不同玉米品种的根系活力与产量性状关系毕业论文.doc

不同玉米品种的根系活力与产量性状关系毕业论文目 录中文摘要2关键词2Abstract2Key words21.文献综述22. 试验材料和方法32.1试验材料32.2 试验方法32.3 试验地玉米品种种植安排43 结果与分析53.1 不同玉米品种苗期植株性状的分析53.2 不同玉米品种根系活力的测定64小结与讨论84.1小结84.1.1不同玉米品种的根系活力与产量之间成正相关的关系84.1.2不同玉米品种苗期地下部根系性状与产量有一定的关系84.1.3不同玉米品种苗期地上植株性状与产量亦有一定的关系94.2 讨论9参考文献9致谢 9 附件(外文文献译文)1111. 文献综述 玉米是世界上最主要的粮饲兼用和高产作物之一，杂种优势的利用是提高玉米产量的主要手段，玉米又是世界上杂种优势利用面积最大的作物。我国从20世纪80年代开始大量研究玉米的杂种优势，主要集中在籽粒性状、生理生化研究和品质性状等地上部植株性状的研究上。根系是植物生命活动中有着重要作用的器官， 它与植物的生长和产量的形成有密切的关系，近些年来，国际上已将根系研究作为进一步提高农作物生产力的一个极具潜力的基础性科研课题，开展了一系列研究，并取得了进展，但由于根系生长的特殊性和限于根系生理研究的技术手段，有关根系活性的资料则不多。根系是作物的主要吸收器官， 根系活力是反映植株吸收功能的综合指标，是衡量根系主动吸收能力大小的重要指标之一，玉米根系对水分、养分的吸收与其地上部生理过程密切相关，但关于玉米根系活力与不同品种的产量关系方面的研究并不多见，有关玉米根系活力的研究较少，把玉米根系活力变化及根系活力与产量性状的关系进行系统的研究更少。为此， 我们对玉米的根系活力变化及其与产量性状的关系进行了初步研究， 以期为玉米高产高效栽培及玉米生理育种提供理论依据。研究方法：采用甲烯蓝法测定不同品种玉米的根系活力，田间种植比较玉米不同品种的产量性状。2. 试验材料和方法2.1 试验材料 选用当前邯郸地区生产上大面积种植的玉米品种10个，分别是西玉3号、锐步1号，中科11，先玉335，郑单958，冀农3号，浚单20，武科2号，邢抗2号和先玉128。试验设备：培养皿若干，穴盘若干，智能光照培养箱，分光光度计，移液管，烧杯，比色管，实验用沙，电子天平。药品材料： 0.0002molL(0.064gL)甲烯蓝2.2 试验方法2.2.1 玉米幼苗的培养（方法一：培养皿育苗）2010年6月23日，取10个玉米品种，每个品种筛选出大小一致的40粒种子做好标记以备用。取40套培养皿并将其清洗干净，经计算每个培养皿装125g左右已消毒的沙子使其占培养基总质量的80%另加水31.25g左右，制成培养基，每个品种用4个培养基，每个培养基里放同一玉米品种的种子10粒，将写有玉米品种名称的标签贴在培养皿外沿边缘。将制做好的培养基依次放入G2P-250B智能光照培养箱里，设定状态为：温度28摄氏度，灭菌。每天定期浇水，观察。6月26日观察并记载玉米品种的发芽势，7月1日观察并记载玉米品种的发芽率,7月2日制作植物根系活力标准曲线。2.2.2 甲烯蓝标准曲线的制作原理根据沙比宁等的理论，植物对溶质的吸收具有表面吸附的特性，并假定被吸附物质在根系表面形成一层均匀的单分子层；当根系对溶质的吸附达到饱和后，根系的活跃部分能将吸附着的物质进一步转移到细胞中去，并继续产生吸附作用。在测定根系活力时常用甲烯蓝作为吸附物质，其被吸附量可以根据吸附前后甲烯蓝浓度的改变算出，甲烯蓝浓度可用比色法测定。已知1mg甲烯蓝形成单分子层时覆盖的面积为1.1m2，据此可算出根系的总吸收面积。从吸附饱和后再吸附的甲烯蓝的量，可算出根系的活跃吸收表面积，作为根系吸收活力的指标。2.2.3 甲烯蓝标准曲线的制作 将甲烯蓝溶液配成0、1、2、4、6、8、10ugml的系列溶液，于分光光度计660nm处比色测OD值，以甲烯蓝溶液浓度为横坐标，OD值为纵坐标，绘制标准曲线。7月2日分别测10个玉米品种的苗高、叶数、茎粗、苗鲜重、根条数、主根长度、根线重、根体积以及玉米根系活力的测定即在分光光度计660nm处比色测的OD值。做好记录以备分析。2.2.4 玉米幼苗的培养（方法二：穴盘育苗）每个穴盘长为10个小格，宽为5个小格，每个穴盘分为两部分，每个品种种25株，共用5个穴盘。6月26日下午进行穴盘育苗，操作过程如下，将无土育苗基质倒入盆中约为盆体积的34左右，倒入水搅拌使其适度湿度在70%-80%左右，即手抓起一把基质可凝聚在一起但不会溢出水；将搅拌好的基质倒入穴盘中，以填平小格即好；筛选10个玉米品种种子各25粒，以粒大饱满为好；放置好一个品种后，用记号笔在带绳的小标签上写上玉米品种名称及标号，将小标签放于穴盘一侧以便于区分；依次放置各个品种；将处理好的穴盘放入实验室外空地上并浇适量水,并做好试验记录7月7日分别测不同玉米品种的苗高、叶数、茎粗、苗鲜重、根条数、主根长度、根鲜重、根体积以及玉米根系活力的测定即用分光光度计测660nm处的OD值。做好记录以备分析。2.3 试验地玉米品种种植安排2.3.1 玉米种植 播种时间为2010年6月15日播种；试验在河北工程大学试验农场玉米试验田进行，试验田为中产水平地块；不同玉米品种播种采用大田对比法，东西两边设置保护行（6行），保护行种植的玉米品种为郑单958，其他每品种种植8行，行距70cm，株距24cm，行长10m，小区面积56m2，重复3次，亩密度4000株左右。玉米生育期间的管理同一般大田。2.3.2 玉米产量与植株性状的测定 2010年9月28日在试验田测定玉米的株高、穗高、穗节数、绿叶数、 穗位节、粒数和产量性状。