Interspecific hybridization in Phalaris: Hybrids between Phalaris tuberosa and the hexaploid race of Phalaris arundinacea

1962 ◽  
Vol 13 (4) ◽  
pp. 585 ◽  
Author(s):  
JR McWilliam
Keyword(s):  
Low Frequency ◽  
Mean Value ◽  
Phalaris Arundinacea ◽  
F1 Hybrids ◽  
Male Sterile ◽  
F1 Hybrid ◽  
Structural Differences ◽  
Close Relationship ◽  
Average Fertility ◽  
Cytological Behaviour

Interspecific hybrids from the cross Phalaris tuberosa (2n = 28) x Phalaris arundinacea (2n = 42) are described. The close relationship between P. tuberosa and the hexaploid race of P. arundinacea is indicated by the ease of hybridization. The F1 hybrid is functionally male-sterile, but sets occasional seed when backcrossed to P. tuberosa. Meiosis in the 35-chromosome F1 hybrids was irregular. Pairing at diakinesis averaged 11.3 bivalents, with a range of 7–14. Univalents were present in all hybrids, averaging 10.3 per cell, and were observed as laggards at anaphase I and II. Sterility appears to be largely chromosomal, associated with numerical and structural differences between partially homologous genomes. The cytological behaviour of the 70-chromosome allopolyploids, produced by doubling the F1 hybrids, was fairly regular. The predominant diakinesis association was in the form of bivalents, with a mean value of 32.1. Univalents and quadivalents were present, but at a low frequency. There was a continued expression of allosyndetic pairing as indicated by the formation of bridges and fragments at anaphase. The average fertility of allopolyploids, despite irregularities at meiosis, was high, and only 30% below the P. tuberosa controls. The growth of the F1 hybrids was superigr to that of the parents, both in the seedling stage and in swards. This superiority was most pronounced in the autumn and summer. In this respect the hybrid combines the seasonal growth characteristics of both parents. The unusual vigour, long growing season, and adaptability of the hybrid justify efforts to develop it as a commercial variety. Three possible plant-breeding approaches to achieve this objective are presented.

Chromosomal Differentiation Among Ecotypes of Phalaris aquatica L.

1980 ◽  
Vol 28 (6) ◽  
pp. 645 ◽  
Author(s):  
E Putievsky ◽  
RN Oram ◽  
K Malafant
Keyword(s):  
Pollen Grains ◽  
F1 Hybrids ◽  
Male Sterile ◽  
Geographic Origins ◽  
Meiotic Irregularities ◽  
Structural Differences ◽  
Two Generations ◽  
Chromosomal Differentiation ◽  
Mother Cells ◽  
F2 Progeny

Seventy-two hybrids of P. aquatica were made among 13 diverse Mediterranean ecotypes and cv. Australian, and five indicators of hybrid abnormality were measured in the first two generations. The proportions of stainable, apparently normal pollen grains formed by F, hybrids varied between 5 and 98% and their spikelet fertility ranged from 19 to 77%. Of the 43 hybrids that were derived from pairs of self-incompatible parents, 13 were highly self-compatible. Crosses between lines from different groups of parents produced F2 progeny containing up to 17% of lethal seedlings and up to 39% of male sterile plants. In the cross between cv. Australian and the Moroccan ecotype, CPI 19331: the frequency ofzebra-striped lethal seedlings was as high as 33% in F2 progenies, but only 0 or 1% in back-crosses to either parent. Hence the zebra-striped phenotype was not caused by a mutation existing in the parents but rather by deletions or duplications generated during meiosis in the F1 hybrids. Many meiotic irregularities were observed in the pollen mother cells of the F1 and F2 hybrids between cv. Australian and CPI 19331. These included small loops, acentric fragments, univalents and multivalents at diakinesis, and bridges at anaphase I, indicating that the genomes of these two lines differed by several inversions and interchanges. These structural differences would lead to a range of duplications and deficiencies in the gametes. and hence could account for each of the five kinds of hybrid abnormality observed in the F1 and F2 generations. One aneuploid F2 plant with 25 chromosomes was found. A dihaploid plant in cv. Australian had an average of 4.3 bivalents per pollen mother cell, whereas virtually all chromosomes in the tetraploid parental lines paired as bivalents. Thus, P. aquatica is a segmental allotetraploid with a system which prevents homoeologous pairing in tetraploids but not in dihaploids. The partial barriers to hybridization between P. aquatica lines are not closely related to their geographic origins or varietal classifications. These barriers may hinder but have not prevented the recombination of parental traits during the development of improved cultivars.

