China is already a world's large soybean consumer and net importer of soybeans, with a serious shortage of soybeans and soybean oil, with low self-sufficiency rate and a relatively concentrated source of imports. How to reduce the foreign dependence of soybeans and improve the supply of soybean oil are very important issue in the current new period, to ensure food security in China. Based on the current supply and demand of soybeans in China, the article analyzes the comparative advantages of soybeans in China from the perspective of oil processing, explains the essential reason of the low self-sufficiency rate of soybean oil, and put forward some suggestions, such as improving the self-sufficiency rate of soybean oil, developing and popularizing high-yield soybean in saline-alkali land, increasing planting area and oil yield of high-oil soybean, popularizing rational soybean oil consumption, and substituting consumption of other oil crops to improve the self-sufficiency rate of soybean oil in China.
This paper defines the connotation of ideal type of rapeseed （Brassica napus） plant and emphasizes the multi-functionality of rapeseed and the functional specificity of its ideal type of plant. The ideal type of rapeseed is defined as the plant form that realizes some function of rapeseed and facilitates the maximization of relevant economic benefits. The relationship between the two dimensions of plant type per plant and population was clarified. The basic context of research on the type of rapeseed plants was combed, and four stages of research on the types of ideal rapeseeds were introduced, including the primary, mature, digital and molecular biotechnology stages. An index system of the types of rapeseed plants was constructed, including the roots, stems, leaves, branches, flowers, pods and canopy structure. These structures were summarized and examined by morphometry, summarization of the experiment, experimental statistics, digital simulation, cultivation regulation and genetic improvements in plant type. A classification of the basic principles for research on the types of rape plants was proposed, including those of photosynthetic efficiency, morphological structure, source-sink-flow, and principles of crop physiology. The characteristics and connotation of four typical types of ideal rapeseed based on high grain yield, mechanical direct seeding, vegetable or forage, and ornamental properties were introduced. The shortcomings in the study of rapeseed plant types were analyzed, the basic characteristics, construction strategies and the research trend of ideal type of rapeseed plant were discussed and proposed.
According to the Seed Law of the People's Republic of China,since May 2017, China has changed the original approval management of rapeseed varieties to registration management. Up to July 2021, a total of 1212 rapeseed varieties have been registered in China. In order to reveal the rapeseed breeding level and to perfect the function of variety registration system, it was reviewed on current situation of rapeseed varieties registered in China with suggestions. Based on the data, nearly half of the registered varieties were newly bred, mainly self bred Brassica napus hybrid varieties （except one from abroad）, registered in provinces of the main production areas. Cold resistance trait received more attention. Disease resistance was enhanced. Oil content was significantly improved, and the quality was significantly improved as well. Problems included that most varieties were not applied for variety right protection, few varieties had short growth period which was becoming important. Thus we suggested to improve the process of variety registration system, including to revise the registration rules and guidelines soon. Considering the breeding direction, we suggested to strengthen the breeding on 3 features: short growth period, mechanized planting, and multifunction (for vegetable, green fertilizer and forage, etc.) for promoting high-quality development of China's rapeseed industry.
In order to improve the breeding efficiency of early maturing rape in triple-cropping system area, the effects of agronomic characters on yield of different maturity stages rape were studied in the paper. National winter rapeseed test results of different maturity stages varieties from 2016 to 2020 in the Henyang and Yichun was used for variance analysis, correlation analysis and path analysis. There is significant difference in plant high, effective branch number, sclerotium disease incidence, disease index, effective pod, numbers per spike grain, thousand seed weight, density, whole period, lodging resistance, oil content and yield significant difference between medium rape varieties and early maturity rape varieties. The yield was significantly positive correlation with numbers per spike grain, density, sclerotium disease resistance, but negatively correlation with sclerotium disease incidence, disease index, whole period, and density had the greatest direct impact on yield in medium rape varieties.The yield was significantly positive correlation with plant high, effective branch number, effective pod, numbers per spike grain, density, oil content, but negatively correlation with sclerotium disease incidence rate. The biggest direct impact on yield is effective branch number in early maturity rape varieties. Therefore, In the triple-cropping system area, the varieties suitable for high-density planting should be selected. Medium rape varieties should increase the effective pod numbers, the selection of effective branch number should be strengthened in early maturity rape varieties.
