Research of Seed Testa Structure and Storage Material of Peanut Germplasm with Different Resistance to A. flavus

There was an obvious relationship between seed testa structure, storage material and resistance to A. flavus of peanut. Results showed that seed testa of peanut germplasm with high resistance （HR） to A. flavus infection had thicker wax layer, integrated and tight epidermis layer, regular vascular tissue range. However, the seed testa of peanut germplasm with high sensitivity （HS） to A. flavus had the reverse results, and results of those with medium resistance （MR） to A. flavus lay in between, but changes of testa thickness were not significant among different resistance kinds. Results also showed that some seed storage materials were closely related with resistance potential to A. flavus. It seemed that varieties with higher resistance to A. flavus had higher oleic acid and protein content, lower linoleic acid and fat content. Content of palm acid, total sugar and VE did not show positive relationship with the resistance to A. flavus.

Fungal community structure analysis of peanut pod rot in soil in Hebei Province,China

In recent years,peanut yield and quality are more seriously affected by pod rot disease in China.However,managing this disease has proven challenging due to the wide host range of its pathogens.In this study,four soil samples were collected from fields with pod rot disease in Hebei Province,and 454 pyrosequencing was used to analyze the fungal communities structure within them.All 38490 ITS high-quality sequences were grouped into 1203 operational taxonomic units,the fungal community diversity of four soil samples was evaluated and compared using Shannon index and Simpson index.The results showed that members of Ascomycota were dominant,followed by Basidiomycota.According to the BLAST results at the species level,Guehomyces had the highest abundance,accounting for about 7.27%,followed by Alternaria,Fusarium,and Davidiella.The relative abundance of Fusarium oxysporum isolated from rotting peanuts in soil with peanut rot was higher than that in the control,indicating that Fusarium oxysporum might be one of the main pathogenic fungus of peanut rot in this area.This study delved into the broader fungal community associated with peanut pod rot,providing a theoretical foundation for preventing and treating this disease in agriculture.

A stable and major QTL region on chromosome 2 conditions pod shape in cultivated peanut(Arachis hyopgaea L.)

Peanut pod shape is a heritable trait which affects the market acceptance of in-shell peanut products.In order to determine the genetic control of pod shape,six component traits of pod shape(pod length,pod width,pod length/width ratio,pod roundness,beak degree and constriction degree)were measured using an image-based phenotyping method.A recombinant inbred line(RIL)population consisting of 181 lines was phenotyped across three environments.Continuous distributions and transgressive segregations were demonstrated in all measured traits and environments.Significant correlations were found among most component traits with broad-sense heritability ranging from 0.87 to 0.95.Quantitative trait locus(QTL)analysis yielded 26 additive QTLs explaining 3.79 to 52.37%phenotypic variations.A novel,stable and major QTL region conditioning multiple shape features was detected on chromosome 2,which spans a 10.81-Mb genomic region with 543 putative genes.Bioinformatics analysis revealed several candidate genes in this region.In addition,73 pairs of epistatic interactions involving 92 loci were identified for six component traits explaining 0.94–6.45%phenotypic variations.These results provide new genetic loci to facilitate genomics-assisted breeding of peanut pod shape.

Comparison of the Δ^(12) fatty acid desaturase gene between high-oleic and normal-oleic peanut genotypes

△^12 fatty acid desaturase gene has been targeted as a logical candidate controlling the high oleate trait in peanut seeds. By RT-PCR method, the full-length cDNAs of △^12 fatty acid desaturase gene were isolated from peanut （Arachis hypogaea L.） genotypes with normal and high ratio of oleic to linoleic acid, which were designated AhFAD2B and AhFAD2B＇, respectively. Sequence alignment of their coding regions revealed that an extra A was inserted at the position ＋442 bp of AhFAD2B＇ sequence of high oleic acid genotypes, which resulted in the shift of open reading frame and a truncated protein AhFAD2B＇, with the loss of one histidine box involved in metal ion complex required for the reduction of oxygen. Analysis of transcript level showed that the expression of △^12 fatty acid desaturase gene in high oleic acid genotype was slightly lower than that in normal genotype. The enzyme activity experiment of yeast （Saccharomyces cerevisiae） cell transformed with AhFAD2B or AhFAD2B＇ proved that only AhFAD2B gene product showed significant △^12 fatty acid desaturase activity, but AhFAD2B＇ gene product did not. These results suggested that the change of AhFAD2B＇ gene sequence resulted in lower activity or deactivation of △^12 fatty acid desaturase in high oleic acid genotype.

