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Guava (Psidium guajava L.), often called the “apple of the tropics,” is a fruit of great nutritional and economic significance. Its adaptability to varied climatic conditions, prolific bearing, and suitability for both fresh consumption and processing make it one of the most important fruit crops in India and across the tropics. With rising demand for health-promoting fruits and growing interest in sustainable farming, guava cultivation has become increasingly relevant for farmers, researchers, and entrepreneurs. This book, Successful Guava Cultivation, has been prepared to provide updated, practical, and research-based information on all aspects of guava production and utilization. The chapters cover propagation techniques, orchard establishment, nutrient and water management, plant protection, post-harvest handling, processing, and recent innovations such as high-density planting, protected cultivation, and organic farming. Emphasis has also been placed on improving profitability through efficient marketing and value addition. The volume brings together the expertise of contributors from different fields, blending scientific accuracy with field-level applicability. It is intended to serve as a useful resource for farmers, students, researchers, extension workers, and agri-entrepreneurs seeking to enhance knowledge and practices in guava cultivation. We acknowledge with gratitude the contributions of colleagues, institutions, and growers whose work has enriched the content of this book. It is our hope that this publication will guide readers towards higher productivity, better quality, and greater sustainability in guava production.

The history of the guava fruit can be traced back thousands of years, and it has a rich cultural and botanical significance. The guava fruit (Psidium guajava) is believed to have originated in the tropical regions of Central America, particularly in present-day Mexico and neighboring countries. Archaeological evidence suggests that guavas were cultivated and consumed by the indigenous people of these regions as early as 2000 BCE. From there, the fruit spread to other parts of South and Central America, the Caribbean, and eventually to other tropical and subtropical regions around the world. Guava holds significant cultural importance in various ancient civilizations. In the Mayan culture, guavas were considered sacred and symbolized fertility (Arévalo- Marín et al., 2021). The fruit was also believed to have healing properties, leading to its use in traditional medicine. The Spanish and Portuguese explorers played a pivotal role in spreading guavas to other parts of the world during the Age of Exploration. They brought the fruit back to Europe, Africa, and Asia, where it quickly adapted to the tropical and subtropical climates. Guava cultivation in Asia can be traced back to the 16th century. It is believed that the Portuguese introduced guavas to India and Southeast Asia (Hussain et al., 2021). The fruit’s popularity grew rapidly in these regions due to its adaptability to various soil and climate conditions. Guavas were introduced to Hawaii in the early 19th century. The fruit quickly naturalized and became a prominent part of the Hawaiian diet. Today, Hawaii is known for its delicious pink-fleshed guavas, and guava-based products such as jams and juices are popular exports (Shigeura & Bullock, 1983). Guava has been recognized for its nutritional and medicinal properties since ancient times. It is a rich source of vitamin C, dietary fiber, and various essential nutrients. Traditional medicine in many cultures used guava leaves, fruit, and roots for treating ailments such as diarrhea, dysentery, and respiratory issues. Guava fruit and trees have also found their way into ancient literature and folklore. In some Indian epics and poems, the guava tree is celebrated for its lush greenery and sweet fruits, symbolizing prosperity and abundance (Reguengo et al., 2022).

2.1 Relatives of Guava The Psidium guajava complex is a group of closely related species that share certain characteristics, making them distinct from other species in the genus. These characteristics include venation pattern, seed number and size, indumentum pattern, and calyx structure. The complex consists of several species, including Psidium guajava, P. guineense, P. guyanense, P. nutans, P. rostratum, and P. rutidocarpum. Their distribution ranges from Mexico to northern Argentina and Uruguay, including the Antilles. A molecular phylogenetic analysis indicates that P. guajava and P. guineense are sister taxa, but the relationships with the other species are not clear due to insufficient representation in the analysis. Psidium guajava and P. rutidocarpum share a unique characteristic of leaves with numerous lateral veins, which is not found in other Psidium species. While P. guajava is a widespread weedy species, P. rutidocarpum is found in a more limited range in natural habitats in the upper Amazon of Peru. Psidium guineense, P. guyanense, and P. nutans are very similar to each other and could be considered as one large variable species, but they can be distinguished using specific characters described in a key proposed by Landrum in 2021. Psidium rostratum is geographically separated from other members of the P. guajava complex. It shares certain characteristics, such as flower size, closed calyx, and placenta, with other species in the complex but differs in having fewer ovules and larger seeds. Its venation is similar to that of P. guineense, which is why it is tentatively assigned to this complex (Gangappa et al., 2022).

