Période de récolte et caractéristiques de l'huile d'olive de quatre variétés en irrigué dans la région de Meknès au Maroc

The objectives of this study were to determine the optimal harvest time and characterization of olive oil of four olive varieties; Arbequina, Dahbia, Haouzia and Menara; under irrigation in the region of Meknes. A varietal effect was found regarding fruit, pulp and stone weights and the ratio pulp/stone. Haouzia showed the largest fruit weight followed by Dahbia, Menara and Arbequina. The Pulp/stone ratio (> 5) is satisfactory for the four varieties with a higher ratio for Haouzia. The relation between these parameters taken individually and maturity index showed a high positive correlation. The oil content per fresh weight reached 23.6% for Menara, 22.5% for Haouzia, 20,0% for Dahbia and 18,0% for Arbequina. The highest polyphenol contents recorded were 1 757 ppm for Arbequina, 2 021 ppm for Dahbia, and 2 120 for Haouzia and Menara. The oil and polyphenols contents were highly and positively correlated with the maturity index. The levels of oleic acid in Haouzia (76.1%), Dahbia (75.3%) and Menara (75.2%) were higher than that in Arbequina (66.2%). The integration of the oil and polyphenols contents allowed to determine an optimal harvest period located between late November and late December. Keywords : Olive oil , maturity index , oil content, polyphenol content , fatty acids, optimum harvest period, Arbequina , Dahbia , Haouzia, Menara.  Les objectifs de cette étude étaient la détermination de la période optimale de récolte et la caractérisation de l’huile de quatre variétés d’olivier; Arbéquine, Dahbia, Haouzia et Menara; en irrigué dans la région de Meknès. Un effet variété a été observé pour les poids moyens du fruit, de la pulpe et du noyau et pour le rapport pulpe/noyau. Haouzia a montré le poids moyen le plus important suivie par Dahbia, Menara et finalement Arbéquine. Le rapport Pulpe/noyau (> 5) se montre satisfaisant pour les quatre variétés avec un rapport élevé pour Haouzia. La relation de ces paramètres pris individuellement avec l’indice de maturité a montré une corrélation positive forte. Les teneurs en huile par rapport à la matière fraîche atteignirent 23,6% pour Menara, 22,5% pour Haouzia, 20,0% pour Dahbia et 18,0% pour Arbéquine. Les teneurs maximales en polyphénols enregistrées étaient de 1 757 ppm pour Arbéquine, 2 021 pour Dahbia et 2 120 pour Haouzia et Menara. Les teneurs en huile et polyphénols étaient également corrélées positivement avec l’indice de maturité. Les teneurs en acide oléique de Haouzia (76,1%), Dahbia (75,3%) et Menara (75,2%) étaient plus élevées que celle d’Arbéquine (66,2%). L’intégration de la teneur en huile et en polyphénols a permis de déterminer une période optimale de récolte qui s’est située entre fin novembre et fin décembre. Mots clés: Olives, variétés, indice de maturité, teneur en huile, teneur en polyphénols, acides gras, période optimale de récolte, Arbequine, Menara, Dahbia, Haouzia.   &nbsp

Genetic diversity of on-farm selected olive trees in Moroccan traditional olive orchards

Selecting desired agronomic traits may lead to a loss of genetic diversity in crop species. A molecular investigation was conducted to determine how well a set of olive (Olea europaea L.) accessions sampled in Moroccan traditional orchards represented the entire Moroccan olive diversity range. We therefore collected, in traditional agroecosystems from northern and central Morocco, a total of 88 olive trees chosen for their agronomic traits based on local farmers' knowledge. Using 12 SSR loci, 45 trees (51.1%) had a genotype identical to the 'Picholine Marocaine' variety, while the remaining samples were classified into 27 different SSR profiles. Two categories of genotypes were identified: (i) genotypes closely related to the 'Picholine Marocaine' variety and probably resulting from intensive vegetative propagation from a limited number of clones, and (ii) genotypes displaying a high number of dissimilar alleles which may have originated from selected spontaneous seedlings. A significant difference in allelic richness was revealed between the 28 on-farm selected genotypes and the overall olive diversity, represented by 57 local genotypes, indicating that the on-farm selected trees represented a subsample of Moroccan genetic diversity. This could be explained by the prevalence of 'Picholine Marocaine' in traditional orchards, while some original genotypes with favourable agronomic traits resulting from local farmers' selection were also identified. Applying an ethnobotany approach combined with criteria to fulfil farmers' household needs could be particularly relevant and better explain the obtained results