POLYPLOIDY AND ITS RELATIONSHIP WITH PLANT BREEDING AND ADAPTATION

Abstract

Polyploidy is one of the major sources of genetic variability that can lead to adaptation in new habitats. Genome doubling (polyploidy) has been and continues to be a pervasive force in plant evolution. Recent studies have refined our inferences of the number and timing of polyploidy events and the impact of these events on genome structure. It has been proved that many polyploids experience extensive and rapid genomic alterations for one time or more. Polyploid formation is often accompanied with genome buffering, increased allelic diversity and heterozygosity, losing and silencing of duplicated genes also some genes will undergo subfunctionalization. In addition to number of epigenetic molecular phenomena that do not involve change in DNA sequence which is capable of altering gene expression. All these aspects by providing novel phenotypic variation participate in increasing selection chances of plant species that can tolerate environmental stresses. However, polymorphism is so important too, along with ploidy. Polymorphism has probably higher probability to occur in ploidy species rather than in diploids, and that gives wider adaptation to the polyploids. Polyploidy has a wide spectrum of applications, such as; overcoming barriers to hybridization, production of sterile varieties and DH production, which considered the most important one and has been widely used in plant breeding and improvement.