【Objective】 In order to understand the response pattern of grain filling characteristics to sowing date and its relationship with thousand grain weight in wheat.【Methods】Twenty-one wheat varieties which were widely popularized or newly approved in Anhui Province were used as experimental materials with three sowing dates October 30（SD1）,November 14（SD2）and November 29（SD3）in 2018,were set up respectively. Split plot design was adopted in the experiment,the sowing date was the main area and the variety was the secondary area.【Results】The results showed that the grain filling rate of different sowing dates showed a single peak curve in the grain filling process.The growth rate was faster in the early stage of grain filling,and gradually slowed down in the later stage. The thousand grain weight decreased significant with the delay of sowing date in each sampling period.Before May 12,the grain filling rate of SD1 was significantly higher than that of SD2 and SD3,and after May 17,the grain filling rate of SD2 and SD3 were significantly higher than that of SD1,and there was no significant difference in harvest time. The thousand grain weight and grain filling rate of different varieties in different sampling periods were different in three sowing periods.Ningmai 21 and Xinmai 26 had higher thousand grain weight than most varieties in each sampling period during the three sowing dates,and the grain filling rate was first high and then gradually decreased. The thousand grain weight of Weilai0818 in different filling periods was lower than that of most varieties,and the grain filling rate was first low and then increased slightly in three sowing periods. Correlation analysis indicated that there was a positive correlation between grain filling rate and thousand grain weight in the early and middle stages of grain filling under different sowing dates,among which the grain filling rate on 17^th May was significantly positively correlated with thousand grain weight at different sowing dates. However,there was no significant correlation between grain filling rate and thousand grain weight in the late stage of grain filling.【Conclusion】In the process of grain filling under different sowing dates,the grain filling rate in the early and middle stages of grain filling rate has a greater impact on the thousand grain weight. The thousand grain weight of each sampling period gradually decreased significant with the delay of sowing date. In the early and middle stages of grain filling,the grain filling rate decreased with the delay of sowing date.In the later stage of grain filling,the grain filling rate increased with the delay of sowing time. Increasing the grain filling rate in the early and middle stages of grain filling can effectively increase the thousand grain weight.

【Objective】The experiment was designed to explore the effects of different previous crops on potato library activity,dry matter accumulation,yield and disease occurrence to provide theoretical basis for selecting suitable previous crops for potato planting in the northern of Yinshan Mountain,Inner Mongolia.【Methods】A fixed-point experiment was conducted in the northern of Yinshan Mountain,Inner Mongolia.There were 4 treatments：green manure pre-planting（LM）,sunflower pre-planting（XM）,oat pre-planting（YM）,and potato pre-planting（MM）.We compared and analyzed the effects of different previous crops on potato library activity,dry matter accumulation,yield and disease occurrence with each area of 0.06 hm²（200 m×3 m）.【Results】 In the northern foot of Yinshan Mountain climates,when the previous crop type is green manure,the activity of potato bank reached the highest value 0.069 4 g/（g·d）,followed by oat crop.In the research of the maximum dry matter growth rate of potato and the rapid accumulation of dry matter of the whole plant,the different previous crop type had great influence on these two values,the order was shown as green manure pre-work>potato pre-work>oat pre-work>sunflower pre-work.And when it turned to maximum growth rate of tuber dry matter and average dry matter accumulation rate of potato tuber during rapid accumulation period,the order was green manure pre-work>oat pre-work>potato pre-work>sunflower pre-work.The equilibrium period of dry matter accumulation of stem,leaf and tuber first appeared,about 34 days after sowing,when green manure and oats were used as the previous crop,but when potato was used as the previous crop,it last appeared,about 56 days. When green manure and oat were used as the previous crop,the yield of potato was the highest,reaching 46 992 kg/hm² and 46 073 kg/hm² respectively. The incidence rate of Fusarium wilt,tuber wilt and tuber black mole disease index were the highest when potato was used for the previous crop.But the tuber scab disease index was lowest when potato was used for the previous crop,followed by the sunflower pre-crop.【Conclusion】 Comprehensive analysis of different pre-crops on potato bank activity,dry matter accumulation,The occurrence of disease and the impact of yield,the pre-crop suitable for potato planting is the best pre-green crop,followed by the oat pre-crop in the northern of Yinshan Mountain,Inner Mongolia.

