Increasing Mango Production Efficiency under the Fast-Changing Climate

Abstract

Mango (Mangifera indica) is an economically and nutritionally significant fruit crop in the tropical and subtropical regions. The demand for mango fruits and processed products has been high both in the internal and external markets due to its taste and its associated health benefits. In meeting the demands requirement, reengineering the various tools that are available to improve mango production in response to the varied stresses in their environment, especially in the era of climate change, is crucial. The prime goal is to demonstrate the effects of climate change on mango growth, yield and quality while showing interventions that have been deployed to combat it. The chapter focuses on the role climate variability plays in the growth and yield parameters of mango trees, as well as the improvement objectives and approaches employed in enhancing their production and quality. It offers the diverse progress made in overcoming the biotic stresses that hinder mango production as well as the intervention made in improving the nutritional and quality traits of mangoes while offering directions for future research works on mango trees.

1. Introduction

High interest shown by farmers including the smallholders in diversifying their farm produce to include fruits crops such as mango and with profit-making goal accounts assist in attaining food security in the fast-changing climate era. Fruit crops such as mango (Mangifera indica L.) plays an essential role in achieving the prime goal of food security and hunger reduction. Mangoes are among the most popular fruits due to changes in consumer preferences [1]. This is partly attributed to its special aroma, colour, taste, juicy pulp and nutritional significance [2, 3]. Mango contains nutrients such as iron, calcium, phosphorus and vitamins A and C [4]. It is recommended that fruit nutrients are required for physical and mental people especially for children [5, 6]. These attributes term mango as the king of fruits. Mangoes as a tropical fruit crops ranks fifth globally in terms of production among major fruit crops [7, 8]. The total volume of mangoes produced globally in 2021 is 58.3 million metric tons, which is projected to increase by 1.9%, reaching 65 million metric tons by 2026 [9]. Mangoes are produced in more than 90 countries globally, with India as the world’s leading producer [10]. Asia is the largest region in terms of mango production, contributing to over 70% of the total mango produced yearly. Africa contributes to 10% of the total mangoes produced yearly [11]. In Ghana, mango is ranked third after pineapple and orange in terms of its fresh juice consumption [12]. Mango production provides an opportunity as an alternative source of livelihood, especially in rural areas and offers high profit [13, 14]. The increase in demand for high-quality mango to meet standards for local, national and international markets has resulted in the designing of new production strategies and techniques that are essential elements for its production in a fast-changing climate. For instance, the amount of rainfall in most producing regions is not adequate to meet mango water requirements, demanding the application of irrigation, biostimulants and paclobutrazol to promote flowering, fruit yield and quality [15, 16, 17]. Unfortunately, there are a number of bottlenecks that underpin the production of mango. Limiting factors implicated in the yield gap of mango production may include pests, diseases, insects, weeds, changes in rainfall pattern, seeds, soil fertility and irregular flowering, among others. These form a larger component of the core production and productivity constraints of mango. A better understanding of these challenges positions the mango industry for higher output through the designing of effective and efficient management systems. However, a number of efforts are geared towards nutritional management by employing a number of fertilisation strategies to limit physiological disorders of mangoes while promoting fruit qualities [18, 19, 20]. Given the wide range of research on mango, the current chapter focuses on climate change and mango production and its effects on the mango tree growth, development, yield and quality. It further explores the farmers’ reactions and adaptation strategies used in combating climate change. Also, general mango improvement objectives, challenges and methods are employed. Lastly, we present post-harvest and value-addition improvement strategies for mango improvement.

2. Climate change and mango production

The actions of humans have increased emissions of greenhouse gases, causing global warming and climate change. The effects of climate change may be helpful, harmful or unbiased, depending on the area [21]. Climate remains a key component in regulating the farming potential of a locality and classifying areas for cultivating certain crops [21, 22, 23]. Climate variability may lead to changes in temperatures, rainfall amount, atmospheric CO2 concentration, drought and soil salinity, among others. Therefore, the growth, development, flowering and yields of mango trees are influenced by prevailing environmental conditions. A shift in the required climatic condition may negatively impact mangoes in terms of their fruit set, quality and yields [24].

