Variabilité des caractéristiques physiques des mangues cultivées au Tchad: caractérisation de la diversité fonctionnelle

Abstract

Variabilité des caractéristiques physiques des mangues cultivées au Tchad : caractérisation de la diversité fonctionnelle 12933 montrent que la variabilité des paramètres étudiés résulterait d'une diversité fonctionnelle des mangues cultivées au Tchad. Mots clés : Variétés de mangues, caractères physiques, diversité fonctionnelle, Tchad et régions de culture ABSTRACT Variability of physical characteristics of mangoes cultivated in Chad: characterization of the functional diversity Objective: Chad produces more than 14 varieties of mangoes; however, their physicals characteristics are little known. The aim of the study was to determine the physical characteristics of these varieties of mangoes in order to contribute to their popularization and valorization. Methodology and results: Physical data were collected from each mango fruit in a sample of 15 ripe fruits of one variety harvested from three mango trees in an orchard. All fruits were harvested from 12 orchards in the four study regions. This study showed that Davis haden, Smith, Eldon, Kent and Coeur de Boeuf mango varieties cultivated in Chad and particularly in the region of Logone Occidental had the best physical parameters including mass, volume, index of caliber, the mass of the pulp and the pulp yield. On the other hand, the local varieties (Bangui, Kassaï and Mangotine) had the most modest parameters except the variety Maïduguri, which is classified among the medium varieties group with José Tchad, Julie Kassawa, Keitt, Palmer and Valencia, but nevertheless possessed the best commercial quality (pulp proportion: 83.26 ± 2.36%). Local varieties had higher firmness (2.33 ± 0.38 to 2.46 ± 0.33) than improved varieties (2.11 ± 0.29 to 2.39 ± 0.23). All these varieties of mangoes grown in Chad were elongated and had at ripe stage a specific weight nearly to 1 (0.99 ± 0.01 to 1.12 ± 1.02). In all these varieties of mango, a perfect positive correlation (r = 1) was found between the mass of the mango and the mass of the pulp. Conclusions and applications of the results: This study showed that there is a great variability of morphological and phycical characteristics between varieties and that they are milieu-dependent. The improved varieties were clearly distinguishable from local varieties by the importance of morphological and physical parameters. The results obtained would allow an appreciation of the adaptive potential of mango varieties and provide the necessary informations to the various actors in the mango sector in order to rationalize the choice of mango varieties. They could in particular allow the sorting of mature and ripe fruits because the ripe fruits have a specific weight nearly to unit, therefore floatable on water. Finally, these results indicated that the variability of parameters studied could be a result of a funtional diversity of mango varieties cultivated in Chad.

Morphological and Physicochemical Parameters of Three Mango (Mangifera Indica L) Varieties Exported In North of Ivory Coast

“…The results showed that its values for the three studied mango varieties were within the range of acceptable values by the European Union (EU) for this indicator. These values were substantially similar to the results of Passannet et al [7] which were 9.72 ± 0.50 for Kent and 9.52 ± 0.60 for Keitt. Moreover our values were appreciably close to those of Diakabana et al [9] who in their studies on the Boko mango in Cameroon, found a size of 8.62 ± 1 (when the values of lengths (L); width (l) and thickness (e) were expressed in centimeter (cm)).…”

“…The sphericity index (Is) and the shape coefficient (Cf) of the studied mango varieties were greater than those of Passannet et al [7] which were respectively between 0.64 ± 0.05 and 0.88 ± 0.07 and between 1.12 ± 0.07 and 1.78 ± 0, 09. This would mean that the mango varieties exported by SODIPEX company were all elongated because their coefficient form is greater than 1 (Cf ˃1).…”

“…These results could be explained by the capacity of absorption of mineral elements by the roots, by the capacity of carrying out photosynthesis and the composition of the fruit. According Passannet et al [7] study in Chad the speed production of assimilates of an organ resulting from both its photosynthetic activity and of its size. As for the volume, it could be a visual trait of appreciation of the amount of pulp (flesh) or mass of a mango.…”

“…The shape of the mangoes was assessed by the grade index (Ic) with formula (2) and the sphericity index (Is) with relation (3) according to the formulas used by Silou [5]. The shape coefficient (Cf) expressed with the formula (4) used by Fagbohoun & Kiki [6], Passannet et al [7] and Frehaut [4]. (2) (3)…”

“…However, the mass of the skin was determined by deduction between that of the fruit and the stone. The proportions of the pulp (Pp) and of the kernel (Pn) were calculated respectively by the formulas (5) and (6) used by Passannet et al [7].…”