Accumulation of heavy metals in two crop seeds due to soil contamination as determined by neutron activation analysis techniques

Samples of two crop seeds (corn and sesame) grown on different contaminated soil sources were collected and prepared for neutron activation analysis. Soil contamination sources were organic waste compost applied to soil amendments namely, sewage sludge(Bs) and municipal solid waste (MSW) at 4%, 6% and 8% respectively. The non destructive NAA technique was used to determine some trace elements accumulation in plant seeds. Results revealed that increasing rate of tested organic waste resulted in dramatic increase in tested heavy metals levels in seeds(i.e., Fe, Zn, Co, Cr, Sc and Hg). Sesame seeds showed higher affinity to accumulate trace elements than corn grains in most tested elements. Moreover, MSW addition enhanced the accumulation of tested metals in seeds more than Bs compost.

Seed Germinability of 23 Crop Species After a Decade of Storage in the National Genebank of China

Seed viability of 18 576 accessions of 23 crops was monitored. After 10-12 years storage in National Crop Genebank ofChina (NCGC), more than 96.12% of the accessions maintained high germination percentage (>85%). The germination of95 accessions, accounting for 0.51% of the total, declined significantly from above 80% to below 70%. For each crop ofcarrot (Daucus carota var. sativa DC.), lettuce (Lactuca sativa L.), cotton (Gossypium sp. L.), flax (Linum usitatissimumL.) and castor-oil plant (Ricinus communis L.), the mean monitored germination percentage declined significantly as awhole, of which carrot and lettuce seeds lost viability more rapidly. Seed initial germination percentage and pre-storageenvironments affect subsequent seed viability in storage.

Chemical Weeding in Dry Direct Seeding Fields of Single Cropping Middlelate Rice

Chemical weeding in dry direct seeding fields of single cropping middle-late rice was studied in Huida vegetable farm of Huizhou City in 2012. The main treatment was herbicide（ pretilachlor ＋ bensulfuron-methyl,Yangguo and butachlor）,and the sub-treatment was application method（ soil treatments,seedling treatment and integrated treatment）. The results showed that 80 g pretilachlor ＋ bensulfuron-methyl（ 36% pretilachlor ＋ 4% bensulfuron-methyl） diluted with 50 kg water could be sprayed or 200 g Yangguo（ 23. 9% butachlor ＋ 1. 1% bensulfuron-methyl） mixed with 15 kg sandy soil could be broadcasted per 667 m2 on the sowing day or the second day under moist condition of soil,which could effectively control weeds in dry direct seeding fields of single cropping middle-late rice.

Influence of Crop Nutrition on Grain Yield,Seed Quality and Water Productivity under Two Rice Cultivation Systems

The system of rice intensification （SRI） is reported to have advantages like lower seed requirement,less pest attack,shorter crop duration,higher water use efficiency and the ability to withstand higher degree of moisture stress than traditional method of rice cultivation.With this background,SRI was compared with traditional transplanting technique at Indian Agricultural Research Institute,New Delhi,India during two wet seasons （2009-2011）.In the experiment laid out in a factorial randomized block design,two methods of rice cultivation [conventional transplanting （CT） and SRI] and two rice varieties （Pusa Basmati 1 and Pusa 44） were used under seven crop nutrition treatments,viz.T 1,120 kg/hm2 N,26.2 kg/hm2 P and 33 kg/hm2 K;T 2,20 t/hm2 farmyard manure （FYM）;T 3,10 t/hm2 FYM＋ 60 kg/hm2 N;T 4,5 t/hm2 FYM＋ 90 kg/hm2 N;T 5,5 t/hm2 FYM＋ 60 kg/hm2 N＋ 1.5 kg/hm2 blue green algae （BGA）;T 6,5 t/hm2 FYM＋ 60 kg/hm2 N＋ 1.0 t/hm2 Azolla,and T 7,N 0 P 0 K 0 （control,no NPK application） to study the effect on seed quality,yield and water use.In SRI,soil was kept at saturated moisture condition throughout vegetative phase and thin layer of water （2-3 cm） was maintained during the reproductive phase of rice,however,in CT,standing water was maintained in crop growing season.Results revealed that CT and SRI gave statistically at par grain yield but straw yield was significantly higher in CT as compared to SRI.Seed quality was superior in SRI as compared to CT.Integrated nutrient management （INM） resulted in higher plant height with longer leaves than chemical fertilizer alone in both the rice varieties.Grain yield attributes such as number of effective tillers per hill,panicle length and panicle weight of rice in both the varieties were significantly higher in INM as compared to chemical fertilizer alone.Grain yields of both the varieties were the highest in INM followed by the recommended doses of chemical fertilizer.The grain yield and its attributes of Pusa 44 were significantly higher than those of Pusa Basmati 1.The seed quality parameters like germination rate and vigor index as well as N uptake and soil organic carbon content were higher in INM than those in chemical fertilizer alone.CT rice used higher amount of water than SRI,with water saving of 37.6% to 34.5% in SRI.Significantly higher water productivity was recorded in SRI as compared to CT rice.

