A Cytogenetical Study on a New Hexaploid Annual Species of the Genus Echinochloa from Sri Lanka

Abstract

A strain of Echinochloa species showing morphological similarity to E. crusgalli was collected in the lowland rice field in Peradeniya, Sri Lanka, This strain (strain no. 77-10) is characterized by the convex, coriaceous and lustrous lower lemma and the lower and upper glumes variegated with reddish or blackish purlple. These characteristics manifested dominantly in all the F₁ hybrids produced in this study. Strain 77-10 is an annual and hexaploid with 2n=6x=54.
Cytological data regarding the hybrids among three hexaploids, strain 77-10, E. colona and E. crus-galli, and tetraploid species E. oryzicola indicated that these three hexaploids are distantly related to each other, probably having a common genome.