عنوان مقاله [English]
Background and Objectives
Canola crops has a special place due to specific features among crop plants and it has drawn the attention of researchers in recent years. During the period before flowering, it is observed that 72 to 83% of the total dry matter in leaves and 17 to 28% accumulates in the stem. In the period post flowering, most dry matter is (50% to 56%) in the stems that most this the material of the leaves will be obtained that they have to 8 to 11 % the total dry matter in the course. At the maturity stage, stems and pods are included 46 to 51% and 49 to 59% of the dry matter respectively. Canola reaches in time of flowering to LAI maximum and then gradually reduced LAI so that at harvest time reaches almost to zero. K value for the products with mainly vertical leaves, or with leaves coincided together that have found host state, is variable between 0.3 to 0.45. The RUE is for winter canola 1.2 and for spring canola 1.5 g/MJ photosynthetically active radiation. This amount at time of filling grain arrives to about 0.4 to 0.75 g/MJ photosynthetically active radiation. This experiment is to investigate share different organs canola cultivar Hyola 401 from allocation dry matter and obtain baseline K and RUE occurred in Ahvaz conditions.
Materials and methods
This experiment done to form factorial whit two factors planting date in three levels (November 29, December 19 and January 8) and the density at four levels (50, 70, 90 and 110 plants per square meter) in randomized complete block design with 4 replications in the 2011-2012 crop year. To measure the relation incoming radiation used from the vertical imaging. Due to having relation incoming radiation for determine the K used from the equation FI= l - exp(-k×LAl). RUE obtained from line slope of dry matter accumulation againts the cumulative radiation received. In order to describe the trend changes LAI againts the days after planting used from the equation LAl= ((a×exp((-a)×(dap-b)×c))/(l-exp((-a)×(dap-b)))2. In order to describe the distribution rate of dry matter in different plant organs from stem elongation to flowering, flowering to pod filling and pod filling to maturity stages used from the equation y=bx.
The results showed that with increasing density, LAI rising. In addition, with delay in planting LAI showed a decreasing trend. K values obtained between the different planting dates and plant density did not show significant differences and the value it for the photosynthetically active radiation canola cultivar Hyola 401was 0.39. In addition, RUE values Obtained about 0.92 g/MJ. Effect of plant density on dry matter distribution was more than planting date.
Increase in LAI by increased density can be considered due to increasing the number of plants and Increase the number of leaves. Reduce the LAI by delayed planting can be considered due to Shorten the growth period and increase in day length and temperature. Lower effect planting date than plant density on dry matter distribution canola cultivar Hyola 401 and as well as non-significance K and RUE in dates and different densities can perhaps be because climatic similarities of view day length and photoperiod and also low time interval between different planting dates.