Crop-weed competition, direct seeded rice, crop canopy
Field experiments were conducted at Research Farm of the Department of Agronomy, PAU, Ludhiana during 2006, 2007 and 2008 on loamy sand soil. The performance of different genotypes of rice under direct seeded conditions were variable. During 2006, performance of PR-115 and PR-113 was found to be significantly superior to other tested genotypes because of more smothering effect on weeds by these cultivars. Among IRRI biotypes, the performance of IR-72164-13-7-2 and IR-71703-587-1-3 was found satisfactory. During 2007, PAU-201, PR-115 and PR-116 recorded higher grain yield both under weedy and weed free conditions but among IRRI varieties 17 A/R 10 produced highest seed yield. During 2008, PAU-201 and PR-115 performed better than other varieties and among rice hybrids RH-257 outyielded other tested hybrids and it was followed by Arize-6444 and Arize-6129. These hybrids smoothered weeds as indicated by less dry matter accumulation by the weeds.