F2 Ratios Research Articles

Study of Effects of Type and Quantity of Diluents on H2-F2 Reaction in a Batch Reactor

Addition of diluents to the reactants may significantly change the behavior of a reactor system. In the present work, experimental trials have been conducted to study the effect of diluents, such as helium, nitrogen, and argon, on change in reactor temperature and pressure in a batch reactor carrying out H2-F2 reactions. The experiments were conducted at different initial pressures but the same H2 to F2 ratio. The thermal response of the reactor is found to be different at different pressure levels. A simple model has been used to explain the thermal behavior of the reactor. The results suggest that, besides fluid dynamics and heat transport behavior, the effect of diluents on kinetics of hydrogen and fluorine reaction cannot be ignored.

Genetic Analysis of Resistance to Pod Shattering in Soybean

Pod shattering (dehiscence) is a major constraint to soybean (Glycine max. (L) Merrill) production in the northern savanna zones of Ghana, but research on improving soybean for resistance to shattering is scanty. Genetic analysis of resistance to pod shattering was undertaken on three soybean crosses involving resistant and susceptible varieties to determine broad-sense (h2 bs) and narrow-sense (h2 ns) heritability, minimum number of genes (MNG) involved cytoplasmic inheritance, and allelic relationship between shattering and non-shattering. Mean h2 bs was 0.92 (range 0.90–0.95), and mean h2 ns was 0.46 (range 0.40–0.53), indicating the importance of both additive and non-additive variances and that shattering resistance can be improved through breeding. Mean MNG controlling shattering resistance was 2 (range 1–3), indicating that genes for shattering resistance differed among parental lines. There was no difference between the mean of any F1 population and it's reciprocal, indicating lack of maternal/cytoplasmic influence and that the character was under nuclear gene control. Observed F2 ratios revealed that inheritance of resistance to pod shattering in soybean was qualitative in nature and under the influence of either duplicate recessive or dominant and recessive epistasis, depending on the parental genotypes used in the cross.

Kombinacione sposobnosti za osobine klasa ječma u dialelnom ukrštanju

Five two-row winter barley (Hordeum vulgare L.) cultivars divergent in spike traits were crossed in all possible combinations excluding reciprocals to produce 10 F1 and F2 hybrids for analysis of combining abilities. The analysis of variance of combining abilities showed significant differences for GCA and SCA in F1 hybrids and F2 generation, suggesting additive and non-additive gene action. The GCA/SCA ratio in F1 and F2 indicated the prevalence of the additive component of genetic variance for spike length, grain weight per spike and spike harvest index. By contrast, the SCA variance for grain weight per spike was higher than the GCA variance, indicating the dominance of non-additive gene action. Good GCAs were found in parents having high values for spike length (Djerdap, NS-293), grain number per spike (Vada, Jagodinac), grain weight per spike (Vada, NS-293) and spike harvest index (Djerdap, Jagodinac). None of the parents had good GCA for all traits, suggesting a potential increase in combining abilities for spike traits. The best SCA were obtained mostly from crosses between parents having high x low, high x high or average x low GCA values. Parents having high GCA values may be used to produce improved lines in hybridisation programmes. Combinations with high SCA values may yield good segregating lines in further selection programmes.

Phenotypic Characterization and Genetic Analysis of Rice with Pubescent Leaves and Glabrous Hulls (PLgh)

ABSTRACTPubescence (hairs or trichomes) of leaves is advantageous against biotic and abiotic stress, and that of hulls is disadvantageous as it interferes with field operations, such as harvesting and processing. Previous phenotypic and genotypic studies on rice (Oryza sativa L.) pubescence used materials that had pubescent or glabrous leaves and hulls. From the National Small Grains Collection (NSGC), two accessions with pubescent leaves and glabrous hulls (PLgh) were identified. These PLgh accessions had more, longer, and softer trichomes on the leaves than traditional pubescent materials. Our objective was to study the inheritance of the PLgh trait. Crosses of PLgh plants with a genotype having glabrous leaves and hulls showed that leaf pubescence in the PLgh material was controlled by a dominant gene because no segregation for glabrous hull in F2 generation occurred. Chi‐square values for 3:1 pubescent leaf and glabrous hull:glabrous leaf and hull F2 ratio were 0.283 (P = 0.626) and 0.919 (P = 0.338) in two PLgh crosses, Wells × IARI 6184B and Wells × Padi Pohon Batu, respectively. However, in crosses of PLgh with three genotypes (You I B, Rondo, and Xieqingzao B) having pubescent leaves and hulls, an F2 ratio of 12:3:1 pubescent leaf and hull:pubescent leaf and glabrous hull:glabrous leaf and hull was found in most cases, suggesting two genes were involved in the inheritance. Use of the PLgh germplasm (pubescent leaves) in rice breeding should be advantageous as a defense mechanism against biotic and abiotic stresses while avoiding the disadvantages of pubescent hulls in transportation and storage.

