Trigenomic hybrids from interspecific crosses between Brassica napus and B. nigra

2010 ◽  
Vol 61 (6) ◽  
pp. 464 ◽  
Author(s):  
Aneeta Pradhan ◽  
Julie A. Plummer ◽  
Matthew N. Nelson ◽  
Wallace A. Cowling ◽  
Guijun Yan

Interspecific hybridisation was carried out between five cultivars of Brassica napus and five accessions of B. nigra in all possible cross combinations including reciprocals. Crossing success was higher when B. napus genotypes were used as female parents. Pollination of 799 B. napus flowers with B. nigra pollen resulted in 433 pods set and 2063 putative hybrid seeds. In the reciprocal direction, pollination of 877 B. nigra flowers with B. napus pollen resulted in 281 pods set and 113 putative hybrid seeds. Pod and seed set varied with genotype and only 19 out of 25 combinations of B. napus × B. nigra and 14 out of 25 combinations of B. nigra × B. napus yielded seeds. Hybridity of 2176 putative hybrid seeds (2063 from B. napus × B. nigra and 113 from B. nigra × B. napus) was tested. Microsatellite markers with known locations for the A, B and C genomes indicated that six plants were true hybrids and one more plant remained unconfirmed for hybrid status. All other plants from putative hybrid seeds had the same DNA banding patterns and similar morphological characters as the female parent. However, the true hybrids had DNA bands from both parents and an intermediate morphology for colour and hairiness of leaf, stem and petiole. Anthers were shrunken and thin with a very limited number of sterile pollen grains. Cytological examination confirmed the triploid status of the hybrid with 27 chromosomes. The unconfirmed hybrid had 9% pollen viability and chromosome count was 27 as with the true hybrid; however, there was no clear B-genome marker from B. nigra.


2016 ◽  
Vol 8 (1) ◽  
pp. 134-138 ◽  
Author(s):  
Tomi Lois OLATUNJI ◽  
Joseph Akintade MORAKINYO

The current study aimed to evaluate the pollen viability of the commonly cultivated varieties of Capsicum species and assessed the potentials for gene exchange among the genotypes through hybridization studies. Capsicum annuum var. abbreviatum, C. annuum var. acuminatum, C. annuum var. grossum and C. frutescens var. baccatum were the species and varieties used in this study. The present findings indicated that the percentage of pollen viability varied in the studied Capsicum genotypes. The highest pollen viability was obtained in C. annuum var. abbreviatum (96.3%), followed by C. annuum var. grossum (95%), and C. annuum var. acuminatum (91.1%). The lowest pollen viability was recorded in C. frutescens var. baccatum (86.2%). The pollen viability was high in most varieties indicating that meiosis is normal, resulting in viable pollen grains. Several intraspecific and interspecific crosses were performed among the Capsicum genotypes and three putative hybrid fruits were produced. Percentage successes obtained in the crosses were low and comparable in both intra and inter-specific crosses. In the entire crosses pattern, pollination success of 10% was recorded for C. frutescens var. baccatum and C. annuum var. acuminatum. Knowing the nature and viability of pollen grains may help in predicting the success rate of hybridization and the successful crosses between C. frutescens var. baccatum and C. annuum var. acuminatum suggest that these two varieties are the closest genetically. 



1999 ◽  
Vol 47 (6) ◽  
pp. 851 ◽  
Author(s):  
I. A. Astarini ◽  
G. Yan ◽  
J. A. Plummer

Interspecific hybridisation within the genus Boronia was attempted by using species with a range of chromosome numbers. Crosses were possible between Western Australian species including those with B. heterophylla as the female parent and pollen from B. molloyae (n = 8), B. megastigma (n = 7), B. purdienana (n = 9) and B. ramosa (n = 18). Cytological studies revealed that B. heterophylla genotypes had different chromosome numbers; ‘Red’ had 2n = 15, whereas ‘Moonglow’ and ‘Cameo’ had 2n = 14. The F 1 hybrid from B. heterophylla ‘Red’ × B. megastigma had 2n = 15. Pollen viability, examined by using fluorescein diacetate, varied from 20% in B. crenulata to 80% in B. purdieana. Pollen of most species could be stored for 12 months in sealed containers at −20°C. Drying with silica gel desiccant did not improve storage, nor did ultra-low temperature (−196°C). Stored pollen was successfully used for interspecific hybridisation.



2019 ◽  
Vol 55 (No. 1) ◽  
pp. 28-34
Author(s):  
Yi-Qian Ju ◽  
Xing Hu ◽  
Yao Jiao ◽  
Yuan-Jun Ye ◽  
Ming Cai ◽  
...  

