Cytological Relationship between Echinochloa oryzicola Vasing. and the French Strain of E. phyllopogon Stapf subsp. oryzicola (Vasing.) Koss

Abstract

A French strain that was collected in a paddy field and has been referred to E. phyllopogon was morphologically and cytologically examined. Judging from Kossenko's description, the French strain could be referred to E. phyllopogon Stapf subsp. oryzicola (Vasing.) Koss. var. genuina Koss., and was confirmed to be a tetraploid, with n=18.
On the other hand, with respect to the principal morphological characters, the French strain of E. phyllopogon was not distinguishable from F-form of tetraploids species E. oryzicola Vasing. (n=18).
Meiosis of the F₁ hybrid of the French strain with E. oryzicola was normal and 18 bivalents were observed, and pollen and seed fertilities were as high as those of the parents. Thus the French strain and E. oryzicola could not be cytologically separated.
Based on the morphological and cytological evidences, E. phyllopogon subsp. oryzicola was considered as a synonym of E. oryzicola.