Functional Analysis of the Phosphoenolpyruvate Carboxylase on the Lipid Accumulation of Peanut(Arachis hypogaea L.) Seeds

Phosphoenolpyruvate carboxylase（PEPC;EC 4.1.1.31） catalyses phosphoenolpyruvate（PEP） to yield oxaloacetate,which is involved in protein biosynthesis.Pyruvate kinase（PK;EC 2.7.1.40） catalyzes PEP to yield pyruvate,which is involved in fatty acid synthesis.In this study,five PEPC genes（AhPEPC1,AhPEPC2,AhPEPC3,AhPEPC4,and AhPEPC5） from peanut have been cloned.Using a quantitative real-time RT-PCR approach,the expression pattern of each gene was monitored during the seed development of four peanut varieties（E11,Hebeigaoyou,Naihan 1,and Huayu 26）.It was found that these five genes shared similar expression behaviors over the developmental stages of E11 with high expression levels at 30 and 40 d after pegging（DAP）;whereas these five genes showed irregular expression patterns during the seed development of Hebeigaoyou.In Naihan 1 and Huayu 26,the expression levels of the five genes remained relatively high in the first stage.The PEPC activity was monitored during the seed development of four peanut varieties and seed oil content was also characterized during whole period of seed development.The PEPC activity followed the oil accumulation pattern during the early stages of development but they showed a significantly negative correlation thereafter.These results suggested that PEPC may play an important role in lipid accumulation during the seed development of four peanut varieties tested.

Identification and Expression Analysis of the Phosphoenolpyruvate Carboxylase Gene Family in Peanut (Arachis hypogaea L.)

Phosphoenolpyruvate carboxylase （PEPC） is widely distributed in plants and bacteria, and catalyzes the carboxylation of phosphoenolpyruvate to form oxaloacetate and inorganic phosphate. To investigate the molecular mechanisms of the regulation and control of peanut oil, with the degenerated primers and RACE-PCR approach, five PEPC genes were cloned from peanut, and designated as AhPEPC1, AhPEPC2, AhPEPC3, AhPEPC4, and AhPEPC5, respectively. The structure and phylogenetic analysis of PEPC protein indicated that AhPEPC1-4 genes encoded a typical plant-type PEPC-enzyme, and AhPEPC5 a bacterial-type. By real-time quantitative RT-PCR approach the expression pattern of each gene was detected in various tissues of normal and high oil-content peanut varieties. It was found that there was a lower expression level of AhPEPCs genes except for the AhPEPC2 in high-oil peanut than normal-oil peanut line. The results provide some fundamental information for the further investigation of plant PEPC proteins and their role in regulation of oil-content in peanut seeds.

Determining N supplied sources and N use efficiency for peanut under applications of four forms of N fertilizers labeled by isotope^15N

Rational application of different forms of nitrogen（N） fertilizer for peanut（Arachis hypogaea L.） requires tracking the N supplied sources which are commonly not available in the differences among the three sources：root nodule,soil and fertilizer.In this study,two kinds of peanut plants（nodulated variety（Huayu 22） and non-nodulated variety（NN-1）） were choosed and four kinds of N fertilizers：urea-N（CONH_2-N）,ammonium-N（NH_4~＋-N）,nitrate-N（NO_3^--N） and NH_4~＋ ＋NO_3^--N labeled by^（15）N isotope were applied in the field barrel experiment in Chengyang Experimental Station,Shandong Province,China,to determine the N supplied sources and N use efficiency over peanut growing stages.The results showed that intensities and amounts of N supply from the three sources were all higher at middle growing stages（pegging phase and podding phase）.The accumulated amounts of N supply from root nodule,soil and fertilizer over the growing stages were 8.3,5.3 and 3.8g m^（-2） in CONH_2-N treatment,which are all significantly higher than in the other three treatments.At seedling phase,soil supplied the most N for peanut growth,then root nodule controlled the N supply at pegging phase and podding phase,but soil mainly provided N again at the last stage（pod filling phase）.For the whole growing stages,root nodule supplied the most N（47.8 and 43.0%） in CONH_2-N and NH_4~＋-N treatments,whereas soil supplied the most N（41.7 and 40.9%） in NH_4~＋ ＋NO_3^--N and NO_3^--N treatments.The N use efficiency was higher at pegging phase and podding phase,while accumulated N use efficiency over the growing stages was higher in CONH_2-N treatment（42.2%） than in other three treatments（30.4%in NH_4~＋-N treatment,29.4%in NO_3^--N treatment,29.4%in NH_4~＋ ＋NO_3^--N treatment）.In peanut growing field,application of CONH_2-N is a better way to increase the supply of N from root nodule and improve the N use efficiency.

