Commercial Mango Orchards Research Articles

Balanço nutricional em mangueiras no semiárido brasileiro utilizando métodos diagnósticos nutricionais

ABSTRACT Nutritional assessment of mango trees based on diagnostic methods considering nutritional balance is recommended. This study aimed to establish optimum nutritional ranges using diagnostic methods, compare them, identify the most efficient diagnostic method, and select the nutrients responding best to the application of the diagnostic method. The study was conducted in commercial mango orchards in the São Francisco Valley. Nutritional content was calculated using the diagnosis and recommendation integrated system (DRIS-Beaufils, DRIS-Jones), modified DRIS (M-DRIS-Beaufils; M-DRIS-Jones), compositional nutrient diagnosis (CND), and mathematical chance (ChM) methods and compared using the chi-square test. Principal component analysis was applied to select the most efficient diagnostic method and the nutrients responsible for the greatest variability. The DRIS-Beaufils, M-DRIS-Beaufils, DRIS-Jones, M-DRIS-Jones, CND, and ChM methods generated nutritional sufficiency ranges for the evaluated cultivars. The nutritional diagnoses of the DRIS-Beaufils and M-DRIS-Beaufils methods were similar and discordant with those of DRIS-Jones, M-DRIS-Jones, and CND. The DRIS-Beaufils method, updated by Maia, proved to be more consistent for the nutritional assessment of mango trees. The nutrients N, P, K, Mg, and S in the Tommy Atkins cultivar; N, P, Mg, S, B, Mn, Zn, Mo, and Cl in the Kent cultivar; and N, P, K, Ca, S, B, Cu, Fe, Zn, Mo, and Cl in the Keitt cultivar showed significant responses to the application of the DRIS-Beaufils method updated by Maia.

Estimating crop coefficients and water use of a full-bearing mango orchard in north-eastern South Africa using the fraction of vegetation cover and a dual source evapotranspiration model

In semi-arid countries like South Africa, commercially produced mango (Mangifera Indica L.) are grown entirely under irrigation. However, there is little accurate quantitative information on the water use of mango orchards, and few accurate water use models currently exist. In this study, we evaluated the performance of the FAO 56 method of estimating crop evapotranspiration (ETc) and a dual source water use model against measurements of actual consumptive water use of a commercial mango orchard. The FAO approach calculates ETc as the product of a crop coefficient (Kc) and the reference evapotranspiration (ETo). We derived Kc for well-watered orchards from readily available data including the fraction of vegetation cover, average tree height, and a stomatal control coefficient. The dual-source model calculated orchard evapotranspiration as the sum of tree transpiration and orchard floor evaporation derived from the modified Shuttleworth and Wallace model. Actual evapotranspiration was measured using an open path eddy covariance system, while tree transpiration was measured using the heat ratio method of monitoring sap flow. Data were collected in a mature ‘Tommy Atkins’ mango orchard grown with micro-sprinkler irrigation in north-eastern South Africa. Results show that the reference evapotranspiration explained most of the variation in orchard transpiration (R2 ∼ 0.78) compared to the solar radiation (R2 ∼ 0.66) and the vapour pressure deficit of the air (R2 ∼ 0.66). Compared with field measured water use data, the FAO method gave relatively accurate estimates of transpiration (R2 = 0.74, NRMSE = ±18.00 %, NMAE = ±15.00 %, NSE = 0.70) and evapotranspiration (R2 = 0.58, NRMSE = ±19.00 %, NMAE = ±16.00 %, NSE = 0.55). NSE is the Nash-Sutcliffe Efficiency. The dual-source model yielded slightly less accurate estimates of transpiration (R2 = 0.61, NRMSE = ±22.00 %, NMAE = ±20.00 %, NSE = 0.39) and evapotranspiration (R2 = 0.52, NRMSE = ±23.00 %, NMAE = ±25.00 %, NSE = 0.51). The basal crop coefficient (Kcb) showed small seasonal fluctuations, varying between 0.40 and 0.60 throughout the year. In contrast, Kc showed clear seasonality varying between 0.59–0.64 at flowering and fruit set and rising to 0.81–0.90 during the fruit growing phase. Estimates of the annual total transpiration (686 mm) from the FAO method were within 5 % of the actual measured values (677 mm) while the dual source model estimated 612 mm of transpiration, which was almost 10 % lower than the measured values. The results highlight that even though the FAO method requires fewer input parameters, it is potentially more accurate in estimating water use in mango orchards than the dual-source model.

