Isolation and functional analysis of two CONSTANS-like 1 genes from mango.

The CONSTANS-LIKE1 (COL1) gene plays an important role in the regulation of photoperiodic flowering in plants. In this study, two COL1 homolog genes, MiCOL1A and MiCOL1B, were isolated from mango (Mangifera indica L.). The open reading frames of MiCOL1A and MiCOL1B are 852 and 822 bp in length and encode 284 and 274 amino acids, respectively. The MiCOL1A and MiCOL1B proteins contain only one CCT domain and belong to the CO/COL group IV protein family. MiCOL1A and MiCOL1B were expressed both in vegetative and reproductive organs but with expression level differences. MiCOL1A was highly expressed in juvenile and adult leaves, but MiCOL1B was highly expressed in flowers. Seasonal expression analysis showed that MiCOL1A and MiCOL1B have similar expression patterns and higher expression levels during flower induction and flower organ differentiation periods. However, MiCOL1A and MiCOL1B exhibited unstable patterns in circadian expression analysis. MiCOL1A and MiCOL1B were localized in the nucleus and had transcriptional activation activity in yeast. Overexpression of MiCOL1A and MiCOL1B resulted in significantly delayed flowering time in Arabidopsis. Furthermore, we also found that overexpression of MiCOL1A and MiCOL1B enhanced drought tolerance in transgenic Arabidopsis. The results demonstrated that MiCOL1A and MiCOL1B are not only involved in flowering regulation but also play a role in the stress response of plants.

Low cuticle deposition rate in 'Apple' mango increases elastic strain, weakens the cuticle and increases russet.

Russeting compromises appearance and downgrades the market value of many fruitcrops, including of the mango cv. 'Apple'. The objective was to identify the mechanistic basis of 'Apple' mango's high susceptibility to russeting. We focused on fruit growth, cuticle deposition, stress/strain relaxation analysis and the mechanical properties of the cuticle. The non-susceptible mango cv. 'Tommy Atkins' served for comparison. Compared with 'Tommy Atkins', fruit of 'Apple' had a lower mass, a smaller surface area and a lower growth rate. There were little differences between the epidermal and hypodermal cells of 'Apple' and 'Tommy Atkins' including cell size, cell orientation and cell number. Lenticel density decreased during development, being lower in 'Apple' than in 'Tommy Atkins'. The mean lenticel area increased during development but was consistently greater in 'Apple' than in 'Tommy Atkins'. The deposition rate of the cuticular membrane was initially rapid but later slowed till it matched the area expansion rate, thereafter mass per unit area was effectively constant. The cuticle of 'Apple' is thinner than that of 'Tommy Atkins'. Cumulative strain increased sigmoidally with fruit growth. Strains released stepwise on excision and isolation (εexc+iso), and on wax extraction (εextr) were higher in 'Apple' than in 'Tommy Atkins'. Membrane stiffness increased during development being consistently lower in 'Apple' than in 'Tommy Atkins'. Membrane fracture force (Fmax) was low and constant in developing 'Apple' but increased in 'Tommy Atkin'. Membrane strain at fracture (εmax) decreased linearly during development but was lower in 'Apple' than in 'Tommy Atkins'. Frequency of membrane failure associated with lenticels increased during development and was consistently higher in 'Apple' than in 'Tommy Atkins'. The lower rate of cuticular deposition, the higher strain releases on excision, isolation and wax extraction and the weaker cuticle account for the high russet susceptibility of 'Apple' mango.

Changes in ploidy affect vascular allometry and hydraulic function in Mangifera indica trees.

The enucleated vascular elements of the xylem and the phloem offer an excellent system to test the effect of ploidy on plant function because variation in vascular geometry has a direct influence on transport efficiency. However, evaluations of conduit sizes in polyploid plants have remained elusive, most remarkably in woody species. We used a combination of molecular, physiological and microscopy techniques to model the hydraulic resistance between source and sinks in tetraploid and diploid mango trees. Tetraploids exhibited larger chloroplasts, mesophyll cells and stomatal guard cells, resulting in higher leaf elastic modulus and lower dehydration rates, despite the high water potentials of both ploidies in the field. Both the xylem and the phloem displayed a scaling of conduits with ploidy, revealing attenuated hydraulic resistance in tetraploids. Conspicuous wall hygroscopic moieties in the cells involved in transpiration and transport indicate a role in volumetric adjustments as a result of turgor change in both ploidies. In autotetraploids, the enlargement of organelles, cells and tissues, which are critical for water and photoassimilate transport at long distances, point to major physiological novelties associated with whole-genome duplication.

