高粱幼叶离体培养的衍生系的耐盐筛选与性状分析

本试验在ＭＳ培养基中附加１．０％ＮａＣｌ胁迫条件下培养高粱幼叶组织，获得了２３２Ｂ衍一系Ｒ３代。经田间和实验室鉴定，Ｒ３形态性状，生育主籽粒品质都有明显变化。１．０％ＮａＣｌ水平上，Ｒ３－１１和Ｒ３－８盐害指数分别比原亲代Ｒ０下降２８．１％和１３．１％，耐盐等级分别提高２个和１个等级。     

离子注入诱发棉花过氧化物酶同功酶及农艺性状变异的研究

本文分析了氮离子注入处理棉花种子诱发Ｍ１植株第二真叶过氧化物酶同功酶（ＩＰＯ）变异的遗传表现；Ｍ＝ＩＰＯ和农艺性状变异的频率及类型，探讨了剂量效应及ＩＰＯ变异与农艺性状变异的关系。结果表明：Ｍ１ＩＰＯ变异有些是非遗传的，Ｍ２中ＩＰＯ不同酶带对氨离子注入的敏感性及最佳诱变剂量不同；氮离子注入能诱发较高频率的ＩＰＯ变异及数量性状和多个性状的同时变异，可在较轻的Ｍ１损伤下获得较高的Ｍ２农艺性状变异频率，Ｍ２ＩＰＯ和农艺性状变异频率与Ｍ１ＩＰＯ变异频率的关系可用Ｙ＝Ａ＋ＢＸ＋ＣＸ２来描述。在Ｍ２铃数和早熟性变异株中均可观察到第二真叶ＩＰＯ第８条酶带，而铃重和株高变异株中可观察到第６条酶带。     

高粱体细胞无性系后代变异与遗传

对９个高粱品系的体细胞无性系后代的变异及其遗传稳定性进行了观察。结果表明：Ｒ１再生植株常出现较大变异，但有许多变异不能遗传给后代。Ｒ２的变异频率虽然较低，但大部分变异能遗传下来，并且在Ｒ３即可表现稳定。另外，还观察到许多性状能发生可遗传的变异，但不同性状的变异频率不相同。有些植株的变异只表现在个别性状上，但也有些植株可同时出现几个性状发生变异。     

高Liang体细胞无性系后代变异与遗传

对９个高Ｌｉａｎｇ品系的体细胞无性系后代的变异及其遗传稳定性进行了观察。结果表明：Ｒ１再生植株常出现较大变异，但有许多变异不能遗传给后代。Ｒ２的变异频率虽然较低，但大部分变异能遗传下来，并且在Ｒ３即可表现稳定。另外，还观察到许多性状能发生可遗传的变异，但不同性状的变异频率不相同。有些植株的变异只表现在个别性状上，但也有些植株可同时出现几个性状发生变异。     

小麦航天诱变育种效果研究

利用返回式卫星搭载两个小麦品种（系）种子进行空间诱变处理，对SP2代农艺性状变异效果进行了分析。结果表明，两个品种（系）的农艺性状均发生了变异，但株系内变异多数为不显著。两个品种（系）的诱变率和性状的变异方向存在差异，豫农201的诱变率高于大粒1号；大粒1号变异株系的性状指标多数为增加，豫农201变异株系的性状指标多数为减少。性状间的诱变率具有差异，株高和粒重的诱变率明显高于其它性状     

陆地棉芽黄近等基因系研究

实施连续回交与自主并针对芽黄性状进行选择，将３个不同的芽黄基因分别导入５个陆地棉品种（系）。１８个性状观察值的方差分析结果表明，不同芽黄基因分１４导入同一达传背景对陆地棉农艺性状的影响存在差异。在中棉所１２近传背景中，ｖ＿（２０）使霜前花（％）下降，ｖ＿（１５）对旱熟性无不良影响，两者均对产量性状和植株形态性状产生极显著的负效应。ｖ＿（１０）、ｖ＿（２０）对鲁棉１号农艺佳状的影响明显不同，ｖ＿（１０）唯一极显著地降低了霜前花（％），而ｖ＿（２０）的不利影响涉及到产量、植株形态和早熟性状。通过芽黄近等基因系和轮回亲尤的比较发现，同一芽黄基因导入不同遗传背景对陆地棉在艺性状影响的范围和程度明显不同。在４个不同的运传背景中；ｖ＿（１０）的导入仅对鲁棉１号的早熟性产生不良影响；而对邢台６８７１的早熟性和纤维长度同时施加显著的负效应；引起８６一１遗传背景的麦克隆值增大以及霜前花比例下降；对ＰＤ９３６４的早熟、产量及植株形态性状产生显著或极显著的负效应。     