scholarly journals Barley CMS detected in Finland in 1976 enabled growing of productive winter-barley F1 hybrids in the European winter-barley zone since 2002

2018 ◽  
Author(s):  
Hannu Ahokas
Keyword(s):  
Winter Barley ◽  
F1 Hybrids ◽  
Cytokinin Activity ◽  
Male Sterile ◽  
Lodging Resistance ◽  
F1 Hybrid ◽  
Alopecurus Myosuroides ◽  
Restorer Genes ◽  
Hybrid Seeds ◽  
The Uk

My wide crossing program of barley (Hordeum vulgare s.l.) in 1976 yielded a system which could be used to produce F1 hybrid seeds. The genotypes were designated as msm1 (male sterile, maternal), and Rfm1a (restorer of fertility in msm1). I later found 19 other strains with dominant restorer alleles, which were carriers of a fertile cytoplasm. Hence, the restorer genes probably evolved in advance creating an opportunity for the cytoplasm to mutate to male sterility. Cytological studies revealed an uncontrolled secretion of sporopollenin in the sterile anthers, leading to their starvation and sterility. The Rfm1a gene was shown to cause an increase in the cytokinin activity of Fraction 7 in the root sap of barley, regardless of the cytoplasm type. In 1980, I found another male sterile cytoplasm, msm2, whose anther can also be restored by the Rfm1 alleles. The msm2 strain originally had complementary partial restorer genes and was found to be more responsive to such restorers than msm1. In Germany, the Rfm1 gene was recently translocated to a rye (Secale cereale) chromosome to study its response in CMS rye. The msm2 cytoplasm could be distinguished from msm1 with electron microscopy at the early stages of the anthers. The msm1 cytoplasm is not known to be associated with increased disease susceptibility, unlike the T-sterile cytoplasm formerly used to produce hybrid seeds of maize (Zea mays). Hybrid cvs: Seeds of msm1–Rfm1a were first requested from me by Hilleshög AB in Sweden. Hilleshög later became a part of Syngenta. Hilleshög techniques for sugar-beet hybrids were applied by Syngenta breeders to produce hybrid barley seeds. Syngenta introduced the first commercial winter-barley hybrid in the UK in 2002. Their hybrid cvs were marketed to countries growing winter-barley in Europe. The ha yields of their hybrids exceeded those of conventional cultivars or parental lines by about 1000 kg. In Spain, the winter-barley hybrid yielded 21 percent more than the conventional cultivars in 2015, when grown in the field scale. For the 2016 harvest, hybrids were sown in Germany on more than 140000 ha, which reflects 11.6 percent of the total feed barley area. In 2017, Syngenta launched a cashback scheme for, if their hybrid cultivars did not comfortably out-yield the farmer's conventional counterpart that season. Hybrid seeds must be acquired for each sowing. Unlike conventional monogenic barley cultivars, the hybrids exploit genetic variability and heterozygosity. Hybrid winter-barley is the most competitive of winter cereals with the aggressive weed Alopecurus myosuroides in the UK. Thick stems in new hybrids increase lodging resistance. The winter-barley hybrid ‘Wootan’ gave ha yields up to 6000 kg in Tammisaari, though incompletely winter-hardy in Finland. Maturing a month later than the hybrid ‘Hobbit’ and with optimal winterhardiness, winter-barley hybrids could exceed ha yields of 10000 kg in Finland. Some other breeding companies seem to work for hybrid barley, too.

