Complete Male Sterility Research Articles

Effects of the fourth chromosome on the sterility of hybrids between Drosophila simulans and its relatives.

Genetic analysis of the fourth chromosome of Drosophila simulans shows that it has no effect on either male or female fertility in hybrids with two sibling species, D. mauritiana and D. sechellia. The lack of effect holds even when the D. simulans chromosome is homozygous in a foreign genetic background. The absence of major fourth chromosome "sterility genes" in these hybridizations contrasts with the presence of a fourth-chromosome gene causing complete male sterility in hybrids of the more distantly related species D. melanogaster and D. simulans.

Breeding of Candidate Lines for Male Sterility-Maintainer by Anther Culture for Hybrid Wheat Production Using an Sv Type Cytoplasm and a 1BL-1RS Chromosome.

We previously proposed a new breeding scheme to develop hybrid wheat utilizing male sterility induced by the interaction between the Svtype cytoplasm of Ae. kotschyi and the IBL-1RS chromosome (Toriyama et al. 1991, 1993). In our proposed scheme male sterility-maintainer lines can be produced by two ways, i. e. the backcrossing method (Nonaka et al. 1993) and anther culture. This article reports the results of anther culture. Donor for the 1BL-1RS chromosome, namely, the strain 911-B-8-10 (abbreviation, st. 911) was crossed to 13 Japanese wheat cultivars. The anther culture was conducted using the F1 and B1F1 plants. Frequency of embryo formation in the Fls was higher than that in the parental Japanese cultivars. The frequency observed in the B1F1s was lower than that in the F1s. High frequencies of embryo formation in st. 911 and the Fls were attributable in part to the 1BL-1RS chromosome. Since the leaf rust resistance gene Lr 26 was located on the 1RS chromosome arm, regenerated haploid seedlings were artificially inoculated by leaf rust (race 21B) to select resistant ones. Doubled haploids with resistance were crossed with (Sv)-Chinese Spring having the IB chromosome and with (Sv)-Salmon having the 1BL-1RS chromosome. The F1s of the former cross showed high selfed fertility, while the Fls of the latter showed complete male sterility. This means that resistant doubled haploids obtained by anther culture can be used as a maintainer for developing male-sterile line.

Outcrossing rate in cultivated autotetraploid potato

Outcrossing rates in potato were measured in an open-pollination field experiment at a location in the Peruvian Andes. Embryo spot, a dominant genetic seed marker, was used to measure outcrossing rate. The source of the dominant marker, the donor, was interplanted among recipient clones lacking the marker (recessive genotype), for which outcrossing was to be measured. Eight out of the 17 clones tested were advanced breeding clones which had wild species cytoplasm. Seven out of eight of these had outcrossing rates above 0.75, showing complete male sterility in one case and partial male sterility in six cases. Among the other clones tested, which were male-fertile, outcrossing estimates ranged from 0.10 to 0.74. Wide variability in outcrossing rate in autotetraploid potato suggests that it should be possible to select for higher outcrossing rate in production of open-pollinated true seed populations of potato for genetic or commercial purposes.

Genetics of reproductive isolation in the Drosophila simulans clade: DNA marker-assisted mapping and characterization of a hybrid-male sterility gene, Odysseus (Ods).

In this study, we address the question of whether there exist major genes that cause complete male sterility in the interspecific hybrids of Drosophila and, if they do, how these genes may be characterized at the molecular level. Our approach is to introgress small segments of the X chromosome from Drosophila mauritiana (or Drosophila sechellia) into Drosophila simulans by repeated backcrosses for more than 20 generations. The introgressions are monitored by both visible mutations and a series of DNA markers. We compare the extent of introgressions that cause male sterility with those that do not. If a major sterility factor exists, there should be a sharp boundary between these two classes of introgressions and their breakpoints should demarcate such a gene. Furthermore, if male sterility is the only major fitness effect associated with the introgression, recombination analysis should yield a pattern predicted by the classical three-point cross. Both the genetic and molecular analyses suggest the presence of a major sterility factor from D. mauritiana, which we named Odysseus (Ods), in the cytological interval of 16D. We thus formalize three criteria for inferring the existence of a major gene within an introgression: (1) complete penetrance of sterility, (2) complementarity in recombination analysis, and (3) physical demarcation. Introgressions of Ods from D. sechellia do not cause sterility. Twenty-two introgressions in our collection have breakpoints in this interval of about 500 kb, making it possible to delineate Ods more precisely for molecular identification. The recombination analysis also reveals the complexity of the introgressed segments--even relatively short ones may contain a second male sterility factor and partial viability genes and may also interfere with crossovers. The spermatogenic defects associated with Ods and/or a second factor were characterized by phase-contrast microscopy.