Characterization of Two Ethephon-Induced IDA-Like Genes from Mango, and Elucidation of Their Involvement in Regulating Organ Abscission.

In mango (Mangifera indica L.), fruitlet abscission limits productivity. The INFLORESCENCE DEFICIENT IN ABSCISSION (IDA) peptide acts as a key component controlling abscission events in Arabidopsis. IDA-like peptides may assume similar roles in fruit trees. In this study, we isolated two mango IDA-like encoding-genes, MiIDA1 and MiIDA2. We used mango fruitlet-bearing explants and fruitlet-bearing trees, in which fruitlets abscission was induced using ethephon. We monitored the expression profiles of the two MiIDA-like genes in control and treated fruitlet abscission zones (AZs). In both systems, qRT-PCR showed that, within 24 h, both MiIDA-like genes were induced by ethephon, and that changes in their expression profiles were associated with upregulation of different ethylene signaling-related and cell-wall modifying genes. Furthermore, ectopic expression of both genes in Arabidopsis promoted floral-organ abscission, and was accompanied by an early increase in the cytosolic pH of floral AZ cells-a phenomenon known to be linked with abscission, and by activation of cell separation in vestigial AZs. Finally, overexpression of both genes in an Atida mutant restored its abscission ability. Our results suggest roles for MiIDA1 and MiIDA2 in affecting mango fruitlet abscission. Based on our results, we propose new possible modes of action for IDA-like proteins in regulating organ abscission.

Isolation and functional characterization of three MiFTs genes from mango.

FLOWERING LOCUS T (FT) is a key integrator of environmental signals and internal cues and plays a central role in the photoperiod response mechanism in Arabidopsis. However, the function of FTs in Mangifera indica L. is unknown. In this study, we identified three MiFTs genes from mango and characterized their role in flowering regulation. The open reading frames of MiFT1, MiFT2, and MiFT3 are 540, 516, and 588 bp in length and encode 180, 172, and 196 amino acids, respectively; the genes belong to the PEBP family. MiFTs share the conserved exon/intron structure of FTs. The nucleotide sequence of MiFT1 is 90% identical to that of MiFT2 and 82% identical to that of MiFT3; MiFT2 and MiFT3 share 81% homology with each other. According to expression analysis, MiFTs were detected at different expression levels in all tested tissues. The expression levels of the three MiFTs were significantly different in leaves during flower development, and MiFT1 expression increased sharply in leaves and was significantly higher than that of the other two MiFTs during flower bud development. All three MiFTs showed daily cycles. Ectopic expression of the three MiFTs in transgenic Arabidopsis resulted in an earlier flowering genotype under long-day conditions, and MiFT1 had the strongest effect in promoting flowering. Additionally, overexpression of three MiFTs in Arabidopsis upregulated the expression levels of several flowering-related genes. Our results suggest that the three MiFTs have positive roles in promoting flowering and suggest that MiFT1 may acts as a key regulator in the flowering pathway.

Evolution of bioactive compounds of three mango cultivars (Mangifera indica L.) at different maturation stages analyzed by HPLC-DAD-q-TOF-MS.

Mango is an important natural source of bioactive compounds with functional properties. However, factors such as variety and maturation stage can have a great influence on the bioactive composition. In this sense, a comprehensive study of chemical composition of three spanish mango varieties (Keitt, Kent and Osteen) at five ripening stages was conducted. The analysis by HPLC-DAD-q-TOF-MS revealed the presence of more than seventy compounds from different chemical families. Subsequently, PCA evidenced that ripening process entailed an important decrease on phenolic compounds which was being more accentuated in Keitt variety. On the other hand, Osteen was revealed as the poorest variety on phenolic compounds meanwhile mangoes from Keitt variety exhibited the major quantities of gallotannins and mono and di-galloyl species at the earliest maturation stages. Therefore, from a functional point of view, unripe mango from Keitt variety seems to be an excellent natural source of bioactive compounds.

Multi-species test and calibration of an improved transient thermal dissipation system of sap flow measurement with a single probe.