Male sterility in field beans (Vicia faba L.). II. Yield trials of F1 hybrid winter beans produced with the aid of male sterility

1964 ◽  
Vol 63 (2) ◽  
pp. 235-243 ◽  
Author(s):  
D. A. Bond ◽  
J. L. Fyfe ◽  
Gillian Toynbee-Clarke
Keyword(s):  
Male Sterility ◽  
Inbred Lines ◽  
F1 Hybrids ◽  
Male Sterile ◽  
Male Sterile Line ◽  
F1 Hybrid ◽  
Vicia Faba L ◽  
The Mean ◽  
Yield Trials ◽  
Field Beans

1. F1 hybrids between inbred lines of winter beans were obtained by roguing male-fertile plants from segregating progenies of a genetic male-sterile line which had been interplanted with a pollinator.2. In a series of trials the mean yields of many hybrids were significantly higher than those of open-pollinated varieties. Over the 4 years, 1959–62, with trials at three centres in each year, the mean advantages of all hybrids over the two control varieties was 6·4 cwt./acre over Gartons S.Q., 4·7 cwt./acre over Throws M.S.

Agronomic Comparison, Heterosis and Hydrocyanic Acid Potential (HCN-p) of Sudangrass-Sorghum and Sudangrass-Sudangrass Hybrids and Their Parents

1969 ◽  
Vol 68 (2) ◽  
pp. 143-155
Author(s):  
A. Sotomayor-Ríos ◽  
S. Torres-Cardona
Keyword(s):  
Crude Protein ◽  
Female Parent ◽  
Management Program ◽  
Hydrocyanic Acid ◽  
F1 Hybrids ◽  
Male Sterile ◽  
F1 Hybrid ◽  
Acid Potential ◽  
The Tropics ◽  
Combined Data

Cytoplasmic male-sterile sudangrass, A Rhodesian (Sorghum arundinaceum), was crossed with two sudangrasses (Sweet Sudan and Piper) and six forage sorghums (Sugar Drip, Brawley, Roma, Collier, Sumac and Meridian 55- 1). The eight F1 hybrids and their male parents were compared for yield of green forage (GF), dry forage (DF), and crude protein (CP); dry matter (DM) and CP contents; plant height, leaf area, number of tillers, leaf/stem ratio and hydrocyanic acid potential (HCN-p). The first cutting was made 60 days after planting and the two subsequent cuttings at a 60-day interval. The second harvest had the greatest DF yields but a lower CP content when compared to the first harvest. The  F1 hybrids were significantly superior than male parents for all traits except HCN-p at 45 and 60 days, leaf/stem ratio and DM and CP contents at each of the three harvests. Combined data for the three cuttings show that the  F1's of A Rhodesian x Sumac and A Rhodesian x Roma produced the greatest DF yields among hybrids. The DF yields of Sugar Drip were the highest among male parents. The average DF yield for  F1 hybrids was 19% more than for the male parents. The DF yields of about 19 t/ha of the best hybrids compared favorably with other high yielding forage sorghums. Heterosis was observed for the most important traits,  F1 hybrid A Rhodesian x Piper exhibiting the greatest value, 60 and 97% more DF than the midparent and high parent, respectively. The excellent DF yields, relatively low HCN-p values and high protein content of hybrids when A Rhodesian sudangrass was the female parent, make them potentially valuable genotypes for utilization in an intensive management program in the tropics. As in a previous study. A Rhodesian sudangrass proved to be a potentially useful male-sterile line in the development of superior F1 forage sorghum hybrids in Puerto Rico.

scholarly journals Performance of F1 Hybrids from Crosses of Three Sudangrasses and Six Forage Sorghums with A Rhodesian Sudangrass

1969 ◽  
Vol 65 (2) ◽  
pp. 142-146
Author(s):  
Antonio Sotomayor-Ríos ◽  
Alma Santiago
Keyword(s):  
Puerto Rico ◽  
Crude Protein ◽  
F1 Hybrids ◽  
Male Sterile ◽  
Male Sterile Line ◽  
F1 Hybrid ◽  
Forage Sorghum ◽  
Cytoplasmic Male Sterile

