Editorial
Fruits and youth...
- Jacky Ganry
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- 23 January 2009, p. 1
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Research Article
Breeding and evaluation of Musa hybrids resistant to Fusarium oxysporum f. sp. cubense race 1
- Thukkaram Damodaran, Neelakandan Kumar, Mathiyazhagan Kavino
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- 23 January 2009, pp. 3-12
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Introduction. Wilt caused by Fusarium oxysporum f. sp. cubense (Foc) is the most important disease of banana worldwide, causing severe yield losses in commercial and local consumption cultivars. Chemical control is currently the most used method to manage the Fusarium wilt of banana, although it is toxic, expensive and dangerous. Therefore, control through genetic improvement is widely encouraged. Hence, breeding was carried out to develop banana hybrids with putative resistance. Materials and methods. Hybridization of identified resistant diploids with commercial triploids and tetraploids was carried out; it resulted in development of 22 hybrids with improved agronomic characters. In a second step, screening of these hybrids for resistance to Foc race 1 was attempted using the double cup method of challenge inoculation with the pathogen in the roots of the hybrids at optimum level. Host responses of the susceptible and resistant hybrids were examined under greenhouse conditions through biochemical and isozyme analysis. Results. Six hybrids among the 22 hybrids with improved agronomic characters were selected based on their yield and they were evaluated for resistance. Three of them were resistant to Foc and the others were susceptible. The resistance mechanism involving the relation of enzymes such as peroxidase (PO), polyphenol oxidase (PPO) and phenylalanine lyase (PAL), and biochemicals such as phenols, proline and lignin showed relatively higher activity in resistant hybrids and parents than susceptible ones. Isozyme analysis of PO and PPO carried out using selected resistant and susceptible hybrids revealed the induction of specific isoforms in the resistant hybrids upon challenge inoculation. Conclusion. Three hybrids were identified as potential hybrids with good yield and resistance to Foc race 1.
Influence of maturity stage of mango at harvest on its ripening quality
- Emmanuel Dick, Achille N’DaAdopo, Brahima Camara, Emmanuel Moudioh
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- 23 January 2009, pp. 13-18
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Introduction. The subjectivity of the external criteria used for the determination of mango maturity at its harvest led to the search for additional more reliable parameters to determine the optimal harvest maturity and able to replace the external and internal morphological indices. Materials and methods. Some physicochemical characteristics, such as colour of pulp, soluble dry extract, titratable acidity and weight loss, were evaluated on fruits of the cv. Kent (Mangifera indica L.) collected in North Cote d’Ivoire. The days necessary for ripening after harvest were estimated. Measurements were correlated to five maturity stages corresponding to the fruit harvest carried out at (76, 82, 88, 94 and 100) days after flowering. On each date of harvest, batches of 52 fruits were gathered. On half of them, maturation was observed as of harvest, the other half being kept at room temperature and the ripening evaluation then being done at the end of storage. Results. According to the harvest date, the soluble dry extract values varied from 8.3 °Brix to 10 °Brix at fruit harvest, and from 14.2 °Brix to 20 °Brix after ripening of the fruits stored at ambient temperature. Titratable acidity was correlated positively with maturity stage. Time to ripen and weight loss continuously decreased with the fruit maturity. For mangos of the cv. Kent, the date of the most suitable harvest seemed to be at 94 days after flowering. Mangos collected at 100 days after flowering developed better organoleptic characteristics such as sugar content, peel aspect and pulp colour than those of the fruit harvested earlier. Conclusion. Starting from the 94th day after flowering, the mango of the cv. Kent collected under the conditions of the North Cote d’Ivoire develops its best organoleptic characteristics during ripening.