Transient thermal dissipation (TTD) systems provide a simple way to measure xylem sap flow with dual or single Granier-type probe, which gives lower energy consumption and higher accuracy due to its lessor sensitivity to thermal interferences. A new system, TTD heat within 5 min (TTD5), proposed on the reduction of the heating duration. This evolution captured interest through decreased energy consumption and increased temporal resolution. Within our study, the first objective was to test and calibrate this new system with a single probe for young rubber tree - Hevea brasiliensis. The second objective was to explore the sources of variability in calibration such as species, individual cut-stems and probe-wood contact. The complementary species consisted of two diffuse-porous species (mango tree - Mangifera indica, eucalyptus tree - Eucalyptus camaldulensis) and one ring-porous species (teak tree - Tectonia grandis). Twenty-eight response curves were assessed over a large range of flux densities from 0.5 to 10 l dm-2 h-1. The incremental rise of temperature from 30 to 300 s (T300-30) after commencement of heating was sensitive to flux density over the complete range. Compared with the full signal at 300 s, the incremental signal markedly reduced the variability between response curves within species and between species. Moreover, a new index K2, defined as (T0 - Tu)/T0, normalized the responses between 0 and 1. However, the responses had a non-linear trend above 5 l dm-2 h-1. Within diffuse-porous wood type, the species did not differ in calibration, whereas the ring-porous species was markedly different. A sigmoid function provided the best fit for the diffuse-porous species. Individual stems were identified as the main source of within-species variability in calibration. The normalizing K2 index removed the influence of probe-wood contacts, controlled through drilling difference; however, there was still an effect of individual stems interacting with flux density (P = 0.019). Replications of cut-stems and response curves are necessary to assess a reliable averaged calibration. In conclusion, the applicability of the TTD5 system with a single probe has been confirmed and several sources of variability in calibration have been evaluated.

Oviposition of fruit flies (Diptera: Tephritidae) and its relation with the pericarp of citrus fruits / Oviposição de moscas-das-frutas (Diptera: Tephritidae) e sua relação com o pericarpo de frutos cítricos

Abstract Fruit flies (Diptera: Tephritidae) represent a threat to fruit growing worldwide, mainly the citrus culture, however, biological studies show that fruit flies are not perfectly adapted to this host. This study investigated oviposition of Anastrepha fraterculus (Wiedemann, 1830) and Ceratitis capitata (Wiedemann, 1824) and its relation with the pericarp of citrus fruits. We evaluated the relationship between depth of oviposition of A. fraterculus and C. capitata and epicarp thickness of orange [Citrus sinensis (L.) Osbeck)] 'Navelina' and tangerine [C. reticulata (L.)] 'Clemenules' and the influence of fruit mesocarp of tangerine 'Clemenules' on oviposition of these species. The study was conducted under controlled conditions of temperature (25 ± 2 °C), relative humidity (70 ± 10% RH) and photophase (12 h). A. fraterculus and C. capitata laid their eggs in the flavedo region of orange 'Navelina' and between the albedo and flavedo of tangerine 'Clemenules'. When fruits with mesocarp exposed were offered, there was no oviposition by both fruit fly species. The results show that epicarp thickness of citrus fruits did not influence oviposition of A. fraterculus and C. capitata as oviposition did not occur only in the presence of the mesocarp, suggesting that other factors are involved in oviposition of these species.

Resumo As moscas-das-frutas (Diptera: Tephritidae) representam um risco à fruticultura mundial, especialmente na cultura dos citros, entretanto estudos biológicos demonstram que as moscas-das-frutas não estão perfeitamente adaptadas à estes hospedeiros. Este estudo investigou a oviposição de Anastrepha fraterculus (Wiedemann, 1830) e Ceratitis capitata (Wiedemann, 1824) e sua relação com o pericarpo de frutos cítricos. Foi avaliada a relação entre a profundidade de oviposição de A. fraterculus e de C. capitata e a espessura do epicarpo dos frutos de laranjeira [Citrus sinensis (L.) Osbeck)] 'Navelina' e tangerineira [C. reticulata (L.)] 'Clemenules' e a influência do mesocarpo de frutos de tangerineira 'Clemenules' na oviposição destas espécies. O estudo foi conduzido em condições controladas de temperatura (25 ± 2 °C), umidade relativa (70 ± 10%) e fotofase (12 horas). A. fraterculus e C. capitata depositaram ovos no flavedo de frutos de laranjeira 'Navelina' e entre o flavedo e o albedo de frutos de tangerineira 'Clemenules'. Quando oferecido frutos com mesocarpo exposto, não houve oviposição por ambas as espécies de mosca. Os resultados demonstram que a espessura do epicarpo de frutos cítricos não influenciou a oviposição de A. fraterculus e de C. capitata, a qual não ocorreu na presença apenas do mesocarpo, sugerindo que outros fatores estão envolvidos na oviposição por estas espécies.