冬小麦花药愈伤组织无性系株高遗传研究

从Ｈ１花药单倍体试管苗基部，取尚未分化绿苗的胚性愈伤组织建立的体细胞无性系，获得４丛Ｒ１结实株系。从田间Ｒ２的观察中发现，Ｒ１的４株后代中有１株４个穗繁衍的８６个单株发生了变异，Ｒ２的株系变异率为２５％。经过这株变异的Ｒ２、Ｒ３的株高连续观察发现：株高变异范围均很大，并有超亲现象，Ｒ２的变异大于Ｒ３；穗系间和穗系内的变异均极显著，穗系间变异大于穗系内变异；Ｒ３有８．１４％的株系已稳定；Ｒ２和Ｒ３的     

K—19型小麦雄性不育系的创建及其育性恢复源的发现

以粘果山羊草Ａｅ．１９（Ａｅ．ｋｏｔｓｃｈｙｉ，１９）为母本，中国春和云南铁壳小麦为桥梁亲本，进行远缘杂交，获得雄性不育株。再用普通麦７８－１等为轮回亲本，与其测交并连续回交，育成了Ｋ－１９－７８－１Ａ等小麦雄性不育系。然后用５００余份普通小麦品种（系）与Ｋ－１９－７８－１Ａ进行测交，获得４６９个组合Ｆ１杂种，其中７３个测交种（占总数的１５．５７％）能完全保持Ｋ－１９型小麦的雄性不育性。其余３９６个测交种（占总数的８４．４３％）对Ｋ－１９型小麦雄性不育系表现不同程度的育性恢复。恢复度幅度为１．０％～９７．５％。３９６份材料中有１４．１４％对Ｋ－１９型不育系表现高度恢复，按国内法计算恢复度达到８０．１％～９７．５％；测交、回交后代产生单倍体频率在０～１７．５％之间，发现一批综合性状好、不产生单倍体的保持系和恢复源。     

EMS诱发大豆突变可筛选高蛋白或高脂肪含量的种质资源

应用０．８％ＥＭＳ处理冀豆１号及冀豆６号大豆湿种子，从Ｍ_２代起，累代选择籽粒蛋白质或脂肪含量高的变异株，选出高蛋白突变系３个，高脂肪突变系２个。     

春化阶段对低温不敏感小麦品系91－1

春化阶段对低温不敏感小麦品系９１－１赵凤梧，李慧敏，李洪武（河北省农林科学院旱作所，衡水市０５３０００）小麦品系９１－１是以冀麦２１为母本、津丰１号作父本杂交后，Ｆ０种子经６０Ｃｏ辐射处理选育而成。该品系春性一半各性，长相清秀，株高７８ｃｍ，穗长８．...     

Genetic Mapping of QTLs for Tissue-Culture Response in Plants

Summary Plant regeneration from cultured tissues has been shown to be under genetic control in a number of plant species. Using quantitative trait loci (QTL) mapping technology, it has become possible to estimate the number of loci controlling genetic variation and to characterize their map position in the genome. With the use of different types of mapping populations such as recombinant inbred lines (RIL), F2 or doubled haploids (DH) it was possible to detect QTLs for tissue culture response (TCR). For the evaluation of TCR numerous parameters describing induction and regeneration steps were applied. However, the lack of consistency with respect to parameters used by different researchers sometimes makes comparisons between QTL studies complicated. Another problem frequently present in works dealing with QTLs for TCR is skewed distributions of the traits used for evaluating tissue culture capability, usually interpreted as the indication of a presence of major genes. The majority of QTL analyses of TCR-traits were conducted with monocots – rice, barley and maize. The number of QTLs detected for a particular characteristic of tissue culture capability ranged from 1 to 8. The percentage of phenotypic variation explained by a single QTL varied from 2.7 to 65.4%, with the values between ca. 6 and ca. 26 % being more common. Determination of molecular markers linked to a QTL of TCR provides valuable tools for biotechnological approaches aimed at improving plant regeneration capability.     