Interaction of Restorer Genes in ‘WA’-type Cytoplasmic Male Sterility System in Rice (Oryza sativa L.)

The inheritance of fertility restoration of ‘WA’ type of cytoplasmic male sterility system in rice was studied using three cytoplasmic male sterile (A) lines and their respective maintainer (B) lines and four restorer lines which were used in crossing to produce three generations (A × R) F1, (A × F1) BC1 and (A × R) F2. Segregation pattern in F2 generation for pollen fertility indicated that the fertility restoration ability was governed by two pairs of dominant genes (Rf 3 Rf 3 Rf 4 Rf 4 ), one of which was stronger in action than the other. The cross combinations, Pusa 6A × Basmati 564, Pusa 3A × HUR-FG-79 and Pusa 6A × HUR-FG-78 exhibited epistasis with incomplete dominance (F2 ratio 9:6:1 and BC1 ratio 1:2:1). In cross combinations, Pusa 3A × Basmati 564, Pusa 3A × HUR-FG-78 and Pusa 5A × Basmati 564, the fertility restoration was governed by dominant genes with recessive epistatic interaction (F2 ratio, 9:3:4 and BC1 ratio 1:1:2). Pusa 5A × HUR-FG-81 the only cross combination which exhibited dominant gene interaction (F2 ratio 12:3:1 and BC1 ratio 2:1:1). An allelism test involving four restorer lines revealed that Basmati 564, HUR-FG-81, HUR-FG-78 and HUR-FG-79 possessed different pairs of fertility restorer genes.

파킨슨병 환자의 말 명료도와 모음 공간 특성

The purpose of this study was to investigate the characteristics of speech intelligibility of spontaneous speech and the vowel space parameters in patients with Parkinson's disease. Ten PD patients (M=5, F=5) and a corresponding control group of ten normal adults participated in this study. Firstly, subjects were asked to tell a story about their hometown and youth in order to analyze speech intelligibility. Secondly, the subjects were also asked to repeat four vowels (/a/, /i/, /u/, /e/) five times in order to compare their vowel spaces. The results were as follows: (1) the speech intelligibility of the PD group was lower than that of the control group. (2) Four parameters including vowel area, vowel articulatory index, formant centralization ratio, F2i/F1u ratio were significantly different in each group. For instance, vowel area and F2 ratio were wider and higher, respectively. As a result, a decrease in speech intelligibility of patients with PD is likely to show different types of errors from the normal group. The results of this research are meaningful in a sense that they could provide the objective standard of speech intelligibility and vowel space parameters.

Regulation of Oscillatory Contraction in Insect Flight Muscle by Troponin

Insect indirect flight muscle is activated by sinusoidal length change, which enables the muscle to work at high frequencies, and contracts isometrically in response to Ca 2+. Indirect flight muscle has two TnC isoforms: F1 binding a single Ca 2+ in the C-domain, and F2 binding Ca 2+ in the N- and C-domains. Fibres substituted with F1 produce delayed force in response to a single rapid stretch, and those with F2 produce isometric force in response to Ca 2+. We have studied the effect of TnC isoforms on oscillatory work. In native Lethocerus indicus fibres, oscillatory work was superimposed on a level of isometric force that depended on Ca 2+ concentration. Maximum work was produced at pCa 6.1; at higher concentrations, work decreased as isometric force increased. In fibres substituted with F1 alone, work continued to rise as Ca 2+ was increased up to pCa 4.7. Fibres substituted with various F1:F2 ratios produced maximal work at a ratio of 100:1 or 50:1; a higher proportion of F2 increased isometric force at the expense of oscillatory work. The F1:F2 ratio was 9.8:1 in native fibres, as measured by immunofluorescence, using isoform-specific antibodies. The small amount of F2 needed to restore work to levels obtained for the native fibre is likely to be due to the relative affinity of F1 and F2 for TnH, the Lethocerus homologue of TnI. Affinity of TnC isoforms for a TnI fragment of TnH was measured by isothermal titration calorimetry. The K d was 1.01 μM for F1 binding and 22.7 nM for F2. The higher affinity of F2 can be attributed to two TnH binding sites on F2 and a single site on F1. Stretch may be sensed by an extended C-terminal domain of TnH, resulting in reversible dissociation of the inhibitory sequence from actin during the oscillatory cycle.

