玉米抗粗缩病遗传及分子标记研究

Maize rough dwarf disease caused by Rice black-streaked dwarf virus (RBSDV) is transmitted by planthopper in China. Identification and development of resistant hybrids are complicated because of the inconsistencies in viral disease pressure every year. Marker-assisted selection can provide means for main-taining virus resistance alleles even in the absence of disease. In this paper a F₂ segregation population was constructed to identity the molecular markers linked to the resistance gene using a cross between a resistant and a susceptible parents (Qi319×Ye107). Fifteen-day-old seedlings of F₂ population were exposed to small brown planthoppers carrying RBSDV for 3 days in specific inoculation chamber. The inoculated plants were transplanted to screenhouse after removing the insects completely. In plant maturity stage the disease resistance of all the individuals were visually assessed. The results showed that 17, 8, 11, 51 and 122 plants were scaled from 0-4 respectively, in which 0 means no symptoms and 4 represents highly susceptible. Chi-square test demonstrated that the segregation ratio of phenotype was 1∶15 (resistant: susceptible) or 1∶6∶9 (resistant∶moderate∶susceptible) in the F₂ population, indicating RBSDV resistance of maize was controlled by two recessive genes. The F₂ individuals DNA were extracted and 261 SSR (simple sequence repeat) primers derived from maize genome ten chromosomes were selected from maize GDB database to construct genetic linkage map. The linkage map consisted of 71 polymorphic SSR markers, spanning a genetic distance of 996.6 cM with an average interval of 14.0 cM between adjacent markers. The resistant and susceptible gene pools were set up for BSA (bulked segregant analysis) and 6 polymorphism markers were obtained with BSA-SSR method between the two pools. The F₂individuals were further analyzed with 6 polymorphism markers. Chi-square test showed that phi 051, umc1407 and umc1432, mapped on chromosome 7 and 10, exhibited segregation distortion significantly and very significantly in susceptible individuals. These three SSR markers were identified as potential markers linked to the resistant loci.     

玉米粗缩病抗性遗传研究

 本文选用3个抗病自交系(齐319、X178、沈137)和3个感病自交系(掖107、掖478、沈5003)按照NCII交配设计配制9套杂交组合研究了玉米抗粗缩病遗传规律。2009-2010年在曲阳、保定采用田间自然发病方法鉴定亲本、F₁、F₂群体的玉米粗缩病抗性,并采用灰飞虱人工接种方法鉴定亲本材料的抗病性。运用QGA station 软件的加性-显性-上位性(ADAA)遗传模型进行数据分析,结果表明,显性效应和加性效应是控制玉米粗缩病抗性的主要遗传组分,分别占表型变异的44.8%和13.1%,杂合显性效应表现负向杂种优势,抗病育种可加以利用。加性×加性上位性效应在玉米自交系和杂交组合抗粗缩病遗传中普遍存在,但因材料不同而表现负向或正向效应。玉米粗缩病抗性易受环境影响,显性与环境互作效应方差占表型方差的比率为39.8%,达到极显著水平。因此,培育抗粗缩病玉米品种应依据基因型选配适当的亲本材料,抗病品种宜进行多年多点鉴定筛选。     

抗、感玉米粗缩病材料对灰飞虱的趋性及生存力影响的研究

通过网棚内人工接种1叶1心至11叶1心期的3份抗玉米粗缩病自交系材料(DB544、沈137、90110)和3份感粗缩病玉米自交系材料(掖107、掖478、5003),调查其发病率,明确了抗病材料7叶前的抗病性与7叶后一致,感病材料7叶后的抗病性比7叶前要强;由此认为,玉米苗期为研究抗、感玉米粗缩病材料对灰飞虱的趋性及生存力影响的适宜时期。进而研究了相同环境条件下,网箱或网罩内灰飞虱在抗、感玉米材料上的落虫数和灰飞虱在上述6份材料上饲养死亡50%的时间。结果显示:灰飞虱对抗、感玉米粗缩病材料的趋性以及灰飞虱在抗病材料和感病材料上的生存力差异均不显著,认为玉米对粗缩病的抗性不是通过抗传毒介体灰飞虱而实现的。     

夏秋季设施番茄绿色防控必须走好前三步

夏秋季设施番茄生产中,健康保障性绿 色防控技术成败的关键在前三步,从维护幼苗 健壮和提高植株自身抗性入手,抓住茎基腐 病、病毒病和传毒媒介昆虫等主要病虫害防治 的关键节点,帮助番茄顺利度过高温高湿和强 光照季节。     

分组合作教学模式在中职基础会计模拟实训课的应用

随着社会经济的发展,社会对人才的要求越来越高,中职学校的教学需要跟随时代变化做出一些改变.文章就在中职课堂开展基础会计模拟实训课进行一定的研究,通过分析其所存在的问题,主要立足于心理学和教育学来进行分析在基础会计模拟实训课堂上进行分组合作教学是否适合,从而促进中职基础会计模拟实训课的发展.     

马铃薯茎叶中茄尼醇提取方法优化与比较

为了探究马铃薯茎叶中茄尼醇适宜的提取溶剂和提取方法,选取从宁夏固原采收的同一批马铃薯茎叶为研究对象,分别以95%乙醇、甲醇为提取溶剂,并设置不同的提取次数和提取时间,优化了加热回流提取马铃薯茎叶中茄尼醇的方法,并比较了加热回流提取、冷浸提取和超声提取马铃薯茎叶中茄尼醇的效果。结果表明,采用95%乙醇加热回流提取马铃薯茎叶中茄尼醇,提取2次,每次提取1.5 h,茄尼醇提取率达到96.85%,明显高于甲醇作为提取溶剂(47.04%);其浸膏得率为7.63%,与甲醇作为提取溶剂(8.07%)相当,可降低后期茄尼醇的精制和纯化的成本。该方法简便、可行,试剂还可反复回收利用,可行性强。     

玉米粗缩病发病叶龄与主要为害性状的相关性分析

对玉米粗缩病进行了系统的田间调查,分析了发病叶龄与玉米粗缩病主要为害性状的关系。结果表明：玉米在其生育期内均可感病,发病越早,病情越重,9叶期后发病症状显著减轻。发病叶龄与玉米粗缩病的严重度（r=-0．938,P〈0．01）、株高（r=0．884,P〈0．01）、穗粒重（r=-0．823,P〈0．01）密切相关。     

乌兰布和沙漠风沙区生态环境浅析

文章通过对乌兰布和风沙区沙漠化严峻态势和恶化的生态环境调查和分析 ,提出防治和改善生态环境的必要性 ,以及使荒漠化得到有效控制的重要意义     

玉米粗缩病的流行因素与预测模型

通过对1977-1984年辛集试验基地调查数据的整理和对此期间3—6月份平均、最高、最低温度以及月降雨量和降雨次数等29个变量与病株率的相关性和相关程度的逐步回归分析，表明：5月份降雨量、5月份降雨次数和3—4月份平均最高温度、越冬代灰飞虱的虫量、带毒率和麦田绿矮病株率为影响玉米粗缩病发生流行的主要因素。本文建立了以越冬代灰飞虱虫量V1、带毒率V2和5月份降雨量V18为测报因子的2个玉米粗缩病的预测预报模型：①Y=0．692 0．93V1 0．314V2 0．059V18②Y=0．263 1．10Vl 0．069V18。经用1996-1999年的试验和气象数据进行检验，准确率均达75％以上。因此，2个模型均可用于河北省中南部玉米粗缩病的预测预报。