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The Scientific World Journal
Volume 2014 (2014), Article ID 641589, 8 pages
http://dx.doi.org/10.1155/2014/641589
Research Article

Response of Rice Genotypes to Weed Competition in Dry Direct-Seeded Rice in India

1Punjab Agricultural University, Ludhiana 141004, India
2International Rice Research Institute, India Office, Hyderabad 500030, India
3Queensland Alliance for Agriculture and Food Innovation (QAAFI), University of Queensland, Toowoomba, QLD 4350, Australia

Received 23 April 2014; Accepted 11 June 2014; Published 30 June 2014

Academic Editor: Antonio Ferrante

Copyright © 2014 Gulshan Mahajan et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The differential weed-competitive abilities of eight rice genotypes and the traits that may confer such attributes were investigated under partial weedy and weed-free conditions in naturally occurring weed flora in dry direct-seeded rice during the rainy seasons of 2011 and 2012 at Ludhiana, Punjab, India. The results showed genotypic differences in competitiveness against weeds. In weed-free plots, grain yield varied from 6.6 to 8.9 t ha−1 across different genotypes; it was lowest for PR-115 and highest for the hybrid H-97158. In partial weedy plots, grain yield and weed biomass at flowering varied from 3.6 to 6.7 t ha−1 and from 174 to 419 g m−2, respectively. In partial weedy plots, grain yield was lowest for PR-115 and highest for PR-120. Average yield loss due to weed competition ranged from 21 to 46% in different rice genotypes. The study showed that early canopy closure, high leaf area index at early stage, and high root biomass and volume correlated positively with competitiveness. This study suggests that some traits (root biomass, leaf area index, and shoot biomass at the early stage) could play an important role in conferring weed competitiveness and these traits can be explored for dry-seeded rice.