糯玉米杂交种孤雌生殖后代的形态和细胞学研究

以不同浓度DMSO（二甲基亚砜）诱导得到的糯玉米杂交种孤雌生殖Pa1代和Pa2代为材料,研究糯玉米孤雌生殖后代的植株形态变化、细胞学行为变化和染色体数目的变异。研究结果表明,Pa1代的植株在表现型上基本整齐一致,但植株呈现退化。DMSO诱导玉米孤雌生殖除获得纯合二倍体植株外,还获得了部分的混倍体,细胞染色体有丝分裂细胞学行为也相对有较大的变异。Pa2代根尖体细胞染色体数目及有丝分裂细胞学行为变异均小于Pa1代。     

利用药剂诱导玉米孤雌生殖Pa1代植株的倍性变异

为研究药物诱导玉米孤雌生殖植株的倍性变异，用2%DMSO 40mg/kgMH诱导掖单13号等材料获得结实。实验结果表明，孤雌生殖根尖体细胞以二倍体细胞最多，其次为非整倍体细胞，其它异倍体和单倍体细胞极少。Pa1植株可分为二倍体和混倍体两类，以二倍体占绝对多数的混倍体植株最多。讨论了体细胞染色体变异的来源问题。     

花生属种间杂种F1的雄配子发生与发育特点研究

本研究以铁矾－苏木精法和改良卡宝品红染色法对载野杂交组合父本Arachis cardenasii（二倍体）、母本铁岭四粒红（四倍体）及杂种F1根尖细胞染色体进行观察，F1为2n＝30。利用醋酸洋红压片法对野生种A.cardenasii花粉母细胞减数分裂及小孢子发育各个时期进行了观察。杂种F1的花粉母细胞减数分裂及小孢子发育与四倍体栽培种花生相比表现出一些特殊的细胞学特点：F1花粉母细胞联会复杂，染色体构型平均值为2n＝9.5Ⅰ＋6.7Ⅱ 1.8Ⅲ 0.4Ⅳ；大发细胞以15：15方式分离。存在染色单体分离提前现象；细胞核发生异型分裂，并形成了在体积上显著小于正常子细胞的小细胞，从而导致形成五分体和六分体；绝大多数小孢子的败育发生在单核居中期至单核靠边;F1 花粉萌发率低，花粉发育不正常。另外F1的部分花粉具有6个萌发孔，特别是以秋水仙素处理恢复育性的F1花粉均具有6个萌发孔。     

丹参三倍体育性的细胞学分析

由丹参四倍体和二倍体杂交获得丹参三倍体,三倍体植株高度不育。为探讨其育性的细胞学机制,我们采用细胞学和解剖学的方法,对其花粉母细胞发育过程中的染色体和细胞学表现进行了观测。结果表明,丹参三倍体植株生长正常,在花粉母细胞减数分裂过程中存在落后染色体、染色体不均等分向两极、染色体桥等异常现象,分裂结果产生三分体、微核等,而且花粉粒形态异常,产生畸变,萌发率极低。这些说明,丹参三倍体在生长发育过程中,由于减数分裂过程中染色体数目不平衡,在减数分裂过程中产生各种畸变、异常的染色体和细胞的行为表现,是造成其不育的主要原因。本研究为丹参三倍体育性研究提供理论依据,也为丹参育种生产实践提供指导。     

大麦（Hordeum vulgareL.）花药培养再生植株染色体的遗传分析和酯酶同工酶

通过观察８２株大麦花药培养再生植株根实细胞有丝分裂和５６株花粉母细胞（ＰＭＣ）减数分裂过程中染色体的结构和分离情况，结果表明，单倍体和二倍体植株各为１７．１％和３５．４％，混倍体植株４７．５％，在混倍体植株中，有二倍体，三倍体，四倍体甚至六倍体细胞和一些非整倍体细胞，但仍以单倍体，二倍体和四倍体细胞为主，根尖细胞有线分裂过程中有染色体结构的变异，如染色体断片，环状染色体等，二倍体ＰＭＣ减数分裂过程     

棉花制片技术中的一种染色法

70年代初,我们结合棉花远缘杂交育种工作,对杂种后代进行了细胞学研究。在花粉母细胞或根尖细胞压片中曾用过醋酸洋红、地衣红、醋酸大丽紫和卡宝品红等染色剂染色。李正理等在1978年《植物杂志》第     