To improve the lodging resistance, Brassica napus determinate inflorescence line was used as donor parent crossed with a maintainer line 144B and other 4 superior restorer lines (111R, 122R, 361R, and 536R) respectively. Molecular markers closely linked with the determinate inflorescence genes Bnsdt1 and Bnsdt2 were used to assist the selection of the breeding in early generations. Results showed that 4 co-dominant molecular markers (S02, InDel02, BnW09 and BnW18) closely linked to determinate inflorescence genes Bnsdt1 and Bnsdt2 were screened out, and could be used for marker-assisted selection during backcross. Thud the maintainer line Y144B, sterile line Y144A and 4 superior restorer lines Y111R, Y122R, Y361R and Y536R with determinate inflorescence and obviously improved lodging resistance were developed. A new B. napus determinate inflorescence variety Qingza determinate 1, was then bred by hybridization and regional test, which had medium plant height, low branching, and improved lodging resistance.
Glycine rich proteins (GRPs) play an important role in plant stress response. In previous study, the candidate gene BnGRP1 in response to low phosphorus stress had been obtained by genome-wide association analysis, but its molecular mechanism was not clear. Sequence analysis showed that the total length of CDS of BnGRP1 was 399 bp, encoding 132 amino acids, of which 62 were glycine, accounting for 47.0% of the total amino acids of the protein. In order to study the biological function of BnGRP1, a double target vector of the target gene was constructed by CRISPR / Cas9 gene editing technology, and was transformed into Brassica napus. Thirteen transgenic positive plants were obtained in the T0 generation. The mutation sites of Bngrp1 in 5 transgenic plants were analyzed by TA cloning and sequencing technology, and 3 of them showed the sequence variation of Bngrp1, which resulted in the inability of encoding the normal BnGRP1 protein. This study not only provides experimental materials for studying the biological function of BnGRP1, but also provides theoretical and experimental basis for further studying the molecular mechanism of BnGRP1 in response to low phosphorus stress.
Chloroplast genome is characterized by its maternal inheritance, haplotype, high conservation, and distinct intraspecific differences. To facilitate germplasm collection and introduction of rapeseed （Brassica napus L.）, chloroplast DNA diversity was investigated using different B. napus varieties. Global collection of 287 B. napus materials was evaluated using specific chloroplast SSR markers. Among the 15 chloroplast specific SSR-specific primer pairs, 5 pairs produced 19 polymorphic bands with the average of 3.8. Using the 19 polymorphic bands, 287 materials were divided into 14 haplotypes. Among them, the more prevalent haplotypes of H01, H02 and H03 occupied 74.91%, 13.59%, and 4.88%, respectively, while the other 11 haplotypes （H04-H14） accounted for 6.62%. Haplotype H02, a unique haplotype to China is cytoplasmic type of Polima or Shaan2A. In the foreign B. napus varieties, those from Russia or Sweden had more abundant haplotypes than those from other countries. Therefore introduction of resources from Russia or Sweden could efficiently broaden the genetic diversity background of Chinese B. napus varieties. Moreover, a rapid identification of Polima and Shaan2A cytoplasmic types was also established through 2 specific bands amplified by MF-4 and ccmp2 primer pairs, which provided methods for identification of Polima and Shaan2A cytoplasmic type.
Screening of phosphorus (P)-efficient germplasm of oilseed rape (Brassica napus L.) will provide elite materials for P heredity and P-efficient breeding. In this study, 400 varieties of natural population of oilseed rape (B. napus) was used to evaluate P efficiency at seedling stage under 2 experiments by hydroponic culture, named EXP. Ⅰ and EXP. Ⅱ, respectively. Under normal P and low P conditions, RDW (root dry weight), SDW (shoot dry weight), RSR (root : shoot ratio), PRL (primary root length) and PEC (phosphorus efficiency coefficient) of the natural population showed normal distribution, indicating that there existed abundant genetic variation in the natural population. P efficiency of the natural population of B. napus at the seedling stage was determined by the parameter of SDWLP and PEC. Among them, 17 P-efficient and 13 P-inefficient candidate varieties were obtained in EXP. Ⅰ, while 17 P-efficient and 18 P-inefficient candidate varieties were obtained in EXP. Ⅱ. Based on the 2 experiments, totally 32 P-efficient and 31 P-inefficient candidate varieties were identified for further work.