Response and adaptation to the accumulation and distribution of photosynthetic product in peanut under salt stress

To clarify the response and adaptability of peanut under salt stress,Huayu 25 was used as the material,and non-salt stress(CK),0.15% salt stress(S1),and 0.3% salt stress(S2) were applied as three treatments.The study analysed the effects of salt stress on photosynthetic characteristics,photosynthetic substances accumulation and distribution as well as the ecological adaptability of peanuts.The results showed that net photosynthetic rate(Pn),SPAD value,leaf area,and peanut yield were reduced under salt stress.Pn in CK was 13.71 and 28.72% higher than that in S1 and S2 at the 50 th day after planting,respectively.At the same growth period,the SPAD value among treatments was ranked as follows: CK>S1>S2.The 100-pod mass,100-kernel mass,kernel rate to pod,and pod mass per plant were reduced under salt stress,and the trend was CK>S1>S2.The distribution proportion of dry matter in different organs of peanut plant was changed to adapt to such stress.Roots under salt stress intensively distributed in a 0-40 cm soil layer for salt resistance.Dry mass proportion in stems and pods increased during the vegetative stage and early period of reproductive stage,respectively.The maximum growth rates of the pod volume,pod dry weight,and seed kernel dry weight all declined,and the pod and kernel volume at harvest were reduced,improving the seed plumpness under salt stress.This finding could be useful in growing peanut in saline soil.

Current Situations and Development Strategies for Integration of Peanut Agronomy and Agricultural Machinery in China

The mechanization level of peanut production is the bottleneck restricting the development of peanut production in China,while integration of agronomy and agricultural machinery is an essential approach for improving mechanization level of peanut production. This paper elaborated requirements of peanut agronomy for agricultural machinery from peanut planting modes,land cultivation,sowing,harvesting,picking,and shelling,etc. Besides,it discussed requirements of agricultural machinery for agronomy from peanut seed quality,variety characteristics,planting modes,and soil condition. In addition,it analyzed existing problems and restricting factors of integration of peanut agronomy and agricultural machinery. Finally,it came up with recommendations for development strategies including increasing government fund input,optimizing industrial distribution,and multidisciplinary joint research.

Simple and Efficient Cultivation Technology for the Peanut under the Standardization Mode of Single-seed Sowing

Single-seed sowing is a new,simple and efficient cultivation mode for peanut that realized from cultivation of healthy individual and construction of high-yielding population. The cultivation mode has the obvious advantages in uniform seedling,strong sprouting,seed saving and cost saving,thus it is considered as one of the effective ways for high-yield and high-efficient peanut cultivation in China in the future.Through integrating with other high-efficiency and simple cultivation measures,the single-seed sowing technology system has made conforming to China's national standardization cultivations of peanut and the technology was already applied in the main producing areas of peanut and gained the significant efficiency and abroad application prospects. Based on many years of researches in single-seed sowing technology,high-efficiency fertilization and scientific chemical control in the research team,by combining with the latest research results in plant protection and machinery,this paper described the key points and matters needing attentions from variety selection,planting mode,rational fertilization,planting specifications and field management.