二倍体糖甜菜花粉母细胞减数分裂的观察与分析

糖甜菜花粉母细胞减数分裂的研究开始于本世纪廿年代,然而,由于甜菜花器和染色体非常小及其减数分裂行为较为复杂,使这方面的研究进展缓慢。随着细胞学技术的飞速发展,糖甜菜花粉母细胞减数分裂的研究与应用的报导越来越多。Levan(1945)首次描述了二倍体和单倍体糖甜菜的粗线期;Walia(1971)报导了二、四倍体种和部分野生种的减数分裂前期特征;De Jang(1979)用Giemoa法分析了二倍体减数分裂异染色质的分布问题;Yu(1977)Nakamura(1982)分别报导了二倍体粗线     

马铃薯胚囊母细胞减数分裂与胚囊形成的研究

<正> 利用能产生较高频率2n配子的二倍体与四倍体杂交是实生种子利用与选育优良品种的重要方法之一。我们在用压片法研究了马铃薯花粉母细胞减数分裂及2n花粉形成机制…。的基础上,用压片法进行了马铃薯胚囊母细胞减数分裂的研究,目的在于了解     

一个新疆杂草黑麦居群的细胞学分析

新疆杂草黑麦(Secale cereale subsp.segetale Zhuk.)是我国发现的一种稀有野生黑麦资源,具有极强的抗病、抗逆性和优异的丰产性状。为系统了解该特殊种质资源的生物学特征,并为这一珍贵种质资源应用于远缘杂交育种、牧草种质开发及其生物多样性保护提供基础的细胞学依据,选取新疆杂草黑麦的一个居群89R38,观察分析其花粉母细胞的减数分裂行为规律及其根尖细胞的核型特点。结果表明,89R38的绝大多数花粉母细胞减数分裂中染色体的行为正常,在终变期同源染色体配对可形成7个二价体,而在少数花粉母细胞减数分裂中(2.06%)观察到落后染色体、染色体桥等异常行为;成熟花粉粒的醋酸洋红染色反应检测其花粉粒的育性为99.08%;核型公式为2n=2x=14=12m+2sm,核型为1A型。     

大麦(Hordeum vulgare L.)花药培养再生植株染色体的遗传分析和酯酶同工酶的研究

通过观察82株大麦花药培养再生植株根尖细胞有丝分裂和56株花粉母细胞（PMC）减数分裂过程中染色体的结构和分离情况。结果表明，单倍体和二倍体植株各为17．1％和35．4％，混倍体植株47．5％，在混倍体植株中，有二倍体、三倍体、四倍体甚至六倍体细胞和一些非整倍体细胞，但仍以单倍体、二倍体和四倍体细胞为主。根尖细胞有丝分裂过程中有染色体结构的变异，如染色体断片，环状染色体等。二倍体PMC减数分裂过程中染色体分离有异常现象，如染色体“桥”，但绝大多数能正常完成。而单倍体和四倍体不能正常完成，单倍体染色体分离以2：5或3：4为主，并在中后期Ⅰ看到染色单体分离现象，四倍体细胞染色体有多种联会形式。酯酶同工酶（EST）聚丙烯酰胺凝胶电泳（PAGE）结果表明，利用Estl座位不同等位基因的分离规律可检出再生植株中的纯合体与非纯合体。不同的二倍体花粉植株在性状上出现明显的分离现象，观察到二类性状有显著差异的植株，Ⅰ类和Ⅱ类，Ⅰ类占6．6％，Ⅱ类占93．4。     

马铃薯体细胞杂种主要形态性状和农艺性状鉴定

试验对来自马铃薯栽培种Solanum tuberosum与野生种S.chacoense原生质体融合产生的131个株系进行了形态学观察。结果表明,与亲本相比,大多数体细胞杂种的生长势较亲本弱,所有杂种的株高均小于融合亲本;匍匐茎长度均小于双亲平均数,其中小于栽培种亲本的体细胞杂种占42.1%;大多数体细胞杂种的叶片呈卵园形,叶形指数小于双亲。65%的体细胞杂种叶片有不同程度的褶皱现象。杂种群体的株高分离呈正态分布,匍匐茎长度的分离呈偏态分布。     