Variation among progenies of diploid plants regenerated from haploid, microspore-derived cell-suspension protoplasts of rice (Oryza sativa L.)

Progenies of 110 diploid R₀ plants regenerated from haploid protoplasts derived from microspore callus cell suspension culture of rice (cv. Miara) were evaluated for 6 traits, along with control lines, in a replicated field trial. Complementary post-harvest observations were carried out for four panicle or grain characters. A wide range of variation was observed for all traits under study among the protoclonal lines. The mean of the protoclonal population was significantly different from that of the control for most traits and 64.5% of the lines differed from the control for at least one field-evaluated trait. A unidirectional shift towards later-maturing, taller, and lower-tillering lines was observed. Of all the lines, 39% were taller than the control by at least 10 cm, 31 % had flowering delayed by at least 5 days, and 13% exhibited significantly longer panicles (P = 0.05). As to the agronomical value of the lines, the variation resulted in a global negative drift although favourable variations were found in a few lines. All but two lines were homogeneous, suggesting that most variations existed in a homozygous form in the R₀ plants. R₂ lines grown from seeds of 17 R₁ protoclonal lines stably inherited the changes and did not segregate, thereby confirming that variations are fixed.     

草莓组培苗体细胞无性系变异研究

组培过程中变异的普遍性,显著影响植物的遗传稳定性,限制组培技术在农业生产上的应用。草莓组培苗已在农业生产中广泛应用,但变异却时有发生,严重影响其生产效益。因此,如何有效控制变异的发生是草莓及其他组培快繁技术中亟待解决的问题。笔者分析了影响组培变异的主要因素有外植体类型、基因型、培养基中激素种类和配比、继代培养的时间和次数,和内在遗传机理如染色体异常、转座子活化和基因突变等,针对这些影响因素,建议选择幼嫩的外植体、优化培养基配方、控制增殖系数和继代次数以及选择合适的光照和温度等培养条件,控制组培过程中变异的发生。同时,利用形态观察和RAPD、SSR等技术对组培苗进行检测,及时剔除变异组织或变异植株,减少变异对生产的不利影响。通过总结草莓组培中变异发生的原因和有效控制变异的途径,为包括草莓在内的植物脱毒组培快繁技术的健康发展提供参考,同时,对变异的深入认识,为植物品种改良和新品种的选育提供了新思路。     

小麦（Triticum aestivum L.）品种的组培特性和转基因受体选择

本研究分析了西南地区地方品种资源的几个组培特性的变异及优良转基因受体小麦品系选育的可能性。研究指出,小麦幼穗的脱分化能力和愈伤组织再分化能力具有基因型间的广泛变异,农家品种和育成品种中的变异趋势一致。在不同的品种中,半愈期和成愈率分别分布在6～28 d以上和15.85%～100%,半愈期呈现了连续的分布,并在12 d     

Somaclonal variation in Lotus corniculatus L. in relation to plant breeding purposes

Summary Seventy-two plants regenerated from leaf-derived calli of a single plant of Lotus corniculatus have been evaluated for several morphological and agronomical traits. The analysis of selfed and polycross progenies of the regenerants indicates that the variation among regenerants was, at least in part, of genetic origin. Most of the mutations induced by tissue culture were recessive and were detected only after sexual propagation. Although in vitro culture had a depressive effect for most of the traits, the selfed progenies of 2 regenerants displayed higher values for leaflet width and seed yield than the selfed progeny of the initial plant. However the somaclonal variation did not increase the variation for any trait with respect to the variation of the donor cultivar of the initial plant.     

Somaclonal variation of regenerated plants in chili pepper (Capsicum annuum L.)