Population structure and association mapping to detect QTL controlling tomato spotted wilt virus resistance in cultivated peanuts

Tomato spotted wilt(TSW)is a serious virus disease of peanut in the United States.Breeding for TSWV resistance would be facilitated by the implementation of marker-assisted selection in breeding programs;however,genes associated with resistance have not been identified.Association mapping is a type of genetic mapping that can exploit relationships between markers and traits in many lineages.The objectives of this study were to examine genetic diversity and population structure in the U.S.peanut mini-core collection using simple sequence repeat(SSR)markers,and to conduct association mapping between SSR markers and TSWV resistance in cultivated peanuts.One hundred and thirty-three SSR markers were used for genotyping 104 accessions.Four subpopulations,generally corresponding to botanical varieties,were classified by population structure analysis.Association mapping analysis indicated that five markers:pP GPseq5D5,GM1135,GM1991,TC23C08,and TC24C06,were consistently associated with TSW resistance by the Q,PCA,Q+K,and PCA+K models.These markers together explained 36.4%of the phenotypic variance.Moreover,pP GPseq5D5 and GM1991 were associated with both visual symptoms of TSWV and ELISA values with a high R^2.The potential of these markers for use in a marker-assisted selection program to breed peanut for resistance to TSWV is discussed.

Improving chemical and sensory quality of high-oleic peanut by application of foliar fertilizer

High-oleic peanut is favored by consumers because its a longer shelf life and benefits for cardiovascular health.Up to the high-oleic standard and with good taste is essential for peanut products in food processing.The aim of present study was to explore the effect of foliar fertilizers on chemical and eating quality of high-oleic peanuts.Three high-oleic peanut cultivars,namely Huayu 09C2,Huayu 9621,and Huayu 962,were used as materials.Huayu 09C2 and Huayu 9621 were planted in Fuxin,Liaoning,foliar sprayed with Fosforil at 2250 mL/ha,and Huayu 962 was sown in Jvnan,Shandong,foliar sprayed with Foliplus at 1500/3000 mL/ha.The chemical and sensory quality of peanut harvested from the treatment plots and controls was evaluated.Results showed that,Huayu 09C2 and Huayu 9621,foliar spraying with Fosforil in Fuxin,Huayu 962,foliar spraying with Foliplus in Jvnan,all still maintained high oleate content levels,and the Fosforil treatment was effective in raising the intensity of sweetness of roasted kernels.This study demonstrated the feasibility of improving chemical and sensory quality of high-oleic peanut through foliar fertilizer.

Effect of variety and seed dressing on emergence of high-oleic peanut under low temperature and high soil humidity conditions

Low temperature coupled with high soil moisture during sowing to emergence generally results in poor peanut stand,thereby posing a non-negligible threat to peanut production in north and northeast China.Five high-oleic(HO)peanut cultivars and 4 seed dressing treatments capable of controlling several diseases and insect pests along with untreated checks were used to find the best combinations to cope with the dual stresses during sowing to emergence period.High broad-sense hereditability estimates of seedling emergence indicated great potential for genetic improvement of this trait.Analysis of variance in the split-plot experiment showed that the main effects of variety and seed dressing and their interaction on seedling emergence were significant.Seed dressing treatments increased seedling emergence percentage by 2.09–35.00 percent points.Four of the 5 HO peanut cultivars yielded satisfactory results.For Huayu 665,Huayu 668 and Huayu 965,Huweisanbao may be the best option;for Huayu 962,Weilidan was highly acceptable.These combinations will be evaluated further in multiple environments before large-scale extension.

Chemical Fertilizer Reduction and High Yield Cultivation Technique for Peanut

For a long time,the amount of fertilizer applied to peanuts in China has been much higher than that of other main peanut producing countries.At the same time of increasing production,chemical fertilizers have also brought many adverse effects,which have brought potential threats to the sustainable development of peanut production.While continuously increasing the yield,reducing the amount of chemical fertilizer has become an urgent problem to be solved in peanut production of China.Based on the research results of our team,this paper appropriately absorbed the latest research progress of chemical fertilizer reduction in related fields,and established the cultivation technique for peanut fertilizer reduction and high yield under different cultivation modes,to realize the synchronization of fertilizer reduction and yield increase for peanut production.The technique includes two parts:common technology and different cultivation mode fertilization schemes.The former includes crop rotation,proper deep tillage,application of organic fertilizer,selection of nutrient-efficient varieties,topdressing of foliar fertilizer,etc.,the latter includes film mulching spring peanut,continuous cropping field,acidified soil,peanuts interplanting with wheat,and summer direct sowing,etc.This technique provides a technical support for the chemical fertilizer reduction of peanut production in China.

