Estimation of winter canola (Brassica napus L.) growth curve under different weed interference durations

摘要

In order to estimate winter canola (Okapy Double Zero) growth curve under different weed interference durations, an experiment was conducted at research field of Tarbiat Modares University (located on Tehran west, Iran) on 2004. The experiment had 14 treatments and 4 replications that divided in two sets of treatments and were arranged in a randomized complete block design. In first set oftreatments, the crop was kept weed-free until 2, 4, 6 and 8 leaf stage, inflorescence emergence,50% silique set and harvest stages. In second set of treatments, weeds were allowed to grow with crop until above stages. Data were obtained via 18 sampling from experimental units during canola growth. Results showed that leaf dry weight trend was rising but after flowering began to fall. Stem dry weight intensively increased in all treatments after winter elapsed and starting the generative stage, then began to decrease after flowering. Total dry weight curve had increasingly pattern but began to reduce after flowering Leaf area in canola expanded until flowering and then began to fall. Regarding to weed free treatment (whole season control) and highly weed infested (all season interference), different interference periods had no effect on crop plant parts.Although in all of growth curve amount of dry matter production in all plant parts and leaf expanding was greatest in weed free plots and was lowest in highly weed infested plots. Attending to weed flora, their population and time of interference, final results showed increasing process of dry matter in all plant parts of canola and expanding leaf area did not affect by weed interference periods.