【Objective】In order to understand the feasibility of the experiment and effectively improve the economic benefits of farmers in Tumochuan area of Inner Mongolia,the experiment of double cropping wheat and bean was designed.【Methods】From 2017 to 2019,after the wheat harvest in the Tumochuan area of Inner Mongolia,the multi-planting hole-sowing method was used to carry out the cultivation experiment of fresh food beans,the variance analysis of the agronomic traits and fresh pod yield of the food beans,and the benefit of multiple cropping fresh food beans after wheat was evaluated.【Results】After the wheat was harvested,the average yield of picking fresh pods of multiple cropping bean was 6 006.5 kg/hm²,the average income was 45 673.50 yuan/hm²,and the average net economic income was 37 999.38 yuan/hm².【Conclusion】On the basis of ensuring grain yield,wheat and bean could be planted twice in one year,which could effectively improve the land use efficiency and significantly improve the benefits compared to the single wheat.

This paper focuses on the current research station of barley breeding,cultivation,and elaborates some questions such as insufficient special varieties,extensive cultivation technology,single cultivation mode,low comprehensive quality level,and high production cost,etc.,from the three aspects of research methods,directions,and effects,respectively. The breeding research goals such as beer,feed,seed and seedling type were put forward. And high-yield and high-efficiency cultivation technology,mechanized and high-efficiency operated methods and other cultivation directions were also put forward. It is recommended to combine modern molecular biology technology with traditional breeding technology in future breeding and speeds up the selection and breeding of new varieties,and at the same time to improve the research and development of high-quality,high-yield and efficient cultivation technology,and the degree of mechanized cultivation,and cost saving.

Yanqing,Beijing and Zunhua,Hebei,which are the locations for the national and Hebei Triticum aestivum regional test varieties to be tested for cold resistance,most of the years were warm winter,and there were problems such as failure to detect Triticum aestivum varieties with poor cold resistance.Therefore,Yuxian County,Hebei Province,where the winter temperature was lower （90% of the year in January,the lowest temperature was lower than -18 ℃）, was selected as the test site for the cold resistance of the new Triticum aestivum breeding early generation （F₄） line,and the ultra-low temperature overwintering method was selected,and it was of great significance to carry out ultra-low temperature overwintering selection method to breed new varieties of cold-resistant and high-yielding Triticum aestivum.This article summarized the identification methods and screening indicators of Triticum aestivum cold resistance from the morphological,physiological and molecular levels,and evaluated the scientific basis,implementation effects and identification technology of the “Ultra-low temperature overwintering selection method”,and it aimed to provide a reference for the application of “Ultra-low temperature overwintering selection method” in the selection and breeding of new Triticum aestivum varieties with high yield and cold resistance.

Mutation breeding is a widely used breeding method,which provides a means for the selection and breeding of new soybean varieties.This paper reviews the application mechanism of chemical mutagenesis（EMS,EI）,physical mutagenesis（ionizing radiation,laser）and aerospace mutagenesis breeding in soybean breeding.The effects of mutagenesis on phenotype,physiology,biochemistry,disease resistance of soybean plant and the screening and identification methods of mutants were analyzed,and also the future soybean mutagenesis breeding technology was prospected.

【Objective】To screen potato varieties with excellent comprehensive characters,outstanding processing characteristics and suitable for planting in Ulanqab,Inner Mongolia,and to provide high-quality materials for breeding and germplasm improvement of new varieties.【Methods】The yield and nutritional quality were evaluated by variance,path,clustering and correlation analysis.【Results】The results of nutritional quality evaluation was as follows：HR066>HR052> YS024>D034>LK99>YS017>Xisen 3>Yunshu 10>HR068>D048>D037>Jizhangshu 12（CK1）>Zhongshu 9>Huashu 1>HR090>Longshu 5>YS008>Shepody（CK2）>YS001>HR075>YS022>YS033; The potato varieties were divided into 3 categories by cluster analysis, CategoryⅠ：YS001,Zhongshu 9,HR090,Huashu 1,HR068,YS033,HR075,Longshu 5,Shepody,YS022,LK99 and Yunshu 10,which were Fried processing categories.Category Ⅱ：D034,HR052 and HR066,which were all powder processing types.Category Ⅲ：D037,D048,YS017,Jizhangshu 12,YS008,Xisen 3,YS024,which were fresh food types.【Conclusion】Six potato germplasm materials with outstanding processing characteristics were screened out,which were significantly better than Jizhangshu 12（CK1） and Shepody （CK2）.Among them,D034,HR052 and HR066 were suitable for starch processing,YS017 and D037 were suitable for fresh food,and Yunshu 10 was suitable for frying.