Preceding Crops Selection, Colza Seeding Norms and Dates Optimization in North Kazakhstan

Colza is a relatively new crop for North Kazakhstan. The increase of colza seeds production is restricted by its cultivation technology imperfection. Empiric model of colza for seeds cultivation is designed, allowing using its maximum potential. It was found out that correct preceding crops selection, optimization of norms and dates of colza seeding provide seeds heavy weight crops, reducing crops production cost and increasing cost efficiency at 62% average.

EFFECTS OF SEEDING DENSITY AND BASIC MANURE ON THE GROWTH OF DRY NURSERY SEEDLINGS IN LATE DOUBLE CROPPING RICE IN SOUTH CHINA

During the period of dry nursery seedling raising of late double cropping indica rice in South China, both chemical fertilizer and farmyard manure did not show obvious effect on the growth of shoot and root in young seedlings at 4-leaf stage （18-day-old seedling）, but had significant effects on root growth in old seedlings with 6-7 leaves （27-day-old seedling） at suitable seeding densities (65-125g m-2). There were satistically significant differences （at 0.01 or 0.05 levels）between treatments in root number and rooting ability of root-pruned seedlings.

Study and Application of "Three High and One Ensuring" Cultivation Mode of Double Cropping Rice

A set of "three high and one ensuring" cultivation mode of double cropping rice, the core of which was high panicle bearing tiller rate, high seed setting rate, high grain plumpness and ensuring high quality, was explored through many years of research. In this study, the effect of "three high and one ensuring" cultivation mode of double cropping rice was compared and investigated by field experiment and multiple location demonstration. The field experiment indicated that "three high and one ensuring" cultivation mode promoted the vegetative growth during early stage, inhibited the formation of ineffective tillers, promoted the growth of effective tillers and the formation of panicles, improved the panicle bearing tiller rate, increased the total number of spikelets, enhanced the seed setting rate and grain plumpness, increased the grain yield by 12.22%-19.73% at highly significant level, and improved the rice quality. Furthermore, the field demonstration also verified the results of field experiment.

Progress of the Research on the Conservation of Crop Germplasm Resources in China

In the last 20 years, China has made considerable achievements in the conservation of crop germplasm resources. A network for crop germplasm conservation has been established by the end of 2002, which includes a national long-term seed genebank and its duplicated genebank, 8 national medium-term seed genebanks, 30 national field genebanks. 2 national in vitro genebanks, and 3 in situ conservation sites including 1 for wild soybean and 2 for wild rice. More than 334 000 crop germplasm accessions are currently stored in the national long-term genebank, covering 35 families, 192 genera and 712 species, which rank in the first place in the world. More than 43 000 accessions of vegetatively propagated crops and perennial crops covering more than 900 species are conserved in the national field genebanks. In addition, 2 300 accessions are stored in the national in vitro genebanks. This paper reviewed the latest advances of techniques for safety preservation of stored germplasm in seed genebank, ultra-dried seed storage and in vitro preservation in China and discussed current highlights in germplasm conservation.

