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A field experiment was conducted at Rezvanshahr, Guilan province, Iran, to evaluate the effects of phosphorus fertilizer rate and Pseudomonas fluorescens strains on growth and yield of field pea (Pisum sativum L.). The experimental design was a randomized complete block in a factorial arrangement with three replicates. Factors were phosphorus fertilizer rates (0, 25, 50, 75, and 100 kg P2O5 ha-1 as triple superphosphate), and seed inoculation with P. florescens strains [control (non-inoculated), inoculated with strain R41, and strain R187). Analysis of variance showed that plant height, seed yield, pod number per m2, 100-seed weight, biological yield, harvest index, and leaf P concentration were significantly influenced by phosphorus fertilizer rate and P. florescens strain. At the same time, phosphorus fertilizer rate × P. fluorescens strain interaction was significant only for 100-seed weight. On the other hand, seed number per pod was significantly affected neither by phosphorus fertilizer rate nor by pseudomonas strains. Result showed that seed yield was significantly increased from 1099 ± 67 to 1898 ± 118 kg ha-1 as P2O5 application rate increased from 0 to 75 kg ha-1, and thereafter relatively remained constant. There was no significant difference in seed yield between plants raised from inoculated seeds with P. fluorescens, strain R187 (1664 ± 97 kg ha-1) and those raised from inoculated seeds with P. fluorescens, strain R41 (1669 ± 104 kg ha-1). At the same time, plants raised from inoculated seeds with P. fluorescens (both strains) produced greater grain yield compared to those raised from uninoculated seeds (1370 ± 80 kg ha-1). Based on the results of this study, P2O5 application at the rate of 75 kg ha-1 and inoculation with pseudomonas bacteria are recommended for obtaining the greatest seed yield in field pea.

A field experiment was conducted at Rice Research Station, Tonekabon, Iran, to determine the effect of N rate on seed yield, protein and oil content of two canola (Brassica napus L.) cultivars. Two canola cultivars (‘Hayola-308’ and ‘RGS-003’) and five N rates (0, 50, 100, 150, and 200 kg ha­-1), organized into a randomized complete block design with a factorial treatment arrangement and three blocks, were applied to plot areas. Results showed that N rate effect was significant (P < 0.01) for seed yield, protein content and yield, and oil yield but not for oil content. On the other hand, cultivar had only significant (P < 0.01) effect on seed protein and oil content. Moreover, the interaction between N rate and cultivar was significant at P < 0.01 for seed, protein and oil yield, illustrating that cultivars showed different responses to N rates for these traits. In general, the quadratic equation provided a good description of the relationship between seed, protein and oil yield and nitrogen rate. For ‘Hayola-308’, seed, protein and oil yield increased significantly as N application rate increased from 0 to 150 kg ha-1, but thereafter remained constant. In contrast, for ‘RGS-003’, seed, protein and oil yield increased significantly as N application rate increased from 0 to 200 kg ha-1. Therefore, at the highest N application rate (200 kg ha-1), ‘RGS-003’ produced greater seed, protein and oil yield than ‘Hayola-308’. Averaged across N application rate, the seed protein content of RGS-003 was significantly (P < 0.01) higher than that of ‘Hayola-308’, while the opposite result was observed for seed oil content. This study demonstrated the differential response of two canola cultivars to N rate in terms of seed, protein and oil yield.