Hyperspectral Imaging for Evaluating Impact Damage to Mango According to Changes in Quality Attributes.

Evaluation of impact damage to mango (Mangifera indica Linn) as a result of dropping from three different heights, namely, 0.5, 1.0 and 1.5 m, was conducted by hyperspectral imaging (HSI). Reflectance spectra in the 900⁻1700 nm region were used to develop prediction models for pulp firmness (PF), total soluble solids (TSS), titratable acidity (TA) and chroma (∆b*) by a partial least squares (PLS) regression algorithm. The results showed that the changes in the mangoes' quality attributes, which were also reflected in the spectra, had a strong relationship with dropping height. The best predictive performance measured by coefficient of determination (R²) and root mean square errors of prediction (RMSEP) values were: 0.84 and 31.6 g for PF, 0.9 and 0.49 oBrix for TSS, 0.65 and 0.1% for TA, 0.94 and 0.96 for chroma, respectively. Classification of the degree of impact damage to mango achieved an accuracy of more than 77.8% according to ripening index (RPI). The results show the potential of HSI to evaluate impact damage to mango by combining with changes in quality attributes.

Multilacunarity as a spatial multiscale multi-mass morphometric of change in the meso-architecture of plant parenchyma tissue.

The lacunarity index (monolacunarity) averages the behavior of variable size structures in a binary image. The generalized lacunarity concept (multilacunarity) on the basis of generalized distribution moments is an appealing model that can account for differences in the mass content at different scales. The model was tested previously on natural images [J. Vernon-Carter et al., Physica A 388, 4305 (2009)]. Here, the computational aspects of multilacunarity are validated using synthetic binary images that consist of random maps, spatial stochastic patterns, patterns with circular or polygonal elements, and a plane fractal. Furthermore, monolacunarity and detrended fluctuation analysis were employed to quantify the mesostructural changes in the intercellular air spaces of frozen-thawed parenchymatous tissue of pome fruit [N. A. Valous et al., J. Appl. Phys. 115, 064901 (2014)]. Here, the aim is to further examine the coherence of the multilacunarity model for quantifying the mesostructural changes in the intercellular air spaces of parenchymatous tissue of pome and stone fruit, acquired with X-ray microcomputed tomography, after storage and ripening, respectively. The multilacunarity morphometric is a multiscale multi-mass fingerprint of spatial pattern composition, assisting the exploration of the effects of metabolic and physiological activity on the pore space of plant parenchyma tissue.

Improved Cold Tolerance of Mango Fruit with Enhanced Anthocyanin and Flavonoid Contents.

Red fruits were suggested to be tolerant to cold. To understand cold-storage tolerance of red mango fruit that were subjected to sunlight at the orchard, mango cv. Shelly from inside (green fruit) or outside (red fruit) the tree canopy was stored for 3 weeks at 5, 8 or 12 °C and examined for flavonoids, antioxidant, volatiles and tolerance to biotic and abiotic stress. Red fruit from the outer canopy showed significant increases in total anthocyanin and flavonoids, and antioxidant activity. Ripening parameters for red and green mango fruit were similar at harvest and during storage. However, red fruit with high anthocyanin and flavonoid contents were more tolerant to biotic and abiotic stresses. After 3 weeks of suboptimal cold storage, green fruit showed significantly more lipid peroxidation and developed significantly more chilling-injury symptoms-black spots and pitting-than red fruit. Volatiles of red and green peels revealed significant modulations in response to cold-storage. Moreover, red fruit were more tolerant to biotic stress and had reduced general decay incidence. However, during long storage at 10 °C for 4, 5 or 6 weeks, red fruit showed a non-significant reduction in decay and chilling injuries. These results suggest new approaches to avoiding chilling injury during cold storage.