The morphological and genetic variations in somaclones of chili pepper (Capsicumannuum L.) derived from tissue culture were evaluated. Cotyledonary node explants of cultivars, Shishitou and Takanotsume, were cultured on Murashige and Skoog (MS) medium supplemented with benzyladenine (BA)5 mg/l for shoots regeneration and regenerated shoots were rooted on MS medium supplemented with naphthalene acetic acid(NAA) 0.1 mg/l and indol-3-butyric acid(IBA) 0.05 mg/l. The regenerated plants(R₀) were selfed to obtain seeds for next generation (R₁ lines). Qualitative characters were studied in R₀generation and both qualitative and quantitative characters were studied in R₁ generation. In R₀ generation, variations were noticed in plant growth habit, stem color, flower color and color of unripe fruits, and expression of anthocyanin in unripe fruits. Comparison among the R₁ lines and their parents were made for morphological and agronomic characters. Significant variation among R₁ lines and differences between R₁ lines and their parents were observed. Genetic variations among three somaclones were revealed by random amplified polymorphic DNA (RAPD) analysis. Variation, such as early flowering and increase of yield components, is an indication of the response to selection for any specific character. Occurrence of productive variants among somaclones of established cultivars, like Shishitou and Takanotsume, indicates the possibility of their improvement through somaclonal variation. This revised version was published online in July 2006 with corrections to the Cover Date.     

Evaluation of Somaclonal and Mutagen Induced Variation in Fingermillet

The effects of gamma rays and EMS on plant regeneration and somaclonal variation in fingermillet were studied. While EMS had an inhibitory effect on plant regeneration, gamma irradiation in low doses (5 Gy) was stimulatory. A wide range of variation was observed for almost all the traits and it was similar in both mutagen treated and untreated regenerants and seeds. This indicates that tissue culture itself induces variation and it can be exploited to advantage for crop improvement.     

Variation in Doubled Haploid Plants of Wheat Obtained through Wheat (Triticum aestivum) × Maize (Zea mays) Crosses

Variation was investigated in 110 doubled haploid (DH) lines of wheat derived from wheat × maize crosses. Field observation revealed visible variations in 15 DH2 lines such as extreme dwarfism, low seed fertility, alteration of spike type and stripes. Six agronomic traits, i.e., heading date, spike number/ plant, culm length, spike length, seed fertility and grain weight were statistically analyzed in the DH2 and DH3 generations. Out of the 88 DH2 lines/DH3 groups, 26 %/64 % showed significant differences from the parental variety in the means of one or more traits. Ranges of the DH3 lines were larger than those of the DH2 lines, except for spike number/plant. Furthermore, analyses of variance within and between DH lines showed the presence of heterogeneity/heterozygosity in the DH2 lines/plants. These results indicated the occurrence of gametoclonal variation in the DH lines. It is considered that most of the variations detected were due to the colchicine treatment rather than to the 2,4-D treatment or in vitro culture.     

Quantitative trait loci for early maturity and their potential in breeding for earliness in Brassica juncea

A doubled haploid population of Brassica juncea, developed from a cross between two parental lines differing for days to maturity, was used to study the efficiency of indirect selection for a primary trait through selection of secondary trait(s) over direct selection for the primary trait when quantitative trait loci information is available for both primary and secondary traits, and applied. Days to maturity was considered as primary trait, while days to first flowering, days to end of flowering, flowering period and plant height were considered as secondary traits. An RFLP linkage map was employed for QTL analysis of maturity and maturity-determinant traits, and a stable QTL B6 simultaneously affecting these two types of traits was identified. This linked QTL explained 11.7% phenotypic variation for days to maturity, 20.7% variation for days to first flowering, 24.3% variation for days to end of flowering and 14.4% variation for plant height. Phenotypic evaluation of maturity and/or maturity-determinant traits, viz. days to first flowering, days to end of flowering and plant height revealed that limited genetic advance for early maturity can be achieved through phenotypic selection of the primary and/or the secondary trait(s). However, the estimates of genetic advance for early maturity based on combined phenotypic evaluation and linked QTL data was found to be, at least, three times higher compared to genetic advance based on phenotypic evaluation only, demonstrating the potential of marker-assisted selection in breeding for early maturity in B. juncea.