Calcium fertilization strategy to improve production and quality of ‘Tommy Atkins’ mango in semi-arid conditions

ABSTRACT Calcium (Ca) is an essential element for the development of mango plants. New technologies are emerging in the market to assist the production process, such as organic acids and amino acids. The objective of this study was to evaluate the effect of different strategies of Ca fertilization on the production and physical-chemical quality of ‘Tommy Atkins’ mango grown under Brazilian semi-arid conditions. The experiment was carried out in two commercial mango orchards, following a randomized block design, with four replications and four plants per block. The factorial design was composed by three formulations of Ca-based products and three forms of application. Fruit were harvested at the physiological maturity to determine yield and quality. There was no statistical difference among treatments for the incidence of internal physiological disorders in mangoes, with mean values ranging from 0.08% to 0.38%. Fruit production and physical-chemical quality were affected by the different Ca formulations and forms of application. Fruit production ranged from 21.5 to 44.4 kg per plant. The Ca foliar application plus fertigation in the form of CaCl2.2 H2O resulted in higher production, as well as higher fruit weight and lower weight loss at 40 days after harvest.

Sooty blotch and flyspeck on mango (Mangifera indica L.) caused by Peltaster-like species in Malaysia

Fungi in the sooty blotch and flyspeck (SBFS) disease complex appear as pigmented blemishes on plant cuticles and are commonly observed on several fruits, including mango. In Malaysia, SBFS on mango has not been reported previously. However, SBFS symptoms were observed in commercial mango orchards in Perak, resulting in economic losses for sale of fresh fruit. Therefore, morphological, molecular, and pathogenicity studies were conducted to identify SBFS taxa on mango in Perak. A total of 27 mango fruit showing SBFS blemishes were collected from several commercial orchards in Perak. Colony morphologies were described on fruit and in purified culture, and DNA was extracted from the cultures. The internal transcribed spacer (ITS) and large subunit (LSU) regions of ribosomal DNA of two representative isolates were amplified, sequenced, and deposited in GenBank. Maximum parsimony (MP) and maximum likelihood (ML) methods were used to construct phylogenetic trees. A modified version of Koch's postulates was performed for the two isolates using unripe, asymptomatic fruit with two inoculation methods: in situ in an orchard and on excised fruit. In each case, two fruit per isolate were inoculated and two additional fruit were sprayed with distilled water as a control. For the in situ inoculation, an additional two non-inoculated fruit were enclosed in bags until harvest. The colonies resulting from the inoculation of mango fruit matched the original isolates in mycelial type and ITS sequence. Two previously unknown Peltaster-like species were identified as casual fungi of SBFS on mango in Malaysia. To increase management effectiveness, more extensive research on SBFS phylogenetic diversity in Malaysia should be conducted.

Precision agriculture tools for liming management in mango orchards in the Brazilian semiarid region

Optimizing the recommendation for the management of Liming Demand (LD) is essential for cost reduction and increased yield mango. Therefore, the objective of this study was to delimit management zones for the limestone recommendation in areas of irrigated mango in the Brazilian semiarid using precision agriculture techniques. The experiment was carried out in three commercial mango orchards located in the region of the San Francisco Valley, Brazil. Soil samples were collected in 0.0-0.2 m and 0.2-0.4 m depths following regular grids where the number of samples varied from 50 to 56. Soil analyses were performed. The kriging and inverse distance weighting method were used to interpolated the maps. The LD map was performed from the potential cation exchange capacity (T) and bases saturation (BS) maps. It was verified that the Mandacaru area obtained 63.42% of the field requiring liming, being subdivided into four management zones. The Sempre Verde area obtained 1.20% of the area requiring liming and the Barreiro de Santa Fé area did not present a need for the LD map. The use of precision farming techniques to delineate management zones was adequate to separate the areas into smaller and more homogeneous zones, for a more precise recommendation of liming demand.