Chemical agents that inhibit pollen development: effects of the phenyl-cinnoline carboxylates SC-1058 and SC-1271 on the ultrastructure of developing wheat anthers (Triticum aestivum L. var Yecora roj�)

Phenylcinnoline carboxylate compounds SC-1058 and SC-1271 cause complete male sterility in wheat when applied at suitable dosages at the pre-meiotic stage of anther development. Anthers from treated and untreated plants were compared using light and electron microscopy from the pre-meiotic stage through the formation of nearly mature pollen. Overall anther development is gradually slowed in treated plants and pollen development is generally arrested in the late prevacuolate or early vacuolate microspore stage, although the first pollen mitosis does sometimes occur. The sporopollenin-containing exine walls are thinner, and show abnormally developed foot and tectum layers with sparse connecting baculi. Microspore cytoplasm degenerates and the cells eventually collapse. At the early, prevacuolate, free microspore stage treated tapetal cells hypertrophy, expanding into the locule. They contain abnormally large vacuoles that appear to form from the fusion of secretory vesicles, and some vacuoles contain electrondense deposits. The sporopollenin-containing orbicular wall and Ubisch bodies are retarded in their development and are structurally deformed. Acetolysis of whole anthers and of thick sections shows that the sporopollen-in-containing structures of treated materials are greatly reduced in thickness and are less rigid than in the control. We conclude that application of these compounds causes interference with the secretory function of tapetal cells which supplies sporopollenin cell-wall polymers to the exine of the microspores and to the tapetal orbicular wall and associated Ubisch bodies. Interference with the tapetal secretion of other nutrients required for microspore development is strongly suggested.

Photoperiod-sensitive cytoplasmic male sterility in wheat with Aegilops crassa cytoplasm

Triticum aestivum cv. Norin 26 with Aegilops crassa, Ae. juvenalis or Ae. vavilovii cytoplasm (all D2 type) has been studied relative to its photoperiodic response of male sterility and fertility restoration patterns. Alloplasmic lines of ‘Norin 26’ with a D2 type cytoplasm showed almost complete male sterility under long-day conditions (≥15 h), but high male fertility under short-day conditions (≤14.5 h). No significant influence of temperature on reduction in male fertility was observed. Thus, this type of male sterility is called ‘photoperiod-sensitive cytoplasmic male sterility’ (PCMS). The PCMS is expressed in the form of pistillody of stamens. Histological studies revealed that there were incomplete ovule-like structures instead of tapetal cells and pollen grains in the pistillate stamens. The floret differentiation stage of the plant is the stage that is sensitive to photoperiod. The PCMS can be used as a new means for hybrid wheat production, named ‘two-line system’. The PCMS line is maintained and multiplied by self-fertilization under short-day conditions, and hybrid seed can be produced by crossing the PCMS line with a pollinator line under long-day conditions. In contrast to the system of hybrid wheat production using the T. timopheevi cytoplasm, the present system requires only PCMS and pollinator lines.

A novel mouse chromosome 17 hybrid sterility locus: implications for the origin of t haplotypes.

