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Almond is the most important tree nut grown commercially worldwide. It is cultivated for its edible kernel of high nutritional and economic values. From an agronomic standpoint and thanks to international breeding programs, several commercial cultivars were released mainly for better kernel quality, self-compatibility, and delayed blooming time to avoid frost risks. Almond phenology also attracted the interest of many researchers but no detailed and specific scale was conceived. To standardize phenological observations among scientists and growers on one hand and accurately schedule timing of agronomic managements on the other hand, a precise phenological scale is needed. To date, BBCH (Biologische Bundesanstalt, Bundessortenamt Chemische Industrie) phenological scale is the most accurate and the widely accepted. In this research work, we characterized almond phenological growth stages using the BBCH scale. Eight of the ten principal developmental stages (0 − 9) from BBCH scale were codified and described. The almond principal growth stages were categorized into reproductive and vegetative phenology. Vegetative phenology included: bud development (stage 0), leaf development (stage 1), shoot development (stage 3), and senescence and beginning of the rest period (stage 9). The reproductive phenology encompassed the four following stages: inflorescence emergence (stage 5), flowering (stage 6), fruit development (stage 7), and fruit maturity (stage 8). To better define these phenological growth stages, illustrative pictures were provided along with codification and description. In addition, we used phenological records over three growing seasons from the main production regions of northern Morocco to draw a schematic representation of the chronological progression of principal growth stages in five widely grown almond cultivars: ‘Ferraduel’, ‘Ferragnes’, ‘Fournat de Brezenaud’, ‘Marcona’, and ‘Tuono’. Some agronomical managements intended to be applicable in an almond orchard were discussed. more...

Changes in leaf relative water content (RWC), water potential (Ψw), transpiration rate (E & Tsp), stomatal conductance (gs), maximum quantum efficiency of PSII (Fv/Fm), total chlorophylls, carotenoids, proline and soluble sugars were investigated in young Moroccan olive varieties (‘Moroccan Picholine’, ‘Menara’ and ‘Haouzia’) grown in pots under three water regimes (well-watering, moderate stress and high stress). The water treatment was applied at different growth stages during three growing seasons (2015, 2016 and 2017). Results from ANOVA analyses showed that all parameters were found to be mainly under the impact of the water regime and growth stage. In fact, the severe stress led to significant reductions in Ψw, gs, E and Tsp by more than 24%, but also in RWC, Fv/Fm and total chlorophylls with percentages lower than 15%. In contrast, water shortage activated the accumulation of proline and soluble sugars by about 13%. Among growth stages, the bud development displayed the highest levels for RWC, Ψw, gs, E, Tsp and Fv/Fm, and the lowest ones for proline and soluble sugars, whilst, the opposite was observed during the fruiting stage. Although the impacts of variety, growing season and interactions were of minor extents, we observed some significant differences. In fact, the young olive trees belonging to 'Moroccan Picholine' have shown more resistance to water stress, especially during the 2017 season. Principal component analysis (PCA) showed that 92% of the total observed variability was explained by the first two principal components, and allowed a good discrimination among the tree water regimes and the five growth stages. In addition, positive relationship was established between proline and soluble sugars, which were found negatively associated with the remaining parameters. more...