Guava is a fast growing evergreen shrub or small tree that can grow to a height of 3-10 m. It has a shallow root system. Guava produces low drooping branches from the base and suckers from the roots. The trunk is slender, 20 cm in diameter, covered with a smooth green to red brown bark that peels off in thin flakes. Young twigs are pubescent. The leaves grow in pairs, opposite each other. The leaf blade is elliptic to oblong in shape, 5-15 cm long x 3-7 cm broad, finely pubescent and veined on the lower face, glabrous on the upper face. The flowers are white in colour, about 3 cm in diameter, solitary or in 2-3 flower clusters borne at the axils of newly emerging lateral shots. The fruit is a fleshy, pyriform or ovoid berry that can weigh up to 500 g. The skin colour is yellowish to orange. The flesh can be white, yellow, pink or red, sour to sweet, juicy and aromatic. The fruit contains a variable number of seeds (about 3-5 mm long) and its mesocarp is characterized by the presence of small (0.1 mm) and hard fibrous structures called stone cells (sclereids), which may cause damage to processing machinery (Toma & Luchian, 2019). 3.1 Reproductive Biology and Pollination Research on breeding systems in Psidium focuses primarily on P. guajava, which is an allogamous species characterized by an open pollination reproductive cycle. Nevertheless, self-pollination can occur. Bee-pollination, in which pollen is the sole reward, is the dominant pollination system in Psidium. Species of the superfamily Apoidea are important pollinators of both P. guajava and P. guineense. Both species are also pollinated by the European honeybee, Apis mellifera. Psidium guyanense, P. nutans, P. rostratum, and P. rutidocarpum lack comprehensive studies of their breeding systems, pollination, and dispersal (Sarkar & Sarkar, 2022).

Guava is a highly nutritious fruit with an impressive array of vitamins, minerals, and dietary fiber. It’s nutritional profile makes it an excellent choice for maintaining a healthy diet. The high vitamin C content, in particular, contributes to its antioxidant properties, which can help boost the immune system and protect against various diseases. The fiber content aids digestion and promotes gastrointestinal health. Incorporating guava into your regular diet can be a flavorful and nutritious way to stay healthy. The Indian population adores the tropical delicacy known as guava (Psidium guajava). It thrives in both commercial and wild orchards throughout subtropical and tropical countries, and it comes in a wide variety of sizes, colours, and forms (i.e pomiforms and pyriforms). Guava is valued for its notable therapeutic properties in addition to its delicious taste. It has shown that both the fruit itself and guava leaf extracts have anti-carcinogenic properties. As a result, it has established itself as a strong rival in the world of anti-cancer fruits. In the field of cancer treatment, diet plays a crucial part in improving the wellbeing of patients receiving chemotherapy while also reducing the risk of cancer development. This remarkable plant has been embraced for its multifaceted attributes, including its antimicrobial, emmenagogue, anti-inflammatory, astringent, antispasmodic, and gastrointestinal advantages (Jiménez-Escrig et al., 2001). In India, guava leaves have a special place in the world of Ayurveda. These leaves are useful for treating a range of medical disorders, including as toothaches, rheumatic diseases, digestive problems, skin wounds, and specific microbiological infections. Guava is used for its ability to treat hypertension (high blood pressure) and influenza infections throughout Southeast Asian countries. The leaves of this plant are used in Malaysia to treat diarrhoea, relieve stomach aches, and aid in placenta discharge after childbirth. Guava is used as an antibacterial, anti-diarrheal, and anti-diabetic agent in China (Daswani et al., 2017).