The effects of heterospecific combinations of mouse chromosome 17 on male fertility and transmission ratio were investigated through a series of breeding studies. Animals were bred to carry complete chromosome 17 homologs, or portions thereof, from three different sources-Mus domesticus, Mus spretus and t haplotypes. These chromosome 17 combinations were analyzed for fertility within the context of a M. domesticus or M. spretus genetic background. Two new forms of hybrid sterility were identified. First, the heterospecific combination of M. spretus and t haplotype homologs leads to complete male sterility on both M. spretus and M. domesticus genetic backgrounds. This is an example of symmetrical hybrid sterility. Second, the presence of a single M. domesticus chromosome 17 homolog within a M. spretus background causes sterility, however, the same combination of chromosome 17 homologs does not cause sterility within the M. domesticus background. This is a case of asymmetrical hybrid sterility. Through an analysis of recombinant chromosomes, it was possible to map the M. domesticus, M. spretus and t haplotype alleles responsible for these two hybrid sterility phenotypes to the same novel locus (Hybrid sterility-4). Previous structural studies had led to the hypothesis that the ancestral t haplotype originated through an introgression event from M. spretus or a related species. If this were true, one might expect that (1) M. spretus homologs would be transmitted at a non-Mendelian ratio within the M. domesticus background, and (2) t haplotypes would be transmitted at a ratio closer to Mendelian within the M. spretus background.(ABSTRACT TRUNCATED AT 250 WORDS)

Intergeneric hybridization between Hordeum and Secale (Poaceae). I. Crosses and development of hybrids

A total of 241 intergeneric combinations between Hordeum and Secale were attempted. It was only possible to obtain hybrid offspring from combinations with Hordeum as the female parent. By the aid of embryo culture technique 81 intergeneric combinations were synthesized, 72 of them not reported earlier. Generally hybridization with the polyploid species of Hordeum was most successful. Morphologically the hybrids were intermediate to the parents in most characters, though an obvious effect of genome dosage could be observed. Only few deviations from the expected chromosome numbers of the hybrids were found. All hybrid plants showed complete male sterility.

Response of Late-Instar Blattella germanica (Dictyoptera: Blattellidae) to Dietary Insect Growth Regulators

Late-instar German cockroaches, Blattella germanica (L.), were used to evaluate the relative effects of single treatments and combinations of three insect growth regulators (IGRs): pyriproxyfen, fenoxycarb, and diflubenzuron. Groups of 15 males or 15 females were held for 2 wk on food treated with varying amounts of IGRs. After removal, newly mature adults were placed with untreated adults of the opposite sex. Mortality, adult phenotype (normal wings, divergent wings, curly wings, and nymphoids), and reproduction were assessed. Mortality occurred largely in the nymphal stage except when all three IGRs were combined. Neither the average number of nymphs per egg case nor hatch of egg cases from phenotypically normal cockroaches (normal wings, occasional darkening of the body) was affected in single treatments or in combinations of two IGRs, but nymphal numbers were reduced when the three IGRs were combined. Hatch from matings of insects with divergent wings varied. At low concentrations (3-10 ppm), hatch was generally normal; at high concentrations, most mating tests were unproductive. Mating tests of cockroaches with curly wings were almost always unproductive. When males with curly wings were mated, females dropped either unfertilized egg cases (no mating) or partially fertilized egg cases. Curly-wing females either dropped unfertilized egg cases or failed to form egg cases because of deleterious effects on ovarian development. Nymphoids did not mate. Diflubenzuron at 100 ppm had no effect other than causing the appearance of a few insects with divergent wings. Effects on phenotype and reproduction began at 3 ppm of both pyriproxyfen and fenoxycarb and at a comparable concentration in the combination of pyriproxyfen + fenoxycarb (1 ppm each). Female sterility was complete at 100 ppm of pyriproxyfen and fenoxycarb. When pyriproxyfen or fenoxycarb was combined with equal amounts of diflubenzuron, the number of productive matings was not reduced at 6 ppm (3 ppm per each IGR). At 20 ppm (10 ppm per each IGR), a reduction in productive matings coincided with the appearance of curly wings. Complete female sterility occurred only at 600 ppm (300 ppm per IGR). The most severe effects occurred in the experiment with equal amounts of pyriproxyfen, fenoxycarb, and diflubenzuron. In addition to reduced hatch from normal phenotypes, this experiment caused complete male sterility (300 ppm; 100 ppm of each IGR). Female sterility was complete at greater than or equal to 90 ppm (30 ppm of each IGR).