Antioxidant and enzymatic responses to oxidative stress induced by cold temperature storage and ripening in mango (Mangifera indica L. cv. 'Cogshall') in relation to carotenoid content.

The effects of 15 days of storage at 12 °C and 7 °C followed by fruit ripening at 20 °C on oxidative status, antioxidant defense systems and carotenoid accumulation were studied for two successive years in mango fruits (Mangifera indica L.) cv. Cogshall. Changes in the non-enzymatic (ascorbate) and enzymatic (SOD, CAT, APX, MDHAR, DHAR and GR) antioxidant systems, as well as oxidative parameters (H2O2 and MDA) and the contents of the major carotenoids were measured for three maturity stages, at harvest and after ripening following cold temperature storage. In control conditions (20 °C), ripening induced an increase in oxidation resulting in ROS production and a decrease in ascorbate content. Fruit tissue protection was activated by means of antioxidant and ascorbate regeneration enzyme systems. Carotenoid accumulated exponentially during ripening. Storage at low temperatures increased respiration crisis intensity and therefore increased oxidation in the fruit pulp. Fruit response to this increase varied according to the maturity stage, i.e., enzymatic responses in younger fruits were very low in comparison to the control, whereas second harvest fruits had a significantly higher degree of enzymatic activity to cope with the oxidative stress. Carotenoid contents decreased with low temperatures and first harvest fruits showed significantly lower values than the control, in opposition to second harvest fruits that appeared not to be affected. We also suggest that, based on a review of the literature, a link can be made between antioxidant system defense and carotenoid metabolism since ROS seems to play a central role as a stress signal in plants.

Estimation of Whole Plant Photosynthetic Rate of Irwin Mango under Artificial and Natural Lights Using a Three-Dimensional Plant Model and Ray-Tracing.

Photosynthesis is an important physiological response for determination of CO2 fertilization in greenhouses and estimation of crop growth. In order to estimate the whole plant photosynthetic rate, it is necessary to investigate how light interception by crops changes with environmental and morphological factors. The objectives of this study were to analyze plant light interception using a three-dimensional (3D) plant model and ray-tracing, determine the spatial distribution of the photosynthetic rate, and estimate the whole plant photosynthetic rate of Irwin mango (Mangifera indica L. cv. Irwin) grown in greenhouses. In the case of mangoes, it is difficult to measure actual light interception at the canopy level due to their vase shape. A two-year-old Irwin mango tree was used to measure the whole plant photosynthetic rate. Light interception and whole plant photosynthetic rate were measured under artificial and natural light conditions using a closed chamber (1 × 1 × 2 m). A 3D plant model was constructed and ray-tracing simulation was conducted for calculating the photosynthetic rate with a two-variable leaf photosynthetic rate model of the plant. Under artificial light, the estimated photosynthetic rate increased from 2.0 to 2.9 µmolCO2·m-2·s-1 with increasing CO2 concentration. On the other hand, under natural light, the photosynthetic rate increased from 0.2 µmolCO2·m-2·s-1 at 06:00 to a maximum of 7.3 µmolCO2·m-2·s-1 at 09:00, then gradually decreased to -1.0 µmolCO2·m-2·s-1 at 18:00. In validation, simulation results showed good agreement with measured results with R² = 0.79 and RMSE = 0.263. The results suggest that this method could accurately estimate the whole plant photosynthetic rate and be useful for pruning and adequate CO2 fertilization.

Oviposition of fruit flies (Diptera: Tephritidae) and its relation with the pericarp of citrus fruits.

Fruit flies (Diptera: Tephritidae) represent a threat to fruit growing worldwide, mainly the citrus culture, however, biological studies show that fruit flies are not perfectly adapted to this host. This study investigated oviposition of Anastrepha fraterculus (Wiedemann, 1830) and Ceratitis capitata (Wiedemann, 1824) and its relation with the pericarp of citrus fruits. We evaluated the relationship between depth of oviposition of A. fraterculus and C. capitata and epicarp thickness of orange [Citrus sinensis (L.) Osbeck)] 'Navelina' and tangerine [C. reticulata (L.)] 'Clemenules' and the influence of fruit mesocarp of tangerine 'Clemenules' on oviposition of these species. The study was conducted under controlled conditions of temperature (25 ± 2 °C), relative humidity (70 ± 10% RH) and photophase (12 h). A. fraterculus and C. capitata laid their eggs in the flavedo region of orange 'Navelina' and between the albedo and flavedo of tangerine 'Clemenules'. When fruits with mesocarp exposed were offered, there was no oviposition by both fruit fly species. The results show that epicarp thickness of citrus fruits did not influence oviposition of A. fraterculus and C. capitata as oviposition did not occur only in the presence of the mesocarp, suggesting that other factors are involved in oviposition of these species.

