洋葱细胞质雄性不育系及保持系小孢子发生的细胞学观察

为揭示洋葱细胞质雄性不育系小孢子的败育时期,利用石蜡切片技术对洋葱细胞质雄性不育系8A及其保持系8B的小孢子发育过程进行观察和比较。结果表明：石蜡切片洋葱细胞质雄性不育系8A和保持系8B造孢组织时期小孢子的生长发育没有明显的差异;洋葱不育系8A花药绒毡层在花粉母细胞时期就与中层完全分离,并逐渐膨大挤压花粉母细胞,最后逐渐降解。其降解后的残余物侵入药室,与小孢子混合粘连在一起,占据药室的一部分空间,并且不能供给小孢子生长发育所需要的营养物质,最终小孢子降解,花药败育。试验明确了洋葱细胞质雄性不育系8A的小孢子败育时期为花粉母细胞时期。因此,在洋葱雄性不育系8A的不育机理研究中,应重点在花粉母细胞时期进行深入研究。     

Limitations of PCR‐based molecular markers to identify male‐sterile and maintainer plants from Indian onion (Allium cepa L.) populations

The main aim of this study was to validate PCR markers for determining cytoplasm and genotypes at the Ms locus in short‐day onion. Three cytoplasmic (OSN, MKFR and accD) and four nuclear (OPT, jnurf13, AcSKP1 and AcPMS1) markers were employed. Sel. 121‐1 had 100% S cytoplasm, whereas Sel. 121‐2, ‘Pusa Red’ and ‘Pusa Madhavi’ had 88%, 33% and 17% S cytoplasm, respectively. ‘Early Grano’ and ‘Pusa Riddhi’ did not possess S cytoplasm. Observations in 33 commercial varieties revealed two with sterile (S) cytoplasm. Nuclear markers were not found in linkage disequilibrium with the Ms locus, and the constitution of Ms alleles by OPT was different from other three markers, which were in conformity with each other. The other three markers predicted that most of the plants should be homozygous recessive. Anther colour also did not confirm the sterility status. It can be concluded that accD may be used for cytoplasm determination based on the ease of its use. For the Ms locus tagging, more markers are needed to be evaluated to isolate maintainer lines from open‐pollinated populations.     

Identification of male sterility maintainer lines for Ogura radish (Raphanus sativus L.)

‘Ogura radish’, a cytoplasmic genetic male sterile line, was crossed with four local and three Japanese cultivars to identify maintainer lines. Out of seven F₁ families, one cross involving a local cultivar, Aushi, produced 100% male sterile (MS) progeny. The crosses involving the other two local cultivars, Tangail Local and Kuni, produced about 90% MS progeny, indicating the presence of maintainer gene(s) for male sterility. The fourth local cultivar, Tasaki, produced 100% male fertile (MF) progeny. All three exotic cultivars appeared to possess the chromosomal gene(s) for controlling the male sterility. In BC₁, BC₂ and BC₃ generations, segregation of MS plants were more frequent when ‘Aushi’ was used as recurrent parent. The expression of male sterility was not affected by seasonal influences. Thus the local cultivar ‘Aushi’ may be used as maintainer line for ‘Ogura radish’. To produce hybrid seed, ‘Tasaki’ can be used as pollinator line as it exhibit high heterosis with ‘Aushi’. This revised version was published online in July 2006 with corrections to the Cover Date.     

洋葱雄性不育恢复位点Ms座位的SSR标记开发及其应用

本研究旨在开发稳定可靠的洋葱育性位点分子标记,并将其应用于育种实践,筛选育种系,从而缩短育种周期,节省育种成本,加速洋葱杂交种的培育进程。以洋葱育性恢复Ms座位的AFLP序列为基础,采用序列比对分析、PCR检测和表型分析等方法,开发、鉴定、应用了WH-SSR-1分子标记。结果表明:WH-SSR-1标记与Ms位点紧密连锁,Ms位点基因型为纯合显性MsMs时,有1条102 bp的扩增带;纯合隐性msms时,有1条99 bp的扩增带;杂合Msms时,有102 bp和99 bp两条扩增带。32份洋葱材料的验证结果证实了Ms座位的标记类型与基因型完全相符。随后从4个OP群体中直接获得了2个配套的不育系与保持系,‘吊玉’和‘天正红玉’因未检测到保持株或不育株,无法简单实现配套。WH-SSR-1标记与Ms位点紧密连锁,能够将其用于育种系筛选的育种实践,从OP群体中直接选择保持株和不育株,同时实现两系配套。     

Spontaneous and induced chromosome doubling in gynogenic lines of onion (Allium cepa L.)