2.1 Impact of climate change on mango tree growth and development

The vegetative and phenological periods in mangoes are mainly controlled by temperature and rainfall. For instance, the best temperature for a mango tree’s vegetative growth is within the range of 20–29°C, and below 15°C; this incites blossoming [25]. Temperatures ranging from 20 to 28°C record a significant effect on leaf size [26], possibly attributed to translocation of dry matter to the root during high CO₂ concentrations [25]. Mango responds differently to rises in temperatures compared to annual crops [27]. Hence, it stays alive under desiccating conditions, and this trait is advantageous for yielding during succeeding growth seasons. However, under stress conditions, the development of the plant may be delayed and may lead to high yield loss [28]. Mango trees experience negative effects under drought and flood stresses by limiting their growth. Matching crop varieties to climate is an imperative action for lucrative mango production in conventional and newer areas. The cold period (wet season) and the dry periods are critical for flowering in mangoes, and wet seasons favour vegetative flow emissions [29, 30, 31]. Usually, the onset of rains during mango flowering can be harmful and may cause total crop failure [32]. Mango trees grow continuously under high temperatures, rainfall and humidity without a distinct pause in growth, thereby impeding flowering. However, extreme drought and vapour pressure deficit negatively impact photosynthesis due to the rapid closure of the stomatal of the mango plant as a product of variations in climatic situations [33]. Flower bud development happens in the shoot of most varieties with termination of growth. Growth chamber studies on mango trees confirm that low night temperatures within 8–15°C, coupled with day temperatures below 20°C, lead to flowering once the shoot initiation happens [34].

2.2 Impact of climate change on mango tree yield and quality

The variation in the climatic elements imposes stress, which causes anatomical, biochemical, morphological and physiological changes in the mango plant, affecting mango tree growth, yield and quality. For instance, drastic change in temperatures coupled with unseasonal rain leads to yield and quality reduction in mango fruits. For instance, the quality and the number of mangoes are lowered as the result of the changes in the plant’s physical features (vigour and canopy), reproductive traits (fruiting potential & fruit size) and quality traits (juice content, shelf life, pest & disease attack). Exposure of mango plants to high temperatures and low humidity lowers the efficiency of transpiration, photosynthesis and water potential in mango leaves [35, 36]. In an attempt by the mango plant to thwart the negative effects of these stresses, it reduces canopy area, inhibiting stomatal conductance and may, in the end, affect its yield [37]. Yields of mangoes are reduced when pre-flowering and flowering time coincides with rains. Moreover, it impedes fruit set and pollination activities. Similarly, storms cause major harvest loss in the later stage of fruit development. Soil water content in the soil has an effect on the fruit size, fruit yield as well as fruit quality parameters (soluble solids and sugar, starch and vitamin C quantity) of mangoes [38]. A number of studies confirm the vital role played by irrigation in supplementing rainfed in a fast-changing climate in attaining higher yield and quality of mango fruits [38, 39, 40]. Variability in climate influences fruit quality and the appearance of matured mango fruits. This is partly attributed to high incidences of pests and diseases such as anthracnose under high humidity and rainfall [32, 41]. During these periods, mango fruits may lose their aesthetic value due to the blackening of the peel, among others [32]. On the contrary, low humidity and rainfall support fruit setting and harvesting and the reduction of biotic stresses [42]. The huge variety in the genomic resources of mango is a benefit for collection and breeding plans to face climatic fluctuations. Fortunately, varietal disparities exist among mango genotypes in terms of their productivity under wet and dry conditions. Thus, these differences can be exploited and mango yields and qualities will be less affected by climate variability when utilised. Adaptation strategies are crucial in flight against climate change and contribute to mango yields and quality. For instance, matching crop varieties to climate results in yield in mangoes in both traditional and newer production areas.

2.3 Mango farmer’ reactions and adaptation strategies towards climate change

Strategies adopted in mango seedling production against climate change include creating drainage channels, applying agrochemicals, grafting, better-quality varieties, establishing trees as shades, irrigation and soil nutrition improvement methods have been applied by farmers to diminish climate inconsistency and variation outcomes [43]. Mango producers’ adaptation behaviour to climate change arises for the purposes of maintaining their farms and also their lives [44]. The provision of resources and knowledge on mitigating the negative consequences of climate alteration is key in mango production. With these, farmers are able to reduce these effects by adhering to weather forecasts while adjusting their time dates and supplying water. Strategies such as substitution and complementation of low temperature via the use of growth retardant coupled with the imposition of moisture stress for about 4 months preceding blossoming, post-harvest reduction of sizeable branches of vigorous and late varieties grown in heavy soils to boost soil moistness loss through winter periods [45]. Similarly, creating trenches along the drip line enhances drainage, thus preventing moisture stress conditions during rain peaks. Traditional measures for managing water deficits are unrealistic in the medium or long term. Mango producers are recommended to adopt deficit irrigation methods to meet drought conditions to save water, improve water use efficiency and maintain yield and quality [42]. Climate change acclimatisation tactics recommended by other researchers embrace drip irrigation approaches, high plant population and cover belts [46]. Mango farmers’ acclimatisation to the changing climate is challenged by some factors which may arise from technological, socioeconomic and institutional barriers [46].