Guava, Psidium guajava L., belongs to the family Myrtaceae, which comprises 3,000 species under 80 genera. It is well-distributed in the tropical and subtropical regions of the world, especially in South America, Asia and Australia. The genus Psidium has about 150 shrubs and P. guajava is wellknown and grown worldwide. The flower of guava is self-pollinated; cross pollination, however, is estimated to be around 35% and pollination mainly carried-out of by bees and other insects. Therefore, seed multiplication will result in genetic heterogeneity that can be observed in orchards and plants in the same orchard. Therefore, seed propagation in commercial orchards to increase productivity is not recommended. The methods of vegetative propagation have been studied for the purpose of the production chain. In addition to the propagation structure, the costs of new technologies must also be taken into account. Progress in guava propagation has taken place in the last 100 years. It is important to know how to use the same methods of graftings and cutting. Detection of growth regulators, information on role of the juvenile stage in reproduction, advances in knowledge of chimeras, micro-propagation and application of vegetative propagation to prevent diseases caused by viruses and other pathogens. One can propagate guava by buddings, air layering, stoolings and inarching are not yet commercially feasible due to different success rates, the lack of a tap root system and burdensome processes. The purpose of this review is to discuss the diverse methods of propagating guava which are used commercially and the advancement made in recently.

Crop regulation in guava, flowering is more in summer season (Ambe bahar) due to the break of winter stress that leads to more fruit production in rainy season. But, in this season due to high temperature and rainfall during fruit maturation, the duration of maturation is reduced to 30 days that causes glut in the market, whereas winter season crop (Mrigbahar) is superior in quality which fetches comparatively higher price. Although, the production is surplus in rainy season (Rathore and Singh, 1974 and Singh et al., 2000), it offers poor quality due to insipid in taste and infestation of pest (Rawal and Ullasa, 1988) in comparison to winter season. On the contrary, in winter season quality fruits are produced with good quality and fetch high monetary returns (Singh et al., 2000). Guava fruit harvest peaks can deviate with prevailing weather conditions and cultural practices because flowers are produced on new growth. So, it is advisable to take only winter season crop every year. This requires crop regulation to obtain the most desirable crop, by the methods like withholding irrigation, thinning of flowers by chemically or manually, pruning, bending, root exposure, etc. The basic principle of crop regulation is to manipulates the natural flowering and fruiting of guava plant in desired season of the year that contribute to increased fruit yield, quality, profitability and sustainability of the environment by reducing the use of the frequency of the pesticides (Mahadevan and Kumar, 2014). The selection of bahar at a 

7.1 Introduction A nursery is a place where plants are cultivated and grown until they reach a usable size. Nursery management has evolved into a commercial venture, with different types of nurseries including retail, wholesale, and private nurseries. Retail nurseries sell planting materials to the general public, while wholesale nurseries supply other nurseries and commercial landscape gardeners. Private nurseries cater to the needs of specific institutions or organizations. Since many horticultural crops are propagated in nurseries, the production of quality planting materials is vital, especially for orchardists whose success largely depends on the quality of these materials, as most fruit crops are perennial. To be a successful grower, it is crucial to consider several factors, including soil and climatic conditions, location, water availability, financial support, labor availability, marketing facilities, demand, and transportation systems. However, the production of quality planting materials plays a pivotal role in determining the success of horticultural ventures, as planting materials form the foundation of the orchard (Chadha, 2001; Singh & Negi, 2010). 7.2 Demand for Seedlings and Seeds in India The availability of quality planting materials is one of the most important factors in the development of a sound horticulture sector. In India, there is an immense demand for quality seedlings and seeds at lower costs, offering scope for large-scale planting. The demand for quality planting materials exists across the country, as these materials contribute to sustainable fruit production systems (Swaminathan, 2007). 7.3 Seedling Supply Chain The primary suppliers of perennial tree seedlings are departmental/ government and industrial nurseries, which produce seedlings and vegetative propagules for their own needs, as well as for public distribution to meet raw material demands. Farmers primarily produce vegetable and ornamental seedlings, benefiting from the availability of improved seeds and the low input requirements. The price of ornamental seedlings depends on factors such as 

