Introduction. Leaf area is often related to plant growth, development, physiology and yield. Many non-destructive models have been proposed for leaf area estimation of several plant genotypes, demonstrating that leaf length, leaf width and leaf area are closely correlated. Thus, the objective of our study was to develop a reliable model for leaf area estimation from linear measurements of leaf dimensions for citrus genotypes. Materials and methods. Leaves of citrus genotypes were harvested, and their dimensions (length, width and area) were measured. Values of leaf area were regressed against length, width, the square of length, the square of width and the product (length × width). The most accurate equations, either linear or second-order polynomial, were regressed again with a new data set; then the most reliable equation was defined. Results and discussion. The first analysis showed that the variables length, width and the square of length gave better results in second-order polynomial equations, while the linear equations were more suitable and accurate when the width and the product (length × width) were used. When these equations were regressed with the new data set, the coefficient of determination (R2) and the agreement index ‘d’ were higher for the one that used the variable product (length × width), while the Mean Absolute Percentage Error was lower. Conclusion. The product of the simple leaf dimensions (length × width) can provide a reliable and simple non-destructive model for leaf area estimation across citrus genotypes.

Introduction. Among the citrus species, C. sinensis has been the most studied given its importance in terms of production and its industrial application in juices. Some of orange juice's organoleptic and functional properties, which make it an attractive product for the consumer, are due to its carotenoid composition. Xanthophylls can be found in either their free form (as the carotenes are found) or in a more stable fatty acid esterified form in the case of mono- and polyhydroxylated xanthophylls. Detection of adulteration of orange juices is of concern to consumers, regulatory agencies and citrus processing industries, and the study of carotenoid ester composition has been proposed to evaluate fruit products' authenticity. In this study, we report on the native (carotenoid esters and free carotenoids) carotenoid profile of orange juices of eight different varieties. Materials and methods. Monovarietal fresh orange juices were obtained from squeezing mid-season oranges (Citrus sinensis varieties: Bionda, Brasiliana, Moro, Ovale, Sanguinello, Tarocco, Valence and Washington) cultivated and supplied by a local producer. After the extraction of the carotenoids from the samples, the analyses were carried out by HPLC-DAD-APCI-MS. Results and discussion. The results showed that, in the juices studied, the xanthophylls were mostly esterified (93% of the total carotenoid mean content). The different varieties investigated showed variations in their carotenoid contents. The total carotenoid contents ranged from 2.42 µg·g–1 in the Washington variety to 15.8 µg·g–1 in the Valencia variety. Among the monoesters, the Valencia variety showed the highest violaxanthin ester amounts (61%), the Brasiliana variety showed the highest β-cryptoxanthin ester content (86.9%) and the Tarocco variety had the highest luteoxanthin ester amount (75.7%). Moreover, in general, in the Brasiliana, Ovale, Sanguinello, Valencia and Washington varieties, the monoester contents were higher than the diesters, whereas in the Bionda, Moro and Tarocco varieties the opposite was determined. To the best of our knowledge, this is the first time that this analytical approach has been applied to characterising, both qualitatively and quantitatively, the whole carotenoid pattern (carotenoid esters and free carotenoids) in orange juices from the Bionda , Brasiliana, Moro, Ovale, Sanguinello, Tarocco, Valence and Washington varieties. This contribution could also be used to establish authenticity markers among orange varieties that could potentially be used to prevent adulteration.

Introduction. La pomme Cythère est un fruit économiquement sous-exploité au Cameroun par manque de connaissances sur les techniques de culture de l’espèce, la conservation post-récolte de son fruit et sa valeur nutritionnelle. L’objectif de notre étude a été d’analyser certains changements morphologiques et biochimiques qui se produisent au cours du développement de la pomme Cythère et de chercher à évaluer le temps s’écoulant entre la nouaison et la maturation des fruits, afin de prévoir une date probable de récolte au Centre Cameroun. Matériel et méthodes. Certains paramètres morphologiques (longueur, diamètre, volume et poids du fruit) et biochimiques (teneurs en eau, en sucres totaux, en lipides, protéines et en éléments minéraux, teneur en chlorophylles a et b) des fruits de S. cytherea ont été mesurés à partir de leur nouaison jusqu’à leur maturation. Résultats et discussion. Les valeurs des paramètres morphologiques mesurés sur le fruit ont augmenté au cours du temps et leur évolution a suivi une courbe à allure sigmoïdale. Les valeurs maximales ont été obtenues à la vingt-huitième semaine avec près de 128 g pour le poids frais, 19 g pour le poids sec, 69 mm pour la longueur, 58 mm pour le diamètre et 116 mL pour le volume. Les chlorophylles a et b ont diminué au cours du développement du fruit. La teneur des fruits en éléments minéraux a diminué avec le temps et le potassium a été l’élément le plus abondant. Sa teneur a varié de 1,6 % à 0,9 % entre la sixième et la trentième semaine après nouaison. Les sucres totaux ont augmenté avec le temps alors que les teneurs en lipides et les protéines diminuaient. Trente semaines après la nouaison, les valeurs ont été de 13,76 % de matière fraîche pour les sucres, de 0,47 % de matière sèche pour les lipides et de 0,43 % de matière sèche pour les protéines. Conclusion. La composition de la pomme Cythère donnerait à ce fruit une valeur nutritive aussi importante que celle de certains fruits tropicaux plus connus comme la banane, la mangue et l’ananas.

