Split-split plot was seedling retention with rectangular （C1） and triangles （C2）. Results showed that CAP increased with the planting density in tuber formative stage, and the differences among 3 treatments were significant （P< 0.05）. CAP increased firstly and then decreased with the density in the middle stage of tuber growth and maturity stage. Chl（a+b） content, Fv/Fm and qP increased with the density in 0 d after tuber formative stage in canopy and lower leaves. Chl（a+b） content, Fv/Fm and qP increased firstly and then decreased with the density in 25-75 d after tuber formative stage. The changes of CAP, Chl （a+b） content, Fv/Fm and qP were in B2> B1 and B2> B3, the differences were significant （P< 0.05） under the same density and seedling retention way. The above indicators were C2>C1, the differences were significant （P< 0.05） under the same density and planting way. A2B1C2 treatment had the highest yield （7520.45 kg/hm2）. Thus a reasonable planting density would be the key to increase C. esculentus yield. Under the appropriate density, reasonable wide-narrow row configuration and triangular seedling retention ways could effectively improve the population structure, CAP, Chl（a+b） content, Fv/Fm and qP, and thus would be an important way to achieve coordination between individual plants and the population, and to increase yield.
To improve the Sunflower Nutrient Expert System, and to facilitate large-scale application, 84 field experiments were carried out from 2017 to 2019 which covered the main sunflower producing areas in China. The efficiency of saving fertilizer, increasing yield, nutrient recovery and economic benefits of sunflower nutrient expert system were analyzed and compared with farmer accustomed fertilization. Results showed that the recommended nutrient rate of sunflower nutrient expert （NE） were 7 kg/hm2 less nitrogen （N）, and 23 kg/hm2 less phosphorus （P2O5） than farmer’s practice fertilization （FP）. Thus the fertilization was more optimized and reasonable. NE produced an average yield increase of 293.1 kg/hm2 compared with FP fertilization, with yield increase rate of 8.4%. The yield response of NE nitrogen, phosphorus and potassium increased significantly compared with FP. Compared with FP, the economic benefit RMB of NE increased by 1754.4 yuan/hm2.The agronomic efficiency of N and P recommended for NE fertilization increased by 1.7 and 3.6 kg/kg compared with FP. Compared with FP, NE improved NPK RE by 8.7, 6.1 and 6.0 percentage points, respectively. It can be seen that sunflower nutrient expert system has the good effect of saving nitrogen and phosphorus fertilizer, increasing yield, economic efficiency improvement and improving nutrient recovery. Sunflower nutrient expert system can be used to recommend fertilization in sunflower production areas.
Blackleg of oilseed rape (Brassica spp.) is caused by Leptosphaeria biglobosa, which has been found to occur widely in oilseed rape-producing areas in our country, resulting in a substantial seed yield loss in the industry of oilseed rape. However, the mechanisms for ecological adaptation and pathogenesis of L. biglobosa have not been elucidated. Therefore, it is necessary to conduct in-depth studies on molecular mechanisms for ecological adaptation and pathogenesis of L. biglobosa. In order to fulfill this objective, this study was done to mutate L. biglobosa by Agrobacterium tumeficens-mediated transformation (ATMT). The contents included optimization of the factors affecting the ATMT, evaluation of the quality of the transformants, and screening of mutants. The results showed that the optimum ATMT factors for L. biglobosa Lb731 were: hygomycin B concentration at 50 μg/mL, transformation recipients (conidia) from the 15-day-old cultures (20℃), conidial concentration at 2 × 107-8 conidia/mL, co-incubation of A. tumeficens-recipients at 25℃ for 72 h. The transformation efficiency reached 80 transformants per million conidia on average. The T-DNA insertion frequency reached up to 100% based on PCR assays with 72.7% single-copy insertion among the transformants based on Southern blottings. Results also showed that the hygromycin-resistance trait in the transformants inherited stably through nuclear mitosis. A total of 32 mutants were screened from 2136 transformants, including 11 mutants with suppressed mycelial growth, 7 mutants with deficiency in pigment biosynthesis, and 14 mutants with deficiency in conidial production. Meanwhile, 7 out of the 32 mutants were identified to completely lose pathogenicity (virulence) on oilseed rape. Using the hiTAIL-PCR technique, three DNA sequences flanking the T-DNA-insertion sites were obtained from three mutants. Overall, these results laid a solid foundation for further elucidation of the molecular mechanisms for ecological adaptation and pathogenesis in L. biglobosa.
In order to detect the different disease resistance of peanut main varieties in Shandong to peanut scab (Sphaceloma arachidis Bitaucourt et Jenkins) and its effect on peanut yield, in 2018-2019, we evaluated 36 peanut germplasm resources for resistance to peanut scab. The evaluation wascarried out in the field and greenhouserespectively,we also analyzed the effect of disease onyield. The result showed that there were 8 accessions as high susceptibility (HS) accounted for 22.22%; 4 accessions rated as susceptibility (S) and accounted for 11.11%; 2 accessions rated as moderate resistant (MR) and accounted for 5.56%; 11 accessions rated as resistant (R) and accounted for 30.56%; 11 accessions rated as high resistant (HR) and accounted for 30.56%.There was an exponent relation between the disease index and yield loss rate, the yield loss rate increased with the increase of decrease index.
