Introduction. The genus Phoenix has 13 species. Dates from P. dactylifera and P. theophrasti are the only ones that have been characterised so far. The aim of our study was to evaluate the physico-chemical and functional characteristics of date fruits in the Khalal and Rutab stages of P. loureiroi, P. canariensis, P. reclinata and P. roebelenii, and compare them with P. dactylifera. Materials and methods. Two samples of 15 date fruits in the Khalal stage and another 15 date fruits in the Rutab stage were chosen from each species for analyses and quality parameters. Results and discussion. Significant differences in the measured parameters were observed among the different species. Dates of P. dactylifera were larger than those of the other species and had the lowest [seed weight/fruit weight] proportion. In the Khalal stage, dates from P. canariensis and P. dactylifera were yellow, P. loureiroi and P. reclinata were dark yellow to orange, and those of P. roebelenii were brown purple. Dates of P. dactylifera (Rutab stage) showed higher sugar and lower organic acid contents than those of the other dates. Dates of P. reclinata, P. roebelenii and P. canariensis presented values of antioxidant activity and total phenols in the Khalal stage that were very high compared with those of P. dactylifera. These species are used as ornamental palms but their fruits are consumed locally as food. These dates presented high nutritional quality and can be used as novel foods for different purposes, such as snacks or food fortification, especially due to their high value in functional properties.

Introduction. Consumers and processors value tomatoes with high fruit sugarcontent; however, most breeding and cultural practices negatively impact this trait. Wildtomato species can accumulate two- to three-fold more fruit sugar than cultivars and areproving to be valuable both as a source of high-sugar loci to broaden thegenetic base of currently produced cultivars, and as research material to understand thistrait. Synthesis. While cutting-edge genomic approaches have taught us muchabout fruit phenotypes, it is still important to assess fruit enzyme activities andmetabolic fluxes in lines with contrasting fruit sugar accumulation. These metabolicfunctions are closest to the ripe fruit sugar trait. In this review, we focus ourattention on the biochemical pathways, especially starch biosynthesis, that may influencetomato fruit sugars. We try where possible to put this information into a physiologicalcontext because together they influence yield. We compare and contrast sugar metabolism incultivars and wild tomato species and identify factors that may influence differences intheir fruit size. Conclusion. Although difficult, we show that it is possibleto develop fruit with high horticultural yield and use the breeding line ‘Solara’ as anexample. In addition, we suggest avenues of further investigation to understand theregulation and control of fruit carbohydrate content.

Introduction. Drought stress is the major factor affecting growth, development and production of walnut trees. In Iran, approximately 33 Mha of land is affected by salinization and drought stress. Finding genetic resources tolerant to drought stress at different growth stages is important for such semi-arid regions. Our aim was to understand better the adaptive mechanisms that enable different genotypes of walnut population to survive under drought stress, and to provide some useful clues for walnut tree breeding toward improved drought tolerance with utilization of existing drought-tolerant genetic resources. Materials and methods. To study the mechanism(s) involved in drought tolerance of some Persian walnut genotypes, drought stress was induced using polyethylene glycol-6000 to produce water potentials of 0 Mpa (control), –0.10 MPa, –0.50 MPa, –0.75 MPa, –1.00 MPa, –1.50 MPa and –2.00 MPa. The amount of proline and soluble sugar accumulation in four walnut genotypes (‘Panegine20’, ‘Lara’, ‘Serr’ and ‘Chandler’) were determined after being exposed to the various water potential levels. Results. The rates of seed germination in all genotypes were significantly reduced by low external water potentials. Plants exposed to water stress had a higher amount of soluble sugars in roots and shoots of tolerant genotypes (‘Panegine20’ and ‘Chandler’) and a lower amount of starch in their tissues. These results imply the important roles of soluble sugars as solutes conferring resistance to drought in these genotypes. The free proline levels were also increased in response to drought stress. They were higher in drought-tolerant genotypes than in sensitive ones (‘Lara’ and ‘Serr’). Proline increased more in shoots than in roots. However, the soluble sugar and starch fluctuations were higher in the roots. Conclusion. Our results support a direct correlation between the degree of drought stress and proline content. As a consequence, proline concentrations could be used as a biochemical marker of drought stress level in walnut plants.

