Skin damage to two new mango cultivars during irradiation and cold storage.

Mangoes can express several skin disorders following important postharvest treatments. Responses are often cultivar specific. This paper reports the responses of two new Australian mango cultivars to some of these treatments. 'Honey Gold' mango develops "under skin browning" early during cold storage. This is thought to be partly caused by a discolouration of the latex vessels which then spreads to the surrounding cells. The symptoms appear to be worse in fruit from hotter production areas and that have been cooled to temperatures below 18C soon after harvest. Current commercial recommendations are to cool fruit to 18C, which limits postharvest handling options. Recent trials have confirmed that delayed or slowed cooling after harvest can reduce under skin browning. The defect may also be associated with physical injury to the skin during harvesting and packing. Irradiation is potentially an important disinfestation treatment for fruit fly in Australian mangoes. The 'B74' mango cultivar develops significant skin damage following irradiation, mainly due to discolouration of the cells surrounding the lenticels. Recent results confirmed that fruit harvested directly from the tree into trays without exposure to water or postharvest chemicals are not damaged by irradiation, while commercially harvested and packed fruit are damaged. Several major harvest and postharvest steps appear to increase lenticel sensitivity to irradiation. Further work is required to develop commercially acceptable protocols to facilitate 'Honey Gold' and 'B74' mango distribution and marketing.

Mango Fruit Genomics

Genomics approaches for marker assisted selection of improved mango fruit.

Honey Gold Mango

To improve the yield of Honey Gold mango through nutrition, pruning and growth regulators.

Vapour heat treatment of honey gold mango

Vapour heat treatment of honey gold mango for access to the Japanese market.

Marker development for genes controlling mango tree architecture

Identification of candidate genes controlling, mango tree architecture.

Testing Postharvest Mango treatments

The effectiveness of Amistar and ASM combinations, in reducing the severity of postharvest anthracnose and stem end rot in mango.

Management of fruit quality and pest infestations of mango and mangosteen for Market access requirements

Management of fruit quality and pest infestations of mango and mangosteen for Market access requirements.

Improving fruit quality and profitability of 'Honey Gold' mango

Honey Gold mango is a new Australian variety owned by a Queensland company, and in high demand because of very good flavour and appearance. It develops under skin browning (USB) when grown in hot areas. It appears after packing and the fruit need to be re-sorted at the markets to remove affected fruit. Production and postharvest treatments will be developed to reduce USB and increase profitability. Other production and harvest factors causing quality loss will be also be identified through a commercial downgrade analysis program in the packhouse. Grower training will reduce downgrades and improve the percentage of fruit in premium grade.

Reducing skin damage and improving efficiency of Calypso mango

Calypso mango is a relatively new variety owned by DEEDI and managed/marketed by One Harvest (Queensland-based). It is a major mango variety for the retail chains. Its main limitation is a sensitive skin, which results in lenticel spotting and skin browning.

Delivering information and technology to the mango industry - Stage 2

Access to relevant and timely information and training resources has emerged as a significant issue from the Delivering Mango Technology (DMT) project. This project will facilitate providing managing information and technology tools for growers. Using a range of methods, including workshops, events, and web based technology facilitated through the Australian Mango Industry Association’s (AMIA) website, DMT stage 2 will develop a high profile delivery vehicle to building industry knowledge and resources .

Reducing the incidence of under-skin browning in 'Honey Gold' mango (Mangifera indica L.) fruit

'Honey Gold' mango is a relatively new cultivar in Australia, with an appealing skin colour and a sweet fibre-free flesh. However, fruit can develop 'under-skin browning' (USB), which appears several days after packing as a distinct 'bruise'-like discolouration under the epidermis and can affect large areas of the fruit surface. We investigated the anatomy of USB and the impact of post-harvest fruit handling conditions on the disorder. Starch accumulated around the resin canals and discoloured cells in the affected area, with no visible change to the cuticle or epidermis. Delays of 1 d at ambient temperature (27 degrees - 35 degrees C) before packing, and 2 d at 18 degrees - 20 degrees C (after packing), before placing fruit at 12 degrees - 14 degrees C and road transportation, reduced the incidence of USB by 83% compared to placing fruit at 12 degrees - 14 degrees C within 13 h of picking. The incidence of USB was 88 100% higher in fruit that were cooled to 12 degrees - 14 degrees C within 13 h of picking, then commercially road-freighted for 4 d at 12 degrees - 14 degrees C, than in fruit held under similar temperature conditions, but not road-freighted. Wrapping each fruit in bubble-wrap to minimise direct contact with other fruit, with the plastic insert, or with the cardboard tray, reduced the incidence of USB by 84% after road-freight compared to not using bubble-wrap. These results suggest that USB is a unique disorder of mango skin associated with a rapid post-harvest reduction in temperature, from high ambient temperatures to 12 degrees - 14 degrees C, and with physical damage during road-freight.

