A natural first-generation hybrid between Rorippa barbareaefolia and R. islandica

1968 ◽  
Vol 46 (8) ◽  
pp. 1079-1081
Author(s):  
Gerald A. Mulligan ◽  
A. E. Porsild
Keyword(s):  
First Generation ◽  
Female Parent ◽  
Yukon Territory ◽  
Male Parent ◽  
Male Sterile ◽  
Pollen Mother Cells ◽  
Mother Cells ◽  
Generation Hybrid

All the seeds taken from a fruiting specimen of Rorippa barbareaefolia (2n = 16) growing in the Yukon Territory produced plants with 24 somatic chromosomes. These plants were first-generation hybrids between R. barbareaefolia (2n = 16) and R. islandica (2n = 23). The female parent, R. barbareaefolia, was male sterile. Pairing configurations in pollen mother cells of these first generation hybrids suggested that the male parent, R. islandica, was autotetraploid.

A trigeneric hybrid between Hordeum, Aegilops, and Secale

Genome ◽  
1992 ◽  
Vol 35 (4) ◽  
pp. 647-649 ◽  
Author(s):  
A. Cabrera ◽  
A. Martin
Keyword(s):  
Chromosome Number ◽  
Chromosome Pairing ◽  
Seed Set ◽  
Female Parent ◽  
Hybrid Plant ◽  
Male Parent ◽  
Cytological Analysis ◽  
Pollen Mother Cells ◽  
Mother Cells

A trigeneric hybrid between Hordeum, Aegilops, and Secale was synthesized. The female parent was a fertile amphiploid between H. chilense and A. squarrosa and the male parent was S. cereale. The hybrid plant had the expected chromosome number of 2n = 21. Cytological analysis of pollen mother cells revealed no chromosome pairing. Morphology of the HchDR hybrid plant was similar to that of the Aegilops. The hybrid was sterile and no seed set was observed even after colchicine treeatment.Key words: Hordeum, Aegilops, Secale, trigeneric hybrid, cytology.

GENETIC MALE STERILITY IN RAPE (Brassica napus L.) CONDITIONED BY INTERACTION OF GENES AT TWO LOCI

1988 ◽  
Vol 68 (4) ◽  
pp. 1115-1118 ◽  
Author(s):  
LI ◽  
Y. QIAN ◽  
Z. WU ◽  
B. R. STEFANSSON
Keyword(s):  
Brassica Napus ◽  
Male Sterility ◽  
First Generation ◽  
Male Sterile ◽  
Brassica Napus L ◽  
Genetic Male Sterility ◽  
Generation Hybrid ◽  
Research Institute

Genetic male sterility (GMS) discovered in the rape (Brassica napus L.) cultivar, No.23, is conditioned by genes at two loci. The genes were designated as Ms1 and Ms2. Plants homozygous or heterozygous for the dominant Ms1 allele (Ms1Ms1 or Ms1ms1) and homozygous for the recessive ms2 allele (ms2ms2) were sterile while plants homozygous or heterozygous for the dominant Ms2 allele were fertile regardless of the alleles present at the Ms1 locus. The double recessive was also fertile. This indicates dominance epistasis at the Ms2 locus over the Ms1 locus. This GMS system can be used to produce first generation hybrid rape if the required genotypes have been isolaed. Pollination of the homozygous male sterile, Ms1Ms1ms2ms2 with the pollen from the double recessive fertile, ms1ms1ms2 ms2 will produce a generation of sterile plants. These sterile plants (Ms1ms1ms2ms2) when pollinated with pollen from genotypes homozygous for the Ms2 allele (Ms2Ms2), will produce a generation of fertile plants. The various genotypes which can be isolated from this GMS system are being used to develop hybrid rape at the Research Institute of the Shanghai Academy of Sciences.Key words: Rape, genetic male sterility, hybrids, Brassica napus

Male sterility in Brassica napus L. associated with an extra chromosome

1985 ◽  
Vol 27 (4) ◽  
pp. 467-471 ◽  
Author(s):  
Z. Fan ◽  
W. Tai ◽  
B. R. Stefansson
Keyword(s):  
Brassica Napus ◽  
Male Sterility ◽  
Extra Chromosome ◽  
Female Parent ◽  
Male Sterile ◽  
Cytological Examination ◽  
Brassica Napus L ◽  
Low Frequencies ◽  
Backcross Populations ◽  
Mother Cells

