Flooding tolerance in the major rice weed Echinochloa crus-galli

Abstract

Weed infestation dramatically reduces rice yields. In the cultivation of paddy rice, this is overcome by the transplantation of rice seedlings to flooded fields, where the anaerobic conditions prevent the establishment of most weeds. The efficacy of this method, however, is undermined during the last decades by the emergence of several flood-tolerant weed species. It is of interest to understand the tolerance mechanisms in these species from the perspective of developing alternative weed management practices and as interesting models for the evolution of flooding acclimation. Here we investigated flooding tolerance in different biotypes of four major rice weed species: Echinochloa crus-galli (common barnyard grass), Echinochloa colona (jungle rice), Leptochloa chinensis (Chinese sprangletop) and Cyperus rotundus (purple nutsedge). Our results revealed considerable tolerance to flooding conditions in all biotypes and species at both the germination and post-germination stages. Within each species, there was no correlation between the collection site (flooded or drained) and the observed tolerance. Even though submergence could successfully repress germination and growth, seeds could germinate, and seedling growth was resumed upon desubmergence. These findings present interesting model systems to further probe the evolution and molecular basis of flooding tolerance. Additionally, these results could have implications for the current water-based weed management protocols in use.

Advances in Weed Management An Indian Perspective

“…Of the 111 rice cultivars evaluated for allelopathic potential against [Echinochloa crus galli (L) Beauv.] at the International Rice Research Institute, Manila, Philippines, 11 cultivars in dry season and 21 in wet season had suppressed the weed growth by more than 50% (Olofsdotter and Navarez, 1996). Similarly in wheat, Wu et al (1998) reported that, some cultivars significantly inhibited both the germination and the radicle growth of Lolium rigidum Gaud.…”