Use of Male Gametocide to Induce Complete Male Sterility in a Partially Male Sterile Rice

Use of Male Gametocide to Induce Complete Male Sterility in a Partially Male Sterile Rice

Effectiveness of Ethrel as a Male Gametocide in Pearl Millet and its Influence on Ergot

AbstractIn field and greenhouse experiments Ethrel (2‐chloroethyl phosphonic acid) was tested for its male garnetocidal effects on pearl millet (Pennisetum americanum) and its subsequent effects on ergot development. Application of Ethrel at 2000 ppm at late boot or early protogyny was the most effective for inducing male sterility in the hybrid, EJ 104. Female fertility in a male sterile line, however, was not affected by Ethrel treatment. Ethrel at 2030 ppm applied at ihe late boot stage resulted1 in partial paniele exsertion, and reduced plant height anc. panide length. In vitro Ethrel (2000 ppm) completely inhibned pollen germination but did not affect germination of conidia of Claviceps fusiformis, the causal agent of ergot of pearl millet. Ergot resistance or susceptibility in pearl millet lines was not affected., probably because Ethrel could not induce complete male sterility.

Induction of male sterility in wheat using organic ligands with high specificity for binding copper

Because copper is extremely important to the development of normal polllen, an attempt was made to induce male sterility in wheat by applying specific copper-binding ligands to wheat plants. Four different chelates were used at two rates in three methods of application. All four chelates, cupferron, neocuproine, benzotriazole and cuprizone, reduced grain yield at high concentration applied to the soil at sowing but benzotriazole was most effective, even when applied at late tillering to either soil or foliage, and it also reduced yield to a lesser extent when applied at low concentration. At high concentration of benzotriazole (50 mg kg-1 of dry soil) the percentage of pollen staining with I2/KI was very low (0–7%) depending on method of chelate application), and this soil treatment resulted in complete male sterility. The appearance of the pollen, anthers, grain, ears and leaves in many cases mimicked that of normal copper deficiency, and also that caused by other recognised gametocides. These results raise the question of whether binding of copper or some other disturbance of copper metabolism may be the mechanism by which andro-gametocidal chemicals work and if so, dictate a theoretical basis for selecting such chemicals for testing.

The MRP-type transposable elements and the genetic activities of mutagens and carcinogens in Drosophila melanogaster I. N, N-Dimethylnitrosamine (DMN)

A technique was developed for the assay of the genetic activities of carcinogens in both the soma and germ line in the course of early larval development and to assess the extent of their modification through the introduction into the genome of the MR IInd autosome P-type transposable elements. The influence of MR on genotoxicity for a given treatment was indicated by the relative frequencies of non- MR ( Cy) to MR-carrying sibs emerging within the same cultures. The viable genetic changes in the soma were classified as recombinational or mutational events on the basis of the comparative yields of mosaic sectors in females heterozygous for the markers y w sn carried in standard order (XS) or multiply inverted (XIn) X-chromosomes. The results with this technique are here described for the carcinogen DMN. In the absence of MR, the optical application of DMN induced no larval lethality up to the highest tested doses (20 mM), but raised the yields of the somatic sectors for all the test markers in the emerging females in accordance with a linear dose fit. Comparison of the XS and XIn data indicated that somatic mutagenesis by DMN entailed the induction of recombinational and mutational events in roughly equal proportions. The introduction of MR into the genome, whether patro- or matroclinously, resulted in dramatic and proportionately equivalent enhancements in the activities of DMN, both with respect to the induction of larval lethality and somatic sectoring. These activities increased exponentially with dose, following a 4th-degree polynomial course up to 10 mM, when larval lethality approached 100%. At lower dose levels, the yields of all sector types in the viable females also followed comparable polynomial curves at different heights, except for y sn in the XIn series, where sector recovery remained at the control level throughout the examined dose range. Analysis of the sector size distribution for eye and bristle mosaicism in the XS control and DMN-treated series gave statistically comparable mean values, irrespective of the presence or absence of MR, indicating that DMN alone, or in conjunction with the P elements, did not alter the timing of aberrant clone initiation. In contrast, estimates of the genetic induction events in the somatic primordia with 5 mM DMN indicated greatly increased response in the presence of MR, which was in excess of 20-fold for the mutational changes involving the sn locus. Germinal mutagenicity after DMN larval treatment could only be assessed at 2.5 mM, since higher doses resulted in complete male sterility, even in the absence of MR. At this dose level, the X-recessive mutations recovered from the MR males were about double those from their non- MR ( Cy) sibs. A comparable enhancement in somatic sectoring by MR occured with 2 mM DMN in the XIn series, where mosaicism was mainly attributable to mutational events.