Fruit crop productivity is greatly impacted by rootstocks in a number of areas, including canopy structure, fruit quality, yield, blooming, and nutritional absorption. Furthermore, they are an essential line of defence against biotic and abiotic stressors such salt, heat stress, soil pathogens, and nutritional imbalances. Because there is a shortage of arable land and a growing market for fruit crops, production frequently takes place in unfavourable environments with high temperatures, little precipitation, floods, salt, and exposure to organic contaminants. The strategic use of appropriate rootstocks is crucial to reducing output losses under these conditions because they can lessen the effect of outside pressures on the scion (Bhandari & Bhattacharya, 2019) Rootstocks are essential to orchard management because they provide anchoring and facilitate the uptake of water and minerals. They also affect the growth of the trees, and they help create “three-piece” trees when they are employed as interstems, placed between the scion and the rootstock during propagation. Interstems assist regulate excessive vigour in desirable rootstocks and handle compatibility difficulties between stock and scion (Singh & Kumar, 2021). Soils that are too dry or too moist can be made tolerable by rootstocks. The potential of rootstocks in commercial fruit crops has not yet been completely utilised in India, despite substantial research internationally on the discovery and use of appropriate rootstocks in crops including apple, pear, citrus, mango, and grapes. Therefore, the crucial next step involves identifying rootstocks with optimal characteristics tailored to specific environmental conditions, acknowledging that the best rootstock for one variety and set of conditions may not be suitable for another (Sahu & Patra, 2018). Presently seedlings from open-pollinated seeds are used to propagate guava instead of homogenous clonal rootstocks. It was determined that many rootstocks, such as P. cattleianum, P. guinesee, P. molle, and Philippine guava, were appropriate. Plants using P. cattleianum rootstock had the best yield and the tallest trees. P. pumilum produced fruits with the largest total sugar content, total soluble solids (TSS), and quantity of seeds possible, exhibiting a dwarfing effect. Despite having uneven and rough skin, P. cujavillis rootstock produced

Guava planting has historically followed a 5 m × 5 m or 6 m x 6 m spacing, providing 278 to 400 plants per hectare in a square planting pattern. Growth, productivity, fruit quality, and leaf nutritional content are just a few of the management characteristics of guava orchards that are greatly impacted by this traditional spacing method. CISH, Lucknow, has recently launched a novel meadow orchard system that comprises growing guava at a greater density of 5000 plants per hectare with a spacing of 2.0 x 1.0 metres. Regular topping and hedging techniques are used in this innovative approach, especially in the early phases of orchard development. Techniques for topping and hedging are essential for regulating tree size and increasing fruit supply. By using strategic management techniques to maximise tree size and fruit output, this meadow orchard system offers a more intense approach to guava cultivation than standard planting methods. It also provides improved plant density. This method’s introduction is a reflection of continuous attempts to improve guava growing methods and adjust to changing agricultural practises. 9.1 Low Density Planting When planting guava, low-density planting differs from traditional or higher-density planting in that the guava plants are spaced widely apart and accommodates about 100-250 plants/ha. According to several studies, this strategy has a number of benefits that are essential for the best possible orchard management and acquires commercial production potential after 7-10 years of planting. According to Singh and Yadav (2014), guava trees are typically planted with a spacing of 6 to 8 metres between rows and 3 to 5 metres between trees within a row in low-density plantings. This spacing and planting density encourages a more open and well-ventilated orchard layout. (Singh & Yadav, 2014). The advantages of low-density planting are numerous, as Paramesha and Ravishankar (2013) have shown. Better fruit quality is the outcome of increased photosynthesis fostered by improved light penetration. Furthermore, the improved air circulation lowers the risk of illness, giving guava trees a better habitat. Additionally, less rivalry among trees promotes greater water and nutrient absorption, which increases tree vigour and productivity overall

The tropical fruit guava is prone to a number of diseases, pests, and disorders. Aphids, fruit flies, and scale insects are common pests; on the other hand, pathogens, such as bacteria and fungus, can cause illnesses like wilt and anthracnose. Deficiencies in some nutrients can occur and have an impact on the general health of plants. For effective control, integrated pest management must be put into practise along with routine inspections and prompt treatments. Maintaining a healthy guava crop involves disease-resistant cultivars, balanced fertilisation, and good orchard cleanliness. A vigorous guava crop is ensured by minimising the influence of diseases disorders, and pests via vigilant and preventative methods. 10.1 Weed control Weeds should be kept under control throughout the year because fruit harvesting is done throughout the year, for the easy mobility of labour. For this purpose, spray Gramoxone @ 6ml/litre of water during March, July and September. To control perennial weeds in March, spray may be done with Round up (Glyphosate) @ 10 ml/litre. Spray of these weedicides should be carried out on a calm day to avoid the damage to guava foliage. 10.2 Insect pests 10.2.1 Fruit fly Fruit fly, the serious threat to guava production particularly during rainy season, lays eggs singly in ripened fruits just below the epicarp which eventually results in appearance of minute depression with dark punctures. Maggots after hatching feed on pulp and make fruit unfit for consumption. They pupate in soil and takes about 12 to 18 days to complete its life cycle during July- August (main season).

