Chromosomal Evolution of Angiosperms

Abstract

At the beginning and developing stages of cytological studies, cytotaxonomists have discussed mainly the interrelationships among taxa based on the observations of somatic metaphase chromosomes or chromosome pairings in meiosis [1–4]. These ordinal cytological characters used are mainly the chromosome numbers and the chromosome shapes, which are very stable within taxa. On the other hand, the genome analysis originated by Kihara and his schools has clarified the relations among chromosome complements, chromosome behavior in meiosis and gamete fertility, based mainly on observations of Triticum [5]. These approaches are still effective methods to understand the biosystematic aspects. All the higher plants have to generate fertile offspring, which arise from mating between female and male gametes or from parthenogenesis, or they could not persist. In some cases, it is very difficult to understand the speciation mechanisms without cytogenetic analysis.