3. Mango improvement in fast-changing climate

3.1 General mango tree improvement objectives

Genetic improvements in most fruit crops like mango are underdeveloped. Most of the improvements in mangoes have arisen from natural selection through several generations. The upsurge in consumer and market demands coupled with a fast-changing climate demands mangos of high yield and quality. Unfortunately, mango breeding takes several years, going beyond 20 years. This is ascribed to its generation period, long juvenile stage, high heterozygosity, one seed in a fruit, recalcitrant seeds, incompatibility among cultivars, polyembryony, large area for evaluating hybrids and high prevalence of fruit shedding naturally. These challenges require a smart solution for improving mangoes. Nevertheless, there is a high range of genetic diversity in mango germplasm in addition to its asexual propagation, facilitating selection at any period along the breeding cycle [47].

The goals of mango improvement are centred on the needs of society in relation to agriculture. Thus, leads to three main pillars, namely, producing fruits of high quality, reduction in environmental impact and high returns on the production. These pillars must form an integral component in any mango improvement programmes to avoid trade-offs among them. However, a number of works also focus on the usage of post-harvest strategies and value-addition development to enhance the safety and quality of harvested fruits to their final consumer while reducing mango fruit wastage [48, 49]. This has resulted in the release of hybrid mangoes around the globe [50, 51]. This is achieved via designed, initiated and implemented well-defined breeding goals, and new varieties are expected to be introduced that are well suited to the changing climate and its associated biotic and abiotic stresses. Preferred traits in mango cultivars vary among producers, consumers and industries. However, a number of the traits such as early and regular bearing, dwarfness, nice appearance (attractive), good size, lack of physiological disorders, firmness, resistance to pests and diseases, and long shelf life, among others, are desirable traits of mango cultivar. A large number of commercial cultivars of mango on the market have been improved in terms of their biennial bearing potential. The combined application of multi-omics techniques has enhanced and limited uncertainty in mango improvement [52, 53].

3.2 Mango tree breeding challenges in fast challenging climate

Most of the improvements in mangoes arise from natural selection over several generations. The upsurge in consumer and market demands coupled with a fast-changing climate. Unfortunately, mango breeding takes several years, going beyond 20 years. This is ascribed to its generation period, long juvenile stage, high heterozygosity, one seed in a fruit, recalcitrant seeds, incompatibility among cultivars, polyembryony, large area for evaluating hybrids, and high prevalence of fruit shedding naturally. Factors that limit progress in traditional fruit tree breeding are the long juvenile phase, long generation time and large resource requirements in field areas and personnel for maintaining and evaluating hybrid populations. In meeting customers’ and processors’ demands for quality traits, traditional breeding approaches render this objective difficult to achieve [54]. In addition to these limitations, mango breeders are faced with high heterozygosity, polyembryony, low crossing rates (0.1%), a high incidence of fruitlet fall and a single seed per fruit [55]. Moreover, mango breeding programmes are challenged with long juvenile periods affecting the evaluation, selection and release of hybrid cultivars. Additionally, large areas are needed to evaluate the hybrid seedlings, coupled with the cost of maintaining them.

4. Approaches used in mango improvement

Mango tree has witnessed improvement via the introduction of new varieties and evaluation, selection (clones, monoembryomic and polyembryomic seedlings), pollination (assisted and controlled), in vitro selection, embryo rescue, molecular markers and multi-omics techniques. Applications of omics technologies such as proteomics, transcriptomics and metabolomics facilitate the development and identification of traits governing key genes of interest, supporting reverse and forward breeding. Genetic transformation in mango via Agrobacterium tumefaciens using genes regulating fruit ripening is reported and markers such as SNPs are efficient in revealing the selfing rate and pollinator behaviour of mangoes at the seedling stage [56]. Both the main approaches (traditional and conventional) have their pros and cons. Similarly, rootstocks have been utilised to improve mango tree cultivation and overcome stresses arising from several factors including drought, salinity and pathogens. Specifically, nanoparticles (nano-zinc oxide and nano-silicon) enhanced mango productivity by improving salinity tolerance [57]. To improve biotic stress tolerance in mango breeding programmes, researchers have used a variety of cutting-edge strategies that combine both the most recent techniques with conventional breeding techniques.

