بررسي اثر تراكم بوته و كود نيتروژن بر عملكرد دانه و برخي صفات مرفولوژيك كلزاي پاييزه (Brassica napus L)

Effects of Planting Density and Nitrogen Application Rate on Yield and some Morphological Traits of Winter Colza (Brassica napus L.)

To study the effects of planting density and urea (46% N) application rate on yield and some morphological traits of winter colza (cv. Zarfam, an inbred variety from Regent x Cobra) a factorial experiment in the framework of a complete block design with 4 replications was conducted in Seed and Plant Improvement Institute, Karaj-Iran in 2002. The treatments were comprised of four levels of planting density and N application rates viz. 150,190, 230 and 270 plants m"2 and zero, 100, 200 and 300 kg urea ha"1. Analysis of variance revealed that different levels of density and N fertilizer significantly affected dry matter accumulation (biomass) at the three stages of plant growth (rosette, stem elongation, and 50% flowering). Increasing planting density and N application rate also significantly affected total biological yield, seed yield, Harvest Index (HI), pod bearing stem length, pod number in main and sub-branches, total pod number plant"1 as well as 1000 seed weight. Increasing N fertilizer exerted progressive effects on all traits, but planting density decreased pod bearing stem length, pod number in main and sub-branches and total pod number plant"1. The highest biomass, HI and 1000 seed weight were obtained from 190 plant m"2 treatment. Increase in planting density as well as in N application rate increased plant height, but did not significantly affect the oil seed percentage. Finally, the planting density of 190 plants m" (equal to seed rate of 8 kg ha"1) along with application of 200 kg of urea ha"1 formated the optimum combination for which the highest seed yield (3122 kg ha"1) had been observed.