Cloning and functional analysis of the promoter of allergen gene Ara h 1 from peanut

Peanut seeds are ideal bioreactors for the production of foreign recombinant proteins or secondary metabolites.Seed-specific promoters(SSPs)can direct the expression of genes specifically in seeds to avoid undesirable effects associated with constitutive expression.However,few SSPs have been identified in peanut.Previous studies have shown that some allergen-encoding genes encode seed storage proteins or exhibit seed-specific/preferential expression.In this study,we characterized allergen-encoding genes from across the genomes of Arachis species to explore seed-specific genes.We found that at least 9 out of 16 identified peanut allergen-encoding genes were expressed specifically in the seeds or were preferentially expressed.A 1493-bp promoter fragment of allergen gene Ara h 1(we named it AHSSP6)was isolated from cultivated peanut genome.cis-element analysis showed that three RY repeat elements which usually exsisted in seed or embryo specific promoter sequence were also present in AHSSP6 sequence.Histochemical analysis showed AHSSP6 could drive the expression of aβ-glucuronidase(GUS)reporter gene specifically in the seeds or cotyledon tissue of transgenic Arabidopsis,while not in other tissues.These findings indicated that these promoters of allergen genes were candidate SSPs,and AHSSP6 was a novel SSP which could be potentially utilized in peanut improvement.

Study on Physiological Characteristics and Supporting Techniques of Huayu 22 Peanut

Huayu 22 Peanut( Arachis hypogaea L.) belongs to ordinary large variety of peanut with high quality,high yield potential and high stress resistance. Study on nutrition characteristics,stress physiology and supporting techniques of Huayu 22 Peanut is conducive to further developing its application value in breeding and exploiting its high yield potential. Compared with Baisha 1016 Peanut,Huayu 22 Peanut has greater shade tolerance. In weak light,both the leaf area and rate of photosynthesis of Huayu 22 Peanut decline slightly,and damage of chloroplast ultramicrostructure is less,light compensation point and chloroplast a / b are lower,and capturing and utilization efficiency of weak light are higher; after removal of shade,Huayu 22 Peanut plant gets recovered quickly with higher growth compensation effect but slight dropping of yield. Characteristics of N supply for Huayu 22 Peanut at different growth stages are as follows: N supply intensity of root nodule takes on unimodal curve with peak at pod bearing stage. The N supply intensity of soil takes on N shape with higher value at pegging stage and pod filling stage; N supply intensity takes on unimodal curve with peak at pegging stage. At seedling stage and pod filling stage,N is mainly supplied by soil; at pegging stage and pod bearing stage,N is supplied by root nodule. At whole growth stage,root nodule has the largest contribution to N supply,accounting for 50. 0%,followed by soil and fertilizer,and the proportion is about 5: 3: 2. The study established standardized supporting technique for simple cultivation of Huayu 22 Peanut with " single-seed planting,high effective fertilizer application,and three sprays and multi-prevention".

Combining ability for main quality traits in peanut(Arachis hypogaea L.)

High-oleic peanuts has been recognized by processing sectors,seed sellers and consumers for their longer shelf life,longer seed life and mutiple healthe benefits.High oleate is becoming a requisite for varietal releases in many peanut breeding programs at present.To select desirable parents for high-oleic peanut breeding,the study was conducted to evaluate the combining ability of 5 high-oleic donors from our research team,based on quality of individual single seeds.General combining ability was significant for oleic,linoleic,stearic and palmitic acid,oil and protein,while specific combining ability was significant for the traits except oil.Among them,oil content was found to be conditioned solely by additive gene actions,and for other quality traits,additive gene effects were more important than non-additive gene effects.High-oleic CTW and normal-oleic Xiaojingsheng were selected as the best general combiners for peanut oleic acid improvement.Narrow-sense heritability was high for quality traits other than protein,suggesting that there was high potential for genetic improvement in these traits.