A cytoplasmic male-sterile sudangrass (A Rhodesian) was crossed with three other sudangrasses (Common, Greenleaf, and Piper) and six forage sorghums (Sart, Millo Blanco, Bloomless, Forage Sorgo x Sugar Drip, Collier, and Brawley). The nine F1 hybrids were compared for yield of green forage (GF), yield of dry forage (DF), crude protein (CP) content, CP yield, and height at lsabela, Puerto Rico. Four cuttings were made. The first was 45 days after planting and the remaining three were at about 30-day intervals thereafter. The second harvest had the highest DF yield but the lowest CP content. The CP content was 15.7, 12.2, 14.6, and 15.6% for harvests 1, 2, 3, and 4, respectively. When data for all four harvests were combined, the F1 hybrid of A Rhodesian sudangrass x Common produced the highest GF ana DF yields, 143 kg•ha-1•day-1 of the latter which was 30% and 29% more than the 2nd and 3rd- highest DF producing hybrids. Differences in CP content among the nine F1hybrids were not significant, but A Rhodesian sudangrass x Common produced the highest CP yields. The tallest F1 hybrids were A Rhodesian x Common and A Rhodesian x Greenleaf. The GF and DF yields of A Rhodesian x Common were excellent. The results indicated that A Rhodesian sudangrass is a male-sterile line with potential for use in the development of superior F1 forage-sorghum hybrids in Puerto Rico.

scholarly journals Sequencing an F1 hybrid of Silurus asotus and S. meridionalis enabled the assembly of high-quality parental genomes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Weitao Chen ◽  
Ming Zou ◽  
Yuefei Li ◽  
Shuli Zhu ◽  
Xinhui Li ◽  
...  
Keyword(s):  
De Novo ◽  
Parental Species ◽  
F1 Hybrids ◽  
Pelteobagrus Fulvidraco ◽  
F1 Hybrid ◽  
Short Reads ◽  
Final Assembly ◽  
Genome Complexity ◽  
Hybrid Genome ◽  
Silurus Asotus

AbstractGenome complexity such as heterozygosity may heavily influence its de novo assembly. Sequencing somatic cells of the F1 hybrids harboring two sets of genetic materials from both of the paternal and maternal species may avoid alleles discrimination during assembly. However, the feasibility of this strategy needs further assessments. We sequenced and assembled the genome of an F1 hybrid between Silurus asotus and S. meridionalis using the SequelII platform and Hi-C scaffolding technologies. More than 300 Gb raw data were generated, and the final assembly obtained 2344 scaffolds composed of 3017 contigs. The N50 length of scaffolds and contigs was 28.55 Mb and 7.49 Mb, respectively. Based on the mapping results of short reads generated for the paternal and maternal species, each of the 29 chromosomes originating from S. asotus and S. meridionalis was recognized. We recovered nearly 94% and 96% of the total length of S. asotus and S. meridionalis. BUSCO assessments and mapping analyses suggested that both genomes had high completeness and accuracy. Further analyses demonstrated the high collinearity between S. asotus, S. meridionalis, and the related Pelteobagrus fulvidraco. Comparison of the two genomes with that assembled only using the short reads from non-hybrid parental species detected a small portion of sequences that may be incorrectly assigned to the different species. We supposed that at least part of these situations may have resulted from mitotic recombination. The strategy of sequencing the F1 hybrid genome can recover the vast majority of the parental genomes and may improve the assembly of complex genomes.

scholarly journals Fitness of F1 hybrids between 10 maternal wild soybean populations and transgenic soybean

2021 ◽  
Author(s):  
Jin Yue Liu ◽  
Ze Wen Sheng ◽  
Yu Qi Hu ◽  
Qi Liu ◽  
Sheng Qiang ◽  
...  
Keyword(s):  
Seed Weight ◽  
Wild Soybean ◽  
F1 Hybrids ◽  
Weed Competition ◽  
Transgenic Soybean ◽  
Wild Progenitor ◽  
F1 Hybrid ◽  
Dry Biomass ◽  
100 Seed Weight ◽  
Pod Number