Caractérisation du fruit du baobab et étude de sa transformation en nectar
- Mady Cisse, Mama Sakho, Manuel Dornier, Codou Mar Diop, Max Reynes, Oumar Sock
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- 23 January 2009, pp. 19-34
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Introduction. Le baobab (Adansonia digitata L.) est un arbre qui pousse à l’état sauvage au Sénégal où le fruit est consommé sous différentes formes. Si l’écologie et la botanique de la plante ont été bien étudiées, les travaux portant sur la transformation du fruit ou sur l’impact des traitements de transformation sur la qualité des produits finis sont rares. Afin d’évaluer le potentiel technologique de ces fruits, en préalable au développement de leurs produits de transformation sur les marchés locaux, régionaux et internationaux, nous avons cherché à mieux caractériser la matière première (composition biochimique et qualité nutritionnelle), et nous avons étudié la transformation du produit en nectar. Matériel et méthodes. L’étude a porté sur douze échantillons de fruits décoqués d’A. digitata prélevés entre 2004 et 2006 dans différentes zones du Sénégal. Les proportions des différents constituants du fruit (pulpe, graines, fibres) ont été déterminées, puis différentes caractéristiques physicochimiques de la pulpe et de la graine ont été analysées. La flore microbienne présente dans les boissons traditionnellement préparées a été étudiée. Les techniques de pasteurisation et de microfiltration tangentielle des nectars ont été appliquées. Les différentes utilisations et les procédés de transformation traditionnels du fruit ont été évalués à partir d’une enquête réalisée sur un échantillon de 93 personnes interrogées à Dakar et Saly. Résultats et discussion. La pulpe a été caractérisée par une faible teneur en eau (6–15 %), une forte acidité (68–201 mEq·100 g–1) et des teneurs élevées en sucres (20–32 %), acide ascorbique (125–312 mg·100 g–1), minéraux (6 %) et amidon (41–47 %). Les chromatogrammes obtenus par CPG/SM sur la pulpe de fruit ont mis en évidence 10 composés d’arôme dont le myristate d’isopropyle, un composé phénolique non identifié et le nonanal. Sans précaution particulière, la composition de la pulpe a évolué au cours du stockage et sa qualité s’est rapidement dégradée. L’enquête réalisée a montré que la pulpe du fruit de baobab est principalement utilisée pour l’élaboration de boissons de type nectar avec un rapport massique [fruit / eau] de [1 / 3]. La stabilisation du nectar peut être obtenue par pasteurisation (80 °C / 10 min) au détriment de la qualité du produit. Des essais de stabilisation à froid par microfiltration tangentielle ont été réalisés sur des nectars avec des rapports massiques [fruit / eau] de [1 / 3] et [1 / 5]. Les densités de flux ont été comprises entre [(23 et 77) L·h–1·m–2] pour des facteurs de réduction volumique compris entre 1 et 2. Les faibles densités de flux de perméat mesurées compromettent l’intérêt de la microfiltration tangentielle pour la stabilisation à froid du nectar. Conclusion. À l’avenir, dans la perspective d’une production locale de nectar de fruit du baobab, les travaux de recherche devront être focalisés sur la stabilisation thermique de la boisson.
Identification of morphometric traits for screening of tejocote (Crateagus spp.) germplasm for better yield potential
- Carlos A. Núñez-Colín, Jaime Sahagún-Castellanos, Fernando González-Andrés, Alejandro F. Barrientos-Priego, Sergio Segura, Raúl Nieto-Ángel
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- 23 January 2009, pp. 35-44
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Introduction. Tejocote (Crataegus spp.) is an edible fruit species that some Mesoamerican cultures have cultivated since pre-Hispanic times in Mexico; however, this fruit crop has not undergone formal breeding. It is unknown whether morphological markers associated with fruit size exist to be used for indirect selection; this could be important, because this species has a large cycle. Our research aimed at studying phenotypic correlations between leaf and stomata characters with fruit weight; such correlations might be used as morphological markers for selection of superior germplasm for fruit weight. Materials and methods. Pearson’s correlation coefficients of 36 leaf variables and three leaf stomata variables with fruit weight were calculated in 94 genotypes of four different species. Results. As expected, the correlations calculated for each species and for the species pool differed. However, the number of veins in leaves of reproductive shoots was positively correlated with fruit weight (P ≤ 0.05) in the two most important horticultural species. On the other hand, C. mexicana was the best option for selecting superior germplasm, and the most significant variables correlated with fruit weight in this species were leaf major axis length of large vegetative shoots, leaf elongation ratio and number of veins of reproductive shoot leaves. Discussion. These variables could be good selection indices or morphological markers that can be used for early screening of germplasm for yield potential.
