Phylogenetic relationships of Echinochloa species based on phenotypic and SSRs markers

Abstract

Echinochloa species are one of the most important weeds, causing many troubles in rice cultivation, but difficult to distinguish among species due to their morphological similarity. Therefore, this study was conducted to investigate their phylogenetic relationships and find SSRs markers and morphological traits that can be used for identification and classification of Echinochloa species. The relationships among 77 different Echinochloa accessions including 57 genotypes from Korea and 5 reference species were studied by applying 23 SSRs markers derived from allied species and assessing the 24 morphological traits. Echinochloa oryzicola accessions were clearly clustered as a distinctive group from E. crus-galli and other Echinochloa species with the lowest phylogenetic relationship among Echinochloa species in both SSRs marker and morphological trait analyses. All E.crus-galli varieties, crus-galli, practicola and formosensis, were clustered in the same group together, and we could not find the differences among these varieties. 5 SSRs makers selected from 23 SSRs produced distinctive bands, which can discriminate E. oryzicola from E. crus-galli and other Echinochloa species. Morphological traits related with seeds were the most influential contributors of classifying Echinochloa species. Although no clear consensus between the results from SSRs markers and morphological trait analyses was founded in this study, our results indicate that both SSRs markers and morphological traits can be useful tools to distinguish among Echinochloa species.

Keywords: Echinochloa crus-galli, Echinochloa oryzicola, morphological marker, SSRs marker, phylogenetic analysis