Applying antagonist yeast strains to control mango decay caused by Lasiodiplodia theobromae and Neofusicoccum parvum

Successfully inserting a biocontrol agent (BCA) in the integrated management of mango fruit decay can be affected by several factors, including BCA inoculum density and the timing of its application. This study focused on improving biocontrol efficacy by adjusting doses of a BCA formulation and the timing for the substitution of synthetic fungicides sprays. Technical grade formulations containing increasing doses (104 – 108) of the yeast strains Saccharomyces sp. ESA45, S. boulardii ESA46, Saccharomyces sp. ESA47, and Pichia kudriavzeviii CMIAT171 were applied to mango fruits, followed by the inoculation of Lasiodiplodia theobromae and Neofusicoccum parvum in artificial wounds. Non-linear regression analysis of increasing doses of the BCAs against severity data and curve slopes comparison showed a significant difference in control efficiency among yeast strains. A log-linear regression model showed that ESA45 and CMIAT171 exhibited lower doses to achieve 90% control. Two field experiments were conducted in commercial mango orchards cultivated with the cultivars ‘Kent’ and ‘Palmer’. Starting the substitution of fungicides by BCA in fruit onset and when fruits achieved egg size resulted in lower fruit rot incidence and severity during cold storage and shelf life. The complete substitution of fungicides during fruit development did not show consistent performance. Similarly, applying BCA formulation only at the end of fruit development did not hinder the establishment of quiescent infections.

Mango Stem Response under Different Irrigation Regimes

ABSTRACT Mexico has dominated the international mango trade having high yields and excellent fruit quality. The use of soil, plant and environmental sensors can monitor plant hydric status and optimize water application. Linear resistance dendrometers were developed and installed in a high-density 8-year old commercial mango orchard during two seasons; 10 in 2019 and 40 in 2020. Stem diameter fluctuations were acquired every 10 minutes to obtain maximum diameter (MXD), minimum diameter (MND), morning slope (MS) and afternoon slope (AS). Mango stem response during flowering, fruit-fall and fruit-growth was analyzed after applying daily irrigation (DI) or reduced deficit irrigation (RDI). Yield was similar for both treatments, but water use efficiency was higher with deficit irrigation. A new variable known as negative integral (NI) was obtained from the dendrometer signature after adding all the values between 8:00 and 18:00. NI provided a stem shrinkage magnitude, peaks attributed to transpiration and slopes showing flow transport to and from the trunk. NI presented a high correlation of 0.85 against T7 during the flowering stage for RDI-1. If NI crossed zero, a severe stress was present; a high AS present in the evening, indicates nutrient solution provided to fruits. Fruit yield depends on panicle number and fruit-drop during the first production stages, being RDI-1 more efficient in retaining fruits.

Accessibility of Orchard of the Commercial Mango Growers for Scientific Management of Mango Orchard

The present investigation was carried out to analyze the Accessibility of orchard of the commercial mango growers for scientifically management of mango orchard by interviewing 240 commercial mango orchard growers have been cultivated their orchard for market purpose.This investigation conducted in Ratnagiri and Sindhudurg districts of Konkan region of Maharashtra state. Purposive sampling methods was study for this investigation. Total six tahsils were selected, eight villages were selected on the basis of large of commercial mango growers. From 48 villages 240 respondents were selected on the basis they have possess minimum 2 ha. of mango orchard on marketing purpose. Finding of this investigation, more than one third of the commercial mango growers were having their orchards at ‘two’ places. One fourth of the commercial mango growers had their mango orchard ’7.01 to 9.00 km’ away from main road, one fourth of the commercial mango growers had their mango orchard 6.01 to 9.00 km away from their home one forth (27.91%) of the commercial mango growers were having their orchards in ‘Hilly + plain + undulating’ type of land. One sixth (30.41%) of the commercial mango growers were having ‘pathway + rough + tar’ type of road to reach the orchard. Majority of respondents fell under fair overall accessibility categories

Assessing the Potential of Sentinel-2 Derived Vegetation Indices to Retrieve Phenological Stages of Mango in Ghana

