Journal of Environmental Biology

Evaluations of allelopathic effect of Echinochloa colona weed

on rice  (Oryza sativa L. ‘Vandana’)

 

Author Details

 

D. Swain

(Corresponding author)

Crop Improvement Division, Central Rice Research Institute (ICAR), Cuttack-753 006, India

e-mail :  dr_dswain@yahoo.com

Seema Paroha

Crop Improvement Division, Central Rice Research Institute (ICAR), Cuttack-753 006, India

Monika Singh

Crop Improvement Division, Central Rice Research Institute (ICAR), Cuttack-753 006, India

H.N.Subudhi

Crop Improvement Division, Central Rice Research Institute (ICAR), Cuttack-753 006, India

 

 

 

 

Publication Data

Paper received:

25 October 2010

 

Revised received:

19  September 2011

 

Re-revised received:

29  November 2011

 

Accepted:

12  December 2011

 

 

Abstract

Echinochloa colona (L.) Link   is a very problematic weed in up land and medium land rice causing significant reduction in yield. In the present investigation, laboratory and field experiments   were conducted to evaluate the nature of interaction E. colona on germination and growth   of the up land rice cultivar ‘Vandana’. The effects of decomposing and decomposed aqueous leachates (1-10%w/v) obtained from the dried biomass of 20, 30, 40 and 60 days old  E.colona   plants  were studied on rice using petridish bioassay technique with   three different types of culture media like filter paper, soil,  and soil + activated charcoal.  The decomposing leachates of E. colona   showed strong toxic effect on root and shoot growth of rice, the highest being noted with 10% leachates of 60 days old plant residue. It inhibited root and shoot growth by 100% and 43.9% respectively as compared to control. The corresponding decomposed leachates inhibited rice germination by 90% and root and shoot growth by 70 and 25% respectively. These toxic effects of leachates showed in filter paper medium were significantly reduced in soil and soil plus activated charcoal media proving their allelopathic nature. In a field experiment, E. colona and rice were grown in proportions of 1:1, 1: 2 and 1:4, the total plant density being maintained at 100 pants m^-2.  The height and dry matter of rice were adversely affected with increasing in E. colona population. From another similar   field trial, data on dry matter of   20, 30, 40, and 60 days old plants were taken and their plant relative yield (PRY) and relative yield total (RYT) values were calculated. The PRY and RYT values were found to be less than unit (<1) throughout the growth period studied which suggested the presence of severe antagonistic interspecific interaction between rice and E.colona due to allelopathy.

Key words

Oryza sativa, Echinochloa colona, Upland rice, Allelopathy

 

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