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1.
[目的]明确贵州猕猴桃根结线虫的种类,为猕猴桃根结线虫病的防治提供理论依据.[方法]从贵州省修文、息烽和大方县采集感染根结线虫的猕猴桃植株,利用改良的贝曼漏斗法分离根结线虫,采用显微镜和扫描电镜对猕猴桃根结线虫进行形态观察与测量,结合分子生物学方法对线虫进行鉴定.[结果]猕猴桃根系被根结线虫侵染后产生根结或瘤状物,形成大小不等的根瘤,直径为0.5~1.0 cm;直径1.5~2.0 mm的须根受害较重,被侵染的须根产生单个或串生结节状肿瘤,瘤状物呈椭圆或近球形.猕猴桃根结线虫雌虫的排泄孔至头端的距离是口针的1倍左右,口针微微向背部弯曲,唇盘呈哑铃状,侧唇与中唇和唇盘分开,分界明显;雄虫唇盘大而圆,比中唇高,中唇外围圆滑,与唇盘分界明显.猕猴桃根结线虫种群与GenBank的南方根结线虫MK784570、KP234265和KF041336等线虫的序列相似度达99%.[结论]侵染贵州省修文、息烽和大方县猕猴桃的根结线虫为南方根结线虫(Meloidogyne incognita).  相似文献   
2.
本文以肥东县土壤墒情为例,选用BP神经网络模型,对土壤墒情预测进行探究。先介绍神经网络相关理论知识,然后针对模型建立需要确定的参数做了详细说明。着重比较了隔日和五日两种预测结果的精度,结果表明隔日预报精度要高于五日预测精度,得出结论 BP神经网络短期土壤墒情预报能取得较高的精度,对农业生产具有实际指导意义。  相似文献   
3.
The upper earshoots with higher superiority usually have higher yield potential and higher efficiency. To determine the key period for the asynchronous differentiation of superior and inferior earshoots and how hormones are involved in this process, a two-year experiment was designed using two maize hybrids: Suyu 41 (S41, single-ear hybrid) and AN 101 (A101, double-ear hybrid). The results showed that the lag of lower earshoot differentiation was not only caused by the delay of the differentiation starting time but also related to extension of the duration in spikelet differentiation (stage II) and sexual organ formation stage (stage IV). From 12 days before silking (DBS), the contents of indole-3-acetic acid (IAA), zeatin riboside (ZR)+zeatin (ZT), and gibberellic acid (GA3) in both upper and lower earshoots of the two hybrids increased dramatically and then decreased quickly. ABA slightly increased in the two hybrids and then decreased slowly in S41, while it was maintained at a high level in A101. At 8 DBS, i.e., the transition period from floret differentiation to sexual organ formation stage, not only the growth of upper-to-lower earshoot difference (ULED), but also the values for ULED of IAA, ZR+ZT and GA3 were all significantly higher in S41 than in A101. Furthermore, the upper-to-lower hormone ratios IAAU//AAL and (ZR+ZT)U/(ZR+ZT)L were also much higher in the single-ear hybrid than in the double-ear hybrid, while the GA3U/GA3L and ABAU/ABAL had no significant differences. In addition, the time course of ULEDhormone/ULEDearshoot growth rate also suggested that the hormones work in different ways in earshoot superiority/inferiority formation. The delayed differentiation of lower ear shoots was conclusively related to the later initiation of differentiation and the longer durations of specific differentiation stages. Compared with the regulating roles of IAA and ZR+ZT in the key period (8 DBS) of superiority/inferiority differentiation, GA3 seems to be affected earlier, while ABA contributes little to this process.  相似文献   
4.