AbstractThe releasing of transgenic soybeans (Glycine max (L.) Merr.) into farming systems raises concerns that transgenes might escape from the soybeans via pollen into their endemic wild relatives, the wild soybean (Glycine soja Sieb. et Zucc.). The fitness of F1 hybrids obtained from 10 wild soybean populations collected from China and transgenic glyphosate-resistant soybean was measured without weed competition, as well as one JLBC-1 F1 hybrid under weed competition. All crossed seeds emerged at a lower rate from 13.33–63.33%. Compared with those of their wild progenitors, most F1 hybrids were shorter, smaller, and with decreased aboveground dry biomass, pod number, and 100-seed weight. All F1 hybrids had lower pollen viability and filled seeds per plant. Finally, the composite fitness of nine F1 hybrids was significantly lower. One exceptional F1 hybrid was IMBT F1, in which the composite fitness was 1.28, which was similar to that of its wild progenitor due to the similarities in pod number, increased aboveground dry biomass, and 100-seed weight. Under weed competition, plant height, aboveground dry biomass, pod number per plant, filled seed number per plant, and 100-seed weight of JLBC-1 F1 were lower than those of the wild progenitor JLBC-1. JLBC-1 F1 hybrids produced 60 filled seeds per plant. Therefore, F1 hybrids could emerge and produce offspring. Thus, effective measures should be taken to prevent gene flow from transgenic soybean to wild soybean to avoid the production F1 hybrids when releasing transgenic soybean in fields in the future.

Nycthemeral Rhythm of the Frequency and Biomechanical Energy of High Frequency Intraocular Pressure Fluctuations

2013 ◽  
Author(s):  
Vincent Libertiaux ◽  
William P. Seigfreid ◽  
Massimo A. Fazio ◽  
Juan F. Reynaud ◽  
Claude F. Burgoyne ◽  
...  
Keyword(s):  
Intraocular Pressure ◽  
High Frequency ◽  
Pressure Fluctuations ◽  
Low Frequency ◽  
Pulse Amplitude ◽  
Mean Value ◽  
Multiple Time Scales ◽  
Dynamic Contour Tonometry ◽  
Multiple Time ◽  
Ocular Pulse

The optic nerve head (ONH) is the site of insult in glaucoma, the second leading cause of blindness worldwide. Intraocular pressure (IOP) is commonly regarded as a major factor in the onset and progression of the disease1 and lowering IOP is the only clinical treatment that has been shown to retard the onset and progression of glaucoma2. However, many patients continue to progress even at an epidemiologically-determined normal level of IOP3. This suggests that in addition to the mean value of IOP, IOP fluctuations could be a factor in glaucomatous pathophysiology. The importance of low frequency fluctuations of clinically-measured mean IOP remains controversial. These studies all rely on snapshot measurements of mean IOP at each time point, and those measurements are taken at relatively infrequent intervals (hourly at the most frequent, but usually monthly or longer). Recently however, there has been some interest in ocular pulse amplitude, or the fluctuation in IOP associated with the cardiac cycle, which can be measured by Dynamic Contour Tonometry (DCT). DCT provides continuous measurement of IOP, but only for a period of tens of seconds in which a patient can tolerate corneal contact without blinking or eye movement, which ironically are two of the most common sources of large high frequency IOP fluctuations according to our telemetric data collected from monkeys4 and previous human studies. In a recent report, continuous IOP telemetry was used in three nonhuman primates to characterize IOP dynamics at multiple time scales for multiple 24-hour periods5.

scholarly journals Reciprocal F1 hybrids of two inbred mouse strains reveal parent-of-origin and perinatal diet effects on behavior and expression

2018 ◽  
Author(s):  
Daniel Oreperk ◽  
Sarah A Schoenrock ◽  
Rachel McMullan ◽  
Robin Ervin ◽  
Joseph Farrington ◽  
...  
Keyword(s):  
Complex Traits ◽  
Detection System ◽  
Inbred Mouse ◽  
F1 Hybrids ◽  
Hybrid Population ◽  
Psychiatric Disease ◽  
Mouse Strains ◽  
Imprinted Genes ◽  
F1 Hybrid ◽  
Parent Of Origin