In 2020, mango (Mangifera indica) exports contributed over 40 million tons, worth around US$20 billion, to the global economy. Only 10% of this contribution was made from African countries including Ghana, largely due to lower investment in the sector and general paucity of research into the mango value chain, especially production, quality and volume. Considering the global economic importance of mango coupled with the gap in the use of the remote sensing technology in the sector, this study tested the hypothesis that phenological stages of mango can be retrieved from Sentinel-2 (S2) derived time series vegetation indices (VIs) data. The study was conducted on four mango farms in the Yilo Krobo Municipal Area of Ghana. Seasonal (temporal) growth curves using four VIs (NDVI, GNDVI, EVI and SAVI) for the period from 2017 to 2020 were derived for each of the selected orchards and then aligned with five known phenology stages: Flowering/Fruitset (F/FS), Fruit Development (FRD), Maturity/Harvesting (M/H), Flushing (FLU) and Dormancy (D). The significance of the variation “within” and “between” farms obtained from the VI metrics of the S2 data were tested using single-factor and two-factor analysis of variance (ANOVA). Furthermore, to identify which specific variable pairs (phenology stages) were significantly different, a Tukey honest significant difference (HSD) post-hoc test was conducted, following the results of the ANOVA. Whilst it was possible to differentiate the phenological stages using all the four VIs, EVI was found to be the best related with p < 0.05 for most of the studied farms. A distinct annual trend was identified with a peak in June/July and troughs in December/January. The derivation of remote sensing based ‘time series’ growth profiles for commercial mango orchards supports the ‘benchmarking’ of annual and seasonal orchard performance and therefore offers a near ‘real time’ technology for identifying significant variations resulting from pest and disease incursions and the potential impacts of seasonal weather variations.

Sensitivity to MBC fungicides and prochloraz of Colletotrichum gloeosporioides species complex isolates from mango orchards in Mexico

Anthracnose, caused by Colletotrichum spp., is the most significant field and post-harvest disease of mango worldwide and is mainly controlled through the use of systemic fungicides belonging to the methyl benzimidazole carbamate (MBC) class. In Mexico, this disease in mango has been associated with at least seven cryptic species belonging to the C. gloeosporioides complex. In this study, the distribution of sensitivity to MBC (benomyl and carbendazim) and prochloraz fungicides of 101 Colletotrichum spp. isolates obtained from 101 commercial orchards in Mexico’s most important mango-producing states was determined. All Colletotrichum spp. isolates were obtained from commercial mango orchards with applications of MBC fungicides and that had not been exposed to applications of prochloraz, or any other DMI (demethylation inhibitors) class fungicide. Isolates were evaluated using an in vitro test to determine the effective fungicide concentration at which 50% of mycelial growth is inhibited (EC50) for each isolate-fungicide combination. EC50 values for benomyl and carbendazim ranged from 0.0967 to 0.3995 µg mL−1 (median = 0.1923 µg mL−1) and from 0.0880 to 0.1703 µg mL−1 (median = 0.1171 µg mL−1), respectively, while those for prochloraz ranged from 0.0066 to 0.0813 µg mL−1 (median = 0.0253 µg mL−1). Our results revealed a wide distribution in Mexico of Colletotrichum spp. isolates from mango sensitive to MBC fungicides and prochloraz. Data obtained in this study will serve as a source of comparison of the evolution of the sensitivity of Colletotrichum spp. populations obtained from mango to MBC and DMI fungicides in the future.

Spatial correlation between soil and leaf macronutrients in semiarid Brazilian mango (Mangifera indica L.) fields

Abstract Understanding the relationship between the levels of nutrients in the soil and those found in the plant is of fundamental importance for site-specific fertility management in mango (Mangifera indica L.) crop fields. This study aimed to evaluate the spatial distribution of macronutrient contents both in the soil and in the leaf and their correlations in commercial mango orchards under semiarid region conditions and to delimit the management zones using soil and leaf data. The experiment was carried out in three commercial areas in San Francisco Valley, Brazil, cultivated with irrigated mango. Soil samples were collected in 0-0.2 and 0.2-0.4 m depths as well as leaf samples following sample grids. Ca, Mg, K, P, and N contents from soil and leaf samples were determined. Descriptive and geostatistics analyses were performed. Co-kriging was used for the delimitation of management zones. Positive spatial correlations were obtained between soil Ca2+ and leaf Ca contents (R2 = 0.80-0.93), soil K+ and leaf K contents (R2 = 0.35-0.61), and soil Mg2+ and leaf P contents (R2 = 0.51). Negative correlations were observed for soil Mg2+ and leaf Ca contents(R2 = 0.79-0.93) and soil Mg2+ and leaf K contents (R2 = 0.98). The soil 0-0.2 m depth had the greatest influence on mango Ca and K uptake. The negative correlation between soil Mg2+ and leaf Ca shows the competition existing in the plant uptake process. It was possible to delimit specific management zones using co-kriging for the three areas using soil and leaf data.

