摘要
Polyploidy refers to two or more complete sets of chromosomes that are combined within a nucleus,and includes both autopolyploidy and allopolyploidy(Otto 2007).Polyploidy is a recurring theme in the evolutionary history of plants and it has been considered an important mechanism for speciation and also for adaptability to changing environments(Shimizu-Inatsugi et al.2017).In nature,about one-third of flowering plants are polyploids,and a great majority of them are allopolyploids.There are many cultivated allopolyploid species,such as cotton,Brassica and potato,the possible evolutionary history of which can be inferred with high certainty.