Leaf area estimation in some species of fruit tree by using models as a non-destructive method
- Hüsnü Demirsoy
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- 23 January 2009, pp. 45-51
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Introduction. Leaf area measurements are used commonly in the study of growth and development of fruit trees. These measurements can be made destructively by using a variety of sensitive instruments and/or non-destructively by using models of leaf area estimation. For models of leaf area estimation, some leaf parameters such as the length and width of leaves are usually used in the measurements. Construction of a model of leaf area estimation. Computer programs such as Excel, SAS and SPSS may be used in this process. In brief, after a leaf has been placed on a sheet of paper and photocopied, a digital planimeter or suitable tool may be used to measure the actual leaf area. The leaf width (W) and length (L) of the leaves sampled can be measured by a simple ruler. After this, regression analysis of the data may be performed separately for each genotype, species or cultivar. The analysis can be conducted with various subsets of the independent variables; for instance, leaf length (L), leaf width (W), L2, W2 and [L2 / W2] to develop the best model for predicting leaf area. Regression analyses should be carried out until the deviation sum of squares is minimized. Models of leaf area estimation for specific crops. In our study, prediction models of leaf area were developed by referring to the relevant current literature that studied such fruits as avocado, banana, blackberry, cacao, cherry, chestnut, grape, guava, kiwifruit, lotus plum, peach, pistachio, rabbiteye blueberry, red currant, red raspberry, sour orange, strawberry, pecan and white mulberry. Advantages and disadvantage of the models of leaf area estimation. Some advantages and a disadvantage of models of leaf area estimation are presented. Conclusion. Our mini-review has shown that the models which have been formulated and which will develop in the future for some fruit species can be reliably used.
Calcium effects on changes in chlorophyll contents, dry weight and micronutrients of strawberry (Fragaria × ananassa Duch.) plants under salt-stress conditions
- Mehdi Khayyat, Soheila Rajaee, AbdorezaSajjadinia, Saied Eshghi, Enayatollah Tafazoli
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- 23 January 2009, pp. 53-59
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Introduction. Today, approximately one-third of the world's irrigated lands suffer some degree of salinity. Although there are several reports about the effects of calcium treatments on strawberry growth and development under saline conditions, there are no reports demonstrating the effect on micronutrient concentrations of strawberry due to supplementary calcium applied to the salt-stressed plants. Consequently, we investigated the effects of high salinity levels, with application of supplementary calcium, on chlorophyll contents, dry weight and micronutrients of strawberry. Materials and methods. Strawberry (Fragaria × ananassa Duch.) plants cv. ‘Selva’ were grown in hydroponic culture in a heated greenhouse to investigate the effectiveness of calcium (Ca) added to nutrient solution applied to plants. Six treatments were applied: nutrient solution alone (= [N]); [N] + NaCl salt (35 mM) (= [NS]); [NS] + CaCl2 (5 mM); [NS] + CaCl2 (10 mM); [NS] + CaSO4 (5 mM); and [NS] + CaSO4 (10 mM). The effect of calcium (different forms and different concentrations) on chlorophyll contents and dry weight of salt-stressed plants was determined. Additionally, micronutrient contents were studied. Results. The results indicated that chlorophyll contents and plant dry weight were decreased by salinity. NaCl application increased Cu, Zn, Mn and Fe concentrations of root parts. In shoot parts, Cu accumulation decreased, while other elements increased. Supplementary calcium could ameliorate the negative effects of salinity on chlorophyll and dry mass production. However, micronutrient concentrations of plant parts as influenced by calcium had contradictory results: calcium induced high levels of zinc, manganese and iron concentrations in roots, but high levels of copper and zinc concentrations in shoots. Moreover, there were significant differences between calcium forms in their actions. Conclusion. Our results suggest that CaSO4 could be applied to improve the growth of salt-stressed strawberry plants.
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The pineapple leaf D – The pistachio tree in Mediterranean regions
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- 23 January 2009, p. A1
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