Effect of Seedling Age and Weed Management on Growth and Yield of Transplanted Rice (Sakha 106 cv).

Two field experiments were conducted at the Experimental Farm of Sakha Agricultural Research Station, Kafrelsheikh, Egypt during 2016 and 2017 summer seasons to study the effect of seedling age and weed management on growth and yield of transplanted rice (Sakha 106 cv). A split plot experimental design arranged in randomized complete block with four replications was used in both seasons. Three seedling ages viz., 21, 28 and 35 days were allocated to the main plots, while five weed control treatments i.e., thiobencarb (50% EC) at 2.39 kg ai ha^-1, oxadiazon (25% EC) at 0.045 kg ai ha^-1, penoxsulam (24% SC) at 0.029 kg.ai ha^-1, hand weeding two times (20 and 40 DAT) and untreated (weedy check) were assigned to the sub-plots. The results showed transplanting rice seedlings at 21 days old recorded the lowest dry weight of Eclipta sp C. difformis E crus-galli and total weeds. Also, the increasing in rice dry weight, number of panicles m^-2, panicle weight, number of filled grains panicle^-1, 1000-grain weight and rice grain yield as compared to rest seedling ages (28 and 35 days). The application of penoxsulam at 0.029 kg ai ha^-1 applied at 15 DAT achieved the lowest dry weight of weed species and total weeds as well as the highest rice yield as compared to weedy check. The interaction between seedling ages and weed control treatments had significant effect on dry weights of weed species, total weeds dry, rice yield and its components. Where, transplanting rice seedlings treatment at 21 days old  treated with herbicide of penoxsulam at 0.029 kg ai ha^-1 at 15 DAT are the best among the studied treatments to achieve the best weed control and the highest rice dry mater, grain yield and its components for Sakha 106 cv. under this study conditions.