Botanique. Originaire d’Afrique tropicale, Detarium senegalense J.F. Gmel. appartient à la famille des Caesalpiniaceae et au genre Detarium Juss. C’est un grand arbre multicaule de (15 à 40) m de haut. Ses feuilles sont composées, paripennées, avec cinq à six paires de folioles opposées, disposées de manière alterne. Répartition. D. senegalense est rencontré sur les lisières de la forêt dense humide, dans les régions côtières, septentrionales et dans la zone soudano-guinéenne. Désigné par le terme « ditax » en Wolof, D. senegalense fait partie des espèces fruitières forestières les plus importantes dans l’économie d’exploitation au Sénégal. Il pousse de façon sauvage dans les îles du Sine-Saloum et en Casamance. Composition et transformation. Le fruit est caractérisé par sa pulpe verte très riche en vitamine C (plus de 1 g·100 g–1). C’est un fruit très populaire et largement consommé au Sénégal principalement sous forme de boisson, de marmelade, de sorbet ou à l’état frais. Le fruit possède également des vertus thérapeutiques contre la toux, les maux de reins et la lèpre. Certaines variétés de D. senegalense produisent des fruits toxiques mais les composés responsables de la toxicité n’ont pas encore été totalement identifiés. Aucune méthode objective permettant de différencier les fruits comestibles des fruits toxiques n’est disponible à l’heure actuelle. Bilan. Malgré ses potentialités nutritionnelles et organoleptiques, le ditax reste sous-exploité. Dès lors, la caractérisation biochimique complète des fruits, l’évaluation du potentiel technologique, le développement de méthodes de détection rapide des fruits toxiques et l’amélioration de la stabilité des produits transformés à base de ditax seraient des perspectives de recherches intéressantes pour mieux valoriser ce fruit riche en vitamine C. La culture contrôlée de la plante mériterait également d’être envisagée pour le développement de la production.

Introduction. Cashew production has been on a decline due to poor yield resulting from poor quality traits of open-pollinated seedling populations that were used to establish plantations. Clones established from outstanding individuals through air-layering root poorly and are not likely to survive transplanting, thus clonal propagation by air-layering has been of little value for cashew propagation. Materials and method. To improve the rooting percentages of air-layering, three auxins (IBA, NAA and IAA) were applied at six concentrations [(0, 1, 2, 3, 4 and 5)%] on four cashew genotypes. Results and discussion. Significant improvement was recorded in terms of layer take, number of roots per layer, number of days to rooting, length of roots and percentage of surviving clones after transplanting. Improvement varied between the different auxins, concentrations and genotypes. We observed that degree of rooting was genotype-specific and influenced by auxin type and specific concentration. Our data showed that, among the auxins tested, IBA was most effective, with optimum performance at the 2% concentration. Conclusion. Using auxins made it possible to significantly improve the rooting and survival of cashew propagules; however, to achieve sufficient rooting and better establishment after transplanting, auxin treatment should not exceed 3% concentration. This intervention would help alleviate the problem of clonal establishment in cashew.

Introduction. Higher allocation of land in favour of fruits is vital to raise the farm income and productivity, but such an opportunity is also complemented with higher risk and uncertainty. Economic expectation assumes a great role, while such decisions have an impact on the welfare of farmers in terms of their income and risk. In this paper, we examined the nature of price expectations, their relationship with other economic factors, and analysed the importance of price and income expectations of the fruit (apple) growers on their land allocation decisions. Materials and methods. In this paper, the elicitation technique was used to obtain both price and income expectations of apple growers. The price expectations were compared with the actual price of apple over the last three years and then linked with farmers' input-use propensities. A regression method was used to identify the role of expectations in the decision of land allocation in favour of apple crops. Results and conclusion. Our results showed that better price expectation improves the input-use (generally labour) propensities. However, for allocation of the inelastic factor of production, i.e., land, in favour of a fruit crop, it is the income expectations that explain farmers’ decisions. Farmers’ capacity to generate higher productivity along with the better market prospects together explain their decision regarding allocating land to high value fruit crops.