Characterization of Neopestalotiopsis Species Associated with Mango Grey Leaf Spot Disease in Sinaloa, Mexico.

Mango is one of the most popular and nutritious fruits in the world and Mexico is the world’s largest exporter. There are many diseases that directly affect fruit yield and quality. During the period 2016–2017, leaves with grey leaf spots were collected from 28 commercial mango orchards distributed in two main production areas in Sinaloa State of Mexico, and 50 Neopestalotiopsis isolates were obtained. Fungal identification of 20 representative isolates was performed using morphological characterization and phylogenetic analysis based on the internal transcribed spacer (ITS) region of ribosomal DNA, part of the translation elongation factor 1-alpha (TEF) and the β-tubulin (TUB) genes. Phylogenetic analysis indicated that the 20 isolates from this study formed four consistent groups, however, overall tree topologies do not consistently provide a stable and sufficient resolution. Therefore, even though morphological and phylogenetic separation is evident, these isolates were not assigned to any new taxa and were tentatively placed into four clades (clades A–D). Pathogenicity tests on detached mango leaves of cv. Kent showed that the 20 isolates that belong to the four Neopestalotiopsis clades from this study and induce lesions on mango leaves. This is the first report of species of Neopestalotiopsis causing mango grey leaf spot disease in Mexico.

Soil sampling optimization using spatial analysis in irrigated mango fields under brazilian semi-arid conditions

Abstract Soil sampling is a fundamental procedure in the decision making regarding the management of the soil, thus, a sampling plan should represent as accurately as possible the evaluated crop field. Therefore, the objectives of this study were to suggest a soil sampling approach and soil sampling point allocation using spatial analyses and compare to the classic statistic method in irrigated mango orchards in the Brazilian semi-arid region. The experiment was carried out in three commercial mango orchards located in the region of the São Francisco Valley, Brazil. Soil samples were collected in 0-0.2 m and 0.2-0.4 m depths following regular grids where the number of samples varied from 50 to 56. Soil texture, soil bulk density, soil total porosity, microporosity, macroporosity, pH, Ca, Mg, Na, K, Al, P, potential acidity, and the sum of basis were evaluated. Classical and geostatistical statistics were used to determine the ideal number of soil samples. Fuzzy c-means clustering technique was used to separate the areas into homogeneous zones and to allocate the sampling points. The wide method of 20 individual soil samples proved to be inefficient. On the other hand, the use of geostatistics proved to be efficient and is required for each crop field. The c-means clustering was adequate to separate the areas into homogeneous zones and, thus, to assist the sampling point allocation.

Survey of fruit nutrient removal by mango (Mangifera indica L.) cultivars for the export market in various producing regions of Mexico

In Mexico there are more than 201 400 ha grown with different mango (Mangifera indica L.) cultivars. This may cause variations in mineral requirement, fruit mineral concentrations and nutrient removal. The objective of this research was to make a survey of mineral concentration in fruit tissues and calculate nutrient removal by fruit tissues during harvest of the most important mango cultivars (Ataulfo, Kent and Tommy Atkins) from several production regions (Campeche, Chiapas, Oaxaca, Nayarit, and Sinaloa) of Mexico. Fruit at physiological maturity were harvested from commercial mango orchards and concentration of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), iron (Fe), copper (Cu), manganese (Mn), zinc (Zn) and boron (B) was determined for skin, mesocarp, endocarp, and seed tissues. Each tissue was cut into thin slices and they were dehydrated in a forced air oven at 70 °C, after that, were pulverized and they were analyzed: nitrogen by semi-microKjeldahl digestion, phosphorus with the ascorbic acid method and the other nutrients with atomic absorption. The removal of nutrients was calculated considering the weight of the fruit and the content of nutrients in each tissue. Signif icant differences in the concentration of N, K, Mg, and Zn were found among cultivars and tissues. Concentration of P, S, Cu, and Mn in the skin, Ca, Cu, and Mn in the mesocarp, Ca, S, Mn, and B in endocarp, and S, Fe, and Mn in the seed were not affected by mango cultivar. Production region affected concentration of minerals in ‘Ataulfo’ fruit more than in ‘Tommy Atkins’ and ‘Kent’. Nutrient removal by mango fruit tissues was little affected in cvs. Ataulfo, Tommy Atkins and Kent. The regions with the greatest nutrient removal were Oaxaca, Campeche and Sinaloa for ‘Ataulfo’, ‘Tommy Atkins’ and ‘Kent’, respectively.