In order to fully coordinate the relationship between yield potential and efficient utilization of climate resources, and investigate the light and temperature utilization efficiency of spring rapeseed under plateau climate in Tibet, 3 spring rapeseed （Brassica napus L.） lines （with different maturity） were selected as materials, and 4 sowing dates were set in field experiments. The lines were analyzed on growth and yield formation under different sowing dates. Results showed that, with the delay of sowing date, the temperature during rapeseed growth period increased, thus it took fewer periods to reach the effective accumulated temperature. Meanwhile, growth period of the lines was shortened, among which seedling stage, bolting stage and flowering stage were also earlier, resulting to a prolonged silique maturation period. Under the late sowing treatment, plants （at stem extension period） encountered more sufficient rainfall and more heat than those of early sowing, thus the plant height increased, and the stem diameter decreased. At the same time, late sowing resulted in insufficient vegetative growth in the early growth stage, and dry matter accumulation in mature stage was less than those of early sowing. Under the late sowing treatment, plants （at mature stage） encountered continuous rainfall which caused the reduction of branch number, silique number and seed weight, as a result, seed yield was significantly lower than that of early sowing. Sowing date changed the light-temperature utilization efficiency of the rapeseed. Early maturing line NY16 had higher light-temperature utilization efficiency at B2 sowing date （March 15, 2021）, as 0.081 g·MJ-1 and 1.017 kg·hm-2·℃-1 respectively. The light-temperature utilization efficiency of medium maturing line NY28 and late maturing line NY52 were higher at B1 sowing date （March 8, 2021）, as 0.1 g·MJ-1, 1.282 kg·hm-2·℃-1, 0.134 g·MJ-1 and 1.712 kg·hm-2·℃-1, respectively. Under the same sowing date, the light-temperature utilization efficiency of medium- and late-maturing lines was higher than that of early-maturing lines. Therefore, timely （and early） sowing could improve the light-temperature utilization efficiency and promote rapeseed yield. Suitable sowing date was from March 15 to March 22 for early-maturing rapeseed, and March 8 to March 15 for medium- and late-maturing lines. Moreover, for the single-cropping system in Tibet, medium- and late-maturing rapeseed breeding might improve the yield of spring rapeseed.
To improve nutrient utilization of winter rape in cold and arid areas of North China, agronomic traits (dry matter, nutrient accumulation and yield traits) of different winter rape varieties were investigated by using 12 cultivars of Brassica rapa L. and B. napus. Results showed that the yield traits of B. napus were significantly better than those of B. rapa. Plant height, branch height, siliques on main inflorescence, siliques per plant, seeds per silique, 1000-grain weight, plant yield and plot yield of B. napus were 12.41%, 108.11%, 56.21%, 66.91%, 5.71%, 70.79%, 103.55% and 103.87% higher than those of B. rapa, respectively. The average dry matter yield per plant of B. napus was 67.693 g, which was 191.613% of B. rapa. The nitrogen and phosphorus content per plant of B. rapa were 2.481% and 29.423% higher than B. napus. But the potassium content per plant of B. rapa was 34.826% lower. Because the higher dry matter yield of B. napus in the same ecological area, the accumulation of nitrogen, phosphorus and potassium in B. napus was significantly higher than that of B. rapa （N 84.647%, P 50.000%, and K 158.616%）. The trend of total nutrient accumulation in winter type rapeseed was K > N > P, and N and P were mainly accumulated in grains; K was mainly accumulated in stems and silique shell. For every 100 kg grain, B. napus needs 6.554 kg N, 0.463 kg P and 14.612 kg K; whilst B. rapa needs 7.143 kg N, 0.572 kg P and 10.467 kg K. The utilization efficiency of N and P in B. napus was higher than in B. rapa, and demand for K was larger.
