Abstract

Polyploidisation is an important process in the evolution of many plant species. An additional set of chromosomes can be derived from intraspecific genome duplication (autopolyploidy) or hybridising divergent genomes and chromosome doubling (allopolyploidy). Special forms of polyploidy are autoallopolyploidy and segmental allopolyploidy. Polyploidy arises from two basic processes: spontaneously occurring disturbances of meiotic division and induced by antimitotic agents’ disruption of mitosis. The first involves the induction and fusion of unreduced gametes, resulting in the formation of triploids and tetraploids. The second process uses antimitotics that disrupt cellular microtubules and prevent chromosome’s sister chromatids motion during anaphase. Colchicine, oryzalin, and trifluralin are the most commonly used antimitotics for inducing polyploids in plants. The exposure time and concentration of the antimitotics and the species, cultivar, genotype, and tissue type affect the efficiency of genome duplication. Polyploids are distinguished from diploids by increased cell size and vegetative parts of plants and increased content of secondary metabolites. Genome duplication generates several changes at the epigenetic level resulting in altered gene expression. Polyploidisation is used in plant breeding to overcome the non-viability and infertility of interspecific hybrids, obtain seedless polyploid cultivars and increase resistance/tolerance to biotic and abiotic factors.

Highlights

  • Polyploidisation is an important phenomenon in plants and animals

  • Heynh., Brassica napus L., are evolutionarily paleopolyploids, whose genomes contain several duplicated genes resulting from multiple rounds of polyploidisation followed by intensive structural and epigenetic transformations [8]

  • The present study shows the methods of polyploid induction, the effect of polyploidy on the growth and morphological traits of plants, quantitative and qualitative modifications of primary and secondary metabolites induced by polyploids, and the importance of breeding and agricultural practice of polyploids of industrial plants that are widespread worldwide

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Summary

Introduction

Polyploidisation is an important phenomenon in plants and animals. One evolutionary mechanism promotes speciation, biodiversity, and adaptation to changing environmental conditions [1]. In order to cover all types of polyploids obtained by hybridisation (allopolyploids, autoallopolyploids and segmental allopolyploids), the term amphiploids is used It refers to hybrids containing two or more sets of chromosomes from each parent [11]. Polyploidisation of the genome can cause negative effects in the form of decreased plant viability and productivity [25] Another frequently observed phenomenon, especially in autotetraploids, is disorders of chromosome pairing during meiosis and the formation of gametes with an unbalanced number of chromosomes, which contribute to decreased plant fertility and sometimes even sterility. Typical industrial species such as hop, cotton, hemp or miscanthus are discussed, and those which, apart from their use in the food or pharmaceutical industry, are applied in other branches of fuel and energy, chemical, wood-paper and textile industries

Methods of Polyploid Induction
Induction of Unreduced Gametes and Artificial Hybridisation
Somatic Polyploidisation
Type of Plant Tissue
Genotype Dependent Polyploidisation
Concentration of Antimitotic Agent and Exposure Time
Triploid Breeding Strategy
Advantages of Polyploidy for Interspecific Hybridisation
Findings
Perspectives of Using Polyploids in Plant Breeding
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