Tree age affects physicochemical, functional quality and storability of Amrapali mango (Mangifera indica L.) fruits.

BACKGROUND: The effect of tree age on physicochemical quality attributes and storage behaviour of Amrapali mango fruit was evaluated. Physiologically mature fruits were harvested from 6-, 18- and 30-year-old trees and kept for ripening under ambient conditions (temperature 35 ± 3 °C, relative humidity 60 ± 5%). Observations were recorded at 3-day intervals. RESULTS: Highest total soluble solids and total sugars were found in the fruit sourced from 18-year-old trees. At the end of storage, least titratable acidity (0.17%) and higher carotenoids (10.86 mg 100 g-1 ) were found in 30-year-old tree fruits during the last day of storage. Highest total phenols (TP) (251.33 µg gallic acid g-1 ), antioxidant capacity (AC) (5.63 µmol Trolox g-1 ) and ascorbic acid (AA) (31.13 mg 100 g-1 ) were reported in fruits from younger trees of 6 years old. Maximum respiratory and ethylene evolution peak was observed in fruits obtained from oldest trees, whereas least activities of pectin methyl esterase (0.31 µmol min-1 g-1 fresh weight) and polygalacturonase (53.67 µg galacturonic acid g-1 h-1 ) were observed in 6-year-old tree fruits at the end of the 9-day storage period. CONCLUSION: Higher total soluble solids and total sugars were found in fruit harvested from middle-age-group (18-year-old) trees during the entire storage period of 9 days. Most of the functional parameters, such as TP, AC and AA, were observed to be higher in fruits from younger (6-year-old) trees. The obtained results revealed that produce from middle-age-group (18-year-old) Amrapali mango orchards suit consumers' and processors' requirements. © 2017 Society of Chemical Industry.

Varietal Preferences and Within-Orchard and Tree Distribution of Newly Recorded Gall Midges, Dasineura amaramanjarae and Procontarinia mangiferae (Diptera: Cecidomyiidae), From Commercial Mango Cultivars in Pakistan.

Gall midges (Diptera: Cecidomyiidae) damage mango by feeding on flowers and fruit tissues, inducing galls on leaves, and providing inoculums of anthracnose. Dasineura amaramanjarae Grover and Procontarinia mangiferae (Felt), two gall midges that damage flowers in all mango-growing areas of the world, have recently been recorded in Pakistan, and studies were conducted in 2011 and 2012 on the within-tree and orchard distribution patterns and cultivar preference of both species in Pakistan at one location (Rahim Yar Khan). Both gall midge species were found on all mango cultivars examined (Chaunsa, Fajri, Dusehri, Surkha, Sindhri, and Anwar Ratul), with the most damage occurring to Surkha and Dusehri. Research on midge distribution patterns in different parts of mango orchards (central, southern, northern, eastern, and western sides) showed these species to be found in all areas, with the greatest numbers in the central and southern regions. In addition, both species were most abundant on the lower parts of the mango tree canopy.

The Effects of a Modified Hot Water Treatment on Anastrepha ludens (Diptera: Tephritidae)-Infested Mango.