4.1 Traditional breeding techniques for mango improvement

For many years, traditional breeding methods have been the cornerstone of mango advancement against biotic stresses (Table 1). Cross-pollination of various mango types is used in these techniques to combine beneficial features, such as disease resistance and pest tolerance. Breeders can find and enhance mango cultivars with increased biotic stress tolerance by repeatedly selecting and evaluating progenies [55]. Similarly, breeders can create mango varieties with increased biotic stress tolerance by using conventional breeding methods in conjunction with thorough screening and evaluation procedures. To speed up the breeding process and improve the overall effectiveness of creating stress-tolerant mango varieties, it is crucial to combine these old methods with contemporary tools like molecular markers and biotechnological developments [65]. Traditional breeding, however, takes time and could take several generations to succeed.

Technique	Description	Examples	Reference
Germplasm selection	Accessions resistant or tolerant to biotic stressors are advanced to the next stage.	Anthracnose and powdery mildew	[58]
Cross-Pollination and Recurrent Selection	Controlled cross-pollination among mango varieties to combine desirable genes for biotic stress tolerance. Repeatedly choosing the most successful offspring for additional breeding cycles.	Increased disease and pest resistance in hybrid mango varieties.	[59]
Backcrossing	Transferring particular biotic stress tolerance genes from a donor parent to a recipient parent.	Mango variety with improved resistance to a specific disease through backcrossing.	[60]
Mass selection	Choosing mango trees from a wide population that has desired characteristics, like tolerance to biotic stressors.	Local landraces with inherent resistance to specific pests or diseases.	[61]
Line breeding	Developing genetically homogenous lines by choosing and breeding mango plants with favourable features over several generations.	Mango lines with improved biotic stress.	[62]
Inbreeding and selection	Controlled inbreeding to concentrate desirable traits for biotic stress tolerance.	Mango varieties with increased resistance to specific diseases.	[63]
Open pollination and selection	Promoting genetic variety by allowing mango trees to undergo natural pollination.	Mango trees with unique biotic stress tolerance traits from open pollination.	[64]

Table 1.

Traditional mango improvement technique.

4.2 Current approaches

Smart solutions are required for improving mangoes. The wide range of genetic diversity in mango germplasm in addition to its asexual propagation, facilitates selection at any period along the breeding cycle [47]. A number of strategies involving marker-assisted selection (MAS), transgenic approaches and genome editing technologies are employed in improving mango production for high yield and quality.

Marker-assisted selection (MAS): To improve mangoes, MAS serves as a potent tool used in addition to conventional breeding methods. Finding molecular markers connected to traits of interest (disease or insect resistance) is the goal of MAS. The time and resources required for phenotypic evaluations are decreased because these markers allow breeders to choose plants with desirable features at the early seedling stage. Mango cultivars with improved resistance to diseases like anthracnose and powdery mildew have been developed successfully using MAS [62]. For instance, to choose mango offspring with favourable alleles for desirable qualities, [54] used MAS to determine which progeny carry the required alleles; the procedure involved genotyping the progeny. These variants can be located using a collection of trait-associated SNP markers that the researchers designed. Thus cutting down on the time and expense needed for field use, maintenance and long-term evaluation of material. In conclusion, MAS is a helpful tool for choosing mango progenies with desirable features and the trait-associated SNP markers created in the study can assist breeders in more effectively identifying these progenies.

Transgenic approaches: A direct and targeted method of introducing particular genes into mango plants to provide biotic stress resistance through genetic engineering. Genes from other organisms, such as those from disease-resistant plants or insecticidal proteins, can be inserted into the mango genome using transgenic techniques [66]. The development of mango cultivars with enhanced resistance to pests like fruit flies has shown potential thanks to this technique. Transgenic methods do, however, also spark worries about potential environmental and regulatory problems.