Vernalization is the main stage of bolting and flowering of winter plants, FLC （FLOWERING LOCUS C） integrates upstream signals to regulate flowering during vernalization. To understand the characteristics of FLC genes in winter rapeseeds （B. rapa） and its function in vernalization, 10 BrFLCs were identified from winter rapeseed genome using 6 Arabidopsis FLC genes as queries, 8 of which contained 7 exons. 10 BrFLCs are distributed on 4 chromosomes with obvious gene duplications. Evolutionary and conserved structure analysis showed that members in the same class were clustered with similar protein conserved motif distributions. The 1500 bp upstream promoter region of all the genes contained light response elements, among which BrFLC4, BrFLC5 and BrFLC6 contained low temperature response elements, and BrFLC3, BrFLC4, BrFLC7 and BrFLC9 contained hormone response elements. BrFLC6 gene sequence located on A02, it was quite different from the annotated Bra031886 in B. rapa. Thus we
Linkage between late leaf spot resistance and poor yield and plant type traits of peanut makes it difficult to find out elite comprehensive materials in China. In this study, the parents and the recombinant inbreed lines （RILs） population derived from Zhonghua 5 × ICGV 86699 were assessed for their resistance to late leaf spot, and also yield and plant-type traits. Results revealed that the late leaf spot disease scores were investigated in 4 environments, and a total of 18 stable highly resistant and 26 resistant lines were identified. In 2 environments, 38 lines were selected with elite traits of hundred pod weight （≥180.0 g） and pods per plant （≥20.0）. Similarly, a total of 54 lines were selected with moderate main stem height （30-60 cm） and total number of branches （≤20.0） in the 2 environments. By comprehensive analysis of late leaf spot disease scores, yield-related and plant-type related traits, 4 novel germplasm were found. Among them, one had high resistance to late spot disease with high yield and elite plant type related traits, 3 had moderate resistance with high yield and elite plant type related traits.
Peanut is rich in resveratrol, which has a very high nutritional value and health care function. Stilbene synthase （STS） is the key enzyme in resveratrol synthesis. In this research, we identified 50 peanut STS and 17 chalcone synthase （CHS） gene members from peanut genome by using multiple bioinformatics methods. Further, the chromosome location, phylogeny, exon-intron structure, and expression pattern of the gene family members was conducted, the results showed that most of the STS genes high expressed in root, testa, pericarp and gynophore, all the expressed 45 STS and 8 CHS genes response to UV treatment. This study laid a foundation for the functional identification of peanut STS/CHS genes, and provided theoretical basis and genetic resources for high-quality peanut breeding.
To investigate the molecular genetic basis of seed size in soybean under multiple environments and to explore SNP loci and candidate genes associated with seed size traits, germplasm of 150 soybean resources was used for phenotypic determination of seed length, seed width, seed thickness and 100-seed weight traits under 6 environments in 2019 and 2020, and genome-wide association analysis was also conducted. Results showed that 896 SNP loci, distributed on 20 chromosomes, were detected significantly associated with seed size traits under 6 environments using CMLM （compressed linear mixed model） method. Seventy-two SNP loci were detected 3 or more times for different traits. SNP loci were detected in two or more years for the same trait, with a contribution rate of 10.68%-24.93%. Thirty-five stably expressed SNP loci were acquired with a contribution rate of 10.92%-23.16% by the analysis of stability and overlap. The most significantly associated SNP loci were detected simultaneously in seed width, seed thickness and 100-seed weight traits, with the highest contribution of 16.51% for rs16533609. Based on the screening of candidate genes by stably expressed SNP, it was hypothesized that the seven genes Glyma.03G006600, Glyma.04G077100, Glyma.08G203600, Glyma.12G195400, Glyma.17G039800, Glyma.18G202100 and Glyma.20G215700 have regulators effect on soybean seed size traits.
Sunflower rust, caused by Puccinia helianthi, often threatens sunflower production. Effectors are proteins secreted during pathogen infection, which promote pathogen invasion or trigger host immunity. In order to clarify the role of P2 effector in rust infection process, P2 gene was analyzed by bioinformatics. cDNA of P. helianthi urediospores was used as template to clone P2 gene. Its expression characteristics during the infection were analyzed by qRT-PCR. Then function of P2 was verified in Nicotiana benthamiana by Agrobacterium transient expression system, and subcellular localization of P2 was performed by transient expression in N.benthamiana. Results showed that P2 encoded 58 amino acids （aa） with 24 aa signal peptide at N-terminal, without nuclear localization signal and transmembrane domain. P2 expression was up-regulated during early stage of P. helianthi infection. Transient expression of P2 in N.benthamiana inhibited BAX-induced cell death. Subcellular localization showed that P2 was localized in cell membrane and nucleus.