As one of the main food sources of ruminants such as cattle and sheep,corn straw has important feeding value,but its utilization rate is low. At present,there are still straw burning,idle waste and environmental pollution. Silage is one of the best ways to improve the utilization efficiency of corn straw. Therefore,according to the general research status of corn silage at home and abroad,the paper mainly expounded the selection of silage corn varieties and silage treatment methods so as to provide reference for the selection of corn silage varieties,silage pretreatment methods and silage conditions screening in Inner Mongolia.

【Objective】To determine the effect of reduced glutenin content on starch grain structure and RVA（rapid viscosity analyzer）spectrum characteristics.【Methods】 Investigate the effect of reduced glutenin content on grain structure and starch RVA spectrum characteristics by the Scanning Electron Microscope（SEM） and viscosity analyzer.【Results】Compared with the background parent Shengdao 735,the plant height of Shengdao LG03 was reduced,the number of grains per panicle was slightly reduced,the total protein content was reduced,and there were no significant differences in other agronomic traits.Compared with Shengdao 735,new low-gluten content Shengdao LG03 had no significant change on the morphology of starch granules,but the size uniformity was reduced,and starch RVA curve showed that peak viscosity（PKV）,hot paste viscosity（HPV）,cool paste viscosity（CPV）,breakdown viscosity（BDV）,pasting temperature（PaT）and peak time（PeT）all had downward trend,while consistence viscosity（CSV）and setback viscosity（SBV）increased.【Conclusion】 The decrease of gluten content had little effect on the morphology of rice starch granules,but the uniformity of particle size was reduced,that may be the reason of the changes of starch RVA characteristic values.

【Objective】The research aimed to identity the function of Arabidopsis thaliana protein gene AtRHD3（root hair defective 3）in anthocyanin biosynthesis.【Methods】Compared the anthocyanin content induced by sucrose in wild type Col-0 and mutant rhd3 and relative expression of genes in anthocyanin biosynthesis pathway by real-time fluorescent quantitative PCR.【Results】With the increasing content of 5% sucrose,anthocyanin content in wild type Col-0 and mutant rhd3 were increased,and the anthocyanin accumulation in mutant rhd3.It is significantly higher than the wild type Col-0,implied that AtRHD3 played negative role in anthocyanin biosynthesis induced by 5% sucrose.The expression levels of structural genes and regulatory genes of anthocyanin biosynthesis pathway in wild type Col-0 and mutant rhd3 after control and 5% sucrose treatment were analyzed.The results showed that compared with wild type Col-0,the expression levels of structural genes（AtDFR、AtANS、AtUF3GT）and positive regulatory genes（AtPAP1、AtPAP2、AtTT8、AtTTG1）expressed higher level than those in wild type Col-0,while the negative regulator AtMYBL2 expressed lower level.【Conclusion】The study indicated AtRHD3 negatively regulated anthocyanin biosynthesis by affecting the expression levels of structural genes and regulatory genes of anthocyanin biosynthesis pathway in Arabidopsis thaliana induced by sucrose.