Survey of fruit nutrient removal by mango (Mangifera indica L.) cultivars for the export market in various producing regions of Mexico

In Mexico there are more than 201 400 ha grown with different mango (Mangifera indica L.) cultivars. This may cause variations in mineral requirement, fruit mineral concentrations and nutrient removal. The objective of this research was to make a survey of mineral concentration in fruit tissues and calculate nutrient removal by fruit tissues during harvest of the most important mango cultivars (Ataulfo, Kent and Tommy Atkins) from several production regions (Campeche, Chiapas, Oaxaca, Nayarit, and Sinaloa) of Mexico. Fruit at physiological maturity were harvested from commercial mango orchards and concentration of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), iron (Fe), copper (Cu), manganese (Mn), zinc (Zn) and boron (B) was determined for skin, mesocarp, endocarp, and seed tissues. Each tissue was cut into thin slices and they were dehydrated in a forced air oven at 70 °C, after that, were pulverized and they were analyzed: nitrogen by semi-microKjeldahl digestion, phosphorus with the ascorbic acid method and the other nutrients with atomic absorption. The removal of nutrients was calculated considering the weight of the fruit and the content of nutrients in each tissue. Signif icant differences in the concentration of N, K, Mg, and Zn were found among cultivars and tissues. Concentration of P, S, Cu, and Mn in the skin, Ca, Cu, and Mn in the mesocarp, Ca, S, Mn, and B in endocarp, and S, Fe, and Mn in the seed were not affected by mango cultivar. Production region affected concentration of minerals in ‘Ataulfo’ fruit more than in ‘Tommy Atkins’ and ‘Kent’. Nutrient removal by mango fruit tissues was little affected in cvs. Ataulfo, Tommy Atkins and Kent. The regions with the greatest nutrient removal were Oaxaca, Campeche and Sinaloa for ‘Ataulfo’, ‘Tommy Atkins’ and ‘Kent’, respectively.

Fruit flies (Diptera: Tephritidae) in commercial mango orchards in a semiarid region of Brazil

Abstract Fruit flies (Diptera: Tephritidae) are important mango (Mangifera indica L.) pests in several parts of the world. Therefore, the main objective of this study was to know the species of fruit flies associated with commercial mango orchards in a semiarid region of Rio Grande do Norte state, Brazil; report the species of quarantine importance; discuss the influence of the semiarid environment on the distribution of the species and verify their faunistic indices. The study was carried out between July 2011 and June 2014 in ten commercial orchards of mango cultivar Tommy Atkins in the semiarid region of the state of Rio Grande do Norte, Northeastern Brazil. Fruit flies were captured in McPhail traps baited with 5% hydrolyzed corn protein (Bio Anastrepha®). Mangoes fruits were also collected. Faunistic analysis was performed to characterize the populations. Eight fruit fly species (Anastrepha spp. and C. capitata) were captured. The species C. capitata had the highest geographic distribution and was the only one to infest mangoes. The faunistic analysis showed that most of the orchards had low species richness and that C. capitata was the most frequent and predominant species.