To improve the seed yield, foliar spraying of potassium fertilizer was studied to explore the effect of potassium-containing organic water-soluble fertilizer on rapeseed growth and yield. Cultivar Wangchengyou 8 was used as material, with 3 spraying periods （seedling, early bloom stage, seedling + early bloom stage） and 5 potassium-containing organic water-soluble fertilizer application rates （0, 375, 750, 1125, 1500 g） treatments. Two-factor randomized block test was designed. Results showed that, after spraying 750 g potassium-containing organic water-soluble fertilizer at rapeseed seedling or early bloom stage, growth and development indexes （including plant height, root neck thickness, and biomass） were significantly increased. And spraying twice at seedling and early bloom stage had a more significant impact on growth and development than spraying at a single period. Spraying 750 g per hectare at both seedling and early blooming increased the number of effective siliques per plant and seeds number per silique. An increase of 39.07% on seed yield and 44.22% on oil production per hectare were also observed compared with control. By spraying 750 g per hectare at seedling and early blooming stages, plant growth, yield, seed oil, and economic benefits could be significantly increased.
To better understand alleviating effect of boron （B） on aluminum （Al） stress of rapeseed （Brassica napus） seedlings, Zhongyouza 28 was used as experimental material, and 2 B （0.25, 25 μmol/L）, 5 Al （0, 50, 100, 200, 400 μmol/L） were used as treatments. Results showed that Al stress significantly inhibited the growth of rape seedlings, increased the content of malondialdehyde, and product of membrane lipid peroxidation, significantly reduced the content of chlorophyll, and thus reduced the biomass. Under Al stress, compared with low B treatment, B addition significantly increased the contents of soluble protein, proline and glutathione in roots, decreased Al accumulation, promoted the absorption of magnesium to synthesize chlorophyll and increased the biomass of rape. In conclusion, Al stress could significantly inhibit rapeseed growth and improve the degree of membrane lipid peroxidation. While B addition could not only make up for the lack of B, but also resist Al stress by regulating antioxidant system and increasing accumulation of protein and proline content.
To clarify the regulating effects of lime and biochar application on acid soil improvement and nitrogen (N) nutrition of peanut, field experiment was conducted to study the effects of lime and biochar application on properties of acidified soil, N uptake and utilization, growth and development of peanut. Results showed that, sole lime application could significantly increase soil pH, organic matter, alkali-hydrolyzable N and exchangeable Ca content, which made N uptake and harvest index significantly increase by 13.1% and 4.6%, and make peanut biomass and yield significantly increase by 11.7% and 16.1%, respectively. Sole biochar application could increase pH, alkali-hydrolyzable N content, soil organic matter content and soil C/N ratio, but had no significant effect on N uptake, biomass and yield of peanut. These results suggested that acid soil significantly inhibited peanut growth, and sole lime application had better effect on peanut growth and N utilization than that of biochar application. The more harmonious soil pH, organic matter, soil alkali-hydrolyzable N, exchangeable Ca content and C/N ratio, the higher N uptake and N use efficiency, biomass and yield of peanut after lime incorporated with biochar application. Among all treatments, 4500 kg/hm2 biochar rate incorporated with 450 kg/hm2 lime rate had the highest N uptake, N harvest index, N use efficiency, biomass and yield, which increased by 30.7%, 8.7% and 5.7%, 27.6% and 35.8%, respectively. Therefore, 4500 kg/hm2 biochar rate incorporated with 450 kg/hm2 lime rate could be effective means for acid soil improvement, with higher N efficiency and higher yield cultivation of peanut.
