MEIOTIC IRREGULARITIES CAUSED BY INTERACTING STERILITY GENES IN CULTIVATED SAFFLOWER (CARTHAMUS TINCTORIUS)

1977 ◽  
Vol 19 (1) ◽  
pp. 103-109 ◽  
Author(s):  
Jirair Carapetian ◽  
Earlene A. Rupert
Keyword(s):  
Pollen Grains ◽  
Carthamus Tinctorius ◽  
Nuclear Genes ◽  
Female Sterility ◽  
Meiotic Irregularities ◽  
Chromosome Bridges ◽  
Normal Meiosis ◽  
Sterility Genes

Microsporogenesis was studied in the male-female sterile F2 segregants of a safflower cross involving 'US-10' and '57-147' cuitivars and was compared with normal meiosis in the F1 hybrids. In the microspores of the sterile plants contraction of chromosomes during prophase was irregular and patchy and they did not stain well with acetocarmine. At MI, most of the 24 chromosomes tended to stick to each other at random resulting in the formation of several chromosome bridges during AI. Multipolar meiotic divisions were observed. The second division was rarely seen. Apparently, meiosis ends with a multipolar AI separation and with the formation of 3- to 9-celled "quartets" which later develop nonfunctional pollen grains. The onset of meiosis in sterile plants was delayed and microsporogenesis subsequently progressed at a much slower rate than in fertile F1 hybrids. Three interacting nuclear genes appear to cause male-female sterility and affect microsporogenesis by interfering with some component essential for normal meiosis.

Effects of Safflower Sterility Genes on the Inflorescence and Pollen Grains

1994 ◽  
Vol 42 (3) ◽  
pp. 325 ◽  
Author(s):  
J Carapetian
Keyword(s):  
Pollen Grains ◽  
Reproductive Organs ◽  
Carthamus Tinctorius ◽  
Female Sterility ◽  
Natural Conditions ◽  
Vegetative Development ◽  
Stainable Pollen ◽  
The Mean ◽  
Pollen Diameter ◽  
Sterility Genes

Three interacting, unlinked, nuclear genes are reported to control the inheritance of male-female sterility in safflower (Carthamus tinctorius L.). In a cross between US-10 cultivar (genotype S(1)S(1)s(2)s(2)s(3)s(3)) and a geographically distant Indian line 57-147 (genotype s(1)s(1)S(2)S(2)S(3)S(3)), F-2 plants segregated 57 fertile:7 sterile. Sterile genotypes set no seed under natural conditions. This study reports the effects of sterility genes on the inflorescence and pollen grains. Floret elongation was limited in sterile plants at bloom. Lengths of florets in the sterile individuals showed a 17% and a 40% reduction one day before and on the day of anthesis, respectively. This resulted in a conspicuous pinched appearance of the capitula. Lack of seed development in sterile plants hindered the expansion of capitula and prevented the dried florets from lying against the imbricate bracts as in normal fertile plants. The percentage pollen stainability was 96.1 in US-10, 87.5 in 57-147, 91.3 in the F-1, 90.5 in fertile F-2, and 1.4 in sterile F-2 plants. However, none of the stainable pollen grains of the sterile F-2 plants was viable. The mean pollen diameter was 53.2 in US-10, 56.3 in 57-147, 53.9 in the F-1, 58.1 in fertile F-2, and 35.8 mu m in sterile F-2 plants. Sterile plants exhibited a greater variation in pollen diameter than the fertile plants. Light and scanning electron microscopy observations revealed the absence of normally sculptured and tricolpate pollen from the sterile plants. The results suggest that the sterility genes have their effects primarily on reproductive organs, but do not hinder vegetative development and growth of sterile plants before they bloom.

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.

Aberrant microspore development in hybrids of maize × Tripsacum dactyloides

Genome ◽  
1993 ◽  
Vol 36 (5) ◽  
pp. 987-997 ◽  
Author(s):  
Bryan Kindiger
Keyword(s):  
Pollen Development ◽  
Cytological Study ◽  
Metaphase Plate ◽  
Pollen Grains ◽  
Female Sterility ◽  
Microspore Development ◽  
Tripsacum Dactyloides ◽  
Male And Female ◽  
Inherent Problem ◽  
Male And Female Sterility

Cytogenetic investigations of meiosis in hybrids between maize and Tripsacum have been well documented; however, the inherent problem of male and female sterility has not been addressed either on a genetic or cytogenetic level. The purpose of this cytological study was to identify some of the probable causes of male sterility in maize × Tripsacum dactyloides hybrids. Disturbances in pollen development of maize × T. dactyloides hybrids, derived from both diploid (2n) and tetraploid (4n) Tripsacum sources, were commonly observed. Anomalies in the development of the microspore apparently occurred because of a failure of the chromosomes to congregate at the metaphase plate, development of a tripolar spindle, and failure of cytokinesis at the first and second meiotic divisions. Phenotypic features of abnormal microspore development were the maturation of large pollen grains, "Siamese" pollen grains, the occurrence of variable invaginations, and a nuclear budding-type behavior. These abnormalities were not observed in the 56-chromosome amphidiploid or the 38-chromosome backcross generations.Key words: maize, Tripsacum, microspore, sterility.