The fundamental idea behind integrated nutrient management, or INM, is to optimize plant nutrient supply in order to maintain the targeted crop yield. It entails using chemical fertilizers, organic manure, and biofertilizers in the right amounts according to the land use system and the environmental, social, and economic circumstances. Vermicomposting is a natural fertilizer that is devoid of chemicals and made from organic wastes that decompose. It is an environmentally benign process. Beneficial microflora, including those that fix nitrogen, dissolve phosphorus, and break down cellulose, are abundant in vermicompost. In addition to having earthworm cocoons, which boost the number and activity of earthworms in the soil, it also has important vitamins, enzymes, and hormones like auxin and gibberellins, which improve the soil’s structure, texture, aeration, and ability to hold water while preventing soil erosion. Additionally, because of its high organic matter content, it increases the soil’s capacity to retain water, improves the macro- and micronutrient quality of the soil, and encourages greater root development and nutrient absorption. Porosity, aeration, drainage, and water-holding capacity are all extremely high in vermicompost (Sinha, 2009). Profile of Nutrients in Vermicompost: C:N ratio of 15.5. N = 1.6%, P = 0.7%, K = 0.8%, Ca = 0.5%, Mg = 0.2%, Fe 175.0 ppm, Mn 96.5 ppm, Zn 24.5 ppm, Cu 5.0 ppm, T = 0.5%. Biofertilizers are substances that include living microbes that, when added to soil, colonize the plant’s interior, or rhizosphere, and increase the host plant’s availability or supply of primary nutrients, so promoting growth. Biofertilizers provide soil with nutrients by utilizing the body’s natural mechanisms of fixing nitrogen, phosphorus solubilization, and growth-promoting material production. It can symbiotically link with plant roots because it is a living entity. Complex organic material could be simply and safely converted into a simple chemical by the involved microorganisms, making it easier for plants to absorb them. Long-term microorganism function leads to an increase in soil fertility. It preserves the soil’s natural habitat. In addition to increasing plant development, it substitutes artificial nitrogen and phosphate by 25% and enhances crop output by 20% to 30%. According to Hazarika and Ansari (2007), biofertilizers have the capacity to fix 20–200 kg N/ha/year, solubilize

12.1 Introduction Guava (Psidium guajava L.) is an important tropical and subtropical fruit crop, valued for its high nutritive content, processing potential, and adaptability to diverse agro-climatic conditions. In recent years, there has been a growing shift from conventional chemical-intensive farming towards eco-friendly and sustainable production systems. Organic farming in guava has gained importance due to its ability to enhance soil fertility, improve fruit quality, and reduce environmental degradation. The integrated use of organic manures, biofertilizers, and reduced chemical fertilizers has been shown to optimize yield while maintaining ecological balance. 12.2 Role of Organic Manures Farmyard manure (FYM), vermicompost, poultry manure, and neem cake are commonly used organic amendments in guava cultivation. These materials improve soil physical properties, enhance microbial activity, and release nutrients gradually. Muhammad et al. (2000) reported that a combined application of FYM with NPK fertilizers significantly increased fruit size, weight, and total yield in guava. Similarly, Ebrahiem and Mohamed (2000) observed that FYM application in ‘Balady’ mandarin improved fruit set and yield, demonstrating the broad utility of organic amendments across citrus crops.