The Mexican fruit fly, Anastrepha ludens (Loew), is a quarantine pest in mango (Mangifera indica L.) that can be controlled by using a hot water treatment (HWT). This treatment is normally followed by a 30-min hydrocooling (HYC) process that reduces the negative effects that the treatment has on fruit quality. However, if hot water-treated fruits are immediately immersed in water at 21 °C, the survival rate of third-instar A. ludens may be increased. The current approved treatment protocol states that if HYC is used, then treated fruit should undergo an additional 10-min HWT or on platform for 30 min before HYC. We aimed to determine the efficacy of HWT without an additional 10-min treatment before being subjected to HYC, while taking into consideration that the most important conditions are the temperature of the fruit core throughout treatment and the type of infestation, either oviposition or inoculation. Two experimental tests were conducted. Our first aim was to determine the effectiveness of HWT followed by HYC using three varieties and different size classes of mangoes ('Ataulfo' 200-375 and 401-570 g; 'Tommy Atkins' 401-500 and 501-700 g; 'Kent' 401-500 g). The four treatment combinations used to test HWT and immediate HYC at 21 °C were 1) HWT, 2) HWT/HYC, 3) HWT + 10 min/HYC, and 4) HWT/30 min on platform/HYC; an independent experiment was used for each variety. The second aim was to validate the HWT/HYC combination by performing confirmatory tests in commercial packing houses. The results showed that as long as the mango core temperature reached 45 °C during the HWT, it was not necessary to add the 10-min treatment to the HWT before HYC at 21 °C was applied. To ensure that the larvae are subjected to the HWT treatment for sufficient time to be lethal, the temperature of the fruit core throughout the treatment must be recorded.

In-Line Sorting of Harumanis Mango Based on External Quality Using Visible Imaging.

The conventional method of grading Harumanis mango is time-consuming, costly and affected by human bias. In this research, an in-line system was developed to classify Harumanis mango using computer vision. The system was able to identify the irregularity of mango shape and its estimated mass. A group of images of mangoes of different size and shape was used as database set. Some important features such as length, height, centroid and parameter were extracted from each image. Fourier descriptor and size-shape parameters were used to describe the mango shape while the disk method was used to estimate the mass of the mango. Four features have been selected by stepwise discriminant analysis which was effective in sorting regular and misshapen mango. The volume from water displacement method was compared with the volume estimated by image processing using paired t-test and Bland-Altman method. The result between both measurements was not significantly different (P > 0.05). The average correct classification for shape classification was 98% for a training set composed of 180 mangoes. The data was validated with another testing set consist of 140 mangoes which have the success rate of 92%. The same set was used for evaluating the performance of mass estimation. The average success rate of the classification for grading based on its mass was 94%. The results indicate that the in-line sorting system using machine vision has a great potential in automatic fruit sorting according to its shape and mass.

Pollination Services of Mango Flower Pollinators.

Measuring wild pollinator services in agricultural production is very important in the context of sustainable management. In this study, we estimated the contribution of native pollinators to mango fruit set production of two mango cultivars Mangifera indica (L). cv. 'Sala' and 'Chok Anan'. Visitation rates of pollinators on mango flowers and number of pollen grains adhering to their bodies determined pollinator efficiency for reproductive success of the crop. Chok Anan failed to produce any fruit set in the absence of pollinators. In natural condition, we found that Sala produced 4.8% fruit set per hermaphrodite flower while Chok Anan produced 3.1% per flower. Hand pollination tremendously increased fruit set of naturally pollinated flower for Sala (>100%), but only 33% for Chok Anan. Pollinator contribution to mango fruit set was estimated at 53% of total fruit set production. Our results highlighted the importance of insect pollinations in mango production. Large size flies Eristalinus spp. and Chrysomya spp. were found to be effective pollen carriers and visited more mango flowers compared with other flower visitors.

Spatial and temporal variations in mango colour, acidity, and sweetness in relation to temperature and ethylene gradients within the fruit.

Managing fruit quality is complex because many different attributes have to be taken into account, which are themselves subjected to spatial and temporal variations. Heterogeneous fruit quality has been assumed to be partly related to temperature and maturity gradients within the fruit. To test this assumption, we measured the spatial variability of certain mango fruit quality traits: colour of the peel and of the flesh, and sourness and sweetness, at different stages of fruit maturity using destructive methods as well as vis-NIR reflectance. The spatial variability of mango quality traits was compared to internal variations in thermal time, simulated by a physical model, and to internal variations in maturity, using ethylene content as an indicator. All the fruit quality indicators analysed showed significant spatial and temporal variations, regardless of the measurement method used. The heterogeneity of internal fruit quality traits was not correlated with the marked internal temperature gradient we modelled. However, variations in ethylene content revealed a strong internal maturity gradient which was correlated with the spatial variations in measured mango quality traits. Nonetheless, alone, the internal maturity gradient did not explain the variability of fruit quality traits, suggesting that other factors, such as gas, abscisic acid and water gradients, are also involved.