Effect of Sowing Date and Weed Interference on the Yield of DryLand of Three Lentil (Lens culinaris Med.) Cultivars in Khramabad

The effects of sowing date, and weed interference on main agronomic characteristics of lentil varieties was investigated in a field experiment in Khorramabad during 2005-06 growing season. The experimental design was a randomized complete block in factorial arrangement with 4 replications. The experiment had 3 factors including: weed interference at two levels (weed free, and weed infested throughout the total growing season), planting date at three levels (autumn, winter, and spring) and three lentil varieties (Gachsaran, Flip93-93, and Lorestan landrace). Lentil biomass yield in autumn planting date was 21.6 and 155.8% more than that in winter and spring planting dates, respectively. Control of weeds, lentil biomass increased by 34.7%. Maximum grain yield (1486 kg ha-1) was achieved in autumn planting date, that was significantly more than two others sowing dates. Lentil grain yield for autumn planting date was 28 and 297.6% more than yield of winter and spring crop respectively. Yield of Gachsaran and Flip cultivars were significantly more than that of Lorestan landrace. Weeding increased lentil grain yield by 46.7%. Weed control caused 48.4, 50.3, and 30.1% increase in grain yield for autumn, winter, and spring sowing dates respectively. Yield losses due to weed interference for Gachsaran, and Flip cultivars were 54.7, and 47.6%, respectively. However there were not significant differences between weed free and weed infested situation for Lorestan landrace. Maximum grain yield (2394 kg ha-1) achieved in autumn sowing by Gachsaran cultivar at weed free treatment. Minimum yield belonged to spring crop of Lorestan landrace in weed infested situation.