13.1 Introduction Since the United Nations Framework Convention on Climate Change was founded in 1992, efforts have been undertaken to address climate change, which is today a serious problem for the entire globe. These programmes made an effort to lessen GHG emissions and lessen the effects of climate change. There have been a number of significant accords made, including the Kyoto Protocol in 1997, the Copenhagen Accord in 2009, and the Paris Agreement in 2015. Despite these accords, the Intergovernmental Panel on Climate Change (IPCC)’s most recent assessment contends that current decarbonization efforts fall short of the goal of keeping global temperature increases to 1.5°C over pre-industrial levels by 2050. Instead, it is anticipated that the temperature will have increased to 2.7°C by 2050 (Anonymous 2021). Analysing how climate change is affecting this sector of the economy is crucial. Fruit production is significantly hampered by changing precipitation patterns, rising temperatures, and extreme weather events. The growth, development, and production of fruit crops may be impacted by these changes, which could lead to financial losses and problems with food security. Improved methods and technologies for fruit production must be used to address these problems and comply with the objective of limiting the increase in global temperature. Adopting sustainable farming methods, bolstering water management systems, investing in crop varieties resistant to climate change, and improving postharvest storage and transportation technology may all be necessary to achieve this. Additionally, strengthening agroforestry systems and safeguarding biodiversity can support the fruit industry’s attempts to adapt to and mitigate climate change. Additionally, in order to lessen the effects of climate change on fruit agriculture, international collaboration and cooperation are essential for the adoption of suitable policies as well as the exchange of knowledge and resources. One example is encouraging collaborations between governments, agricultural organisations, researchers, and farmers to create and implement climate-smart practises and technologies. It is important to support various carbon capture and storage (CCS) technology that can remove CO2 from the atmosphere or prevent its release in order to fulfil the Sustainable Development

    14.1 Dry land ecosystem of Jammu and Kashmir Geographically, Jammu and Kashmir state is divided into various zones- the mountainous plain known as Kandi belt, hills including Shiwaliks ranges, mountains of Kashmir valley and Pir Panjal range, and Tibetan tract of ladakh and kargil. The maximum areas of Jammu division is existing in rainfed condition and are known as kandi belt or sub-mountane region which includes the lower shiwalik region. The soils of kandi belt are light to dark colored, well drained, severely eroded and with varying degree of stoniness. These soils are neutral to slightly alkaline nature, low organic matter and poor in fertility. In these areas, mango, guava, aonla, phalsa, citrus, bael, ber and jamun are commonly grown as all these fruit crops are survived under rainfed condition or require less irrigations. In these areas the normal rainfall is nearly 900-1000 mm with a high co-efficient of dissimilarity. The rainfall division patterns are especially erratic in time and space which leads to moisture stress situation. About 70 to 80 per cent the annual rainfall occurs during from July to September as a result of the South-West monsoon. April to June and October to November are the driest months and is scarcity of water. Therefore the farmers are suffering by growing the agricultural crops and they have tremendous scope for growing fruit crops. These crops are less water requiring as compared to agricultural crops. Therefore RRSS, Raya, SKUAST-Jammu was initiated since 2016 for systematic research work for collection of germplasm, conservation, evaluation and utilization of red flush guava strains for growers community (Anonymous, 2022).

In India, during the early days, guava plants were generally propagated by seeds from limited varieties available with nurserymen and pomologists. The seedling population obtained by open pollination gave rise to considerable variation in the form and size of fruit, the nature and flavour of pulp, seediness and other morphological characters such as spreading or erect growth habit of trees (Naik, 1949). Cheema et al., (1954) observed all the cultivars of guava to be highly heterozygous. Commercial producers utilized the variation thus obtained for selection of desirable genotypes and propagated them vegetatively. Assessment of genetic diversity and relationship among Psidium spp was carried out by Sharma et al (2007). They observed a high genetic similarity between Chinese guavas grouped with Psidium guajava cultivars. It has been observed that only a few named varieties are under cultivation. Most of these varieties suffer from one defect or the other. Hence, guava improvement by breeding was started mainly with the following objectives for developing new cultivars: i) dwarf plant habit suitable for high density planting ii) fruits with uniform shape, size, good colour, firm and thick pulp, good aroma, few and soft seeds, high TSS and high pectin iii) long shelf life iv) resistance to Fusarium wilt 15.1 Major breeding methods used Plant introduction- Most of the guava varieties have evolved as selections from seedling variants. Variability has come about because of open pollination from highly heterozygous parents. Several introductions of promising genotypes have been made in guava growing countries. In India, many introductions made from Hawaii, Brazil, Thailand, etc. are being cultivated and used in breeding programmes. Similarly, introductions of Indian cultivars like Allahabad Safeda and Sardar have given excellent results in other parts of the world (Gonzaga et al, 1999). Although introduction is a potential tool in