Influence of Seed Priming on Performance and Water Productivity of Direct Seeded Rice in Alternating Wetting and Drying

Direct seeded rice is promising alternative to traditional transplanting, but requires appropriate crop and water management to maintain yield performance and achieve high water productivity. Present study evaluated the effect of seed priming and irrigation on crop establishment, tillering, agronomic traits, paddy yield, grain quality and water productivity of direct seeded rice in alternate wetting and drying （DSR-AWD） in comparison with direct seeded rice at field capacity （DSR- FC）. Seed priming treatments were osmo-priming with KCI （2.2%）, CaCI2 （2.2%） and moringa leaf extracts （MLE, 3.3%） including hydro-priming as control. Among the treatments, seed osmo-primed with MLE emerged earlier and had higher final emergence, followed by osmo-priming with CaCI2. Tillering emergence rate and number of tillers per plant were the highest for seed priming with CaCI2 in DSR- AWD. Total productive and non-productive tillers, panicle length, biological and grain yields, harvest index were highest for seed priming with MLE or CaCI2 in DSR-AWD. Similarly, grain quality, estimated in terms of normal grains, abortive and chalky grains, was also the highest in DSR-AWD with MLE osmo-priming. Benefit cost ratio and water productivity was also the highest in DSR-AWD for seed priming with MLE. In conclusion, seed priming with MLE or CaCI2 can be successfully employed to improve the direct seeded rice performance when practiced with alternate wetting and drying irrigation.

Gel Electrophoresis of Proteins for the Identification of Crop Varieties

With the development of the international trade and agricultural science and technology, especially after the execution of the rules on protection of new plant varieties, considerable emphasis has been placed on variety identification. Many evidences have suggested that gel electrophoresis have great influence on this area. This paper reviewed study status of various gel electrophoresis, including development of the meth-

Factors in fluencing farmers' participation in crop intensification program in Rwanda

The crop intensification program（CIP）was introduced in Rwanda in 2007 by the Ministry of Agriculture and Animal Resources（MINAGRI）,Rwanda,as a solution to the land fragmentation,low use of agricultural inputs and low access to extension services.However,due to the voluntary nature of farmers’participation and their reluctance to participate,this study aimed at assessing the factors that influence their participation.Data were collected from 340 respondents through a household survey in Mayange and Rusarabuye sectors.Descriptive statistics and binary logistic regression model were used to analyze the data.Results show that the factors that significantly influenced the farmers’participation in the CIP include gender,non-farm income,farmland size,farming experience,land acquisition means,market access,trust and agro-ecological conditions.In fact,the non-farm income significantly increased the farmers’decisions to participate in the CIP（P〈0.001）as it eases the financial capital needed to invest in the CIP activities.On the land acquisition means,the farmers who inherited or bought the land positively and significantly participated in the CIP（P〈0.05）because they had the land tenure security.However,the participation in the CIP was hindered by inadequate irrigation and mechanization facilities,lack of farmers’participation in the CIP planning process,inadequate extension services,inadequate agricultural inputs and inadequate post-harvest technologies.Closer collaboration between farmers,local leaders,extension agents and agricultural service providers as well as the farmers’practical skills in irrigation and mechanization could enhance the participation to the program.Therefore,there is a need on the part of policymakers to empower farmers with adequate knowledge on better cropping practices and agricultural technologies through appropriate extension services and bottom-up based program.

Evaluation of a Metabolic Cotton Seedling Emergence Model

A model for cotton seedling emergence (MaGi) based on malate synthase kinetics was evaluated. Cotton seeds were planted through the early spring and into typical planting times for the areas. Soil temperatures at seed depth were used as inputs into MaGi and a commonly used seedling emergence model based on heat unit accumulation (DD60). Time to 50% emergence was calculated and compared with predicted emergence using MaGi and DD60. MaGi yielded predictive capability without the need to resort to lengthy experimentation required by traditional methods. The results suggest that a physiological or semi-empirical approach incorporating both enzyme kinetics and whole plant temperature responses would be useful for rapidly constructing seedling emergence models.

