A grapevine variety consists of an array of clones descended by vegetative propagation from a single selected vine grown from a single seedling. A majority of the clones within a variety are identical, but some can show divergent genotypes and, to some extent, divergent phenotypes. Polymorphism results mainly from somatic mutations that occur naturally during plant growth. Various types of mutations were shown to be responsible for genetic diversity among clones: point mutations, large deletions, illegitimate recombination or variable number of repeats in microsatellite sequences. In most cases, somatic mutations do not affect the whole plant; rather, they affect only one cell layer, leading to periclinal chimeras. Such structures do not threaten the plant's fitness and are stable through vegetative propagation. Occasionally, cellular rearrangements in the chimera lead to homogenization of the genotype of the whole plant. Through these molecular and cellular mechanisms, the genotypes of clones drift over time and grapevine varieties evolve.
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AGRIS - 国际农业科技情报系统
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出版者
Elsevier Ltd
其它主题
Chimerism; Molecular; Phenotype; Species specificity; Biological; Genetic; Genotype; Phenotype
语言
英语
注释
Includes references
类型
Journal Article; Text
2024-02-27
2026-02-03
MODS