并将每个品种的每个重复收获的玉米果穗材料各30个带回实验室，做风干处理。2010年10月20日，将风干的不同玉米品种的果穗材料进行测量穗粒数、单穂重量和千粒重，以确定不同品种玉米的实际产量。3 结果与分析3.1 不同玉米品种苗期植株性状的分析3.1.1 玉米苗期植株性状的测定每个品种分为3组，每一组测量5株。分别测定10个玉米品种的发芽势、发芽率、苗高、单株叶数、茎粗、幼苗鲜重、单株根条数、主根长度、根鲜重和根体积等植株性状，然后求得平均值，其数值如表1所示。表1 玉米苗期植株性状的测定发芽势（%）发芽率（%）苗高（cm叶数(叶)茎粗（cm）苗鲜重（g）根条数（条）主根长度（cm）根鲜重（g/根）根体积（ml/根）浚单208597.5022.8930.3131.0709.9314.651.0081.20冀农3号8097.5022.0030.3271.0109.814.450.9761.00郑单9588095.0022.7130.3070.8719.6015.230.9730.90武科2号8097.5022.0130.3230.8438.8010.190.8300.81西玉3号8092.5020.0330.2870.8278.4010.370.8770.80中科118092.5021.7930.2860.8158.139.890.8730.80先玉3358092.5019.3530.2400.8307.679.510.7970.77锐步1号8090.0019.1230.2430.6966.538.570.6100.67邢抗2号7588.5019.7130.2470.6447.008.500.6070.62先玉1285577.5019.3730.2340.6046.537.350.5870.65 对表1中的玉米植株性状分析：比较不同玉米品种的发芽势和发芽率可以看出，郑单958、冀农3号、浚单20、武科2号等最高，其次是西玉3号、中科11、先玉335、锐步1号； 发芽势和发芽率较低的为邢抗2号和先玉128；比较玉米苗期地上部幼苗性状即苗高、茎粗、苗鲜重分析得出浚单20、冀农3号、郑单958、武科2号、西玉3号、中科11的地上部性状较好；较弱的是先玉335、锐步1号、邢抗2号、先玉128；比较不同玉米品种地下根部性状如根条数、主根长度、根鲜重和根体积可看出地下根部性状较好的是浚单20、冀农3号、郑单958；较差的是锐步1号、邢抗2号、先玉128。由上述分析可以总结，不同玉米品种在苗期（三叶期）整体性状最好的是浚单20、冀农3号、郑单958，较差的是锐步1号、邢抗2号、先玉128；其余品种如武科2号、西玉3号、中科11、先玉335的苗期整体性状处于中间水平。3.2 不同玉米品种根系活力的测定（甲烯蓝测定法）3.2.1 标准曲线的绘制根据表2，以甲烯蓝浓度为横坐标，以OD值为纵坐标，绘制根系活力标准曲线表2 甲烯蓝浓度和OD值甲烯蓝溶液浓度mgml00000.0010.0020.0040.0060.0080.010OD值00000.1250.2900.6720.9251.2621.5383.2.2 根系活力的测定在测定根系活力时常用甲烯蓝作为吸附物质，其被吸附量可以根据吸附前后甲烯蓝浓度的改变算出，甲烯蓝浓度可用比色法测定。已知1mg甲烯蓝形成单分子层时覆盖的面积为1.1m2，据此可算出根系的总吸收面积。从吸附饱和后再吸附的甲烯蓝的量，可算出根系的活跃吸收表面积，作为根系吸收活力的指标。记录如表3表3 不同玉米品种的活跃吸收面积和比表面积浚单20冀农3号郑单958武科2号西玉3号中科11先玉335锐步1号邢抗2号先玉128活跃吸收面积（%）65.763.565.755.049.749.549.035.335.034.3比表面积（m2cm-3）0.6400.6360.6330.6200.6190.6170.6180.5980.5830.580 从表3中可以看出浚单20，冀农3号，郑单958等3个品种的根系活力最高，而锐步1号，邢抗2号，先玉128的根系活力最差，其余品种在二者之间。这与不同玉米品种苗期幼苗地下根部性状中的根条数、主根长度、根鲜重、根体积等性状的表现相一致。3.2.3 不同玉米品种收获期产量性状，记录如表4表4 玉米收获期产量性状的测定穗粒数（粒）千粒重（g）穗重量（g/穗）亩穗数（穗/亩）产量（Kg/亩）浚单20521293.2152.84020614.4冀农3号561274.8154.04013618.6郑单958518295.6153.14000612.3武科2号498303.2151.04011605.7西玉3号500278.8139.44005558.5中科11515275.6141.94010569.8先玉335489268.7131.44000525.5锐步1号494252.6124.83995498.6邢抗2号503239.7120.74009483.8先玉128500243.6121.83989485.8 从表4中分析得出不同玉米品种的产量较高的是浚单20，冀农3号，郑单958，武科2号；而锐步1号，邢抗2号，先玉128的产量相对较低，其余品种如武科2号，西玉3号，中科11，先玉335的产量在10个品种属于中间水平。进一步对玉米产量的构成因素进行分析可以看出，亩穗数基本相同，决定玉米品种产量的主要因素为穗重量，影响玉米穗重量的因素是穗粒数和千粒重，所以不同玉米品种产量的高低与玉米单穗重量的高低是一致的。