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Rapeseed is one of the most important oilseed crops in the world and, in Morocco, it may contribute to the improvement of food security in edible oils through developing performant cultivars and optimizing the crops management including nitrogen fertilization. The objective of this study was to evaluate the response of different Moroccan varieties to nitrogen application. Field trials were carried out at the experimental station of National School of Agriculture in Meknes, during two cropping seasons (2017–2018 and 2018–2019). Five varieties (“Narjisse”, “Moufida”, “Alia”, “Adila”, and “Lila”) were combined to different nitrogen rates (0, 30, 60, and 90 kg N ha−1). The experimental design adopted is a split split-plot with three replications, where nitrogen treatment was affected to main plot, variety to subplot, and year to sub-subplot. Results showed that dry matter, harvest index, oil content, seed yield per plant and yield components were significantly affected by nitrogen rates, with an upward trend in seed yield as the nitrogen rates increased. On average, seed yield increased by 50.33% for application of 90 kg N ha−1 compared to the control (without N fertilization). However, oil content declined from 41.08% to 37.81% with the increase of nitrogen level from 0 to 90 kg N ha−1. Additionally, for the other traits studied, the highest mean values were observed for 90 kg N ha−1, except harvest index which exhibited the greatest value for 60 kg N ha−1. Variation among the varieties was significantly large for all traits studied with a superiority of the variety “Alia” for seed yield per plant (9.82 g plant−1), number of pods per plant (151), and number of seeds per pod (24.05).

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A field experiment was conducted to test the new approach for estimating crop nitrogen (N) uptake from organic inputs. The soil was prelabeled with 15 N by applying 15 N fertilizer to sunflower crop (Helianthus annuus L. var. Viki). The 14 N plots, which received unlabelled fertilizer, were also set up. At harvest, 15 N labeled residues were added to the unlabeled soils at a rate of 73 kg N ha 21 (direct technique) and unlabeled residues were added to the 15 N-labeled soils at the same rate (indirect technique). Control plots without residues were also established. All plots were sown with the wheat (Triticum aestivum L. var merchouch)-fababean (Vicia faba L.)-wheat (Triticum aestivum L. var merchouch) cropping sequence.In the cropping sequence, the first, second and third crop derived respectively 12.01, 2.4, and 1.93 kg N ha 21 from crop residues estimated by the direct method and 14.77, 3.3, and 1.85 kg N ha 21 estimated by the indirect method. The results showed no significant difference between the two techniques, which suggests that the new soil prelabeling technique compares well with the direct technique.

Summary — Serological study of Moroccan strains of Agrobacterium tumefaciens, the causal agent of crowngall in stone-fruit trees. To investigate the possibility of using serological diagnosis methods for Agrobacterium tumefaciens, the causal agent of crown-gall of stone-fruit trees, and particularly in order to distinguish between pathogenic and non-pathogenic strains of the bacterium, we tested antisera against 40 bacterial cultures with three serological techniques. The serological reactions were very variable. Some of the antisera showed strain specificity whereas others reacted with all strains without any link to the chosen strain or the immunizing protocol. None of the 12 studied antisera was biovar-specific. No