【Objective】Explore the fertilization effect of oats in the northern Yinshan Mountain,and provide scientific basis for the rational fertilization of dryland oats in the northern Yinshan Mountain.【Methods】Based on the long-term positioning experiment（started in 2004）of Wuchuan dry farming experimental station in Inner Mongolia,the effects of different fertilization measures on oat yield,plant nutrient absorption and oat water and fertilizer utilization efficiency under long-term fertilization conditions were studied.【Results】Oat yield,1 000-grain weight,plant high,panicle length and spikelet number per plant could be significantly increased under the combination use of chemical and organic fertilizer（NPK+O） and balanced fertilization（NPK）.The grain yield under NPK+O and NPK conditions could be increased by 49.86% and 38.97% compared with oat planted without fertilization（CK）.The oat LAI,biomass,and amount of absorption of N,P,and K could be significantly increased under NPK+O and NPK treatments,the maximum LAI,and biomass were 2.62 and 6 066 kg/hm²,respectively.The max amount absorption of N,P and K was 115.28,26.77 and 132.92 kg/hm²,respectively.Combined application of NPK+O and NPK could significantly increase the water use efficiency in oats,reaching 8.17 and 7.84 kg/（hm²·mm）,respectively,which were 46.5% and 40.0% higher than CK.The use efficiency of N,P₂O₅,and K₂O under NPK was 36.37%,17.93%,and 59.92%,respectively.Each 100 kg oat absorbed N 3.38-6.21 kg,P₂O₅ 1.09-1.49 kg,K₂O 3.98-7.43 kg,with a value of 4.93,1.31,and 5.77 kg,respectively.【Conclusion】The combination use of chemical and organic fertilizer（NPK+O）and balanced fertilization（NPK）could significantly increase yield,nutrient absorbs,water and fertilizer utilization efficiency of oats,which were nutrient management models for high efficient resource utilization and oat yield increase.

【Objective】Screen out suitable types of new compound fertilizer of potato under drip irrigation in Wuchuan County of Inner Mongolia,to investigate the effects of new compound fertilizers application on potato commercial rate,yield and economic benefits under drip irrigation.【Methods】Four new compound fertilizers were used as the test material,and eight treatments were set in two experimental designs of equivalent fertilizer（with the same price）and equivalent fertilizer（with the same total nutrient amount）.【Results】In the equivalent fertilizer test,the highest yield of A2 was 33.45×10³ kg/hm²,9.31% higher than A-CK.Except for A1,potato commercial rate of each treatment was higher than A-CK,while A3 and A2 were 14.67 and 6.33 percentage points higher than A-CK,respectively.In the comparison test of the equivalent fertilizer,the yields of B1 and B3 were the higher,39.45×10³ kg/hm² and 38.85×10³ kg/hm²,respectively,which increased by 21.20% and 19.35% compared with B-CK.Potato commercial rate of other treatments was higher than B-CK,and there was no significant difference among other treatments.【Conclusion】B3（slow controlled release fertilizer,750 kg/hm²）has a good performance in yield,economic benefit and commercial rate,and it has valuable promotion potential in Wuchuan County.

【Objective】To screen the suitable fertilization model for flax production in Ulanqab City,Inner Mongolia,and provide scientific basis for flax high-efficient cultivation in Ulanqab City.【Methods】Eight kinds of compound fertilizers with different content of NPK were selected and randomized block design was used to explore the effects of different content of NPK on yield and related traits in flax.【Results】Proper fertilization was helpful to improve the emergence rate of flax.The emergence rate and the yield related character of Laisiweite was the highest;three kinds of compound fertilizers,Batian,Laisiweite and Lianmeng significantly increased the flax yield.【Conclusion】Comprehensive analysis showed that the content of NPK in the compound fertilizer of Laisiweite was suitable for flax production in Ulanqab City.

【Objective】To reveal the effects of potassium deficiency on the growth and development of Lactuca sativa L..【Methods】The soil-less substrates were used for cultivation,and morphological indexes such as number of leaves,root length,leaf length,leaf width,underground fresh weight,above-ground fresh weight,underground dry weight,above-ground dry weight,leaf area and root-crown ratio were determined under the treatment of no potassium deficiency（CK）,50% potassium deficiency and 100% potassium deficiency.【Results】The effects of different degrees of potassium deficiency on the growth status of lettuce was most obvious on the 28^th day.The lettuce grown with no potassium nutrient solution had the best growth,with the largest number of leaves,leaf length,leaf width,leaf area,root length,weight,and the highest water content. Lactuca sativa L. treated with 100% potassium deficiency nutrient solution had the smallest plant,the smallest number of leaves,the largest leaf length,leaf width,leaf area, root length,weight,and the smallest water content.The plant growth of lettuce that was treated with 50% potassium deficiency nutrient solution was in the middle.【Conclusion】Potassium could promote the growth and development of Lactuca sativa L.,and increased the root length,leaf length,leaf width,leaf area,weight,and lettuce is sensitive to potassium.