Economics of Residues Incorporation and Phosphorus Application for Direct Seeded Rice and Wheat under Saline Soil

Two-year long field study was conducted using a permanent layout to investigate the economics of crop residues incorporation (2 t&middotha-1) and P application (0, 40, 80 and 120 kg P2O5 ha-1) to directly sowing of rice and wheat crops gown under naturally salt-affected calcareous soil (ECe = 4.59 dS m-1;pHs = 8.38;SAR = 6.57 (mmolc L-1)1/2;CaCO3 = 3.21%;Extractable P = 4.07 mg&middotkg-1;sandy clay loam) at farmers field in district Hafizabad during the year 2012-13. Split plot design (crop residues in main plots and P application in sub plots) was followed with three replications. Agronomic data on growth and yield were collected at the time of each crop maturity. Maximum growth and yield of both the crops were harvested from the plots where P2O5 was applied @ 80 kg&middotha-1 along with crop residues incorporation. On an average of two years, maximum paddy (3.26 t&middotha-1) and wheat grain (3.56 t&middotha-1) yield were produced with P application @ 80 kg P2O5 ha-1 along with crop residues incorporation. Although, the yield harvested with this treatment (80 kg P2O5 ha-1 + crop residues) performed statistically equal to 120 kg P2O5 ha-1 without crop residues incorporation during both the years, however, on an average of two years, grain yield of directly sowing rice and subsequent wheat was significantly superior (22% and 24% respectively) than that of higher P rate (120 kg&middotha-1) without crop residues. Overall, continuous two-year crop residues incorporation further increased (17%) paddy yields during the follow up year of crop harvest. Economic analyses of both the crops were carried out to choose the best treatment with adequate economic benefits as compared to those without crop residue incorporation. Maximum net benefit of Rs = 108,680/- for direct seeded rice and Rs = 99,362/- for wheat grown with 80 kg P2O5 ha-1 application under crop residues incorporation was determined. Among P application treatments without crop residues incorporation, the maximum net benefit (Rs = 75,874/- and Rs = 65,725/-) and highest residual values (49,809 and 39,160) for direct seeded rice and wheat respectively, were obtained with extended P application rate (120 kg P2O5 ha-1) which was not again as much as that of 80 kg P2O5 ha-1 application with crop residues incorporation.

油料作物种子中神经酸含量提升研究进展

神经酸(NA)是一种超长链单不饱和脂肪酸,为大脑神经纤维髓鞘的核心成分,具有修复受损大脑神经纤维、促进神经细胞再生等功能。因此,NA受到越来越多的研究和关注。目前NA主要依赖于从天然物种中提取,难以满足市场需要,限制其进一步发展和应用。近年来,随着基因工程以及合成生物学的发展,通过多基因策略,在现有物种中构建NA代谢路径,可经济且可持续地获得NA,以满足营养、制药和化学工业等领域的需求。本文综述了NA的生物功能、生物来源、合成途径,并比较了基因工程生产NA各底盘的优劣,进一步探讨了十字花科油料作物底盘生产富含NA种子油的影响因素,以期为将来通过转基因技术和分子育种调控NA的生产,获得可再生的NA资源提供一定的思路和策略。

国外作物种业优秀发展经验及对中国种业发展的思考

农作物种业是国家战略性、基础性核心产业,中国不仅是农业生产大国,也是种子需求大国。中国种业发展正处于市场化改革的关键时期,但在育种技术研发、市场监管、产业链整合等方面依然存在许多不适应市场化的问题。本研究从国外种质资源保护、企业发展历程、种子研发与技术创新3个角度深入剖析了国外种业创新发展现状,并从种质资源管理、创新育种技术、种业产业链整合和产业运行机制4个方面,总结了对突破当前国内种业所面临问题具有参考意义的借鉴经验。最后,提出了加强种业创新体系建设、推动种业企业做大做强、推动种业人才培养和引进、推进种业产业链协同发展等旨在全面提升中国种业国际竞争力,为保障粮食安全和农业可持续发展做出更大贡献的对策建议,对于认识中国种业发展过程中存在的问题,并积极探索优化解决措施,具有重要的价值和现实意义。

