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In order to the evaluate the effect of planting dates on phenological traits, plant height, pods per plant and seed yield of rapeseed spring varieties, a split-split plot experiment based on randomized complete block design with four replications was conducted during 2 years at Agriculture Research Station of Baykola, Mazandaran, Iran. Treatments were planting dates (September 29, October 9, October 19, October 29 and November 8) as main plot and sub-plots were three cultivars ( Hyola401, Option500 and RGS003. All the traits were affected by planting date and variety. The mean values of seed yield of Hyola401, Option500 and RGS003 were 3274, 2898 and 3040 kg ha-1, respectively and Option500 and RGS003 had not statistically significant difference. Non significant interaction effects of planting dates and varieties for seed yield indicated that yield reduction of the varieties in late planting dates had similar trend and Hyola401 and Option500 had the most and the least seed yield, respectively. Seed yield reduction at late planting date was related to insufficient vegetative growth before flowering stage. Significant positive correlation between plant height and number of pods per plant was the main reason that in late planting date reduction of plant height imposed reduction of pods per plant and finally seed yield was decreased.

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Studyign of soybean cultivars under abiotic stress conditions to improve their yield is important. This experiment was carried out as a strip plot based on a randomized complete block design with three replications in the Safiabad Argicultural Research Center. Vertical factor consisted of foure levels of irrigation (Irrigation after 50, 90, 130 and 170 mm evaporation from class A pan) and horizontal factor was 6 soybean genotypes (504, Katoul, Safiabadi, BP×Safiabadi, Migmat and Salend). Results showed that the effect of drought stress, genotypes and their interactions were significant on grain yield. The mean comparison of drought stress × genotype interaction showed that the highest grain yield (4522 Kg ha-1) achieved in irrigation after 50 mm evaporation from class A pan in Migmat and the lowest grain yield (1017 Kg ha-1) belonged to Katoul genotype with irrigation after 170 mm evaporation from class A pan. Pod number per plant decreased by 16%, 28% and 51% with increasing irrigation intervals to 90, 130 and 170 mm compared to irrigation after 50 mm evaporation. The treatments did not have any significant effect on the number of grain per pod. It is concluded that, irrigation after 50 mm evaporation from class A pan would be suitable for Migmat and BP×Safiabadi genotypes. Irrigation after 90 mm evaporation from class A pan appropriate for 504, Salend, Katoul and Safiabadi genotypes.