Breeding Potential of Potato Somatic Hybrids: Evaluations for Adaptability,Tuber Traits,Late Blight Resistance,Keeping Quality and Backcross (BC<Subscript>1</Subscript>) Progenies

Ten tetraploid interspecific potato somatic hybrids developed earlier through protoplast fusion between the dihaploid Solanum tuberosum L. ‘C-13’ and the diploid wild species Solanum pinnatisectum Dun. were used in this study. Somatic hybrids and standard control cultivars were evaluated for adaptability, tuber traits, late blight resistance and keeping quality attributes (dormancy, sprouting, weight loss and appearance after 75 days of storage) during two successive winter crop seasons (short-days) in the sub-tropical plains of India, where nearly 90% of India’s potatoes are grown. Somatic hybrids showed medium to good plant vigour and late to very late plant maturity. Though none of the somatic hybrids produced equal or higher tuber yield than the control cultivars, except clone P7, all other somatic hybrids produced significantly higher marketable and total tuber yield after a 90-day growth than the parent C-13. Most of the somatic hybrids possessed higher tuber dry matter concentration, resistance to late blight and better keeping quality attributes than the control cultivars. Notably, the tubers of somatic hybrids showed a tendency for colour change from white to purple on exposure to sunlight. Breeding potential of somatic hybrids was further assessed by crossing them with commonly grown local potato cultivars for the development of backcross (BC₁) progenies. In the hybridization programme, berries were formed while somatic hybrids were used either as male or female parents with common cultivars. Our results revealed that the use of bulk pollen of somatic hybrids not only resulted in higher pollination success but also helped to achieve higher numbers of true potato seeds (TPS) per berry. Despite the formation of berries, TPS was absent in 22 crosses using somatic hybrids as a female or male parent which may be due to ovule or embryo abortions. Segregating BC₁ generations were evaluated under the same sub-tropical conditions for further exploitation in potato breeding. Based on our study, the somatic hybrids P4, P8 and P10 can be utilized for the introgression of important characters such as high tuber dry matter concontration, resistance to late blight and excellent keeping quality attributes into the cultivated potato via conventional breeding methods for cultivar development in the sub-tropical plains of India.     

Interspecific somatic hybridization betweenSolanum tuberosum L. andS. bulbocastanum dun. as a means of transferring nematode resistance

Interspecific somatic hybrids were produced between tetraploidSolanum tuberosum and a nematode-resistant accession of the diploid speciesSolanum bulbocastanum by protoplast fusion. Hybrid cells were selected using dual fluorescent labeling of protoplast preparations prior to fusion. Hybridity of regenerated plants was confirmed with a combination of morphological assessment, chromosome counting and isozyme analysis. Somatic hybrids had the same level of resistance to infection by race 1 of the nematodeMeloidogyne chitwoodi as theS. bulbocastanum parent used in the fusion. Some of the somatic hybrids were fertile as females when crossed with tetraploidS. tuberosum breeding lines. Thus, these hybrids can be used in a potato improvement program to incorporate a valuable pest resistance     

马铃薯种间体细胞杂种植株的细胞学观察和过氧化物同工酶谱分析

对马铃薯双单倍体品系81－15（2n＝2x－24）和南美二倍体栽培种Solanumphureja（2n＝2x＝24）体细胞融合获得的15个林系、81－15和二倍体野生种S．chacoense（2n＝2x＝24）体细胞融合获得的10个株系进行了细胞学鉴定和过氧化物同工酶谱分析。结果表明,杂种植株除一个株系为非整倍体外（染色体数为37）,其余株系均为四倍体（2n＝2x＝48）,是两个亲本的染色体数之和。与二倍体的双亲相比,杂种植株的叶下表皮气孔保卫细胞内叶绿体数目较多,但单位面积气孔数目较少,明显地表现出了四倍体的特征。杂种植株的过氧化物同工酶谱是其双亲酶谱谱带的总和。     

分蘖筛选技术在稻工程苗抗褐飞虱特性评价中的应用

分蘖筛选技术在稻工程苗抗褐飞虱特性评价中的应用傅强，陈伟，张志涛（中国水稻研究所，杭州３１０００６）关键词：褐飞虱；抗虫性鉴定；工程苗ＥｖａｌｕａｔｉｏｎｆｏｒＲｅｓｉｓｔａｎｃｅｏｆｔｈｅＩｎｔｅｒｓｐｅｃｉｆｉｃＳｏｍａｔｉｃＲｉｃｅＨｙｂｒｉｄ...     

