The effect of seed rate on grain yield and some agronomic traits of spring sown canola under dryland farming conditions

Rapeseed is one of the most important oilseed crops that has major role in edible oil supply. In order to determine the best cultivar and seed rate for rapeseed and mustard under cold dryland conditions, this factorial experiment was conducted based on RCBD with four replications, two cultivars (Bard-1 and Hyola-401) and five seed rates (2, 3.5, 5, 6.5 and 8 Kg/ha equal to 50, 87, 125, 162 and 200 plants per square meter) during 2004-6 at North Khorasan Dryland Research Station (Shirvan). The traits including emergence and plant establishment percent, days to flowering, plant height, days to maturity, number of pods per plant, number of seeds per pod, thousand- kernel weight and grain yield were recorded. The effect of cultivar on all traits was significant (P < 0.01). Seeding rate had significant effects on days to maturity, days to flowering and emergence and establishment percent (P < 0.01). The cultivar Bard-1 with 814 Kg/ha had higher grain yield than Hyola-401 (736 kg/ha). The greatest seed yield (821 Kg/ha) was obtained where the seeding rate of 6.5 Kg/ha was used. According to the results of this experiment, seeding rate of 6.5 Kg/ha for spring sowing of the hybrid Hyola-401 and oil mustard Bard-1 under cold dryland farming conditions seem suitable. Moreover, sowing 00 and early maturity cultivars are preferable to canola cultivars under dryland farming of cold regions of Iran.