Troponin Isoforms and Stretch-activation of Insect Flight Muscle

Oscillatory contraction of insect indirect flight muscle (IFM) is activated by sinusoidal length changes. Work done by oscillating fibres is measured from the area of loops on a length-tension plot. At [Ca2+] above 10 μM, progressively less oscillatory work is produced because fibres contract isometrically and are unable to relax fully after each cycle of oscillation. Periodic stretches during oscillations activate fibres through the action of TnC F1, which binds one Ca2+ in the C-lobe. Activation of isometric contraction by Ca2+ acts through F2, which binds Ca2+ in both N- and C-lobes. Lethocerus IFM fibres substituted with F1gave oscillatory work, which did not decline at high [Ca2+], while fibres substituted with F2 produced more isometric tension as [Ca2+] was increased. Varying proportions of F1 and F2 gave maximal work with an F1:F2 ratio of 100:1, which is higher than the in vivo ratio of 7:1. The structure of F1, and the interaction with TnI, were determined by NMR. The N-lobe of F1 is in the closed conformation in apo and Ca2+- bound forms and does not bind TnI. Unexpectedly, the C-lobe is open in both states, and binds the N-terminal domain of TnI independently of Ca2+. The affinity of F1and F2 for a complex containing tropomyosin, TnT and TnH (Lethocerus TnI) were measured by isothermal calorimetry in the presence of Ca2+. The affinities of F1 and F2 for the complex were 5.4 μm and 65 nM respectively. This difference is likely to be due to a single TnI binding site on F1 and two sites on F2. Stretch may be sensed by an extended C-terminal domain of TnH, and transmitted to the C-lobe of F1, resulting in a change in the interaction of the TnI inhibitory domain and actin.

Changes of voice and articulation in children with cochlear implants

Objective: The different speech sounds are formed by the primary voice signal and by the shape of the articulation tract. With this mechanism, specific overtones, the formants, are generated for each vowel. The objective of this study was to investigate the fundamental frequency (F0) of the voice signal and the first three formants (F1–F3) as a parameter of the articulation in prelingually deafened children at different timepoints after cochlear implantation (CI) compared with children with normal speech development. Methods: Using the Kay CSL 4300B, the fundamental frequency and the formants F1–F3 of the Swiss–German vowel /a/ were investigated at different timepoints after CI in 20 prelingually deafened children aged 3.8–10.2 years by means of spectrographic and linear predictive coding (LPC) analysis. Results: Children who had been operated before their fourth birthday showed no significant deviation in their fundamental frequency from age- and sex-matched peers, whereas a significant difference was documented in children who were older at the time of implantation. The first formant was very stable in every child and showed only discrete deviations from the normal range. The second and third formants, however, developed a broader scatter, but there was no systematic deviation of these formants to higher or lower values. The F1:F2 ratio was normal in children who were implanted at the age of up to 4 years and more centralized in children who were older at the time of implantation, as is known from the hearing impaired. Conclusions: Our results indicate that prelingually deaf children who receive a cochlear implant before their fourth birthday attain a better acoustic control over their speech, normalizing their fundamental frequencies and improving their articulatory skills.