Introduction. Grewia coriacea is a widespread plant species that occurs spontaneously in tropical forests of Central Africa. It is one of the most important commercial spontaneous fruit crops in the Republic of Congo (Brazzaville), where it is harvested, sold and consumed on a rather large scale. However, similar to many other spontaneous products of the tropical rain forest in Africa, G. coriacea remains poorly studied and its nutritional potential is unknown. Because the fruit of G. coriacea is an important food for indigenous people in a large portion of the Congo River Basin, we studied the evolution of some compounds of this fruit starting from its fruit setting until its maturation. Materials and methods. The contents of various pigments (chlorophyll a and b, and carotenoids), and concentrations of soluble sugars, ascorbic acid and soluble proteins of the fruit pulp of G. coriacea were analyzed in the laboratory and they were followed during maturation. Results and discussion. The curves of evolution of the studied parameters followed some anticipated trends: increasing, decreasing or relative stability. Increasing applied to the carotenoids (3,0 mg·g–1 at the beginning of the fruit development up to 8.2 mg·g–1 at the end of its maturation), soluble sugars (9,9 µg·g–1 up to 75,4 µg·g–1), ascorbic acid (25 mg·100 g–1 up to 230 mg·100 g–1) and soluble proteins (7 µg·g–1 up to 40 µg·g–1). In contrast, the two chlorophyll pigments (chlorophyll a and b) showed an overall decreasing trend. Finally, the concentration of soluble proteins remained rather constant in the later stages, despite an initial increase in the early stage of development. Conclusion. To our knowledge, these results are the first data published concerning the temporal changes in physico-chemical parameters of G. coriacea fruits in tropical Africa. The study shows that the studied fruits have high nutritional potentials, and that their ability to accumulate rather high levels of ascorbic acid could make them a potential source of vitamin C.

Introduction. Fruit production is faced with water shortage, especially in areas with a Mediterranean climate characterized by a very long, dry and hot summer. Thus, the growers under such conditions must manage irrigation carefully by finding new strategies, including water stress management. Materials and methods. Effects of water stress (WS) and crop load (CL) on the carbon assimilation rate, fruit growth, crop yield and fruit quality (size and soluble solids content) were evaluated in a 7-year-old ‘Elegant Lady’ peach orchard (Winters, California, USA). The experimental design consisted of a completely randomized block factorial design with 2 × 3 factors: irrigation with two levels (control and WS trees) and crop load with three levels (light, commercial and heavy). Results and discussion. Both CL and WS affected fruit growth during the last stages but not early on. Crop load did not affect trunk water potential (TrWP) which, however, was significantly reduced by WS throughout the day and the season. The stomatal conductance (gs), transpiration rate (E) and CO2 assimilation rate (A) were not affected by CL, but they were reduced by WS. There were poor correlations between TrWP and either gs or A in control trees, indicating relatively poor coordination between leaf functions in peach trees under optimal conditions. Both WS and CL delayed the harvest date through their effect on ripening. Water stress significantly reduced the average crop fresh yield but hardly affected crop dry yield. Both WS and CL affected the distribution of fruit size categories, with the proportion of large fruit decreasing with the increase in crop load and the severity of WS. Conclusion. Water stress reduced fruit fresh weight and fruit fresh yield but not fruit dry weight or dry yield. Crop load reduced fruit fresh and dry weights and yields. Crop load had a negative effect on soluble solids content, while WS had a positive effect. Thus, CL reduced fruit size and soluble solids content, while WS reduced size but improved soluble solids concentration.