    16.1 Introduction Guava (Psidium guajava L.) is one of the most important tropical fruit crops, valued for its vitamin C content, nutraceutical compounds, and adaptability to diverse agro-climatic conditions. However, guava production faces problems of seedling variability, prolonged juvenile phase, susceptibility to wilt and anthracnose, and poor success rates of vegetative propagation (Singh et al., 2022). Biotechnological tools, ranging from micropropagation to molecular diagnostics, provide solutions to these challenges. These methods complement conventional horticultural practices by ensuring clonal fidelity, enabling rapid multiplication of elite genotypes, characterizing genetic diversity, and offering prospects for disease resistance and quality improvement (Kumari et al., 2021; Mishra et al., 2020). 16.2 Micropropagation: Commercial-scale Clonal Propagation Micropropagation is the most widely used biotechnology tool in guava. Nodal segments and shoot tips cultured on Murashige and Skoog (MS) medium with cytokinins such as benzylaminopurine (BAP) can produce multiple shoots, while rooting is induced using auxins like indole-3-butyric acid (IBA) (Singh et al., 2022). Juvenile explants generally perform better, and the addition of antioxidants (ascorbic acid, polyvinylpyrrolidone) or activated charcoal reduces tissue browning. Plants require careful acclimatization under mist chambers before field planting. Micropropagation ensures large-scale, disease-free, uniform planting material for high-density orchards (Singh et al., 2022).

Varietal description and nomenclature of different guava varieties grown in India are greatly confusing. Some varieties were named according to shape of the fruit, skin colour and pulp colour, while, several other varieties were named after in the place of origin. Pandey (1968) made detailed studies in different cultivars of guava and classified them into the white pulp group and the red pulp group. Guava is largely a self-pollinated crop, but crosspollination also does occur. This results in a large variability in the seedling population from which promising genotypes have been selected in different agro-climatic regions of the country. Promising cultivars of different Indian states are given below: About 160 genotypes, including somePsidum spp., are available in Indian collections and are maintained at several centres within the country in field gene banks. Nomenclature of the cultivars of guava grown in India is not yet well established. Some of the varieties have been named according to shape, colour, and smoothness of skin or by the place of their origin. Characters like plant growth, yield and physico-chemical composition of different guava varieties were reported by several workers. Varietal evaluation was carried out by many workers who reported performance of these varieties under

The Myrtaceae family tree, the guava (Psidium guajava L.), is grown in tropical climates all over the world and bears fruit in the summer, autumn and winter. Guavas are widely grown in Mexico, Brazil, India, and other countries. They have climacteric respiration patterns. Harvested at different maturities, it frequently causes early senescence because to its quick ripening within 1-2 days after physiological maturity. The fruit has notable losses (20–30%) during handling, storage, and transportation because to its thin peel, high moisture content, and inadequate post-harvest infrastructure. Though processing levels in the nation are still low, effective post-harvest management techniques can reduce these losses, improve fruit availability, and even increase processing. Product quality may be increased by better preservation methods and adherence to hygienic guidelines (Basak & Chakraborty, 2020). 18.1 Maturity Indices The ideal consumption stage, which varies depending on the type, determines when to harvest guava. Fruits should be collected at the mature, hard stage before any symptoms of ripening if they are to be consumed when still green. Harvesting for those intended to be soft and ripe happens when a noticeable green to yellow colour shift and initial softening are observed. Postponing harvesting to a more mature stage might lead to a rise in fruit fly infection. In green fruit, the Soluble Solids Content (SSC) varies from 3% to over 10%, whereas the Titratable Acidity (TA) varies from 0.2 to 1.5%. Variations in seasonal acidity are possible, but cultivar sweetness and acidity are distinct (Ghosh & Gupta, 2015). 18.2 Harvesting Harvesting guava, a climacteric fruit, is ideal when mature but still firm, ensuring excellent taste and distinctive flavor upon ripening, showcasing the unique characteristics of each cultivar. While seedling guavas may bear fruit after 5–6 years, grafted or air-layered plants exhibit precocity, yielding the first crop at 2 to 3 years of age. Individual hard and firm fruits are picked regularly (Reddy & Kumar, 2019).