【Objective】To provides a basis for improving water resource utilization efficiency and supporting related agronomic measures in dry farming areas.【Methods】Based on the daily meteorological data of Wuchuan County in the northern area of Yinshan Mountain of Inner Mongolia from 2000 to 2019,the water demand characteristics of potato and spring wheat in each growth period and the coupling conditions of water demand and precipitation of crops were analyzed.【Results】The water requirements for potato and spring wheat during the whole growth period were 337.70 and 315.30 mm,respectively.The water demand of potato during tuber expansion was the largest,accounting for 32.17% of the total water demand during the whole growth period.The water requirements of spring wheat in jointing and heading stage were the largest,accounting for 25.56% and 21.28% of the water demand in the whole growth stage respectively.The water demand of potato and spring wheat during the whole growth period is greater than the effective precipitation in the same period.During the main growth period,if the coupling degree（λ）of water demand and precipitation between potato and spring wheat was λ<1,precipitation cannot meet the water demand of crops.The coupling degree of spring wheat water demand and precipitation showed a good third-degree polynomial relationship with month,with a high degree of fitting,and the determination coefficient（R²）was 0.934 3.【Conclusion】In the northern area of Yinshan Mountain,due to precipitation structure and insufficient precipitation effectiveness,the coupling degree with the water demand in the main growth period of crops is low,that is,the demand for water resources in the key growth period of crops cannot be satisfied.This research explored the balance relationship between water demand and precipitation of crops production in dry farming agricultural areas from both theoretical and practical aspects.

【Objective】Understand to effect of the photosynthetic characteristics,¹⁵N absorption and distribution of strawberry under different dormancy states.【Methods】The differences of strawberry leaf morphological indexes and photosynthetic characteristics were compared between deep dormancy（dwarfed plant）strawberry with non-deep dormancy（not dwarfed plant）during the dormancy period of strawberry in winter. The isotopic tracer method was used to study the difference of ¹⁵N absorption and distribution of strawberry under different dormancy degrees.【Results】The petiole became shorter and the area of single leaf became smaller as the dormancy strengthened.The net photosynthetic rate of strawberry with deep dormancy was lower than that of strawberry with shallow dormancy,but the intercellular CO₂ concentration of the deep domant strawberry was higher.The stomatal conductance of the deep dormant strawberry was higher than that of the shallow dormant strawberry from 8：30 am to 10：30 am.In the dormant state,the root system was the organ with the largest dry matter accumulation and the organ with the highest nitrogen distribution and utilization rate in strawberry. The root system had the strongest ability to absorb and regulate ¹⁵N in the strawberry as the dormant strengthened,while the leaves had the strongest ability to absorb and regulate ¹⁵N for the strawberry as the dormancy shallow.The ¹⁵N distribution rate of strawberry leaves decreased significantly with the deepening of dormancy.The ¹⁵N distribution rate was 18.84% in the deep domant strawberry leaves,and it was 36.74% in the shallow dormancy leaves.【Conclusion】In winter,the dormancy depth of strawberry affected the photosynthesis,nitrogen uptake and distribution of strawberry in solar greenhouse.