The presence of 2,4-dichlorophenoxyacetic acid (2,4-D) or naphthaleneacetic acid (NAA) and 6-benzyladenine (6—BA) in the medium is required to induce an acceptable yield of gynogenic embryos from unfertilized ovary and flower cultures in onion. Four different exposure times of ovary and flower cultures to exogenous growth regulators (15, 30, and 45 days, and the entire culture period) were assayed. The objective was to ascertain the effect of these substances and of their period of application on the formation of gynogenic embryos and on the yield of haploids. An exposure of 15 days was sufficient for ovaries and flowers to be stimulated towards the gynogenic response, whereas, for the remaining period of 30—80 days, the pro-embryos could easily grow on a growth-regulator-free medium. In the gynogenic material obtained, phenotypic differences were visible between genetically independent lines but not between plants within each line, even when they had a different ploidy level (n or 2n). Almost all lines obtained by gynogenesis were sterile. Only a small percentage (1%) became fertile through spontaneous chromosome doubling, and these produced 2—20 seeds each, giving normal plants. The recovery of fertility occurred more often during the generations of bulbils. To exploit this natural propensity towards diploidization in this phase, different amounts and numbers of applications of colchicine were evaluated in two experiments. The treatments corresponding to 10 and 100 mg/1 of colchicine applied for 24h gave the highest number of diploid cells in root tips but no diploidization occurred in the shoot apices. Three days of colchicine treatment at 10 mg/1 produced 46% of plants completely diploid in the shoot apex. The flower fertility of these doubled haploid plants is being evaluated.     

两份玉米CMS-C恢复系的育性恢复力测定及恢复基因的分子标记定位

为了发掘更多玉米C型不育胞质的强恢复系资源,本研究对2份自交系Z16和7250-14-1进行了恢复能力的测定、恢复基因的遗传分析及恢复基因的分子标记定位。结果表明, Z16和7250-14-1对C黄早四、C478、C698-3和CMo17均表现为育性恢复,而对C48-2则均表现为育性部分恢复。通过对玉米CMS-C不同亚组胞质测交鉴定发现, Z16对G48-2、EC48-2、ES48-2、RB48-2及类48-2均表现为不育性保持,而7250-14-1对G48-2、EC48-2、ES48-2表现为育性部分恢复,对RB48-2和类48-2则表现为不育性保持。Z16和7250-14-1对CMS-T不育系均表现为不育性保持,而对CMS-S不育系则均表现为育性部分恢复。遗传分析显示, Z16对C478和C黄早四的育性恢复均受1对基因控制;而7250-14-1对C黄早四及C478的育性恢复分别受1对基因及2对基因控制。利用(C黄早四×Z16)F2、(C黄早四×7250-14-1)F2群体分别对恢复基因进行分子标记定位,其中Z16的恢复基因被定位于标记B-1至第8染色体短臂末端区域,物理距离为494 kb; 7250-14-1的恢复基因被定位于第8染色体短臂的标记B-1和Chr8-86080之间,物理距离为249kb。该研究不仅为玉米CMS-C三系配套的生产利用提供了恢复基因资源,也为玉米CMS-C恢复基因的克隆及恢复机制的研究奠定了一定基础。     

Identification and Inheritance of Fertility Restorer Genes for 'tour' CMS in Rapeseed (Brassica napus L.)

Eighteen genotypes of Brassica napus were crossed to a cytoplasmic male sterile (CMS) line of B. napus BO 15 carrying B. tournefortii cytoplasm (‘tour’ cytoplasm). Fourteen genotypes were found to be stable maintainers of the ‘tour’ CMS. Of the remaining four genotypes, GSL-1 and ‘Asahi-natane’ were found to be heterozygous and ‘Mangun’ and ‘Yudal’ were homozygous for the restorer gene. Analysis of the F₁ and F₂ progenies of (CMS) BO 15 בMangun’ and (CMS) BO 15 בYudal’ showed that fertility restoration is controlled by a single dominant gene. The availability of a number of stable maintainer lines and the simple inheritance pattern of fertility restorer gene makes ‘tour’ CMS a useful system for hybrid seed production in rapeseed.     