3.2.5 不同玉米品种收获期植株性状比较见表5表5 不同玉米品种的植株性状比较株高（cm）穗位高（cm）绿叶数（片）穗位节数（节）浚单20204.499.37.19.7冀农3号197.598.67.19.5郑单958200.295.57.09.9武科2号209.798.07.19.8西玉3号227.487.78.58.3中科11217.787.38.68.5先玉335189.287.08.08.6锐步1号198.380.95.37.9邢抗2号200.083.05.67.9先玉128201.579.06.07.3 从表5中可以看出，不同玉米品种在收获期的植株性状没有明显的规律。3.2.6 不同玉米品种的根系活力与产量关系的比较如表6表6 不同玉米品种的根系活力与产量性状之间的关系浚单20冀农3号郑单958武科2号西玉3号中科11先玉335锐步1号邢抗2号先玉128（ck）活跃吸收面积（%）65.763.565.755.049.749.549.035.335.034.3根系活力百分比（%）191.5185.1191.5160.3144.9144.3142.8102.9102.0100产量（kg/亩）614.4618.6612.3605.7558.5569.8525.5498.6483.8485.8产量百分比（%）126.5127.3126.0124.71150117.3108.2102.699.5100.0由表6中可以看出：不同玉米品种的根系活力高的其产量也高。浚单20和冀农3号的根系活力最高其产量也最高，而先玉128和邢抗2号的根系活力最低其产量也最低，其他品种的根系活力与产量之间的关系也是随根系活力的提高而产量增加。进一步对不同玉米品种根系活力和产量的百分比分析得出：玉米的根系活力越高，其玉米品种的产量越高。4 小结与讨论4.1 小结4.1.1 不同玉米品种的根系活力与产量之间成正相关的关系，不同玉米品种的产量随根系活力的提高而增加不同玉米品种的根系活力高的与产量最高的是浚单20，冀农3号；而锐步1号，邢抗2号，先玉128的根系活力较差而且产量较低；其余品种的根系活力和产量之间的关系是随根系活力的提高而产量增加；进一步对不同玉米品种根系活力和产量的百分比分析得出：玉米品种的根系活力越好，其收获期的产量越高。 4.1.2 不同玉米品种苗期地下部根系性状与产量有一定的关系比较不同玉米品种地下根部性状如根条数、主根长度、根鲜重和根体积等可看出地下根部性状较好的是浚单20、冀农3号、郑单958；较差的是锐步1号、邢抗2号、先玉128；其它品种的根部性状处于中间水平，这与玉米的产量高低趋势表现相一致。4.1.3不同玉米品种苗期地上部植株性状与产量亦有一定的关系玉米苗期地上部植株性状即苗高、茎粗、苗鲜重分析得出浚单20、冀农3号、郑单958的地上部分植株性状较好；地上部植株性状较差的是邢抗2号、先玉128，这与玉米的产量高低趋势表现基本一致。上述分析可知，不同玉米品种产量高低与玉米苗期地下地上植株性状有一定的关系；不同玉米品种产量高低与玉米根系活力呈正比关系；这在玉米育种和选育良种的过程中通过苗期玉米根系活力的测定，就可大致判断玉米产量的高低，为玉米高产高效栽培及玉米生理育种提供理论依据。4.2 讨论本试验是初步研究，只研究观察了玉米苗期根系活力及植株性状与玉米产量关系，再进一步研究时应进行玉米全生育期根系活力、植株性状与玉米产量关系的研究，以进行更加全面深度的探讨。参考文献1 宋海星等，玉米根系活力及吸收面积的空间分布变化J 西北农业学报2005，14（1）：137-1412 周广生 梅方竹 陈艳华等，冬小麦根系活力与产量性状关系的研究J 华中农业大学学报 Dec,2001,531-5343 王空军等, 我国玉米品种更替过程中根系生理特性的演进J 作物学报 Mar,2002,185-1894 常程，张书萍，刘晶等密度对不同株型玉米产量和农艺性状的影响J 辽宁农业科学，2008(2)：27295 汪君利，姚彩杰，曲金平施肥对土壤养分变化及玉米产量的影响J 现代农业科技。2007(24)：108109致谢在此论文撰写过程中，要特别感谢我的导师李彦岭老师的指导与督促，同时感谢他的谅解与包容。导师渊博的专业知识，严谨的治学态度，精益求精的工作作风，诲人不倦的高尚师德，朴实无华、平易近人的人格魅力对我影响深远。导师不仅授我以文，而且教我做人，虽历时一年，却赋予我终生受益无穷之道。本论文从选题到完成，几易其稿，每一步都是在导师的指导下完成的，倾注了导师大量的心血，在此我向我的导师李彦岭老师表示深切的谢意与祝福！本论文的完成也离不开其他各位老师、同学和朋友的关心与帮助, 求学历程是艰苦的，但又是快乐的。感谢我的班主任赵敏老师，谢谢她在这四年中为我们全班所做的一切，她不求回报，无私奉献的精神很让我感动，再次向她表示由衷的感谢。感谢各位任课老师在这四年对我的教导与帮助。在这四年的学期中结识的各位生活和学习上的挚友让我得到了人生最大的一笔财富。在此，也对他们表示衷心感谢同时还要感谢专业的同学们，在科研过程中给我以许多鼓励和帮助。回想整个论文的写作过程，虽有不易，却让我除却浮躁，经历了思考和启示，也更加深切地体会了法学的精髓和意义，因此倍感珍惜。谢谢我的父母，没有他们辛勤的付出也就没有我的今天，在这一刻，将最崇高的敬意献给你们！本文参考了大量的文献资料，在此，向各学术界的前辈们致敬！附件(外文文献译文)利用玉米种子白蛋白和球蛋白乳酸聚丙烯酰胺电泳鉴定品种宋同明 郑大浩 刘岩（北京农业大学，北京100094）摘要：采用改进的乳酸-PAGE技术对不同玉米（Zea mays）自交系和杂交种种子的白蛋白和球蛋白进行了系统电泳分析，发现此方法具有高度的分辨力和稳定性，彼此可以区分，视作它们各自的“指纹”。全籽粒电泳谱带与胚的电泳谱带基本相同。胚乳产生谱带少而弱，且大都和胚的谱带发生重叠。亲本自交系的不同谱带在杂交种F1发生互补。杂种谱带等于两亲本共同谱带与各自独有谱带之和。