The fastest-growing agricultural technology is transgenic technology [67]. It refers to a group of strategies for introducing desired genes into a particular plant by unconventional means from any source (including plants, animals, microbes and even genes that have been artificially created). The primary benefit of transgenic technology is the ability to change plants by using the genes governing a variety of crucial agronomically significant features that may be obtained from any organism, including plants, bacteria, etc. As a result, the target plant can easily adopt unique features from any background.

The defensin J1 gene was discovered to have been used to create transgenic mango embryos (Mangifera indica) cv. “Ataulfo.” Defensins are tiny cysteine-rich peptides with antibacterial activity against a variety of pathogens, including bacteria, fungi and viruses. The transgenic mango plants exhibited enhanced resistance to anthracnose, a fungal disease caused by Colletotrichum gloeosporioides [68]. According to the study, creating disease-resistant mango types may be facilitated through genetic engineering.

Genome editing technologies: The development of genome editing technologies, particularly CRISPR-Cas9, has completely changed how mangoes can be improved to withstand biotic stress. Without adding foreign DNA, genome editing enables precise alterations of particular genes inside the mango genome. Breeders can now use this technology to increase the expression of genes related to pest tolerance or disease resistance [69]. While resolving the ethical issues with transgenic methods, genome editing has enormous potential for accelerating the production of stress-tolerant mango varieties [70]. Key genes linked to disease resistance in mango have been edited using CRISPR-Cas9. The possibility of creating disease-resistant mango varieties has been demonstrated by targeting genes involved in plant-pathogen interactions, such as those in charge of resistance to anthracnose and powdery mildew [71]. CRISPR-Cas9 may be used by scientists to improve mango’s resistance to environmental challenges including salinity and drought. The goal is to create mango varieties that are more tolerant to harsh environmental conditions by focusing on genes implicated in stress response pathways [72]. CRISPR-Cas9 can be used to change the genes responsible for the size, flavour and ripening of fruit. Mango cultivars with enhanced flavour and longer shelf lives may be developed by focusing on specific genes involved in fruit scent, sugar content and texture [72]. Additionally, CRISPR-Cas9 is being investigated as a way to improve resistance to viral infections that damage mangoes and cause diseases including mango malformation disease and mango leaf distortions. Researchers want to develop mango cultivars with improved virus resistance by introducing particular mutations in genes that are sensitive [73].

Multi-omics approaches: Understanding the molecular pathways underpinning mango’s ability to withstand biotic stress is now substantially easier due to multi-omics technologies (genomics, transcriptomics, proteomics and metabolomics) by deepening our understanding of how mango genes and stressors interact [74]. Breeders can design tailored breeding strategies for biotic stress tolerance by understanding these relationships of key genes and their metabolic processes involved in stress responses. Recent genome sequences on mango varieties (Carabao, Tommy Atkins, Alphonso & Irwin) facilitate the study of mangoes at the transcriptomics, comparative genomics and genotyping to provide reliable gene sets and references [75, 76, 77]. A number of molecular markers are also used to explore genetic diversity, generate genetic linkage maps and identify markers for key traits (pulp colour, fruit colour, taste and flavour) [54, 78, 79, 80]. These investigations aid in the identification of the genes and proteins involved in early and late flowering, various stages of fruit development and biotic stress situations. The regulation of post-harvest and biannual flowering is possible through metabolomic research on the mango, which sheds light on the metabolites, hormones and pathways involved in fruit softening and flower induction [81].

Public and private collaboration: Mango enhancement for biotic stress tolerance depends critically on collaboration between governmental research institutions and private businesses [82]. Public institutions frequently have significant collections of germplasm, the ability to conduct fundamental research and knowledge of breeding methods. On the other side, private businesses can make investments in cutting-edge biotechnological equipment and market the stress-tolerant mango cultivars that have been created. Collaboration between these industries can hasten the creation and spread of enhanced mango cultivars that are resistant to a variety of biotic stressors. An evaluation of the extensive collection of germplasm in mango breeding is urgently needed [61]. Germplasm is employed to find sources of resistance to different biotic stresses in the context of mango breeding for biotic stress. It is important to screen the polyembryonic cultivars for these stresses because their variability is lower, and they are typically found in areas with significant rainfall. To improve the quality of these cultivars, it is also necessary to introduce diversity into them. Using markers to identify zygotic and nucellar embryony might aid in the selection of new recombinants.