Male sterility was investigated in backcross populations from hybrids between Diplotaxis muralis and Brassica napus using the former as the female parent. The F1 was male sterile and low frequencies (less than 20%) of male sterile plants were obtained from subsequent backcross generations. The data did not fit any Mendelian genetic ratios. Cytological examination of pollen mother cells from 52 plants of these backcross populations indicated the presence of an extra chromosome in all 22 male sterile plants and the normal chromosome number (2n = 38) in the remaining 30 fertile plants. Thus an extra chromosome which is derived from Diplotaxis muralis appears to be the sole cause of male sterility in these backcross populations.Key words: male sterility, Brassica napus, Diplotaxis muralis.

A separate control for frequency and within-bivalent distribution of chiasmata in rye (Secale cereale L.)

Genome ◽  
1987 ◽  
Vol 29 (3) ◽  
pp. 419-424 ◽  
Author(s):  
V. Lein ◽  
T. Lelley
Keyword(s):  
Secale Cereale ◽  
Chiasma Frequency ◽  
Positional Distribution ◽  
Pollen Grains ◽  
Female Parent ◽  
Close Correlation ◽  
Strong Negative Correlation ◽  
Pollen Mother Cells ◽  
Chiasma Distribution ◽  
Mother Cells

Six genetically different inbred genotypes of spring-type rye Secale cereale with differences in the average number and in the positional distribution of chiasmata were used in this study. The line with the lowest chiasma frequency was chosen as the female parent and crossed with the other five lines. Parental, F1, and F2 data were collected on chiasma number and on chiasma distribution between and within bivalents. Evidence for a polygenic control of both phenomena was found. Chiasma distribution between bivalents within pollen mother cells obviously follows a binomial distribution. This is effected by a mechanism that prevents the formation of a second chiasma on a chromosome arm as long as chromosome arms without chiasma remain; i.e., with 14 chiasmata seven ring bivalents will generally be formed. This mechanism causes a very strong negative correlation between frequency and between-cell variance of chiasmata. The number of chiasmata is independent of their position within the bivalents. A very close correlation between the number of pollen mother cells without univalents and the number of fertile pollen grains was found. Key words: inbred rye, genetic control, chiasma frequency, chiasma distribution, heterosis.

scholarly journals Male parent birds exert more effort to reproduce in two desert passerines

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Donghui Ma ◽  
Mengjie Lu ◽  
Zhichang Cheng ◽  
Xingnan Du ◽  
Xiaoyu Zou ◽  
...  
Keyword(s):  
Reproductive Output ◽  
Female Parent ◽  
Northwest China ◽  
Reproductive Behaviour ◽  
Male Parent ◽  
Hatching Rate ◽  
Feeding Rates ◽  
Passerine Species ◽  
Arid Desert ◽  
Habitat Environment

Abstract Background Parental investment by birds is limited by the habitat environment, and a male parent increases its effort to reproduce in birds that live in high-altitude areas. Methods A study of the reproductive behaviour of the Saxaul Sparrow (Passer ammodendri) and the Isabelline Shrike (Lanius isabellinus) was carried out at the Gansu An’xi Extremely Arid Desert National Nature Reserve in northwest China to determine the reproductive input of passerine species in desert habitats. Results In Saxaul Sparrows, compared to the female parent, the male parent exhibited a significantly higher frequency of nest-defense behaviour (chirping and warning) during nesting, hatching and feeding periods. In addition, in comparison to the female parent, the male parent exhibited almost equal frequencies of nesting and incubation but fed nestlings significantly more times. Similar to the male sparrows, the feeding rates of the male Isabelline Shrikes were significantly higher than those of the females. The hatching rate and fledging rate of the Saxaul Sparrow on average in this study were 81.99 and 91.92%, respectively, while those of the shrike were 69.00 and 96.53%, respectively. Conclusions These two different passerine species living in the same desert environment exhibited the same trend in their reproductive investments. Adapting to desert environments is a strategy that may have evolved in passerines where male parent birds put more effort than females into reproduction to ensure high reproductive output.

