Response of Lentil (Lens culinaris Med.) Genotypes Growth to Planting Date, and Weed Interference

Abstract\ud Growth response to sowing date and weed interference among lentil varieties was investigated in dryland situation of Khorramabad during 2005-2006 growing season. The experimental design was a randomized complete block in factorial arrangement with 4 replications. The experiment had 3 factors: weed interference at 2 levels (weed free, and weed infested throughout the total growing season), planting date at 3 levels (autumn, winter, and spring) and lentil varieties at 3 levels (Gachsaran, Flip 92-12L, and Lorestan landrace). Overall, weeding increased lentil yield by 46 percent. Based on sigmoid equations, maximum dry matter of lentil in autumn crop was 24.7 and 300.4% more than the potential of winter and spring crops, respectively. Maximum dry matter per plant for autumn lentil was 4 times more than that estimated for spring crop. Autumn and winter cultivations, respectively, with average yield of 1486 and 1161 kg/ha, had four and three times higher performance over the spring cultivation. Reproductive period (flowering to maturity) for the autumn planting was more than three times the cultivation of spring. Accordingly, shorter growth period resulted in less dry matter accumulation and declined grain yield.\ud \ud Keywords: Lentil, Planting date, Crop variety, Weed competitio