而且正、反交F1谱带以及它们两亲本种子提取液机械混合产生的谱带完全相同，表明谱带的差异是一种由核基因控制的遗传性状。F1的谱带类型可由两亲本谱带类型预测，也可由两亲本种子提取液混合而产生的电泳图所演示关键词 玉米； 白蛋白；球蛋白；聚丙烯酰胺；品种鉴定IDENTIFICATION OF CORN VARIETIES USING LACTATEPOLYACRYLAMIDE GEL ELECTROPHORESIS OFSEED ALBUMINS AND GLOBULINSSong Tong-ming , Zheng Da-hao and Liu Yan（Beijing Agricultural University, Beijing100094)Abstract:Systematic electrophoresis analysis of albumins and globulins of the inbred and hybrid corn ( Zea mays) seeds was carried out on an improved lactate-poly acry lamide gel electrophoresis, a method with high resolving power , good reproducibility and stability. The elect roph regram w as classified into four groups designated as , and! Respectively。 Each inbred or hybrid had its own unique band pattern distinguishable from the others, regarding as its fingerprint . T he band pat tern of the whole kernel was basically similar to that of its embryo, except t hat of the endosperm showing less bands wit h weaker staining intensity; and most of the patterns overlapped wit h t hose of the embryo. T he band number of the F1 hybrid w as exactly equivalent t o the number of t he common bands and the specific bands of t he two parent s, indicating that the difference of band patterns w as a genetic trait controlled by t he nuclear genes. T he F1 elect rophoregram could be predicted by t hose of the two parent s. T he band pattern of t he F 1 hybrids was identical with t hat produced from me chanically mixed extract of t he two parent inbreds.This procedure could be used in corn cultivar identification and as a test f or genetic purity.Key words：Corn; Albumin; Globulin; Polyacrylamide gel electrophoresis; Varietal identificationZein is the main component of corn seed proteins. It consists of a number of polypeptides of similar molecular weight but with considerable heterogeneity in bioelectric point, so electrophoresis especially isoelectric focusing ( IEF) analysis of the zein family had been extensively used f or corn cultivar identification. Different genotypes containing between 8 to 15 components has been identified from t heir zein band-patterns on the isoelectric focusing electrophoregram. The zein IEF pat tern has been regarded as a genetic marker. The IEF w as also used in mapping of genes coding for zein. However, t he zein IEF pattern does not have enough capacity in differentiating between hybrids and their female inbred parents. Certain band differences