Molecular mapping of S-c, an F1 pollen sterility gene in cultivated rice

Hybrids between indica and japonica rice varieties usually show partial sterility, and are a major limiting factor in the utilization of heterosis at subspecific level. When studying male-gamete (pollen) abortion, a possibly important cause for sterility, six loci (S-a, S-b, S-c, S-d, S-e and S-f) for F1 pollen sterility were identified. Here we report genetic and linkage analysis of S-c locus using molecular markers in a cross between Taichung 65, a japonica variety carrying allele S-cj, and its isogenic line TISL5, carrying alleleS-cj. Our results show that pollen sterility occurring in the hybrids is controlled by one locus. We used 208 RFLP markers, as well as 500 RAPD primers, to survey the polymorphism between Taichung 65 and TISL5. Six RFLP markers located on a small region of chromosome 3, detected different RFLP patterns. Co-segregation analysis of fertility and RFLP patterns with 123 F2 plants confirmed that the markers RG227, RG391, R1420 were completely linked with the S-c locus. The genetic distances between the markers C730, RG166 and RG369 and the S-c locus were 0.5 cM, 3.4 cM, and 3.4 cM respectively. Distorted F2 ratios were also observed for these 4 RFLP markers in the cross. This result suggests that the `one locus sporo-gametophytic' model could explain F1 hybrid pollen sterility in cultivated rice. RG227, the completely linked marker, has been converted to STS marker for marker-assisted selection.

Inheritance of virulence of Puccinia triticina culture X47, the F1 of the cross 71-112 x 70-1

Cultures 71-112 (SBD) and 70-1 (BBG) of Puccinia triticina were purified, crossed, and the resulting F1 culture X47 (LBB) was selfed to study the inheritance of virulence on several near-isogenic lines of Triticum aestivun. The phenotype of the parents, the F1 and ratios of F2 progeny were used to explain the inheritance of pathogenicity, Results of the F2 segregation from the reciprocal cross (70-1 x 71-112), labeled X59 (CBB), were compared to results of the current study. The F2 cultures in this study segregated as if single dominant genes conditioned avirulence on near-isogenic lines with Lr2a, Lr2c, Lr10, Lr17, Lr28, Lr29, and Lr33. The avirulence genes were independently inherited. Linkage was detected between pathogen genes p2a and p2c with p29. Two genes appeared to control virulence on near-isogenic lines with Lr3, Lr3c, Lr11, Lrl6, Lr21, Lr26, and Lr30. The F2 ratios could be explained by classical gene-for-gene interactions except for the digenic ratios, which may indicate a more complex interaction.

Genetic Relationships between Loci Controlling the High Stearic and the High Oleic Acid Traits in Sunflower

Sunflower (Helianthus annuus L.) lines with seed oils containing either high oleic (C18:1) or high stearic (C18:0) acid have been obtained through induced mutagenesis. The combination of the seed oil phenotypes of these lines would result in a novel oil quality of great value for the food industry. The objectives of this study were (i) to determine the genetic relationships between the high C18:0 and the high C18:1 traits, and (ii) to combine both characters. The sunflower lines HAOL‐9 (high C18:1), carrying the high C18:1 Ol alleles, and CAS‐3 (high C18:0), with the high C18:0 alleles es1 and es2, were reciprocally crossed. The fatty acid content of the F1, F2, BC1F1 to both parents, and F3 seeds was analyzed by gas–liquid chromatography (GLC). The segregation patterns for C18:0 (F2 ratio of 15:1) and C18:1 (F2 ratio of 1:3 or 7:9) in the F2 and BC1F1 to both parents fit those previously reported when each fatty acid was studied independently. However, a distortion was observed in their combined segregation, indicating that neither character was independently inherited. Furthermore, the analysis of the F3 generation revealed that F2 half seeds with the highest C18:0 concentration in a high C18:1 background were still heterozygous for either the C18:0 or the C18:1 levels, suggesting a genetic linkage between the alleles Es2 and Ol These alleles determine a lower C18:0 and a higher C18:1 content, respectively. No F2 recombination between them was achieved, resulting in the absence of high C18:0/high C18:1 phenotypes. However, some intermediate C18:0/high C18:1 F2 seeds led to stable F3 seeds with this phenotype (130 g kg−1 C18:0/790 g kg−1 C18:1).

Allotetraploid segregation for single-gene morphological characters in quinoa (Chenopodium quinoa Willd.)