To improve yield and economic benefit of the South China peanut production under sugarcane / peanut intercropping, field trials with 4 gradients of NPK fertilizers were conducted to investigate the fertilizer ratio on yield, NPK nutrient absorption and economic benefit. Results showed that the highest peanut yield and economic benefits could be obtained under 80 kg/hm2 N, 70 kg/hm2 P2O5, and 80-90 kg/hm2 K2O, and the harvest index and nutrient utilization rate are also higher. NP absorption in intercropped peanut increased with the NP fertilizer application, while excessive K fertilizer application inhibited K absorption by peanuts. The key period of dry matter accumulation and nutrient absorption of intercropped peanut was from anthesis needling to pod expansion. The dry matter accumulation of intercropped peanuts increased with NPK application. For each 1000 g dry matter forming, it needed to absorb and assimilate 17.7 g N, 1.7 g P2O5 and 11.3 g K2O, with the absorption ratio as 10.4 : 1 : 6.6 （N : P2O : K2O）. The nutrient absorption ratio per 100 kg pods varied depending on NPK fertilizers ratio, as 6.83-7.98 kg N, 0.65-0.80 kg P2O5, and 4.10-5.32 kg K2O. Therefore, the recommended N, P2O5 and K2O application rate of intercropped peanut in South China with the best economic benefit was 80 kg/hm2 N, 70 kg/hm2 P2O5, and 80-90 kg/hm2 K2O.
To investigate the effects of chitooligosaccharide （COS） soaking on germination and physiological metabolism of peanut seeds under low temperature, seed germination and related physiological indexes of peanut were observed following immersion in chitooligosaccharide solution. Results showed that 250 mg/L COS significantly increased peanut germination at low temperature. Compared with no soaking control, both germination rate and relative germination rate increased by 44.45 percentage points, germination index and seed vigor index increased by 5.59 and 24.83, respectively. COS soaking also significantly increased gibberellin content and decreased abscisic acid content of peanut seeds during germination. The content of gibberellin in germinating seeds at 0, 12, 24, 36 and 48 h were significantly increased by 7.94%, 3.84%, 8.52%, 12.40% and 19.20%, and abscisic acid content was significantly decreased by 38.41%, 36.99%, 38.03%, 41.20%, 40.12%. Meanwhile, COS soaking increased the activities of lipase, protease, α-amylase, superoxide dismutase, peroxidase and catalase, and accumulated the quantities of adenosine triphosphate, soluble sugar, soluble protein and proline, while decreased the contents of malondialdehyde and hydrogen peroxide. Studies revealed that COS could regulate hormone level of peanut seeds and improve the activities of hydrolase at the early germination stage under low temperature environment, promote the decomposition of storage substances, and also enhance the activity of antioxidant enzymes, increase the content of osmotic regulatory substances, slow down lipid membrane peroxidation, which promote seed germination.
In recent years, soybean staygreen syndrome, named ‘Zhengqing’ in China, has appeared occasionally in the summer soybean field of Huang-Huai-Hai regions, which becomes a serious threat to local soybean production. To explore the relationship between dry heatwave and Zhengqing, we conducted dry-heatwave-simulated treatments (HT) in artificial growth chamber from the full bloom stage (R2) to full pod stage (R4) with the duration of 3 d and 7 d, respectively. The results showed that soybean plants grown well after HT treatment for 3 d started from full bloom stage (R2), however, the HT treatment for 7 d caused various degree of staygreen syndrome of different soybean materials. The subsequent identification confirmed that severe reduction of effective pod number and normal seed number were detected after 7 d HT treatments at R2, R3, or R4 stages of soybean plants. The sequence of decrease amplitude compared with the control was R3 (85.14%) > R2 (62.12%) > R4 (50.97%) for effective pod number and R3 (81.02%) > R2 (60.00%) > R4 (56.32%) for normal seed number. In conclusion, staygreen syndrome could be induced by dry heatwave stress at R3 stage of soybean plants for 7 d. Soybean staygreen syndrome could be described as without seeds in pods, without pods, partial staygreen, and whole plant diapause. Regeneration of new leaves and flowers at lower nodes could be used an early diagnosis indicator of staygreen syndrome.