Mango fruit peel and flesh extracts affect adipogenesis in 3T3-L1 cells

Obesity is associated with many chronic disease states, such as diabetes mellitus, coronary disease and certain cancers, including those of the breast and colon. There is a growing body of evidence that links phytochemicals with the inhibition of adipogenesis and protection against obesity. Mangoes (Mangifera indica L.) are tropical fruits that are rich in a diverse array of bioactive phytochemicals. In this study, methanol extracts of peel and flesh from three archetypal mango cultivars; Irwin, Nam Doc Mai and Kensington Pride, were assessed for their effects on a 3T3-L1 pre-adipocyte cell line model of adipogenesis. High content imaging was used to assess: lipid droplets per cell, lipid droplet area per cell, lipid droplet integrated intensity, nuclei count and nuclear area per cell. Mango flesh extracts from the three cultivars did not inhibit adipogenesis; peel extracts from both Irwin and Nam Doc Mai, however, did so with the Nam Doc Mai extract most potent at inhibiting adipogenesis. Peel extract from Kensington Pride promoted adipogenesis. The inhibition of adipogenesis by Irwin (100 mu g mL(-1)) and Nam Doc Mai peel extracts (50 and 100 mu g mL(-1)) was associated with an increase in the average nuclear area per cell; similar effects were seen with resveratrol, suggesting that these extracts may act through pathways similar to resveratrol. These results suggest that differences in the phytochemical composition between mango cultivars may influence their effectiveness in inhibiting adipogenesis, and points to mango fruit peel as a potential source of nutraceuticals.

Mango (Mangifera indica L.) peel extract fractions from different cultivars differentially affect lipid accumulation in 3T3-L1 adipocyte cells

Plant phytochemicals are increasingly recognised as sources of bioactive molecules which may have potential benefit in many health conditions. In mangoes, peel extracts from different cultivars exhibit varying effects on adipogenesis in the 3T3-L1 adipocyte cell line. In this study, the effects of preparative HPLC fractions of methanol peel extracts from Irwin, Nam Doc Mai and Kensington Pride mangoes were evaluated. Fraction 1 contained the most hydrophilic components while subsequent fractions contained increasingly more hydrophobic components. High content imaging was used to assess mango peel fraction effects on lipid accumulation, nuclei count and nuclear area in differentiating 3T3-L1 cells. For all three mango cultivars, the more hydrophilic peel fractions 1-3 inhibited lipid accumulation with greater potency than the more hydrophobic peel fractions 4. For all three cultivars, the more lipophilic fraction 4 had concentrations that enhanced lipid accumulation greater than fractions 1-3 as assessed by lipid droplet integrated intensity. The potency of this fraction 4 varied significantly between cultivars. Using mass spectrometry, five long chain free fatty acids were detected in fraction 4; these were not present in any other peel extract fractions. Total levels varied between cultivars, with Irwin fraction 4 containing the highest levels of these free fatty acids. Lipophilic components appear to be responsible for the lipid accumulation promoting effects of some mango extracts and are the likely cause of the diverse effects of peel extracts from different mango cultivars on lipid accumulation.

Prediction of breeding values for average fruit weight in mango using a multivariate individual mixed model

Mango is an important horticultural fruit crop and breeding is a key strategy to improve ongoing sustainability. Knowledge of breeding values of potential parents is important for maximising progress from breeding. This study successfully employed a mixed linear model methods incorporating a pedigree to predict breeding values for average fruit weight from highly unbalanced data for genotypes planted over three field trials and assessed over several harvest seasons. Average fruit weight was found to be under strong additive genetic control. There was high correlation between hybrids propagated as seedlings and hybrids propagated as scions grafted onto rootstocks. Estimates of additive genetic correlation among trials ranged from 0.69 to 0.88 with correlations among harvest seasons within trials greater than 0.96. These results suggest that progress from selection for broad adaptation can be achieved, particularly as no repeatable environmental factor that could be used to predict G x E could be identified. Predicted breeding values for 35 known cultivars are presented for use in ongoing breeding programs.

Integrated disease management of stem end rot of mango in the Southern Philippines

This research aimed to develop and evaluate pre- and postharvest management strategies to reduce stem end rot (SER) incidence and extend saleable life of 'Carabao' mango fruits in Southern Philippines. Preharvest management focused on the development and improvement of fungicide spray program, while postharvest management aimed to develop alternative interventions aside from hot water treatment (HWT). Field evaluation of systemic fungicides, namely azoxystrobin ( Amistar 25SC), tebuconazole ( Folicur 25WP), carbendazim ( Goldazim 500SC), difenoconazole ( Score 250SC) and azoxystrobin+difenoconazole ( Amistar Top), reduced blossom blight severity and improved fruit setting and retention, resulting in higher fruit yield but failed to sufficiently suppress SER incidence. Based on these findings, an improved fungicide spray program was developed taking into account the infection process of SER pathogens and fungicide resistance. Timely application of protectant (mancozeb) and systemic fungicides (azoxystrobin, carbendazim and difenoconazole) during the most critical stages of mango flower and fruit development ensured higher harvestable fruit yield and minimally lowered SER incidence. Control of SER was also achieved by employing postharvest treatment such as HWT (52-55°C for 10 min), which significantly prolonged the saleable life of mango fruits. However, extended hot water treatment (EHWT; 46°C pulp temperature for 15 min), rapid heat treatment (RHT; 59°C for 30-60 sec), fungicide dip and promising biological control agents failed to satisfactorily reduce SER and prolong saleable life. In contrast, the integration of the improved spray program as preharvest management practice, and postharvest treatments such as HWT and fungicide dips (azoxystrobin, 150-175 ppm; carbendazim, 312.5 ppm; and tebuconazole, 125-156 ppm), significantly reduced disease and extended marketable life for utmost 8 days.