Cytological evidence suggests the Andean grain crop quinoa is an allotetraploid, but in the few genetic studies which have been published a functionally diploid (disomic-monogenic) model has been assumed for segregation at individual loci in this species. In this study, controlled crosses using male sterile plants as female parents produced F1 and F2 generations segregating for three different single-gene morphological traits. Allelic segregation analysis revealed a range of F1 and F2 ratios indicative of both disomic-digenic and tetrasomic inheritance in two of these traits, as well as distorted F2 ratios suggesting erratic multivalent formation at meiosis. These results are consistent with allotetraploidy in quinoa, with functional alleles having been retained at some duplicate loci and at least some association occurring between homoeologous chromosomes. Tetrasomic segregation ratios observed in a minority of families may be due to reciprocal fragment exchange between homoeologues. The occurrence of tetraploid segregations at some loci in quinoa complicates breeding and genetic studies in the crop.

Genetic Control of Dinitroaniline Resistance in Foxtail Millet (Setaria italica)

Inheritance of dinitroaniline resistance was investigated in F2 and F3 populations of crosses between a resistant green foxtail and three foxtail millet cultivars (Se-taria viridis and Setaria italica, respectively). Resistance was assessed on the basis of inhibition of root growth of seedlings in trifluralin solution. Results indicated that resistance was recessive but did not give a monogenic segregation ratio in F2. Distortion of segregation or two linked loci (r =.23) might account for only 15% resistant plants in F2 progeny. Quantitative analysis showed that part of the response to trifluralin is under the control of further minor genes.

Inheritance of Peanut Testa Colors Involved in Market Acceptability

The only acceptable testa colors in the U.S. peanut (Arachis hypogaea L.) market are tan, pink, and red. A better understanding of peanut testa color genetics would be helpful to breeders in developing new cultivars to meethese marketing parameters for human consumption. The objective of this study was to gain further knowledge on the inheritance of these very important testa colors. Six single crosses using three tan testa germplasm accessions (PI 203395, PI 203396, and PI 203397) as female parents and two new peanut cultivars (Georgia Runner and Georgia Browne) as male parents were made in 1989. Seed harvested from F1, F2, and F3 generations were classified during 1990, 1991, and 1992, respectively, for testa color, and data were analyzed for goodness‐of‐fit to expected genetic ratios. Testa color segregation fit a 15 tan + pink:l red F2 ratio, which confirmed a duplicate recessive loci model for red testa color. Genotypes, R2R2r3r3 and r2r2R3R3, are proposed for the three germplasm and the two Georgia parental peanut lines, respectively.

Development of genetic markers in celery based on restriction fragment length polymorphisms

Linkage relationships are reported for 34 markers in celery (Apium graveolens L. var 'dulce') including 21 RFLP, 11 isozyme, and 2 morphological traits. The mapping was carried out in a cross between celery and an annual accession from Thailand, A143, and based on F2 segregation of 136 plants. A total of 318 centiMorgans (cM) are covered by the markers distributed in 8 linkage groups. Probes for the identification of RFLPs were isolated from a celery cDNA library and were also obtained from heterologous sources. EcoRV, EcoRI, and HindIII were the most useful restriction enzymes in uncovering polymorphism. In our cross, 18% of the cDNA probes were found to be polymorphic for at least one of the enzymes used. Six of the markers showed significant deviations from expected F2 ratios.

Acoustic validation of vowel error patterns in developmental apraxia of speech

Acoustic analyses of vowel error patterns in five children with DAS validated the perceptual judgements described in a study by Pollock and Hall (1991). Results of the present study showed that perceptual judgements of diphthong reduction corresponded highly with second formant (F2) movement ratios of 0·20 or less. Perception of correct diphthong production was perceived with F2 ratios of 0·23 or greater for θ, 0·24 or greater for θ, and 0·36 or greater for θ. The perception of laxing and tensing errors for high vowels often corresponded to the location of F1-F2 coordinates. The perception of laxing of/e/, however, was more often associated with F2 ratios of less than 0·20, indicating a lack of change in vocal tract configuration or a loss of diphthongization. Derhotacization errors were perceived when there were abnormally high F3 frequencies and F2 and F3 coordinates that were far removed from the mean for normal children. These results demonstrated the fact that, for these data, perceptual judgements were a valid and reliable means of assessing vowel and diphthong productions.

