Effect of different densities of parthenium weed (Parthenium hysterophorus L.) on the performance of direct-seeded rice under aerobic conditions

ABSTRACT

Parthenium weed (Parthenium hysterophorus L.) is an emerging weed species in direct-seeded aerobic systems of rice production. This two-year field study was conducted to evaluate the effect of five different densities (0, 5, 10, 15 and 20 plants m⁻²) of parthenium weed on rice yield and yield-related attributes. Parthenium weed produced ca. 38 to 178% higher biomass at its densities of 10 to 20 plants m⁻² as compared to the lowest density of 5 plants m⁻². The paddy yield and yield-related attributes were negatively affected with an increase in the parthenium weed density. In both years, the highest reductions in number of rice panicles (14 to 17%), panicle length (10 to 11%), number of grains per panicle (11 to 18%), 1000-grain weight (8 to 21%) and paddy yield (30 to 35%) were recorded at the highest parthenium weed density (20 plants m⁻²) tested. However, the lower densities of 5 to 15 parthenium weed plants m⁻² also caused 11 to 24% and 12 to 26% losses in paddy yield during the years 2016 and 2017, respectively. Therefore, this weed species should be controlled below the density of 5 plants m⁻² to avoid the substantial yield losses (over 15%) in direct-seeded rice.

KEYWORDS:

• Direct-seeded rice
• Parthenium hysterophorus
• yield losses
• weed management

Acknowledgments

This study is part of the PhD project of Ali Ahsan Bajwa who is thankful to The University of Queensland, Australia for the provision of Research Training Program and UQ Centennial Scholarships. Authors are thankful to the technical staff at the Postgraduate Agricultural Research Station, University of Agriculture, Faisalabad, Pakistan for their support in conducting this study. Authors are also thankful to four anonymous reviewers for their invaluable comments and suggestions that significantly improved the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by The University of Queensland [Research Training Program Scholarship and UQ Centennial Scholarship awarded to the first author.]