Breeding for resistant variety will reduce its damage of Cercospora sojina to soybean. Association mapping is a method based on linkage disequilibrium (LD) to detect alleles in natural population. In current study, a natural populations including 202 soybean varieties in the past 25 years were constructed, and the resistance of all materials was determined by artificial inoculation with Race 10. Genetic diversity, population structure and linkage disequilibrium loci were estimated with 187 simple sequence repeat（SSR）markers. Association analysis for soybean resistance was performed by GLM (general linear model) and MLM (mixed linear model) program. To further analyze the relationship between elite alleles and phenotypic effects of resistance associated loci. The results showed that valuable coefficient of the resistance in 202 varieties was 14.26%. 809 polymorphic alleles were detected with 187 pairs of SSR primers. For each pair primer, 2 to 10 alleles were detected in all cultivars with an average of 4.42 alleles. The average PIC value of chromosome 17 was the highest (0.64) and that of chromosome 12 was the lowest (0.26). 146 specifically existent alleles and 58 rare alleles were detected. Linkage disequilibrium was detected extensively not only among syntenic markers but also among nonsyntenic ones, while the loci pairs with R2<0.05 accounted for 21.65% of the total ones. 202 soybean varieties were classified into three subpopulations, the genetic distance between subpopulations POP1 and POP3 is the smallest (0.03), and the genetic distance between subpopulations POP2 and POP3 is the largest (0.35). A total of 11 SSR markers were found to be significantly associated with soybean resistance to Race 10 in both models..Satt549 showed the highest contribution rate of 14.74%. 24 positive alleles were revealed among them 7 alleles had a positive phenotypic effect value greater than 10. Satt703-247 (19.62) showed the highest positive phenotypic effect, and was carried by Hefeng29; the second one was Satt587-185 (19.58). the carrier varieties was Dongnong50. Average positive allele effect of Satt549 locus was the highest (13.87), and that of Sat_366 locus was the lowest (0.84). The clustered multiple alleles and carrier varieties could be used in parent selection for pyramiding novel alleles and marker-assisted selection for breeding soybean varieties resistant to Cercospora sojina Hara.
Puccinia helianthi Schw. is an important pathogenic fungi for sunflower. To better understand their pathogen-plant interacting, rust-effectors were predicted from secreted proteome of this sunflower rust pathogen. Among 900 secretory proteins, 497 candidate effectors were predicted. Protein characteristics showed that their length of open reading frame was mostly between 200 and 399 bp. Length of signal peptides were mainly （92.96%） between 16 and 27 amino acids.The most frequent amino acid in signal peptides was leucine, followed by alanine and isoleucine. Signal peptide recognition sites were mainly SpⅠ type. qRT-PCR on 7 candidate effector-encoding genes in inoculated leaves showed that they were up-regulated compared with pure spores （control）, indicating their involving in pathogenesis of sunflower rust.
High oleate peanut is increasingly in favor of peanut customers and processing enterprises, due to its high nutritional value and prolonged shelf-life. However, it is hard to visually distinguish high oleate peanut from normal oleate peanut. Currently, identification of high oleate peanut is mainly dependent on gas chromatograph and near infrared spectrometer, which are normally large-sized, heavy and costly in use. As specialized laboratories and professional technician are needed, so that these facilities are less applicable for small peanut production and processing enterprises. Based on the negative correlation between refractive index of peanut oil and temperature (R2=0.999), as well as oleic acid content (R2=0.802), this study established a model of high oleate peanut identification using refractive index and developed a portable instrument for identifying high oleate peanut. Thirty peanut lines were identified by this instrument, and the result for each line was consistent with its oleic acid content from gas chromatograph. The accuracy of this instrument was 100%. The development of this portable instrument filled the blank market of economic and removable apparatus for identifying high oleate peanut. This portable instrument provided not only a quick, cheap and easy way to identify high oleate peanut, but also a technical support for promoting the development of high oleate peanut industry.
Weed is one of the most serious biological disasters that seriously damage the yield and quality of Brassica napus. Cultivating herbicide resistant B. napus varieties is an effective and economic way to control weeds in rapeseed field. In this paper, three kinds of herbicides, glyphosate, glufosinate and ALS enzyme inhibitors, which have the greatest potential for field application are mainly reviewed. The mechanisms of herbicide action and herbicide resistance are summarized. The research advances of B. napus resistant germplasms in China and abroad are further reviewed according to the germplasm creation methods. Finally, the development strategies of herbicide resistant rapeseed germplasm are put forward: strengthening the research of resistance mechanism and gene exploration, and using new technologies such as gene editing to create new non-transgenic rapeseed germplasms with multi herbicide resistance.
Tiger nut （Cyperus esculentus L., TN）, is a perennial herb of Cyperus Linn. It has the advantages of wide adaptability, short growth period, large biomass and high oil content. Stems and leaves of TN can be used as silage, and tubers of TN can be eaten raw or cooked. Noteworthily, TN can be used for oil production, and the cake can be further applied for feed. Therefore, as a new crop, TN integrates food, oil and fodder as a whole and has high economic value and development potential. In order to deeply understand TN and promote its high-value utilization, the research progress of the main nutrients such as oil, protein and polysaccharide in TN were summarizd. The physiological functions of TN in reducing blood lipid, lowering blood glucose, antioxidantion and protecting liver were expounded in detail. Moreover, the market scale and scientific research prospect were forecasted.