【Objective】 The effects of low temperature on the germination indexes of different watermelon materials were studied,and the low temperature tolerant germplasm materials were screened to provide theoretical reference for the breeding of low temperature tolerant watermelon varieties.【Methods】Thirty-nine watermelon varieties（lines）and combinations were used as experimental materials,and a few incubators were used to simulate different low temperature stresses（15/10 ℃,15 ℃ and 17 ℃）.The effects of low temperature stress on germination potential,germination rate,radicle length,vigor index,chilling injury index and recovery ability of watermelon seeds were analyzed,furthermore,and the low temperature tolerance of different watermelon materials was evaluated by pole-sorting method.【Results】Germination potential,relative germination rate,relative radicle length and relative vigor index were decreased under low temperature stress,and the inhibition was more obvious with the decrease of stress temperature.The germination potential,relative germination rate,relative radicle length and relative vigor index of watermelon seeds were significantly correlated with the comprehensive evaluation score of low temperature tolerance,and the relative vigor index and the evaluation scores exhibited the highest correlation（r=0.949）.Different watermelon materials had different tolerance to low temperature during germination.At 17 ℃,there were significant differences in germination potential,relative germination rate,relative radicle length and relative vigor index among different watermelon materials.The four indexes and chilling injury index were selected and the comprehensive evaluation score of each watermelon material was obtained by using the pole sorting method.The results showed that the comprehensive evaluation score of 170-1 was higher than 5,which was a low temperature resistant material.The comprehensive score of Qianli 4,Sumi 1667,Qianli 1,reciprocals of Qianli 4,Qianmei 1,135-2,161-5,17A-81×17A-82 were lower than 2,which were low temperature sensitive materials,anothers were medium low temperature resistant materials.【Conclusion】Low temperature inhibited the germination of watermelon seeds,17 ℃ could be used as the suitable temperature for identification of low temperature tolerance of different watermelon materials at germination stage,watermelon materials with different low temperature tolerance could provide experimental materials for breeding of low temperature tolerant varieties and basic theoretical research.

【Objective】To explore the effects of different fertilizers and their ratios on the yield and quality of Chinese cabbage.【Methods】Five different treatments was designed：no fertilizer （T1,CK）,single chemical fertilizer （T2）,2/3 chemical fertilizer combined with 1/3 organic fertilizer （T3）,2/3 chemical fertilizer + 1/6 organic fertilizer combined with 1/6 straw （T4）,and pure organic fertilizer （T5）.Among them,the contents of nitrogen,phosphorus and potassium in T2,T3 and T4 were the same,while the contents of nitrogen in T5 and T2,T3,T4 were the same without considering the content of phosphorus and potassium.【Results】T3 treatment had the highest yield and survival rate of Chinese cabbage,the values were 188.01 t/hm² and 90.70% respectively,and the highest nitrogen fertilizer agronomic efficiency and partial productivity,the values were 163.33 kg/kg and 696.34 kg/kg respectively.T3 and T5 treatment had the highest soluble sugar content,reached 2.58%,and T5 treatment had the highest VC content,which was 30.6 mg per 100 g.【Conclusion】Under the experiment condition of this study,T3 treatment 2/3 chemical fertilizer combined with 1/3 organic fertilizer was a better mixed application.

【Objective】Screen out daylily cultivars suiting for planting in Northern Jiangsu Province.【Methods】Twenty-five domestic common varieties were introduced for field cultivation,and the main botanical characters and flower bud quality were investigated and analyzed.【Results】The flowering time of Sanyuehua,Datonghuanghua and C1 were 16,8 and 7 days earlier than that of the control,and the flower bud weight was 4.07,3.40 and 4.27 g,respectively.The yield of Datonghuanghua was significantly higher than that of the control（P<0.05）,but the yield of C1 was not significantly different with that of the control（P>0.05）.The contents of soluble sugar,free amino acid,VC and flavonoids in Sanyuehua were significantly higher than those in the control（P<0.05）,while the colchicine content was significantly lower（P<0.05）.The contents of soluble sugar and polyphenols in Datonghuanghua were significantly higher than those of the control（P<0.05）,and the contents of polyphenols,VC and flavonoids of C1 were significantly higher than those of the control（P<0.05）,and their adaptability and resistance were better. The flowering period of Qiezihua and Changzuizihua was similar to that of the control,the number of flower buds and yield were significantly higher than those of the control（P<0.05）,the flavonoids content of Changzuizihua was significantly higher than that of the control（P<0.05）,and the protein content of Qiezihua was significantly higher than that of the control（P<0.05）. Their content of other nutritional quality were not significantly different with that of the control（P>0.05）,their adaptability and resistance were better.【Conclusion】Sanyuehua,Datonghuanghua and C1 had better performance in early maturity,flower bud weight,quality,and resistance,which were suitable for early production in Plastic Greenhouse. Qiezihua and Changzuizihua had better performance in yield,quality,and resistance,which were more suitable for drying and quick freezing production.