Introduction. During ripening, the pigment content, starch index and sugar content of banana fruit change, providing accurate indicators for maturity classification. However, at present, banana fruits are traded according to their color stage. This study is aimed at investigating a non-destructive, rapid instrumental method to measure fruit maturity and quality more precisely. Materials and methods.Musa cavendishii L. grown in Honduras were ripened in a commercial ripening chamber and selected at four different color stages. Visible (VIS) and near-infrared spectroscopy (NIRS) in reflectance mode were investigated for the non-destructive detection of fruit chlorophyll and sugar contents. Partial least squares regression was applied to auto-scaled spectral data. Reference analyses were performed using spectrophotometry after a diethyl ether extraction of chlorophyll and high performance liquid chromatography for individual sugar analysis. Results. Calibration models for spectral readings and laboratory destructive tests gave multivariate correlation coefficients of determination of $R^2 > 0.70$ for chlorophyll a, R2 = 0.96 with standard errors of calibration (scal) of 1.6, and standard errors of cross-validation (scval) of 1.8 for glucose; R2 = 0.94 with scal of 0.8, and scval of 0.9 for sucrose; R2 = 0.96 with scval of 2.5 and Scval of 2.7 for fructose (g$\cdot$kg-1 on a dry weight basis). Conclusion. This paper shows the potential of VIS/NIRS for non-destructively predicting the maturity and quality of whole banana fruit based on determining fruit chlorophyll and sugar contents.

Introduction. La salinité du sol et de l'eau d'irrigation, aggravée par la rareté des précipitations, est une menace permanente pour la culture des agrumes au Maroc. Le choix d'un porte-greffe tolérant à ce stress abiotique serait un moyen efficace pour pallier ce problème. L'expérimentation présentée a permis d'évaluer, vis-à-vis du stress salin, trois porte-greffes récemment introduits au Maroc. Matériel et méthodes. Des plants de citrange Carrizo et de deux hybrides, H1 et H2, issus du croisement Poncirus trifoliata × Citrus sunki Hort. ex Tan. ont été évalués pour leur tolérance à la salinité. Les plants âgés de 18 mois ont été irrigués par une solution nutritive additionnée de (25, 35, et 70) mM de NaCl durant un ou deux mois alors que les plants témoins recevaient la solution nutritive sans NaCl. Après traitement, les teneurs en proline et en sucres solubles ont été mesurées dans les feuilles des porte-greffes traités. Résultats. L'accumulation de proline a été indépendante de la présence de NaCl dans la solution d'irrigation mais elle a varié en fonction du porte-greffe. En revanche, NaCl a fortement stimulé l'accumulation des sucres solubles chez les trois porte-greffes et cette accumulation a été très importante chez le porte-greffe H1. Discussion et conclusions. Ces résultats concordent en partie avec certains des travaux déjà publiés. Dans nos conditions expérimentales, l'effet des concentrations salines utilisées a pu être compensé par l'accumulation de sucres solubles dans les feuilles, notamment dans celles du porte-greffe H1. Celui-ci ayant montré moins de toxicité foliaire que les deux autres porte-greffes, l'accumulation de sucres solubles dans la feuille d'agrumes pourrait être un indice de tolérance à la salinité.

Investigations were carried out to establish the phagostimulatory effects of cheaply available materials (bag sugar, sucrose, molasses) on Chilo partellus larvae. Sugar and analytical grade sucrose (1% w/v solutions) were the best phagostimulants tested. Molasses was the least effective but a 10% w/v solution induced a significant feeding response. These stimulants, in combination with a Bacillus thuringiensis treatment, were tested to determine their effects on increasing the efficacy of the pathogen against this pest species. Larval mortality levels were significantly higher in the presence of a feeding stimulant than when B. thuringiensis alone was administered; inclusion of such adjuvants in a B. thuringiensis preparation could significantly enhance the field efficacy of the pathogen against C. partellus.