ABSTRACTParent-of-origin effects (POEs) in mammals typically arise from maternal effects or from imprinting. Mutations in imprinted genes have been associated with psychiatric disorders, as well as with changes in a handful of animal behaviors. Nonetheless, POEs on complex traits such as behavior remain largely uncharacterized. Furthermore, although perinatal environmental exposures, such as nutrient deficiency, are known to modify both behavior and epigenetic effects generally, the architecture of environment-by-POE is almost completely unexplored. To study POE and environment-by-POE, we employ a relatively neglected but maximally powerful POE-detection system: a reciprocal F1 hybrid population. We exposed female NOD/ShiLtJxC57Bl/6J and C57Bl/6JxNOD/ShiLtJ mice, in utero, to one of four different diets, then after weaning recorded their whole-brain gene expression, as well as a set of behaviors that model psychiatric disease. Microarray expression data revealed an imprinting-enriched set of over a dozen genes subject to POE; the POE on the most significantly affected gene, Carmil1 (a.k.a. Lrrc16a), was validated using qPCR in the same and in a new set of mice. Several behaviors, especially locomotor behaviors, also showed POE. Interestingly, Bayesian mediation analysis suggests Carmil1 expression suppresses behavioral POE, and Airn suppresses POE on Carmil1 expression. A significant diet-by-POE was observed on one behavior, one imprinted gene, and over a dozen non-imprinted genes. Beyond our particular results, our study demonstrates a reciprocal F1 hybrid framework for studying POE and environment-by-POE on behavior.

scholarly journals Evaluation of onion samples (Allium cepa L.) of various origins in the foothill zone of the North Caucasus and creation of source material fo

2021 ◽  
pp. 58-64
Author(s):  
I. S. Mastyaev ◽  
A. F. Agafonov ◽  
L. V. Krivenkov
Keyword(s):  
Climatic Conditions ◽  
Source Material ◽  
Biologically Active ◽  
F1 Hybrids ◽  
North Caucasus ◽  
F1 Hybrid ◽  
The North ◽  
Long Term Storage ◽  
Economically Valuable Traits ◽  
High Yields

Relevance. The success of breeding work is largely determined by the source material, the search and creation of which for target breeding begins with the collection and study of collectible samples for the alignment of morphological features; for the precocity and amity of maturation; for the keeping quality and transportability of bulbs; for the quality of vegetable products (high content of biologically active substances and antioxidants); for resistance to biotic and abiotic stressors of a specific growing zone.Materials and methods. On the basis of the North Caucasus branch FSBSI FSVC, 90 samples of spring onions from 26 countries of the world were evaluated in the number nursery for the period from 2017 to 2019, 71 of them were varieties and 19 were F1 hybrids. In a hybrid nursery, 25 hybrid combinations obtained from FSBSI FSVC (VNIISSOK) were evaluated. The laying and placement of experiments, agricultural techniques of cultivation, accounting and evaluation of economically valuable traits, biochemical analyses were carried out according to generally accepted methods. The standards are the new Primo and Ampex varieties of the selection of the FSBSI FSVC and the Italian F1 hybrid Ranko, which were placed every 10 collection samples.Results.According to the results of the assessment, among the studied F1 varieties and hybrids, sources of economically valuable traits such as yield (20-27 t/ha), precocity (80-90 days), preservation (more than 85%) when laid for long-term storage up to 7 months, purple, white and pink color of bulbs, as well as sources of long-shaped bulbs were identified. The greatest interest for breeding for yield is represented by 9 promising varieties and 9 F1 hybrids of onions of various origins, as well as 4 hybrid combinations that were distinguished by high yields, the yield of marketable products and the mass of marketable bulbs. These samples are recommended for use in the breeding process as sources for the creation of new varieties and hybrids with high yields for the agro-climatic conditions of the foothill zone of the North Caucasus.r breeding

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