Mosyakin and Robertson gave the most comprehensive classification of the three subgenera under the genus, which is also the most widely used subgenus classification up to now 10, 11 (Fig. The latest taxonomy revision of monoecious species was completed by BayГіn 2, and the comprehensive dioecious taxonomy was SauerвЂ™s monograph 1. Many authors have studied on the taxonomy and evolution of the genus.

However, the taxonomy of Amaranthus has always been difficult, especially because of the large number of complex taxa which are difficult to define due to the interspecific hybridization and gene introgression. Accurate identification of these species is the basis of weed prevention and control. tuberculatus invade gradually into the new continents out of their origins, and were detected their resistant biotypes 14. The genus is the focus of weed scientific research 13, because of these amaranth weeds posed a certain threat to agricultural ecology in the new habitat. Of these, 9 species were listed as вЂњintroduced, invasive and noxious plantsвЂќ in the USDA Plants Database, and 21 species as вЂњagricultural weedsвЂќ in the Global Compendium of Weeds 12. Acnida (L.) Aellen ex K.R.Robertson, and Amaranthus subgen. crispus were transient colonization (Xu, unpublished).ДЄccording to inflorescences position, the number of perianth segments and urticle dehiscent/indehiscent 2, 10, as well as dioecious or monoecious, are divided into three subgenera: Amaranthus subgen. were newly intercepted and controlled (Xu, unpublished). dubius 9 from the collected specimens in China. Since then, some authors have successively found new alien amaranths: A. The Flora of China (eFloras edition) recorded 15 species and two varieties, all of which were alien except for A. The genus contains pseudocereals crops such as A. The genus of Amaranthus includes 74 species, of which 55 species native to the Americas and the rest originated from the Euraisa, South Africa and Austrilia/Oceania 1, 2. In general, the chloroplast genome is of certain value for the identification of the similar species of Amaranthus, which provides more evidence for clarifying the phylogenetic relationships within the genus. The trnk-UUU-atpF, trnT-UGU-atpB, psbE-clpP, rpl14-rps19, and ndhF-D can distinguish several similar species. The rpoC2, ycf1, ndhF-rpl32 were good at distinguishing most amaranths. Albersia were clustered into a monophyletic branch. Acnida form monophyletic branches separately and cluster together. In the topological tree constructed by chloroplast genome, species in subgen. In LSC, SSC and IRs regions, there were four 30В bp forward and reverse repeats, and the repeats in SSC and LSC were in nearly opposite positions in circular genome structure, and almost divided the circular genome into symmetrical structures. Two InDels in ndhE-I on the SSC make the three subgenera clearly distinguished. The longest InDel was 387В bp, which occurred on ycf2, followed by 384В bp InDel on psbM-trnD. The frequencies of SNPs and InDels in chloroplast genomes were 1.79% and 2.86%, and the variation mainly occurred in the non-coding regions. It was found that the length of the chloroplast genome of Amaranthus varied from 149,949В bp of A. We studied the genetic variation and structure of the chloroplast genomes of 22 samples from 17 species of three subgenera. Amaranthus is a complex taxon with economic importance as well as harmful weeds.

Geneious prime 2020 citation