Interspecific crosses play an important role in gene introgression, plant improvement and speciation. However, poor fertility of F<sub>1</sub> generation was commonly found, which hampered backcrossing and ideal progeny generation. To explore useful materials for further breeding programs, sterile hybrids (DD1, FD1, ZD3) from different cross combinations of Lagerstroemia indica and L. speciosa and the fertile hybrid (ZD6) were selected. The results showed that pollen grains of sterile hybrids had no germination ability while ZD6 showed 25.90% pollen germination rate. The morphology of stigmas and their papilla cells showed no apparent difference. Normal pollen tubes could be detected in ovaries of ZD6 and ZD3 24 h after pollination. However, the enlarged ovaries of ZD3 began to abscise at 72 h after pollination, which suggested that the barriers occurred during post-fertilization phases. As a consequence, ZD6 can be used as either male or female parent for further Lagerstroemia breeding programs, while the sterile hybrids may be used as female parent through embryo rescue culture.  



Phytotaxa ◽  
2014 ◽  
Vol 161 (1) ◽  
pp. 43 ◽  
Author(s):  
Yu-Hsin Tseng ◽  
Jer-Ming Hu

Explosive pollen dispersal is common in Urticaceae and they are thought to be wind-pollinated. Despite a lack of obvious mechanism for preventing cross-species pollination, putative hybrid species in Urticaceae are rarely documented. Here we described the first natural hybrid in Urticaceae Elatostema ×hybrida from Taiwan. Morphological characters in E. ×hybrida are intermediate between putative parental species: E. lineolatum var. majus and E. platyphylloides. Six hybrid populations of E. ×hybrida were found in Taiwan that exhibited largely overlapping distribution patterns with its putative parents. Phylogenetic analysis of chloroplast DNA showed that the hybrid species is more closely related to E. lineolatum var. majus suggesting that the latter is the maternal parent and that hybridization is unidirectional. The chromosome number of E. ×hybrida remains the same as its putative parents (2n = 26). We speculate that the examined hybrids are natural first-generation results of independent hybridization events. Based on the morphology, spatial distribution, DNA sequence data, pollen viability and cytological observations, we hypothesize that E. ×hybrida is derived from natural hybridization events between E. lineolatum var. majus (♀) and E. platyphylloides (♂).



2019 ◽  
Vol 47 (3) ◽  
Author(s):  
Neiva Izabel PIEROZZI ◽  
Mara Fernandes MOURA

‘Niagara’ is a hybrid table grape (V. vinifera × V. labrusca). Several spontaneous somatic mutants from this grapevine have already been described. However, cytological information about these mutants is scarce. Therefore, studies in the microsporogenesis have been carried out in two of these mutants, a seedless and a large berry mutant (giant mutant). A low percentage of abnormalities such as precocious chromosome segregation, bivalent not aligned, laggard and stickiness chromosomes were seen in both mutants.  A merging process of microspores was observed in several tetrads in the seedless mutant: the microspore came together by large cytoplasmic bridges giving rise to a large and amorphous single-celled tetrad, which eventually collapsed. The giant mutant showed 10.29% of tetrads with microcytes. However, these tetrad abnormalities did not hinder pollen viability. Significant differences were seen concerning stomata and pollen grain sizes, stomata frequency and anther number per flower between the mutants. The chromosome count at diakinesis (n=19) and in diploid tapetal cells (2n=38) clarified the fact that the seedless somatic mutation was not associated with any ploidy event. Conversely, the giant mutant showed n=38 at diakinesis and 2n=76 in diploid tapetal cells, pointing to a case of spontaneous chromosome duplication. Since these abnormalities did not disturb the percentage of pollen viability very much, in both mutants (higher than 86%), the seedless one may be used as a male parent in crossing, regarding the desirable seedlessness character, while the mutant giant may be employed as female parent for the obtainment of seedless triploid plants.   ********* In press - Online First. Article has been peer reviewed, accepted for publication and published online without pagination. It will receive pagination when the issue will be ready for publishing as a complete number (Volume 47, Issue 3, 2019). The article is searchable and citable by Digital Object Identifier (DOI). DOI link will become active after the article will be included in the complete issue. *********



2014 ◽  
Vol 65 (1-2) ◽  
pp. 167-170 ◽  
Author(s):  
Romana Izmaiłow

A preliminary study of reproductive strategy was carried out on plants representing four cytotypes of the <em>Ranunculus auricomus</em> complex. Diploid plants reproduce sexually, triploids, tetraploids and hexaploids have an apomictic mode of reproduction (apospory combined with pseudogamy). Some morphological characters of the plants connected with reproduction were analyzed at various phases and compared in two successive seasons. The following characters were estimated at the individual level: number of ovules and primary pollen grains per plant, pollen viability, pollen-ovule ratio, number of achenes per plant and their germinability, seed-ovule ratio. Most of data characteristic of reproductive strategy were calculated according to the formulae proposed by Urbańska (1989, 1990). Apomictic cytotypes have both a significantly lower pollen viability and seed-ovule ratio (the lowest values in triploids) than sexual diploids.