Genetic Control of Temperature-Sensitivity of Cytoplasmic Male Sterility (cms) in Chives (Allium schoenoprasum L.)

In earlier experiments with chives (Allium schoenoprasum L.) temperature-sensitive and temperature-insensitive cms plants could be selected. To obtain information about the site and nature of the genetic factor(s) responsible for the temperature sensitivity of the cms, temperature-insensitive and temperauire-sensitive cms plants were crossed with maintainers as well as with one another. In the progenies each genotype was cloned into two clone members, and these were examined concerning their male sterility under normal (20 °C/14 °C, day/night) as well as under constantly high temperatures (24 °C/ 24 °C). The results indicate that the temperature-sensitivity of the cms is controlled by a dominant nuclear gene “T”. This acts like a restorer gene at high temperatures and is ineffective at normal temperatures. Accordingly, important conclusions can be drawn with regard to the selection of temperature-insensitive cms-lines as well as to the propagation of the cmi-lines. The results are discussed in connection with the mitochondrial polypeptides probably responsible for the formation of the cms.     

Genetic Control of Tetracycline Sensitivity of Cytoplasmic Male Sterility (cms) in Chives (Allium schoenoprasum L.)

The expression of cms in chives is controlled by a cytoplasmic factor (5), a restorer gene X/x (Tatlioglu 1982) and a temperature gene T/t (Tatlioglu 1987). In recent investigations (Tatlioglu 1986) it could be shown that tetracycline also influences the expression of 0731. To obtain information about the genetic control of tetracycline sensitivity of cms, tetracycline-sensitive and tetracycline-insensitive cms plants were crossed with each other as well as with maintainers and the reaction of their progeny to tetracycline base was investigated. The results indicated that the promotion of fertility due to high-temperature conditions (24°C/24 °C, day/night) and tetracycline · base are independent of each other. The results of crosses can be explained by a nuclear gene, A/a, causing the tetracycline sensitivity when recessive. By using different genotypes of the three loci for restoration, temperature and tetracycline sensitivity highly advantageous material can be constructed for the investigation of the interaction between the nuclear and the mitochondrial genome in higher plants, for the molecular and functional basis of cms and for its use in plant breeding.     

The genetic relatedness analysis of male sterile and their maintainer lines of onion (Allium cepa L.) by using RAPD primers

RAPD markers analysis was performed to investigate genetic relatedness among nine sterile (A), maintainer lines (B), and male parents (C) of onion. Initially, 180 arbitrary decamer primers were screened; of these 20 primers were selected which yielded 812 bands, 45.34% of which were found to be polymorphic. Squared-Euclidean Distance matrix revealed a minimum genetic distance between the genotypes MS 48A and MF 65C and a maximum genetic distance between the genotypes MLT 84C and MF 65B. Cluster analysis grouped the nine onion genotypes into two major clusters. The first cluster consisted of two male sterile groups, i.e. MS-65 (Arka Lalima) and MS-48 (Arka Kirthiman) of single bulb onions. The second cluster consists of MLT (Multiplier) group. PCA re-confirmed the results of the dendrogram, revealing the precision in estimation of genetic relatedness among the genotypes tested. None of the primers produced unique banding patterns to distinguish all nine genotypes. This information about genetic relatedness among the nine genotypes would be better utilized in further onion breeding programs.     

Influence of Tetracycline on the Expression of Cytoplasmic Male Sterility (cms) in Chives (Allium schoenoprasum L.)

To influence the expression of cytoplasmic male sterility (cms), different clone members of male sterile genotypes of chives were treated with different chemicals, especially antibiotics which are known to act as protein synthesis inhibitors. A remarkable number of male sterile plants turned to partial or full male fertility after the treatment with tetracycline HCl and tetracycline base. Pollen grains produced by tetracycline on male sterile plants were viable and able to fertilize the egg cells. By using the perennial nature of Allium schoenoprasum L. it could be shown that the fertility induced on male sterile plants by tetracycline is reversible. This could be of practical importance for the multiplication of male sterile parents in hybrid breeding. None of the chemicals had any effect on the fertility of male fertile plants. Differences in reaction indicated that genetic differences exist between male sterile plants responding to tetracycline and those which do not. The results are discussed in view of the influence of tetracycline on the mitochondrial protein biosynthesis.     

