Polyploidy and its implications in plants breeding – A review

Abstract

Polyploidy is a prominent force of shaping the evolution of in most of ferns and flowering plants. Polyploidy has tremendous contribution in plants improvement program. It is the polyploidy breeding through which new crops can be developed and interspecific genes can be transferred and also the origin of crops can be traced. It is now an interesting field of study to reveal the evolution of crop plants and utilizing their variability in the field of crop breeding. Polyploidy generally differ markedly from their progenitors in morphological, ecological, physiological and cytological characteristics that can contribute both to exploitation of a new niche and to reproductive isolation. As a result, polyploidy is a major mechanism of adaptation and speciation in plants. Another implication of polyploidy is development heterosis in plant breeding. Unlike diploids which may lose heterosis with each consecutive generation due to segregation, polyploidy imposes pairing of homologous chromosomes, thus preventing intergenomic recombination. In this way, heterozygosity is maintained throughout generations. One of the immediate and obvious consequences of polyploidy in plants is an increase in cell size which in turn leads to enlarged plant organs relative to diploids. It is also used in bridge crossing, development of seedless fruits like watermelon and production of apomictic crops.