2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Wenji Xu ◽  
Gangjun Luo ◽  
Xiaoyin Lian ◽  
Fengyang Yu ◽  
Yang Zheng ◽  
...  

Abstract Pollen characteristics are very important for Iris interspecific hybridisation. In this study, the pollen viability and male meiosis were studied in yellow-flowered Iris dichotoma (Y2), I. domestica (S3) and their hybrids F1, F2 and BC1 (BC1-Y and BC1-S). The BC1-Y hybrids showed higher pollen viability than that of F1, F2 and BC1-S hybrids, which were between I. dichotoma (26.1%) and I. domestica (35.1%). Two sterile hybrids, F2-1 and BC1-S-1, exhibited more meiotic abnormalities (57.3% and 58.7%) than other individuals. During the first meiotic division, a diffuse diplotene stage was observed for the first time in the genus Iris. The meiotic abnormalities included non-congressed chromosomes, chromosome bridges, lagging chromosomes, unequal division, abnormally oriented spindle fibres, nonsynchronous division and polyad, and resulted in reduced pollen fertility. The relatively high frequency of 2n pollen grains was found in hybrids of BC1-Y-2, BC1-Y-1, BC1-S-2, BC1-S-3 and BC1-S-4. Our research provides a new resource for meiotic behaviour and pollen fertility of the genus Iris.



Biology ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 290
Author(s):  
Abdul Kader Alabdullah ◽  
Graham Moore ◽  
Azahara C. Martín

Although most flowering plants are polyploid, little is known of how the meiotic process evolves after polyploidisation to stabilise and preserve fertility. On wheat polyploidisation, the major meiotic gene ZIP4 on chromosome 3B duplicated onto 5B and diverged (TaZIP4-B2). TaZIP4-B2 was recently shown to promote homologous pairing, synapsis and crossover, and suppress homoeologous crossover. We therefore suspected that these meiotic stabilising effects could be important for preserving wheat fertility. A CRISPR Tazip4-B2 mutant was exploited to assess the contribution of the 5B duplicated ZIP4 copy in maintaining pollen viability and grain setting. Analysis demonstrated abnormalities in 56% of meiocytes in the Tazip4-B2 mutant, with micronuclei in 50% of tetrads, reduced size in 48% of pollen grains and a near 50% reduction in grain number. Further studies showed that most of the reduced grain number occurred when Tazip4-B2 mutant plants were pollinated with the less viable Tazip4-B2 mutant pollen rather than with wild type pollen, suggesting that the stabilising effect of TaZIP4-B2 on meiosis has a greater consequence in subsequent male, rather than female gametogenesis. These studies reveal the extraordinary value of the wheat chromosome 5B TaZIP4-B2 duplication to agriculture and human nutrition. Future studies should further investigate the role of TaZIP4-B2 on female fertility and assess whether different TaZIP4-B2 alleles exhibit variable effects on meiotic stabilisation and/or resistance to temperature change.



2020 ◽  
pp. 1-8
Author(s):  
Mohammad Ashna ◽  
Ali Es-Haghi ◽  
Maryam Karimi Noghondar ◽  
Dheyaa Al Amara ◽  
Mohammad Ehsan Taghavizadeh Yazdi


Genes ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 82
Author(s):  
Yunxiao Wei ◽  
Guoliang Li ◽  
Shujiang Zhang ◽  
Shifan Zhang ◽  
Hui Zhang ◽  
...  

Allopolyploidy is an evolutionary and mechanistically intriguing process involving the reconciliation of two or more sets of diverged genomes and regulatory interactions, resulting in new phenotypes. In this study, we explored the gene expression patterns of eight F2 synthetic Brassica napus using RNA sequencing. We found that B. napus allopolyploid formation was accompanied by extensive changes in gene expression. A comparison between F2 and the parent shows a certain proportion of differentially expressed genes (DEG) and activation\silent gene, and the two genomes (female parent (AA)\male parent (CC) genomes) showed significant differences in response to whole-genome duplication (WGD); non-additively expressed genes represented a small portion, while Gene Ontology (GO) enrichment analysis showed that it played an important role in responding to WGD. Besides, genome-wide expression level dominance (ELD) was biased toward the AA genome, and the parental expression pattern of most genes showed a high degree of conservation. Moreover, gene expression showed differences among eight individuals and was consistent with the results of a cluster analysis of traits. Furthermore, the differential expression of waxy synthetic pathways and flowering pathway genes could explain the performance of traits. Collectively, gene expression of the newly formed allopolyploid changed dramatically, and this was different among the selfing offspring, which could be a prominent cause of the trait separation. Our data provide novel insights into the relationship between the expression of differentially expressed genes and trait segregation and provide clues into the evolution of allopolyploids.



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