Inheritance of Resistance to Downy Mildew (Peronospora destructor [Berk.] Casp.) from Allium roylei Stearn in the Backcross Allium cepa L. × (A. roylei ×A. cepa)

Allium roylei Stearn and both reciprocals of the interspecific hybrid between Allium cepa L. and A. roylei displayed no symptoms of Peronospora destructor (Berk.) Casp. after artificial or natural inoculations, whereas A. cepa was susceptible. In the offspring from the backcross A. cepa× (A. roylei ×A. cepa) resistant and susceptible plants segregated after artificial inoculations, fitting a 1: 1-ratio. This suggests that resistance is controlled by a single, dominantly-inherited locus (designated Pd₁) from the nuclear genome of A. roylei. During a severe epidemic in the field, plants from the same backcross segregated resistant and susceptible individuals in a 3: 1-ratio. Escapes may explain the deviation from the 1: 1-segregation, but the presence of a second resistance locus segregating independently from Pd₁ cannot be excluded, implicating possible differences in virulence between populations of P. destructor. The occurrence in the backcross offspring of plants having a morphology similar to A. cepa without showing symptoms of downy mildew opens perspectives for breeding P. destructor-resistant onion varieties.     

Identification,characterization and geographic distribution of male-sterility restorer and maintainer lines from diverse pearl millet germplasm

Summary To determine the distribution and geographic specificity of sterility maintainers in pearl millet, Pennisetum americanum (L.) Leeke, 428 diverse pearl millet germplasm accessions representing variation from 12 countries were crossed with a male-sterile line 5141A. The F₁ hybrids were classified as male-fertile or male-sterile based on the seed set on bagged ear heads and an other morphology. Among these, 87 (20.3%) were classified as male-fertile, 32 (7.5%) as male-sterile, 282 (65.9%) as segregating for male-fertile/male-sterile and 27 (6.3%) behaved as male-fertile in the rainy and male-sterile in the postrainy season. Restorer lines were distributed in all the countries studied except Cameroon and USSR. Maintainer lines were observed from six countries but were concentrated in India. These maintainer lines differ from one another in several morphological and agronomic characters such as flowering, plant height, spike length and grain size. They may prove to be useful sources of material for generating new male-sterile lines. The restorers can be used to produce commercial hybrids.Submitted as J.A. No. 719 by the International Crops Research Institute for the Semi-Arid Topics (ICRISAT).     

Development of a cytoplasmic male‐sterile line NJCMS4A for hybrid soybean production

Cytoplasmic male‐sterile (CMS) lines are being used to produce hybrid seeds. Thus far, four CMS sources in soybean [Glycine max (L.) Merr.] have been reported in China. However, they are not sufficient or efficient in meeting the requirements of commercial soybean hybrid seed production. In this study, 33 varieties were tested for CMS using 45 crosses among 37 landraces and 17 annual wild soybean accessions (Glycine soja Sieb. et Zucc.). The cross of N23661 × N23658 showed partial to complete male sterility in backcross generations, while the corresponding reciprocal cross showed normal male fertility. Thus, the cytoplasm of N23661 is male‐sterile, the continuously backcrossed line is a male‐sterile line (designated NJCMS4A), and N23658 is its maintainer (designated NJCM4B). The male fertility of NJCMS4A was restored by another accession, Nansheng9403. Accordingly, NJCMS4A along with its maintainer and restorer composes a complete set of three lines for producing hybrid soybean. Using mitochondrial markers and sequence analyses, NJCMS4A is a CMS line with its cytoplasm not identical to the four previously reported CMS sources in soybean.     

A short review of research on male sterility and prospects for F1 hybrid varieties in field beans (Vicia faba L.)

Summary It has not yet been possible to utilise cytoplasmically inherited male sterility (CMS) in Vicia faba, in the commerical production of F₁ hybrids. The main problem has been a rapid increase in the proportion of fertile revertants during multiplication. Investigations, mainly in France, have clarified environmental causes of phenotypic instability, CMS and maintainer lines with improved stability have been selected, and two new cytoplasms have been produced by mutation of the first two. CMS is known to be associated with cytoplasmic spherical particles, and recognisable types of double stranded RNA, and there may also be an association with mitochondrial DNA, and polypeptides of mitochondrial origin.The better understanding of CMS may eventually lead to more easily managed forms, either through genetic manipulation or biochemical assays that breeders can use for screening for stability.