 丁香假单胞菌猕猴桃致病变种生物型3(Pseudomonas syringae pv. actinidiae biovar 3,Psa3)是猕猴桃溃疡病菌的世界流行群体,但仅在中国存在复杂的遗传多样性。开发适于Psa3群体分型的MLVA(multilocus variable-number tandem-repeat analysis)技术是探索中国Psa3起源与流行学特性的基础。本研究对7个Psa3菌株进行了全基因组测序,结合已公布的86个全基因组数据,进行比较分析发现,中国Psa3至少存在7个亚群;在各亚群间存在多态性的24个串联重复序列中,其中10个可以通过琼脂糖凝胶电泳区分开且变异指数合适,据此建立了适于Psa3的MLVA技术。采用该技术对分别来自贵州和陕西的62和9个Psa3菌株进行群体分型,分型结果与全基因组分析高度一致,证明该MLVA体系分型准确。MLVA分型结果表明:贵州主产区修文县Psa3有3个MLVA群体,其中亚群4的组内分化明显,代表最早发生的群体;而亚群 1和3的结构单一,且多在新果园发现,是新传入群体。总之,本研究建立了一套可用于Psa3群体分型的MLVA技术,将有助于解析中国各猕猴桃产区Psa3群体结构,以及探索中国Psa3的起源、传播和流行学特征。  相似文献   
5.
Two cotton (Gossypium hirsutum L.) cultivars, Kemian 1 (cool temperature-tolerant) and Sumian 15 (cool temperature-sensitive) were used to study the effects of cool temperature on carbohydrates, yield, and fiber quality in cotton bolls located at different fruiting positions (FP). Cool temperatures were created using late planting and low light. The experiment was conducted in 2010 and 2011 using two planting dates (OPD, the optimized planting date, 25 April; LPD, the late planting date, 10 June) and two shading levels of crop relative light rate (CRLR, 100 and 60%). Compared with fruiting position 1 (FP1), cotton yield and yield components (fiber quality, leaf sucrose and starch content, and fiber cellulose) were all decreased on FP3 under all treatments. Compared with OPD-CRLR 100%, other treatments (OPD-CRLR 60%, LPD-CRLR 100%, and LPD-CRLR 60%) had significantly decreased lint yield at both FPs of both cultivars, but especially at FP3 and in Sumian 15; this decrease was mainly caused by a large decline in boll number. All fiber quality indices decreased under late planting and shading except fiber length at FP1 with OPD-CRLR 60%, and a greater reduction was observed at FP3 and in Sumian 15. Sucrose content of the subtending leaf and fiber increased under LPD compared to OPD, whereas it decreased under CRLR 60% compared to CRLR 100%, which led to decreased fiber cellulose content. Therefore, shading primarily decreased the “source” sucrose content in the subtending leaf whereas late planting diminished translocation of sucrose towards cotton fiber. Notably, as planting date was delayed and light was decreased, more carbohydrates were distributed to leaf and bolls at FP1 than those at FP3, resulting in higher yield and better fiber quality at FP1, and a higher proportion of bolls and carbohydrates allocated at FP3 of Kemian 1 compared to that of Sumian 15. In conclusion, cotton yield and fiber quality were reduced less at FP1 compared to those at FP3 under low temperature and low light conditions. Thus, reduced cotton yield and fiber quality loss can be minimized by selecting low temperature tolerant cultivars under both low temperature and light conditions.  相似文献   
6.
群体调控对夏玉米抗倒伏性状指标的影响   总被引:1,自引:0,他引:1  
以创玉198为试验材料,研究群体调控对夏玉米(Zea mays L.)抗倒伏性状指标的影响。结果表明,随着群体密度的增加,玉米倒伏率、株高、穗位高、穗位系数均逐渐升高;基部茎节间长增加,茎粗、茎粗系数降低;茎秆穿刺强度、单株茎秆干物重逐渐增加,茎秆抗折力先增加后降低;田间倒伏率增加,茎秆抗倒伏能力下降。得出创玉198玉米品种合理群体密度为6.00万~6.75万株/hm2,此群体结构有利于提高抗倒伏能力。  相似文献   
7.
利用自育的质核互作型不育系106A及对应的保持系106B分别作母本,用自选的优质、纯黄籽、早熟的质不育系的恢复系自9106C作轮回亲本,采用杂交、测交、回交及自交相结合的方法转育成新的优质、纯黄籽、早熟的质核互作不育系9106A及其对应的保持系9106B。9106A具有低芥酸(0.10%)、低硫甙(19.60μmol/g)、高含油量(46.42%)、纯黄籽、高配合力、早熟等优良性状,较易配制出强优势的杂交组合,具有较好的开发应用前景。  相似文献   
8.