scholarly journals Sterile mutation in Drosophila melanogaster

1977 ◽  
Vol 30 (2) ◽  
pp. 107-113 ◽  
Author(s):  
Takao K. Watanabe ◽  
Won Ho Lee
Keyword(s):  
Drosophila Melanogaster ◽  
Male Sterility ◽  
Female Sterility ◽  
Sterility Genes ◽  
Lethal Genes

SUMMARYThe number of loci which are potentially able to produce sterility genes was estimated for Drosophila melanogaster. There appear to be, on the second chromosome, about 80 loci capable of producing male sterility and about 60 loci capable of producing female sterility. These figures seem to be considerably less than (400–500) loci responsible for lethal genes.

scholarly journals FERTILITY GENES IN NATURAL POPULATIONS OF DROSOPHILA MELANOGASTER. I. FREQUENCY, ALLELISM AND PERSISTENCE OF STERILITY GENES

Genetics ◽  
1973 ◽  
Vol 74 (2) ◽  
pp. 351-361
Author(s):  
Chozo Oshima ◽  
Takao K Watanabe
Keyword(s):  
Natural Populations ◽  
Pleiotropic Effect ◽  
Female Sterility ◽  
Male And Female ◽  
Random Combination ◽  
Cage Population ◽  
Male And Female Sterility ◽  
Fertility Genes ◽  
Sterility Genes ◽  
Lethal Genes

ABSTRACT Three or four percent of the wild flies in natural populations of D. melanogaster have been found to be sterile. An analysis of sterility associated with the second chromosome revealed a much lower frequency of genetically sterile flies. The accumulation of sterility genes in a cage population was proportional to that of lethal genes, as were their equilibrium frequencies in several natural populations. Many sterile chromosomes were associated with low viability due to pleiotropic effects. The number of chromosomes leading to sterility in both sexes was larger than the expectation based on random combination of male and female sterility genes. This suggests that there is some linkage disequilibrium between male and female sterility genes, as well as a pleiotropic effect of single sterility genes. Some sterility genes were maintained in natural and cage populations, and the patterns of persistence of the sterility genes were very similar to those of lethal genes.

FEMALE STERILITY IN POTATOES

1943 ◽  
Vol 21c (2) ◽  
pp. 41-56 ◽  
Author(s):  
T. J. Arnason
Keyword(s):  
Irish Cobbler ◽  
The Other ◽  
Female Sterility ◽  
Gametophyte Development ◽  
Potato Varieties ◽  
Number Of Seeds ◽  
Flower Abscission ◽  
Sterility Genes

Between 600 and 900 ovules are estimated to begin development in single normal potato ovaries. The number of seeds per fruit ranged from 0 to 183 in 1941, from 7 to 472 in 1942.Sectioned ovules from several potato varieties were examined. Estimates of the proportion of aborted ovules from freshly opened flowers or nearly mature buds were as follows: Minn. 75-5: 10%, Earlaine: 15%, Early Ohio: 20%, Irish Cobbler: 30–40%, Sebago: 60%, U.S.D.A. 46000: 80%, Netted Gem: 100%. Pollen from the first two varieties only in this list has been used successfully in crosses. In Netted Gem few gametophytes began development, most of the abortion occurring earlier. In the other varieties a larger proportion of the abortion became evident after gametophyte development had been initiated. In Sebago many embryo sacs were immature in freshly opened flowers. Inexact distribution of chromosomes at meiosis probably accounts for a part of the observed abortion. Sterility genes may be responsible for a part. Premature bud and flower abscission lowers the expressed fertility of all varieties but is more effective in some: e.g. Netted Gem and Early Ohio, than in others, e.g. Minn. 75-5 and Earlaine. Fertilization in Irish Cobbler occurred mainly two to four days after pollination; 50% of ovules in the upper half of the ovary showed endosperm divisions. Evidence of fertilization was seen in less than 5% of ovules of U.S.D.A. 46000 taken four days after pollination. Nutritive cells of the integument became considerably enlarged in many ovules containing aborted embryo sacs.