Due to the fusion of conventional breeding techniques with cutting-edge biotechnological methodologies, mango development for biotic stress resistance has advanced dramatically. The way mango breeders create stress-tolerant cultivars has been transformed by the use of omics technology, transgenic methods, genome editing technologies and marker-assisted selection (MAS). The effectiveness and efficiency of mango improvement programmes have been further improved by collaboration between the public and commercial sectors. The future of mango breeding for biotic stress tolerance is bright as research advances; it has the potential to provide sustainable mango production and availability, protecting this beloved tropical fruit for future generations.

5. Improving mangoes against biotic stresses tolerance

Biotic stressors present a number of difficulties in mango farming. A wide range of diseases caused by fungi, bacteria, viruses and nematodes pose a serious danger to crop productivity [83]. Additionally, a variety of pests, including insects and mites, can seriously harm mango plants and fruits. Mango growers around the world continue to face chronic challenges from common diseases and pests like the mango hopper and fruit fly, as well as diseases like anthracnose, powdery mildew and bacterial black spot [84]. For instance, yield loss attributed to fruit fly (Diptera: Tephritidae) is billions of dollars annually globally, with country-specific losses of around USD 242 million from Brazil and 50% losses from the entire mango produced in Mali [85, 86]. Recent studies demonstrate that penetration of sunlight in mango plantation activates the defence signals in mango fruits. For instance, mango fruit develops tolerance to fungal pathogen Collectotrichum gloeosporioides by activating defence-related pathways and hormones (ethylene, brassinosteroid and jasmonic acid), which triggers phenylpropanoid biosynthesis [87]. Rootstocks from polyembryonic are used to improve mango tree resistance to fruit fly occurrences and mango wilt disease [88, 89]. Current research has designed mango fruit trap detection to monitor their population on the field and to establish an economic threshold for managing them [90]. Scientists are keen on improving the genetic base of mango cultivars to enhance their resistance to varied biotic stress (Table 2). However, current management of these stresses largely uses integrated management approaches.

Stress	Key Management Approach	Reference
Anthracnose	MiPR1A genes enhanced resistance to Colletotrichum gloeosporioides	[91]
Powdery mildew	Resistant cultivars and sulphur-based fungicides application	[92]
Bacterial black spot	Copper-based sprays and pruning of affected tissues	[93, 94]
Fruit fly	Fruit fly integrated pest management, trap-based monitoring and protein bait sprays	[95, 96]
Anthracnose	Cultural practices (pruning and sanitation) and fungicide application	[97]
Mango hopper	Biological control (parasitoids) and neem-based insecticides	[98]

Table 2.

Prevalent major biotic stresses in mango production.

6. Post-harvest and value addition improvement strategies

6.1 Post-harvest losses in mango

The promotion of mango production among smallholder mango farmers contributed to the development and reduction of poverty. However, post-harvest losses and challenges in value addition have hindered its full potential in the market [99]. Post-harvest losses in mango occur due to factors such as physiological changes, mechanical damage, fungal and bacterial infections, and inadequate storage and transportation [100]. Climate change-induced factors like extreme temperatures and unpredictable rainfall patterns also contribute to losses. However, the short shelf life of mango fruit, the difficulty in regulating the post-harvest quality, and the lack of preservation technology are the main problems that need to be solved in the mango industry. Post-harvest practices encompass all the activities that take place after a crop is harvested until it reaches the ultimate market or consumer. These essential steps include harvesting, packing, storing, transporting, processing and marketing of the mango. Implementing effective post-harvest practices is crucial as it not only enhances the overall quality and value of the mango but also minimises the extent of deterioration. By gaining insights into the ideal conditions for handling your specific product, you can significantly reduce losses and optimise the outcome.

6.2 Post-harvest handling and management

Mango is a climacteric fruit with a relatively short shelf life, making post-harvest management crucial for maintaining quality and reducing losses. In recent years, climate change has further exacerbated post-harvest challenges, necessitating innovative strategies to ensure food security and economic sustainability. Post-harvest management is the careful processing of agricultural products to preserve their quality and freshness and lengthen the shelf life before marketing in order to increase market value [99]. The first step in post-harvest handling is to ensure that the mangoes are harvested at the optimum maturity stage and subsequently ripened to obtain the desired flavour and texture [99]. For instance, mangoes harvested too early will not have developed their full flavour and aroma, while those harvested too late will be prone to decay. Once the mangoes have been harvested, they should be handled with care (Figure 1). During and after harvesting, mangoes are critically susceptible to damage; once the fruit is damaged, all the biological processes, including ethylene production and respiration, proceed ahead swiftly, producing/leading to its rapid deterioration. After mangoes are harvested, procedures like sorting, grading, pre-cooling/washing, packaging, storage, transportation and marketing, among others, are said to be crucial [100]. Spreading fruits on a paddy straw cushion floor in the orchard’s yard for nearly 24 hours, followed by washing the fruit to remove dirt, has been described as being a very important step in extending the shelf life. They should be packed in clean, well-ventilated containers and stored at a cool temperature. The ideal storage temperature for mangoes is 10–12°C [101].