Inheritance of Stringless Pod in Pisum sativum L.

In crosses between stringless and stringy podded pea cultivars, all plants of the F1 and backcross to the stringy parent had stringy pods. F2 ratios varied widely among crosses, and populations always had more stringy plants than expected, based on a single locus. The ratio of nonsegregating (stringy): segregating F3 families derived from stringy F2 plants fit a single-gene hypothesis in half of the crosses. Backcrosses of F1 to the stringless parent fit the expected 1:1 ratio when the pollen parent was stringless, but the reciprocal backcrosses showed a deficiency of stringless plants, suggesting that poor competitive ability of pollen bearing the stringless factor was the reason for deficiencies of stringless plants. It is concluded that stringlessness is controlled by a single recessive gene for which the designation sin-2 is proposed. A reduction in pod size, plant height, and number of wrinkled seed segregates was associated with stringlessness.

The nucleolus organizer regions (Nor loci) of hexaploid wheat cultivars

We have used the techniques of molecular genetics to analyse the nucleolus organizer regions (Nor loci) of a broad range of Australian, Chinese, and other hexaploid wheats (Triticum aestivum L. em Thell.). Genomic DNA was extracted from the leaves of 260 wheat cultivars, 94 different F1 hybrids, and from more than 800 F2 plants. Samples of the DNA were digested with the restriction enzyme TaqI and electrophoretically separated in agarose gels. The DNA fragments were then transferred to DNA filters by Southern blotting and assayed with the probe pTa250.4. This probe specifically detects the intergenic spacer DNA sequences which alternate with the ribosomal-RNA (rRNA) genes in highly repeated tandem arrays within the Nor loci. Analyses of the spacer DNA restriction fragments present in P, F1 and F2 plants show that allelic variants of the Nor loci can be distinguished by the existence of different lengths of spacer DNA fragments, different combinations of different length fragments, or differing amounts of the same length fragments. Eight alleles of the Nor-B1 locus on chromosome 1B (Nor-Bla to Nor-B1h) and 20 variants of the Nor-B2 locus on chromosome 6B (Nor-B2a to Nor-B2t) have been identified. The DNA fragments present in the different alleles are expressed in a co-dominant fashion to give phenotypic F2 ratios of 1 : 2 : 1 and 1 : 2 : 1 : 2 : 4 : 2 : 1 : 2 : 1, indicating segregation at one or two loci, respectively. With two exceptions, individual alleles segregated in a 1 : 1 ratio. On the basis of the presence of different combinations of Nor-B1 and Nor-B2 alleles, the wheat cultivars investigated were divided into 53 phenotypic groups. These groups clearly reflect the germplasm used in wheat breeding programs in different countries. Hybrid wheats could also be recognized and plants with new combinations of alleles were produced.

Genetic control and linkage relations of additional isozyme markers in chick-pea

Allozyme polymorphisms of nine enzymes - aspartate aminotransferase (AAT), diaphorase (DIA), esterase (EST), formate dehydrogenase (FDH), β-galactosidase (GAL), β-glucosidase (GLU), malate dehydrogenase (MDH), malic enzyme (ME), and peroxidase (PRX) - were described in chick-pea (Cicer L.). Thirteen isozyme loci, Aat-c, Dia-4, Est-2, Est-4, Est-10, Fdh, Gal-2, Gal-3, Gal-4, Glu-3, Mdh-2, Me-2, and Prx-2, were genetically defined. Alleles of each of these isozyme loci expressed codominantly in heterozygotes and exhibited a codominant, single-locus segregation ratio in F2. The loci Est-2, Mdh-2, and Me-1 were expressed only in flower. Linkage relations were determined for these 13 and several previously defined isozyme loci. The following new genetic linkages were identified: Pgm-p (locus for plastid phosphoglucomutase) - Est-10; Ald-p1 (one of the duplicate loci for plastid aldolase) - Glu-3 - Gal-2 - Est-2,3; Gal-3 - Aco-m (locus for mitochondrial aconitase) - Prx-2,3; Gpi-c (locus for cytosolic glucosephosphate isomerase) - Fdh; and Est-4 - Me-1. This study provides further confirmation on the existence of several conserved linkage groups among Cicer, Pisum, and Lens.