北沙参化感作用对其种子萌发及幼苗生长的影响

探究北沙参根系研磨液及其根际土壤浸提液对北沙参种子萌发及幼苗生长的影响,以初步确定北沙参化感自毒作用的存在。本试验先制备0.05 g/mL的北沙参根系研磨液(RT)和0.50 g/mL的根际土壤浸提液(ST),继而测定其对北沙参种子萌发、幼苗生长及其生理生化指标的影响。结果表明:RT与ST对北沙参种子萌发有显著抑制作用;其幼苗生长也受到较大影响,根长、株高、根粗与鲜重大多显著降低,叶片总叶绿素含量显著下降,类胡萝卜素含量显著升高。两处理幼苗叶片的PSⅡ最大光化学效率(Fv/Fm)、电子传递速率(ETR)、PSⅡ潜在活性(Fv/Fo)、光化学猝灭系数(qP)、实际光化学效率[Y(Ⅱ)]均受到明显抑制;幼苗渗透调节系统受到显著影响,叶片脯氨酸、可溶性蛋白含量显著升高,可溶性糖含量显著降低;幼苗叶片的抗氧化系统响应胁迫后超氧化物歧化酶活性显著降低,抗坏血酸过氧化物酶活性显著升高,丙二醛含量显著增加。综之,北沙参根系研磨液及其根际土壤浸提液中存在化感自毒物质,影响北沙参种子萌发与幼苗生长,且化感自毒作用可能是北沙参连作障碍产生的主要原因之一。

中国农作物种子进出口贸易现状及发展对策研究

种子是农业生产的重要物资,对于保障国家粮食安全和农业发展具有重要意义。本文在研究梳理2017~2023年中国农作物种子进出口贸易的基础上,通过贸易差额、贸易竞争力指数、对外贸易依存度、国际市场占有率、比较优势指数等评价指标,探讨中国农作物种子进出口贸易的影响因素,并提出了中国农作物种子产业发展的对策建议。分析结果显示,中国农作物种子进出口贸易总体呈逆差状态,对外贸易依存度指数很低,在全球种子贸易市场中份额较小,比较优势指数较低。总体来说,目前我国仍是种子进口大国,种业研发推广的比较优势相对较低,在一段时间内还需依靠进口种子满足我国种业市场需求。目前中国农作物种子进出口贸易的影响因素主要有人口因素、耕地资源、经济因素、汇率因素、科研投入、外资投资、植物新品种权等方面,可通过优化种子产业结构、提高种子质量与竞争力、加大育种关键技术的研发与投入力度、加强种业国际合作以及强化种业科技成果的转化和推广等方面进一步促进中国农作物种子产业发展。

2011~2020年全球农作物种子贸易格局与主要贸易国竞争力分析

分析了2011~2020年全球农作物种子贸易和主要贸易国竞争力。全球农作物种子出口量和贸易额呈波动上升趋势,进口量和贸易额也呈增长趋势,表明全球种子贸易持续增长。大田作物种子占主导地位,蔬菜种子和花卉种子占比较小,但贸易额占比相对较高。美国、荷兰、法国、德国既是全球前四大种子出口国也是前四大种子进口国,但这4个国家在进出口的具体排名有所不同。荷兰、法国、美国市场占有率较高,匈牙利、法国、荷兰显示性比较优势指数较高。荷兰、法国、匈牙利、美国在这10年中持续保持贸易顺差状态,贸易竞争力指数和显示性竞争比较优势指数均大于0,表明具有较强的竞争优势,中国在这2个指标上均小于0,竞争力较弱。

农学类专业作物种子学实验教学改革与实践

作物种子学实验是作物种子学课程教学中的重要内容,是农学类专业培养本科生实践能力、创新能力和科研能力的重要手段。本文以安徽农业大学为例,针对作物种子学实验教学存在的突出问题,从教学设计、教学方式、考核办法等方面对本课程进行了改革和探索,旨在为高等农业院校农学类专业作物种子学实验课程建设和教学改革提供参考。

浙江省作物种子品质现状与提升对策

为进一步加强浙江省农资市场监管,打击生产经营假冒伪劣农资的违法行为,维护农民群众合法权益,确保农业生产和农产品安全,为农业生产及种子市场管理提供借鉴。文章对2017—2021年浙江省监督抽检和例行抽检的4 049个大田作物种子样品数据进行统计,分析大田和蔬菜作物种子品质状况,发现非单粒播玉米种子标准过低、大豆种子水分合格率较低、蔬菜种子整体合格率偏低等问题,并提出了合理建议。