【Objective】To reserve simplified and intensive supporting technologies for the development of the tea chrysanthemum industry,it was necessary to improve the stability of the integration of seedling raising and mechanized transplanting technologies.【Methods】This experiment used tea chrysanthemum variety‘ZHONGNONGXINGFANG’ as test material,4 types of seedling blocks were introduced,and the application technology of tea chrysanthemum seedling block was screened by comparing with the traditional pot plate matrix.【Results】The trial object showed that the tea chrysanthemum seedling with a diameter of 30 mm non-woven fabric seedling block was suitable. The seedlings showed good growth state and developed root system,and the performance of mechanized transplanting seedlings was stable with lower incidence of seedling root breaking and missed planting,and the cost was lower.【Conclusion】The seedling raising technology of tea chrysanthemum is suitable to be applied.Based on the comprehensive analysis of various indexes and costs,the seedling raising block with a diameter of 30 mm non-woven cloth drum has certain potential of industrialization promotion.

【Objective】To establish a tissue culture and regeneration system of Sorghum-Sudangrass for the research of Sorghum-Sudangrass transgenic breeding.【Methods】The experiment used MS as the basic medium,and the mature seeds of Sorghum-Sudangrass were used as explants to study the effect of different exogenous hormone ratios（2,4-D,NAA,6-BA,IBA）on callus,induction and differentiation of adventitious buds and influence of seedling rooting.【Results】The suitable callus induction medium was MS+2,4-D（1.5 mg/L）,and the induction rate reached 65.63%;adventitious bud inductions MS medium with NAA（0.5 mg/L）and 6-BA（1.5 mg/L）was optimal,with a adventitious bud induction rate of 80.21%;the optimal rooting medium was MS medium containing 1.0 mg/L IBA,with a rooting rate of 74.30%;for transplanting tissue culture seedlings,the nutrient soil of flower soil∶perlite∶vermiculite = 3∶1∶1 was selected as the transplanting substrated.【Conclusion】 The regeneration system of mature seeds of Sorghum-Sudangrass was induction medium MS+2,4-D（1.5 mg/L）,and the bud differentiation medium was MS+NAA（0.5 mg/L）+6-BA（1.5 mg/L）,and rooting medium was MS+IBA（1.0 mg/L）.

【Objective】By investigating the usage and residual status of plastic film in Tongliao area of Inner Mongolia,to provide reference for the reasonable usage of plastic film and the pollution control of residual film in Tongliao area.【Methods】Using the way of questionnaire and sampling in typical splots,the use and residue status of soil plastic film in Tongliao area from 2015 to 2019 were investigated and analyzed.【Results】From 2015 to 2019,the mulching area and the amount of plastic film used in Tongliao area decreased from 132 400 hm² and 6 900 tons to 66 500 hm² and 3 500 tons;in 2019,the residual amount of plastic film on chili field in Kailu County was 5.82-88.90 kg/hm²,of which,the residual amount of plastic film at 2 sites was more than 75.00 kg/hm²,which was harmful to crop growth; the residual amount of plastic film of sugarbeet in Horqin Zuoyi Middle Banner was 12.24-23.45 kg/hm²,which had little effect on the growth of crops.【Conclusion】The years of mulching and the recovery technology of plastic film are one of the important factors affecting the residual amount of plastic film.The longer the filming time,the higher the residual amount.The better the residual film recovery technology,the less the residual amount. In order to provide some reference for the use of plastic film and the recovery of residual film in Tongliao area,some countermeasures were put forward,such as source reduction,popularization and use of new standard film and alternative technology,and improvement of film recycling compensation system.

Based on the data of 3 233 journal articles in the saline-alkali land collected by CNKI,this paper analyzes the current scientific research status of saline-alkali land management in domestic.The research hotspots and development trends in the field of saline-alkali land in China are demonstrated by using the methods of bibliometrics,cooperation rate and cooperation degree,co-occurrence analysis and cluster analysis.In the past 10 years,the output of scientific research papers in the field of saline-alkali land in China showed a rapid upward trend.The core output institutions are concentrated in agricultural scientific research institutions and a small number of forestry colleges.In addition to saline-alkali land,the high-frequency keywords include coastal saline-alkali land,soil improvement,and yield.The research hotspots mainly focus on rice,cotton,afforestation,greening and etc.,and some focus on the improvement technology research of coastal saline-alkali land.