could be detected among the inbred by using SDS-PAGE procedure to analyze proteins extracted from t he seeds and seedlings, but this difference was influenced by t he buffer solution. From the comprehensive survey of irony me variability in corn inbred and hybrids using SGE to fractionate proteins from 5-day -old coleoptiles tissue and staining f or 12 is enzymes, 88 out of 113 ( 80% ) public inbred being utilized in Canadian hybrids and 146 out of 155 ( 94% ) commercial hybrids w ere distinguished by using SDS-PAGE procedures. T he heterogeneity of the album ins and goblins of corn seeds w as also used t o identify part of the corn inbred and hybrids. All of t he above-mentioned electrophoresis procedures were carried out under basic pH condition. Wang et al. first used t he gradient palmary limed eagle electrophoresis to analyses the 1 mol/ L urea ex tract able proteins of corn seeds under acid pH condition and had been highly praised f or t he possible validity of t his method f or corn seed purity testing. An acid lactate-PAGE procedure has been developed in our laboratory as a basic method of w heat cultivar electrophoresis identification. T his procedure was preliminarily proved t o be suit able for separating corn albumin and globulin fractions. The aim of t his study was to evaluate the feasibility of this procedure in distinguishing different corn genotypes, its resolving power, stability, reproducibility and t he genetic expression of parent inbred in term s of band patterns in their F1 hybrids, so as t o explore the possibility of its application on corn genetic purity testing and cultivar identification.1 MATERIALS AND METHODSSample preparationA tot al of 141 inbred and 153 hybrids of corn ( Zea mays) were studied. T he former comprised of 9 high oil inbred developed from Illinois high oil ( IHO) C80, 14 high oil inbred from Alexon high oil synthetic C23, and 6 sweet corn inbred from a commercial single cross of Rogers Seed Co. T he latter comprised of 26 hybrids w it h com on female parents but different male parent s, and 16 w it h common male but different female parents. All seed samples were provided by our own laboratory . A single corn seed w as ground w it h a sing le seed mill or soaked in tap water under 0 over-nig ht , after which t he embryo and endosperm w ere dissected with a razor blade. After naturally dried, the embryo or endosperm was g round separately. T he ground powder w as put into 2. 