Reduced productivity in tretamine-treated adult populations of Aedes aegypti (Diptera: Culicidae).

Male and female Aedes aegypti mosquitoes of the feral strain PUGU were given orally 0.001, 0.025, 0.050, and 0.075% triethylenemelamine (tretamine or TEM). Productivity, or the average number of progeny surviving in a population over a 2-wk period, was used to assess mutagenic effects. The mean number of progeny decreased in all but 1 of the experimental populations. Populations in which the parental females were treated with TEM approximated a linear decrease in the total mean number of F1 progeny as dosage of TEM increased. Progeny derived from TEM-treated parental males showed a slight decrease in number in the 0.001% group and a significant decrease in the 0.025 and 0.075% populations. Doses of 0.050% TEM induced complete sterility in males.

Production and characterization of alloplasmic lines of a triticale ‘Rosner’

The transfer of cytoplasms of various Triticum and Aegilops species to a hexaploid triticale ('Rosner') has been attempted using 30 alloplasmic lines and a euplasmic line of common wheat as cytoplasmic donors. The average rate of F1 hybrid production (seed setting rateXgermination rate) following an ordinary method of crossing is only 0.09%, whereas this rate is increased to 3.1% by use of embryo culture. The first backcross of the F1 plants with triticale pollen is again difficult, the hybrid production being 0.9%. Further backcrosses proceed smoothly in most cases. As a consequence, the following seven cytoplasms have been transferred to triticale: T. dicoccum, T. aestivum, Ae. squarrosa, Ae. cylindrica, Ae. juvenalis, Ae. ovata and Ae. speltoides. None of these alien cytoplasms causes more meiotic instability than does the triticale's own cytoplasm. Two cytoplasms of T. dicoccum and T. aestivum, both belonging to the B plasma type, have no effect upon any of triticale's characters. Two D type cytoplasms of Ae. squarrosa and Ae. cylindrica cause about 50% reduction of male fertility but exert no other remarkable effects. This fact suggests a partial functional compensation of the effect of a 1D chromosome upon interacting with D cytoplasm by a rye chromosome substituting for it in triticale. A D(2) cytoplasm of Ae. juvenalis causes earlier heading and complete male sterility, accompanied by some reduction of growth vigor. An M(0) type cytoplasm of Ae. ovata and an S type cytoplasm of Ae. speltoides cause a great heading delay, complete male sterility, and severe reduction of vigor. From the viewpoint of triticale breeding, none of these cytoplasms appears superior to the triticale's own cytoplasm. However, from the viewpoint of genetics, the hexaploid triticale is an effective tester for differentiating the B, S, and D plasma types.

An evaluation of intergeneric hybridization of Fragaria spp. x Potentilla spp. as a means of haploid production

Unidirectional intergeneric crosses using octoploid and hexaploid Fragaria species as a female parent and diploid and tetraploid Potentilla species as a male parent were performed, producing in toto 1345 fruits with an estimated 46089 seeds. The germinating seeds obtained by using P. anserina mostly perished at the cotyledon stage, a few developing into matroclinous octoploid seedlings. The seeds obtained by using P. fruiticosa produced two types of seedlings: matroclinous octoploids and genuine intergeneric hybrids. It is considered that the matroclinous octoploids resulted from contamination during the emasculation process. A great majority of the hybrid seedlings were slow in growth and development and perished before reaching the flowering stage. No haploids have been recovered. Possible reasons for absence of haploid genotypes in the progenies of these intergeneric crosses are considered. Among the seedlings of F. x ananassa cv. Tioga x P. fruiticosa, a seedling of an unusual phenotype was noticed, which upon chromosome determination, proved to be 2n=9x=63. This genotype displayed complete male and female sterility. The implication of the sterility of this seedling for bridging of the two genera is discussed.