Production and characterization of “second generation” somatic hybrids derived from protoplast fusion between interspecific somatohaploid and dihaploidSolanum tuberosum L.

Protoplasts were fused to produce somatic hybrids between a triploid (2n=3x=32-34) interspecific somatohaploid betweenSolanum brevidens Phil. andS. tuberosum L., and a dihaploid (2n=2x=24) anther-derived line ofS. tuberosum cv. Van Gogh. A total of 265 plants were regenerated from protoplast fusion derived calli and their hybridity was verified using fusion partner specific RAPD markers. These “second generation” somatic hybrids were aneuploid pentaploids (2n=5x=51-65) with a 2C DNA content ranging from 3.36 to 4.43 pg, which corresponded to the sum of the 2C values of each of the fusion partners (somatohaploid: 2.22 pg; and the dihaploid line of cv. Van Gogh: 1.87 pg). Most of the “second generation” somatic hybrids were vigorous, but variable in morphology. They were extremely resistant to PLRV and they had tolerance to PVY infection derived from the somatohaploid fusion partner. Even though most of the “second generation” hybrids tuberized, the tuber morphology was variable and most were poorly shaped. InErwinia soft rot resistance tests, the tubers showed higher level of resistance than the tetraploidS. tuberosum cultivars, the dihaploidS. tuberosum fusion partners and the hexaploid somatic hybrids betweenS. brevidens andS. tuberosum. The “second generation” somatic hybrids were all male sterile and failed to produce berries or seeds.     

锦葵科悬铃花的核型分析

利用根尖压片法对悬铃花进行核型分析。结果表明：悬铃花体细胞的染色体数为2n＝28, 相对长度系数组成为：2L＋10M2＋8M1＋6S,核型不对称系数为：59.95%;其核型公式为：20m＋8sm,属2B核型。为今后锦葵科悬铃花属植物核型分析研究提供一定的借鉴和依据。     

Transfer of PLRV resistance fromSolanum verrucosum Schlechdt to potato (S. tuberosum L.) by protoplast electrofusion

Summary Somatic fusions between an accession of the diploid wild speciesSolanum verrucosum and a dihaploid S.tuberosum genotype were produced in order to incorporate resistance to potato leafroll virus (PLRV). In total 15 somatic hybrids out of 16 regenerants were obtained. Identification of hybrids was based on additive RAPD patterns, general morphological characteristics, chromosome numbers and chloroplast counts in stomata guard cells. A field trial was performed with the hybrids, their two parents and the control cultivar Kennebec to assess field performance and phenotypic variability. Yield parameters varied considerably among somatic hybrids. Some of the hybrids gave significantly higher yields, tuber numbers and tuber weights than both parents. Pollen fertility of hybrids ranged from 19 to 77%. Twelve hybrids were found to be resistant to PLRV.     

Erwinia resistance in backcross progenies ofSolanum tuberosum x S. tarijense andS. tuberosum (+) S. commersonii hybrids

Summary The resistance to tuber soft rot caused byErwinia carotovora ofSolanum tuberosum x S. tarijense andS. tuberosum (+) S. commersonii hybrids and their backcrosses is reported. A number of resistant diploid sexual hybrids and tetraploid/hexaploid somatic hybrids were selected. Backcross progenies were obtained through 2x×4x crosses involving a resistant diploid hybrid and tetraploidS. tuberosum, and through 4x×4x crosses between a resistant somatic hybrid andS. tuberosum. The hybrids showed high variability interms of resistance to tuber soft rot. The resistance of progeny from 2x×4x backcrosses was similar to that of the parental sexual hybrid. By contrast, the resistance of genotypes deriving from 4x×4x backcrosses was reduced compared with the resistant somatic hybrid. In general, tuber characteristics of the backcross hybrids improved considerably as compared with their parents, and tuber yield per plant was good.