To allivate phytotoxicity, a degrading strain TW-1 （with atrazine as the sole nitrogen source） was isolated from farmland in Anda City, Heilongjiang Province by selective medium enrichment culture. It was identified as Arthrobacter sp. The degradation rate of 100 mg / L atrazine in the medium by strain TW-1 could reach 99.5% within 48 h. The results of pot experiment showed that strain TW-1 could increase the chlorophyll content of soybean plants, increase the contents of catalase and peroxidase, effectively alleviate the atrazine damage of soybean plants. It was considered to have a good application potential.
To better understand how to improve the germination of tiger nut tubers during planting, disinfection method and optimal germination conditions of tiger nut tubers were optimaized by screening soaking conditions, disinfection methods and combinations of different concentrations of plant growth regulators using 3 tiger nut varieties A2, Z1 （Zhongyousha 1） and ND （Neimenggu Dali）. Results showed that the best disinfection effect was achieved at 75% alcohol for 3 min and chlorine for 16 h, and their germination rates all reached the highest at 35°C for 3 days, as 58.33%, 51.67% and 43.33% respectively. The highest germination rate was obtained under MS+1.0 mg/L 6-BA+0.5 mg/L NAA for both A2 （70.00%） and Z1 （63.33%）. While for ND, 55.00% was the highest germination rate under MS+0.5 mg/L 6-BA+0.2 mg/L NAA. Although 6-BA had significant effect on tuber germination, but increased concentration might inhibit the germination.
In order to investigate the growth development and grain yield formation of oilseed flax under different ridging modes and plastic film mulching modes in dryland, four different planting modes （including film mulching and micro-ridge with soil covering, film mulching and micro-ridge with no soil covering, film mulching and flat planting with soil covering, film mulching and flat planting with no soil covering） were set, and the seedling emergence rate, plant height, stem diameter, dry matter accumulation, growth rate and grain yield of oilseed flax were studied using conventional open field strip sowing as the control （CK） in the growth season of oilseed flax from 2016 to 2017. The results showed that micro-ridge improved the growth and development of flax, the seedling emergence rate was significantly higher than that of CK, dry matter accumulation was the highest under micro-ridge with no soil covering treatments from seedling to budding stage and the highest under the micro-ridge with soil covering from anthesis to maturity stage, which were 39.3%-69.8% and 36.0%-53.7% higher than that of CK, respectively. The grain yield of oilseed flax under the micro- ridge with soil covering treatment was significantly higher than that of CK by 26.8%. The correlation analysis showed that the dominant factors affecting the grain yield of oilseed flax were the number of capsules and the number of grains. The results of correlation analysis showed that the grain yield of oilseed flax was significantly and positively correlated with grain yield components and dry matter accumulation. The results indicated that the micro-ridge with soil covering and hole sowing without soil could significantly improve the emergence rate of oilseed flax, promote dry matter accumulation, increase the number of capsules and grains per plant, and improve grain yield, which was a suitable planting mode of oilseed flax in dryland agricultural area.
Verticillium wilt is a plant vascular disease caused by soilborne fungus Verticillium dahliae which severely limits sunflower production. Molecular detection method of the pathogen requires high sensitivity and poor repeatability, while conventional dilution plate coating method takes a long time. It is important to establish a method for rapid and quantitative detection of microsclerotia in the prediction and control of sunflower verticillium wilt. To quantitatively detect microsclerotia number in soil and find out difference among farming systems, a sampler-dry sieve method, for rapidly and quantitatively detection of soil microsclerotia was summarized. It combines a microbial sampler with a selective medium, and based on the impact method principle of the microbial sampler. And soil microbial particles are accelerated to impact petri dish surface of the selective medium, and single colony formation could be seen after culturing. This method was used to quantitatively detect microsclerotia in soil samples collected from different sunflower verticillium wilt disease sites in Bayannur City, Inner Mongolia. Results showed that in soil of the two-year sunflower continuous cropping field （plot 1）, the number of micro sclerotia was the most （32.80 per gram of soil）. In the plot of rotation with the non-host crop maize （plot 2）, the number of microsclerotia was the least, containing 11.80 per gram of soil. The number of microsclerotia in the rotation plot （plot 3） was between the other two plots. It indicated that the number of microsclerotia colonized in soil could be clearly distinguished among different plots by using this method.