温光互作对棉花不同空间部位纤维品质的影响   总被引:3,自引:0,他引:3  
【目的】为采取适宜栽培措施减轻花铃期不适宜温光条件对棉花纤维品质的影响提供理论依据。【方法】以温度敏感性差异较大的科棉1号(低温弱敏感型品种)和苏棉15号(低温敏感型品种)为材料,通过分期(4月25日、5月25日、6月10日)播种和花铃期遮阴(相对光照率CRLR为100%、80%、60%),形成花铃期不同的温光条件,研究温光互作(用铃期内累积辐热积PTP表示)对棉花不同空间部位纤维品质的影响。【结果】(1)铃期内日均温、日均最高温、日均最低温和光合有效辐射是造成棉纤维品质差异的主要气象因子,棉株不同空间部位各气象因子值纵向随果枝数增加、横向随果节数增加均逐渐降低。(2)纤维品质指标中马克隆值对温光互作最为敏感,其次为纤维比强度、纤维长度。(3)各空间部位棉纤维长度、比强度、马克隆值随铃期内PTP的增加均呈抛物线型变化。各空间部位各纤维品质指标理论最大值,纵向比较内围果节以中部果枝最大,下部次之,上部最小,横向外围果节的理论最大值均小于其内围果节。中部内围铃各纤维品质指标达到优质棉A级、AA级时适宜PTP范围最广。低温敏感型品种各纤维品质指标适宜PTP范围皆低于低温弱敏感型品种。(4)纤维比强度的适宜PTP范围较小,是优质棉A级的主要限制因素;马克隆值和比强度适宜PTP匹配性差,是优质棉AA级的共同限制因素。棉纤维品质在PTP 183.5—633.7 MJ·m-2(科棉1号)、229.0—589.6 MJ·m-2(苏棉15号)时达到优质棉A级,在304.7—452.9 MJ·m-2(科棉1号)、346.6—357.8 MJ·m-2(苏棉15号)时达到优质棉AA级,两年试验中除6月10日播期CRLR60%处理外其余处理均达到优质棉A级;而达到优质棉AA级的只有4月25日播期CRLR80%、CRLR60%处理和5月25日播期CRLR80%处理。【结论】棉花各纤维品质指标均有其适宜的PTP范围,纤维比强度和马克隆值是各空间部位达优质棉的限制因素,一定程度的晚播(如5月25日)与弱光有利于优质棉纤维品质的形成。  相似文献   
9.
在田间试验条件下,研究施用生物有机肥和生物炭对稻田Cd和Pb污染的钝化修复效果。研究结果表明:施用生物有机肥和生物炭处理可以提高土壤p H值以及土壤养分含量,并显著降低土壤有效态Cd和Pb的含量,且土壤p H值与土壤有效态Cd和Pb的含量呈极显著负相关;生物有机肥和生物炭处理还可以降低水稻体内Cd和Pb的含量,其中水稻糙米Cd降幅达到了22.00%和18.34%,水稻糙米Pb含量的降幅也达到了33.46%和12.31%,且水稻糙米Cd和Pb的含量与土壤有效态Cd和Pb的含量呈显著正相关。综合各处理对土壤p H值、土壤养分含量、土壤有效态Cd和Pb的含量以及水稻Cd和Pb的影响,可以看出生物有机肥和生物炭处理对于Cd和Pb污染稻田土壤有较好的修复效果。  相似文献   
10.
为筛选出50%二氯喹啉酸WP的替代药剂,选择30%氯酰草膦EC、33.6%苯吡唑草酮SC、315 g/L异噁唑草酮·噻酮磺隆SC作为替代药剂与50%二氯喹啉酸WP在同一玉米地进行田间试验。结果表明:30%氯酰草膦EC除草效果及对玉米的安全性均未达到50%二氯喹啉酸WP同等水平,不宜作为替代药剂;33.6%苯吡唑草酮SC杂草防治效果与50%二氯喹啉酸WP相当,玉米的生长情况与50%二氯喹啉酸WP差异不显著,虽可以降低二氯喹啉酸的药害风险,但考虑到用药成本和半衰期远大于50%二氯喹啉酸WP,亦不宜作为替代药剂;315 g/L异噁唑草酮·噻酮磺隆SC的除草效果优于50%二氯喹啉酸WP,且易降解,可作替代药剂用于玉米-烤烟轮作区玉米地杂草防除,可以解决二氯喹啉酸对后茬烟草的药害问题。  相似文献   
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