Molecular mapping of five soybean genes involved in male-sterility, female-sterility

Genome ◽  
2015 ◽  
Vol 58 (4) ◽  
pp. 143-149 ◽  
Author(s):  
Benjamin Speth ◽  
Joshua P. Rogers ◽  
Napatsakorn Boonyoo ◽  
A.J. VanMeter ◽  
Jordan Baumbach ◽  
...  
Keyword(s):  
Molecular Mapping ◽  
Female Sterility ◽  
Chromosome 11 ◽  
Male Sterile ◽  
Sterile Female ◽  
Fertility Reduction ◽  
And Function ◽  
Fertility Genes ◽  
Sterility Genes

In soybean, asynaptic and desynaptic mutants lead to abnormal meiosis and fertility reduction. Several male-sterile, female-sterile mutants have been identified and studied in soybean, however, some of these mutants have not been mapped to locations on soybean chromosomes. The objectives of this study were to molecularly map five male-sterile, female-sterile genes (st2, st4, st5, st6, and st7) in soybean and compare the map locations of these genes with already mapped sterility genes. Microsatellite markers were used in bulked segregant analyses to locate all five male-sterile, female-sterile genes to soybean chromosomes, and markers from the corresponding chromosomes were used on F2 populations to generate genetic linkage maps. The st2, st4, st5, st6, and st7 genes were located on molecular linkage group (MLG) B1 (chromosome 11), MLG D1a (chromosome 01), MLG F (chromosome 13), MLG B2 (chromosome 14), and D1b (chromosome 02), respectively. The st2, st4, st5, st6, and st7 genes were flanked to 10.3 (∼399 kb), 6.3 (∼164 kb), 3.9 (∼11.8 Mb), 11.0 (∼409 kb), and 5.3 cM (∼224 kb), and the flanked regions contained 57, 17, 362, 52, and 17 predicted genes, respectively. Future characterization of candidate genes should facilitate identification of the male- and female-fertility genes, which may provide vital insights on structure and function of genes involved in the reproductive pathway in soybean.

scholarly journals Cytogenetic Characterization and Nuclear DNA Content of Diploid and Tetraploid Forms of Stokes Aster

HortScience ◽  
2008 ◽  
Vol 43 (7) ◽  
pp. 2005-2012
Author(s):  
Jessica Gaus Barb ◽  
Dennis J. Werner ◽  
Shyamalrau P. Tallury
Keyword(s):  
Dna Content ◽  
Nuclear Dna ◽  
Nuclear Dna Content ◽  
Chromosome Length ◽  
Slight Reduction ◽  
Meiotic Pairing ◽  
Meiotic Irregularities ◽  
Cytogenetic Characterization ◽  
2C Dna Content ◽  
Chromosome Bridges

Stokesia laevis (J. Hill) Greene is a herbaceous perennial native to the southeastern United States. Most cultivars of Stokesia are diploid (2n = 2x = 14) except for ‘Omega Skyrocket’, a tetraploid (2n = 4x = 28) form selected from a natural population. A comparative study of the karyotypes and meiotic behavior of diploid cultivars, seed-derived accessions of ‘Omega Skyrocket’, synthetically derived autotetraploids, and triploid progeny from these taxa strongly suggest that ‘Omega Skyrocket’ is an autotetraploid form of Stokesia. Total karyotype length, 161 μm and 293 μm, and average chromosome length, 11.5 μm and 10.5 μm, of the diploid cultivars and tetraploid accessions of ‘Omega Skyrocket’, respectively, were determined. The karyotype of the diploid cultivars consisted of eight metacentric (m) and six submetacentric (sm) chromosomes with average arm ratio values ranging from 1.12 to 2.06. The karyotype of ‘Omega Skyrocket’ consisted of 23 m chromosomes and 5 sm chromosomes with average arm ratio values ranging from 1.22 to 2.02. Meiotic pairing in the diploids was normal. No meiotic irregularities such as laggards or bridges were observed and disjunction was balanced (7:7). Accessions of ‘Omega Skyrocket’ demonstrated a high frequency (60%) of quadrivalent formation; however, later stages of meiosis were regular with balanced disjunction (14:14) occurring in 95% of the cells. Meiotic configurations in synthetically derived autotetraploids and triploid hybrids from crosses of diploid cultivars × ‘Omega Skyrocket’ consisted of univalents, bivalents, trivalents, quadrivalents, and pentavalents. Abnormalities, including laggards, unequal and/or premature disjunction, chromosome bridges, and chromosome stickiness were observed. Average nuclear 2C DNA content was 20.3 pg for the diploid cultivars and 39.9 pg for the newly synthesized autotetraploids. Average nuclear 2C DNA content for ‘Omega Skyrocket’ was 37.3 pg, which was 8.2% less than twice the average 2C DNA content of the diploid accessions and 6.4% less than the newly synthesized autotetraploids, suggesting that genomic downsizing in ‘Omega Skyrocket’ has occurred. Similarity of the karyotypes of the diploids and ‘Omega Skyrocket’ and the slight reduction in nuclear DNA content suggest that ‘Omega Skyrocket’ has diverged little from its original diploid progenitor.

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