EFFECT OF DIFFERENT LEVELS OF PHOSPHORUS ON GROWTH AND YIELD OF TWO VARIETIES OF RAPESEED (Brassica napus L.)

A field experiment was carried out in the winter season of 2018-2019 in two sites, the first one was in the research station of the College of Agriculture and Forestry/University of Mosul and the second one was in Wana-district, and it was in clay and Sandy loam soil, respectively. The aim of the study is to investigate the effect of five levels of phosphorus (0, 30, 60, 90 and 120 kg P/ ha) in growth and yield of two rapeseed cultivars (Pactol and Srew). The experiment was carried out as a factorial trial with a randomized complete block design (RCBD) with three replications. The results showed that there were significant differences between phosphorus levels in all the studied traits and for both study sites. The fertilizer level 60 kg P/ha showed the highest rate of plant height, number of branches/plant, number of siliques/plant, Silique length, number of seeds/Silique, seed yield and oil percentage, while the level of 90 kg/ha showed the highest average weight of 1000 seeds. The cultivars had a significant effect on all the studied traits and for both study sites, as the Srew recorded the highest rate of plant height, number of branches/ plant, number of siliques/plant, Silique length, number of seeds/silique, seed yield and oil percentage, while the Pactol recorded the highest rate of 1000 seed weight. The overlap between phosphorus levels and cultivars was significant in some traits and for both study sites. The fertilizer level 60 kg P/ha and the Srew recorded the highest results for the two traits of leaf area and number of siliques/plant.