Ground based hyperspectral imaging for extensive mango yield estimation

Fruit yield estimation in orchard blocks is an important objective in the context of precision agriculture, as it makes it easier for the farmer to plan ahead and efficiently use resources. Nevertheless, its implementation is labour-intensive and involves the manual counting of the fruit present in the trees. While colour (RGB) has been widely shown to be successful and arguably sufficient for yield estimation in orchards, hyperspectral imaging (HSI) shows promise for more nuanced tasks such as disease detection, cultivar classification and fruit maturity estimation. Therefore, it is important to ask how appropriate is HSI for the task of yield estimation, with a view to performing all of these tasks with just one sensor. This paper presents a novel mango yield estimation pipeline using ground based line-scan HSI acquired from an unmanned ground vehicle. Hyperspectral images were collected on a commercial mango orchard block in December 2017 and pre-processed for illumination compensation. After tree delimitation and mango pixel identification, an optimisation process was carried out to obtain the best models for fruit counting, using mango counts obtained by manually counting the fruit on-tree, and using state-of-the-art RGB techniques for yield estimation. Models were validated and tested on hundreds of trees, and subsequently mapped. In testing, determination coefficients reached values of up to 0.75 against field counts (predicting 18 trees) and 0.83 against RGB mango counts (predicting 216 trees). These results suggest that line-scan HSI can be used to accurately estimate yield in orchards, especially in scenarios in which this technology is already chosen for the determination of other traits.

First Report of Bacterial Dry Rot of Mango Caused by Sphingomonas sanguinis in China

First Report of Bacterial Dry Rot of Mango Caused by <i>Sphingomonas sanguinis</i> in China

Baseline light distribution in ‘Kensington Pride’ mango (Mangifera indicaL.) tree canopies in North Queensland

Future mango orchards systems will have canopies optimally designed for tree size, density, light and crop load relationships. Poor distribution of light within mango canopies is one of the reasons for current low orchard efficiency. Light (radiation), plays an important role in driving the photosynthesis, the developmental tree morphology, crop load and fruit quality. This study established a baseline for light transmission through the canopy (distribution) in four different ages of ‘Kensington Pride’ trees in Queensland commercial mango orchards. Light distribution patterns were established by measuring photosynthetically active radiation (PAR) (µmol m s) distribution in three dimensional matrix inside the canopy, at seven equally separated transects across the canopy from north to south and 4 sectors (west, middle-west, middle-east and east) on each transect at 5 heights above the ground. Mean light transmission within the canopy increased with tree age and canopy volume, and was related to pruning and training method. Highest light transmission was recorded 73.91 µmol m s at 75% of tree height. Light transmission was 60.90 µmol m s at 50% tree height, 58.23 µmol m s at 25% tree height and 62.81 µmol m s on the ground. In the horizontal plains, light distribution was lower in the middle parts of the canopy compared to the edges. There was a significant (p<0.05) relationship between light transmission and tree height, indicating large variation in light distribution within the canopy, with many leaves in shade where photosynthesis efficiency may be low. Some of the outer canopy may be receiving too much light and possible photo-inhibition as indicted by sun burn on leaves and fruit. This baseline understanding of light distribution will assist research in to improved light distribution in mango canopies and in the development of high density mango orchard systems.

An alternative inoculation technique of Colletotrichum gloeosporioides on mango for early anthracnose tolerance screening

The importance of having a technique that allows an efficient expression of symptoms of anthracnose is based on the early differentiation of cultivars and the optimization of genetic, material and financial resources. The objective of this research was to generate an alternative inoculation technique for Colletotrichum gloeosporioides on mango for early anthracnose tolerance screening. On this technique was optimized some of the most relevant components such as isolate virulence, conidial density, the inoculum deposition on leaves and using of surfactants. The study was carried in Iguala, Mexico, during the production cycles 2015-2016. C. gloeosporioides was biologically and culturally characterized. Gro and Sin monosporic strains were isolated from leaves, flowers, fruits and branches with anthracnose symptoms from commercial mango orchards located in Guerrero and Sinaloa states, Mexico. These strains show mycelial growth at 2.2 and 2.1 cm of diameter per day, spore density of 4.3x106, 3.9x106 conidia/ml, germination of 27 and 26%, virulence, with incubation period 4.5 and 4.1 days after inoculation, incidence of 90 and 92% and severity of 3.2 and 3.5 cm of diameter. The highest incidence and severity values with the lowest incubation period, was obtained using Gro isolate (1x105 conidia/ml) and polyoxyethylene-20-sorbitan monolaurate as spreader-sticker inoculated on the abaxial surface on detached young leaves, 15-20 days old, with a soft brush and incubated under dark condition. This inoculation technique allowed the optimal expression of C. gloeosporioides virulence in mango leaves and could be incorporated as a tool in the early differentiation of tolerance and susceptibility among cultivars.