5mL centrifuge tube, w it h t he addition of equal-volume of ex tract ion solution( 0. 5 mol/ L NaCl, containing 15% sucrose and 0. 05% methyl green) , mixed thoroughly and extracted for 1 h at room temperature, then centrifuged at 4000 r/ min f or 5 min. The supernatants were used f or electrophoresis.Preparation of the working solutionsT he stock solution, tank buffer, separation gel and concentration gel w ere preparedaccording t o the proportion and volume in T able 1.Table 1 Recipes for stock, extraction and buffer solutionsStock solutionsMixed ratio1 .A crylamide 95 g, Bisacrylamide 3. 8 g, distilled water 500mL2. Sodium lactate2. 81mL+lacticacid to pH3. 2,H2O100mL3 Ascorbicacid0.48g,ferroussulfate(7H2O)8mg,H2O100mL4. Sodium lactate3mL+lactic acid to pH5. 6,H2O100mL5 A crylamide 26 g, bissacrylamide 5. 2 g, H2O 200mL6 A mmonium persulph at e 11. 41 g, H2O 100mL7 Distilled waterSeparation gel14ml2ml2ml8ul2mlConcertration gel1ml2ml80ulTank buffer: Glycine 4 g+ lactic acid to pH 3. 4, H2O 2000mLElectrophoresisT he vertical plate electro phoretic apparatus w as used w it h 11. 0mm10. 0mm0. 75mm gelslab. Electrophoresis w as carried out at 500 V, 30mA for 1. 5 h. The gel was stained with Coomassie Brilliant Blue R250 ( 40mL 0. 14% Coomassie Brilliant Blue R250alcohol solution dissolved in 12. 5% trichloroacetic acid 160 m L) .2 RESULTS AND DISCUSSIONResolving powerThis electrophoretic procedure showed high resolution t o album ins and globulins of corn seeds. In general, the inbreds or hybrids showed 40 bands or so, up t o over 50, among which t he clearest resolving bands might reach 35. Among all these bands, only one which was heavily stained and stable in location seemed t o be common t o all inbreds and hybrids. It s relativemigration rat e w as 0. 52 ( Fig. 1,arrow 1) . Another t w o bands also existed in most cases, w it h t heir relative migrationrates of 0. 72 and 0. 40 respectively ( Fig. 1,arrow 2 and 3) . For convenient descript ion, the w hole lot of the bands w ere classified in-to four groups, designated as ， ， and inrelation to the above-mentioned three common or nearly common bands as markers. T he band group w as fast moving with migration rates ranging from 0. 72 to 1. 