Genetic diversity of the cytoplasm in Triticum and Aegilops. X. The hexaploid triticale as an effective tester for plasma type distinction.

To test the usefulness of hexaploid triticale (genome constitution AABBRR) as a plasma type tester for Triticum and Aegilops cytoplasms, six alloplasmic lines and a euplasmic line of both triticale cultivar Rosner and a common wheat cultivar Chinese Spring were grown under the same experimental design, and the effects of the individual alien cytoplasms on 16 morphological or physiological characters of Rosner and Chinese Spring were compared. Cytoplasms used in this study were derived from common and emmer wheats belonging to the B plasma type, Ae. Squarrosa and Ae. cylindrica belonging to the D plasma type, the D2 plasma type Ae. juvenalis, the M° plasma type Ae. ovata, and the S plasma type Ae. speltoides.D2, M° and S type cytoplasms caused severe growth depression, delayed heading and complete male sterility in Rosner triticale, thus affecting almost all its characters. D type cytoplasms caused about 50% reduction in seed fertility and slight decrease in culm diameter. The cytoplasm of common wheat was the same as that of Rosner which originated from an emmer wheat. By contrast, in Chinese Spring wheat, only the M° type cytoplasm affected several characters greatly. D and D2 cytoplasms exerted a significant influence on only one to two characters. B and S type cytoplasms behaved the same. Thus, it is concluded that the hexaploid triticale is a useful tester for critical distinction among the B, D, D2 and S type cytoplasms.

Gynodioecy in Plantago lanceolata L I. polymorphism for plasmon type

Studies of the morphological polymorphism for the expression of male sterility in the gynodioecious species Plantago lanceolata revealed two separate series of stamen forms from sterile to fertile. The first type of complete male sterility (MS1) shows a disturbed development of the stamens, which are strongly reduced in size. The second type (MS2) has stamens which are petaloid. In the latter type the corolla and sometimes the pistil are also affected. Evidence is presented that these differences in expression of male sterility are cytoplasmically determined. The plasmon types are designated R and P respectively. In each plasmon type a series of intermediate sex forms occurs. Field counts showed that these intermediates are a non-negligible proportion of most populations. On the average MS1 reaches higher frequencies than MS2. Twenty two out of 27 populations appeared to be polymorphic for plasmon type. The remaining five populations are probably fixed for plasmon P and their distribution over the habitats studied suggests that the fitnesses of the different sex genotypes depend on environmental conditions.

Resistance of lettuce (Lactuca) to the leaf aphid Nasonovia ribis nigri. 1. Transfer of resistance from L. virosa to L. sativa by interspecific crosses and selection of resistant breeding lines

Interspecific crosses were carried out between the three Lactuca species L. virosa, L. serriola and L. sativa to transfer resistance to the leaf aphid Nasonovia ribis nigri from L. virosa to the cultivated lettuce. L. sativa, L. serriola was used as an intermediate parent between the other two species. Many irregularities were observed in the interspecific hybrids, ranging from premature dying of F1 plants resulting from a kind of bastard necrosis till complete male and female sterility and deviating microsporogenesis. Using in vitro culture and after several backcrosses male and female fertile plants were obtained with a L. sativa habit and with resistance to the leaf aphid.

Sterility in mutant (t Lx/t Ly) male mice III. In vitro fertilization

ABSTRACT Mice which are heterozygous for two complementary lethal t mutations (t6/tw32) exhibit complete male sterility. Experiments have been conducted to determine if spermatozoa from these heterozygous males can fertilize oviducal ova in vitro. The experiments have been designed so that specific barriers which are present during in vivo fertilization can be sequentially removed and the fertilizing ability of the spermatozoa tested after each barrier is eliminated. Our results show that spermatozoa from t6/tw32 males are unable to effect fertilization even after all of the barriers normally imposed by the female reproductive tract have been removed.