Supporting Techniques for High Yield and High Quality Huayu 22 Peanut

This paper mainly studied the effects of different sowing dates and densities on the main agronomic traits and yield of Huayu 22 peanut under field conditions. The sowing date experiment obtained following results.( i) From April 25 to May 25,with the delay of the sowing date,the main stem height,the number of branches per plant,the number of pods per plant,full-seed pod rate and the yield decreased in Dongming test site,while the sowing date had little effect on the double-seed pod rate,and the best sowing date was April 25;in Wendeng test site,with the delay of the sowing date,the main agronomic traits and yield were firstly increased and then decreased,the yield was highest on May 10,followed by May 5 and April 30,the difference between the three treatments was not significant,and the appropriate sowing date was from April 30 to May 10,and the best sowing data was May 5.( ii) In the range of 90 000-210 000 holes/ha,with the increase of the density,the main stem height,lateral branch length and the number of pods per plant showed a decline trend,the density had little effect on the number of branches per plant,and the double-seed pod rate was the highest at 120 000 holes/ha,the yield and full-seed pod rate were the highest at 150 000 holes/ha,so the optimum density was 150 000 holes/ha.

Evaluation of SRAP markers efficiency in genetic diversity of Aspergillus flavus from peanut-cropped soils in China

In order to evaluation the efficiency of SRAP markers on genetic diversity of Aspergillus flavus,we screened out 17sets of primer pairs which could produce clear and reproducible SRAP bands from 150 SRAP primer pairs.The size of SRAP fragments ranged from 120 to 2100 bp.Primer pair Me10/Em9 produced the maximum number of polymorphic bands(12 bands),while Me8/Em13 produced the fewest number of polymorphic bands(only 1).Through analysis genetic diversity ability of different sets of primer pairs,the set of 12 primer pairs was selected for SRAP genetic marker of A.flavus.Cluster analysis was performed based on the genetic similarity coefficients,which ranged from 0.53 to 0.89.A dendrogram assembled using the unweighted pair-group method with arithmetic averages grouped A.flavus samples into 5 main clusters.The results suggested that SRAP marker is a useful molecular technology for the diversity of A.flavus from peanut soils in China.

Physiological Characteristics of Nitrogen Nutrition in Peanut and Efficient Nitrogen Application Technology

Nitrogen plays a very important role in peanut nutrition and fertilization.For peanuts,the nitrogen nutrition comes from root nodules,soil and fertilizer,which are separately referred to as root nodule nitrogen,soil nitrogen and fertilizer nitrogen.The research obtained following findings.(ⅰ)The nitrogen supply ratio of the three nitrogen sources for peanut is about 5∶3∶2.There are significant differences in the nitrogen supply capacity of the three nitrogen sources.The root nodules have the largest variation in nitrogen fixation and have a high potential for development.Nitrogen fixation in root nodules is closely related to carbon metabolism indicators such as photosynthesis in peanut leaves.Phosphorus application could increase the accumulation of three nitrogen sources,and the increase in nodule nitrogen accumulation is greater than that of soil nitrogen and fertilizer nitrogen.(ⅱ)Nitrogen fertilizer has a significant effect on nitrogen nutrition of peanuts.Different forms of nitrogen fertilizers,such as amide nitrogen,ammonium nitrogen,nitrate nitrogen and mixed ammonium nitrate nitrogen,have significant effects on nitrogen metabolism and nitrogen accumulation in peanuts.Amide nitrogen fertilizer is beneficial to improving the activity of enzymes related to nitrogen metabolism and nitrogen accumulation.Controlled-release fertilizer can significantly increase the content of soluble protein and improve the activities of NRase,GDH,GS,GPT,etc.in roots and leaves at the pod setting and mature stages of peanuts,which is favorable for delaying the plant senescence and increasing the yield of peanuts.Mixed application of common nitrogen fertilizer and slow-release fertilizer can increase the soil nitrate nitrogen level at the later growth stage,which is beneficial to the development of the root system at the later stage of growth,increasing the distribution ratio of nitrogen in the pods,and also favorable for increasing the yield and nitrogen utilization rate.(ⅲ)Increasing the ploughing depth,improving fertilization methods,selecting nitrogen-efficient varieties,paying attention to foliar topdressing,and adopting fertilizer-water integrated cultivation are conducive to increasing the nitrogen utilization rate of peanuts,reducing the amount of nitrogen fertilizers,accordingly saving costs,increasing efficiency and realizing sustainable development of agricultural production.