0,containing 8 10 bands. All bands in t his group stained lighter w it h unclear boundary line so it w as difficult t o use them as cultivar identification markers. T he band group w as less fast moving , including bands with migration rates from 0. 52 to 0. 72. 79bands could be identified, among which 34 bands had heavier stains and clearer boundary , so t hey could be used as identification markers. T he band group was the moderate-moving region with migration rates of 0. 400. 52, containing 912 bands. All of t hem stained heavy and clear, so t his group w as t he main distinguish region for cultivar identification. 18 20 slow -moving bands with migration rates less than 0. 4 were designated as group , most of which were narrow but heavily stained and distinctive bands, showing marked difference among cultivars. Thus this group is also a major region f or cultivar identification.F ig . 1Electrophoregrams of lactate-PA G E for 11cor n inbred seeds1.Gy2 37; 2. 478; 3.Huangzao4; 4. 8112; 5.Gy798; 6. M o 17;7. Gy 246; 8. Zong 31; 9. G y 220; 10. 5003; 11. 1127Unique band pattern of corn inbreds and hybridsFig. 2 Lactate-PAGE electrophoregrams of 11 corn hybrid seeds1. G y 237478; 2. 1351127; 3. Bs 3Bs 5; 4. T 23W3-9; 5.Huangzao4 8112; 6.Dan340 478; 7.Zong 31 5003; 8. Gy220 1127; 9. Huangzao4 G y798; 10. G y 2378112; 11. Zong31Gy 2Fig .1 and Fig . 2 show t he electrophoregrams of 11 corn inbred and 11 hybrids. It show s very clearly that each inbred or hybrid has its own specific pattern in band number, staining intensit y, migration posit ion, et c. easily distinguishable from the others in ， or regions.In our studies, 135 out of 141 ( 96% ) inbreds w ere distinguished by t heir own unique band pattern or fingerprint , including even inbreds samples extracted from very close genetic background, such as IHO C80 and AlexhoC23. How ever, w e also found it difficult to distinguish some of t he recycled inbreds from individual single crosses. T he electrophoregrams of 4 inbreds and 6 hybrids harvested in three different years and two different locations revealed that the unique band pat tern of each inbred and hybrid w as completely consistent ( Figure not shown) , indicating a good stability and reproducibility of their electrophoretic profile with the lactate-PAGE procedure.Electrophoregraphic comparison ofembryo, endosperm and whole kernel of cornFig . 3Lactate-PAGE electrophoregrams for w hole kernel, embryo and endosperm of corn inbred G y237 and 8112 1. G y 237 w hole kernel; 2. G y 237 e