Chromosome localization of genes that control synchronous development of pollen mother cells in wheat

Caryologia ◽  
2003 ◽  
Vol 56 (3) ◽  
pp. 275-279 ◽  
Author(s):  
Wei Li ◽  
Jun Yang ◽  
You-Fu Pan ◽  
Guang-Qin Guo ◽  
Guo-Chang Zheng
Keyword(s):  
Chromosome Localization ◽  
Pollen Mother Cells ◽  
Synchronous Development ◽  
Mother Cells

An ultrastructural study of cytomixis in tobacco pollen mother cells

PROTOPLASMA ◽  
2011 ◽  
Vol 248 (4) ◽  
pp. 717-724 ◽  
Author(s):  
Sergey R. Mursalimov ◽  
Elena V. Deineko
Keyword(s):  
Ultrastructural Study ◽  
Pollen Mother Cells ◽  
Tobacco Pollen ◽  
Mother Cells

Persisting demibivalents: a unique meiotic behaviour in Cuscuta babylonica Choisy

Genome ◽  
1987 ◽  
Vol 29 (1) ◽  
pp. 63-66 ◽  
Author(s):  
Batia Pazy ◽  
Uzi Plitmann
Keyword(s):  
Key Words ◽  
Chromosome Segregation ◽  
Meiotic Behaviour ◽  
Chromosome Behaviour ◽  
Chromosome Movement ◽  
Pollen Mother Cells ◽  
Key Words Meiosis ◽  
Mother Cells ◽  
Telomeric Association

Idiosyncratic chromosome behaviour during meiosis was found in pollen mother cells of Cuscuta babylonica Choisy, a thread-like holoparasitic herb. Its main features are among the following: (i) telomeric association between homologues through most stages of the process, which leads to persisting chromatid bivalents (= "demibivalents"); (ii) uncommon chromosome segregation in first and second anaphase; and (iii) prolonged intensified heterochromatinization. Although "regular" in its own way, this process leads to the formation of unviable products. Its further investigation might contribute to our understanding of the role of the spindle and chromosome movement in the ordinary process of meiosis. Key words: meiosis (abnormal), persisting demibivalents, Cuscuta babylonica.

scholarly journals Construction of a weight-based seed sorting system for the third-generation hybrid rice

Rice ◽  
2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Jianxin Wu ◽  
Shijun Qiu ◽  
Menglong Wang ◽  
Chunjue Xu ◽  
Xing Wang Deng ◽  
...  
Keyword(s):  
Hybrid Rice ◽  
Pollen Grains ◽  
Third Generation ◽  
Male Sterile ◽  
Specific Expression ◽  
The Third ◽  
Genes Encoding ◽  
Wild Type Male ◽  
Sorting System ◽  
Generation Hybrid

Abstract Background The third-generation hybrid rice technology can be constructed by transforming a recessive nuclear male sterile (NMS) mutant with a transgenic cassette containing three functional modules: the wild type male fertility gene to restore the fertility of the mutant, the pollen killer gene that specifically kills the pollen grains carrying the transgene, and the red fluorescence protein (RFP) gene to mark the transgenic seed (maintainer). The transgenic plant produces 1:1 NMS seeds and maintainer seeds that can be distinguished by the RFP signal. However, the RFP signals in the partially filled or pathogen-infected maintainer seeds are often too weak to be detected by RFP-based seed sorting machine, resulting in intermingling of the maintainer seeds with NMS seeds. Results Here we constructed a weight-based seed sorting system for the third-generation hybrid rice technology by silencing the genes encoding ADP-glucose pyrophosphorylase (AGP) essential for endosperm starch biosynthesis via endosperm-specific expression of artificial microRNAs (amiRNAs). In this system, the NMS seeds have normal endosperm and are heavy, but the maintainer seeds have shrunken endosperms and are light-weighted. The maintainer seeds can be easily and accurately sorted out from the NMS seeds by weight-sorting machines, so pure and fully filled NMS seeds are available. Conclusions The weight-based seed sorting system shows obvious advantages over the RFP-based seed sorting system in accuracy, efficiency, and cost for propagation of pure male sterile seeds. These characteristics will significantly increase the value and transgenic safety of the third-generation hybrid rice technology.

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