The taxonomic riddle of Chenopodium album L. complex (Amaranthaceae)

C.album L. complex is a heterogenous assemblage of many taxonomic entities of cosmopolitan distribution. This is because many weedy and semi-domesticated forms have arisen due to hybridization and polyploidy. These distinct forms have been perpetuated by their breeding system characterized by high level of selfing and also by the phenological differences. The interrelationships in this aggregate of various taxa are now beginning to be explored. This is mainly because of the economic importance of many semi-domesticated forms providing nutritious leafy vegetable and grains and the economic impact of weedy forms on other crops. The work done on cytology, genome size estimation and molecular markers on various populations and cytotypes has provided tangible results in explaining genetic relationships among different types as well as in unraveling the genomic constitution and origin of polyploid forms. The studies show a great diversity of morphological types and three ploidy levels (2n = 18, 36, 54) in C.album complex. The 4x type from North West India is genetically different from 2x and 6x types. The 6x types have been shown to be allopolyploids based on karyotypes, genomic in situ hybridization, flavonoid profiles and SOS1 homeologs.