Figure 1.

Technical practices and management of harvest.

6.3 Strategies for enhancing mango shelf life

A number of methods such as waxing, modified atmosphere packaging (MAP), controlled atmosphere storage and hot water treatment are used to prolong the shelf life of mangoes.

• Waxing: Waxing/Coatings can be effectively used to increase the shelf life and marketable period of mango [99]. Beeswax-emulsified chitosan–Aloe vera has been used to coat mangoes to extend the shelf life.

• Modified atmosphere packaging (MAP): Modified atmosphere packaging (MAP) involves altering the atmospheric composition around the fruit to slow down respiration and reduce ethylene production. Several studies have shown the efficacy of MAP in extending mango shelf life and reducing post-harvest losses.

• Controlled atmosphere (CA) storage: This involves maintaining specific gas concentrations (oxygen and carbon dioxide) and temperature levels. Research has indicated that CA storage can effectively delay ripening and extend the storage life of mangoes [101].

• Hot water treatment: Hot water treatment is an alternative quarantine method that is effective in controlling fruit fly infestation. Studies have demonstrated that hot water treatment significantly reduces fruit fly infestation without compromising fruit quality [102]. The mangoes are dipped in hot water for a short period of time, which kills the bacteria and fungi that can cause decay.

6.4 Value addition improvement strategies

Value addition in agriculture is the process of enhancing the quality, quantity and marketability of agricultural products. It entails transforming raw materials into more valuable forms. Value addition not only raises the revenue of farmers and agribusinesses but also creates employment opportunities and reduces post-harvest losses, therefore improving food security. Value addition can also contribute to environmental sustainability by reducing waste and greenhouse gas emissions. Value addition entails converting a raw product into a mango and processing it into puree and concentrates. Processing mangoes into a variety of products, such as juice, pulp, chutney, pickle, jam, puree and concentrates, not only extends their shelf life but also adds value to the fruit than fresh mangoes, and they can be exported to other countries. These products are used as ingredients in various food products and beverages, increasing the marketability of mangoes [103]. Value-addition improvement strategies include:

• Drying and dehydration: These are traditional preservation methods that reduce moisture content, thereby inhibiting microbial growth and enzymatic reactions. Solar drying and vacuum drying are among the commonly used techniques for mango preservation [104].

• Mango by-product utilisation: By-products of mango processing, such as peels and seeds, can be utilised to produce value-added products like pectin, mango kernel oil and animal feed [105].

In the era of climate change, post-harvest and value-addition improvement strategies are essential for enhancing mango production and reducing losses. The adoption of innovative technologies and processing techniques can lead to increased market opportunities, significant income generation and overall sustainability in mango production.

7. Conclusion

Mango has an established export market and poses bright opportunities for export in the international market, whether in fresh or processed forms. Similarly, the mango industry has provided livelihood opportunities to its growers and those involved in its marketing channel. The development of mango varieties that are climate-smart with improved qualities is desired. Also, current mango improvement programmes should focus on the development of pests (fruit flies) and diseases (black spot disease) resistance, early maturing, wide adaptation and identification of key traits controlling yield, pulp colour and fruit shape. There should be a strong linkage between research institutions and farmers in order to combat the key challenges confronting the mango industries. In addition, value addition along the mango production chain should be strengthened especially in African countries where post-harvest losses in handling and marketing are higher. Similarly, since mangoes are seasonal fruits, there is scope to establish mango preservation factories. Considerable amounts of waste material, e.g., mango stones and peels, remain unutilized and can be used properly by processors to earn more profit. This will also help to improve sanitary conditions around factory premises. High-quality commercial cultivation of mango trees by using improved planting and drip irrigation leads to multiple benefits, viz.

Conflict of interest

The authors declare no conflict of interest.