Chapters 5.52
5.52 -Guava for Smallholder Farmers in the Efforts to Mitigate Climate Change
Emma Starratt, University of Guelph, Canada
Suggested citation for this chapter.
Starratt,E. (2022) Guava for Smallholder Farmers in the Efforts to Mitigate Climate Change, In Farmpedia, The Encyclopedia for Small Scale Farmers. Editor, M.N. Raizada, University of Guelph, Canada. http://www.farmpedia.org
Background of Guava
Guava (Psidium guajava), also known as the “apple of the tropics” originated in Mexico, Tropical America (Menzel, 1985). Through foreign voyages, guava was first introduced into the Philippines and India in the early seventeenth century before spreading around the world (Menzel, 1985). Guava is now common in the tropics and subtropics of Central America, Asia, and parts of Africa such as Egypt (Morton, 1987).
Guava is a large dicotyledonous shrub or a small hardy tree that ranges from 3-10 m high (Orwa et al, 2009). This small evergreen tree belongs to the myrtle, Myrtaceae, family (Menzel, 1985). It has many branches, often close to the ground (Orwa et al, 2009). The fruit produced is considered to be a berry which has a yellow skin, surrounding a thick edible flesh and a soft pulp interior that encases its seeds (Orwa et al, 2009). Though all guava fruit have relatively the same composition, there are large variations of certain traits among different varieties. The three major classes of guavas are processing, dessert, and dual-purpose types (Menzel, 1985). Processing types are highly acidic and consist of red or pink flesh (Menzel, 1985). Dessert types are less acidic, mainly white fleshed, and do well in hot, dry climates (Menzel, 1985). Dual-purpose types are a compromise between both dessert and processing varieties (Menzel, 1985). Combining these three major classes, there are more than eighty different varieties of guava (Morton, 1987).
Nutrient Content
The nutrient content of a guava depends on the variety that is grown. On average the fruit is a rich source of vitamins, minerals, dietary fibre, and antioxidants (Singh, 2011). It has an extremely high content of Vitamin C. Whole ripe guavas, can contain between 10-20000 mg of ascorbic acid per 100 g of fruit (Orwa et al, 2009). Other important vitamins contained in guavas are Vitamin A (carotene) and the B Vitamins. Whole ripe fruits can contain 200-400 I.U. of Vitamin A, 0.6-1.068 mg of Vitamin B3, 0.03-0.04 mg of Vitamin B2, and 0.046 mg of Vitamin B per 100 g of fruit (Morton, 1987). In terms of minerals, guavas contain between 9.1-17 mg of calcium, 17.8-30 mg of phosphorus, and 0.3-0.7 mg of iron per 100 g of fruit (Morton, 1987). Whole fruits also contain between 2.8-5.5 g of fiber per 100 g of fruit, hence it is a good source of dietary fiber (Morton, 1987). Overall guavas are an excellent source of micronutrients and fiber which could be quite beneficial to smallholder farmers especially pregnant women and young children.
Growing a Guava Tree
Guava trees can be grown from seed or vegetatively propagated. The first method of growing a guava tree, from seed, may be largely inaccessible to many smallholder farmers as seed may not be readily available. Regardless, guava seeds tend to germinate between 2-3 weeks but can take up to 8 weeks (Morton, 1987). Something accessible for smallholder farmers to speed up germination could be boiling seeds for 5 minutes, or soaking seeds for 2 weeks (Morton, 1987). Seedlings are ready to be transplanted at approximately 6 months old, (Menzel, 1985) and should be moved into a field between 1-2 years of age (Morton, 1987). From seed, trees will begin to fruit in 2-4 years (Morton, 1987).
The second method of growing a guava tree may be obtained by budding, or cuttings. Budding is performed by grafting a bud of a developed tree of the same diameter onto a seedling stock (Hamilton & Seagrave-Smith, 1959). Cuttings are root cuttings between 4-6 inches long and □(1/4) - □(1/2) inches thick that are planted in 1-2 inches of soil (Hamilton & Seagrave-Smith, 1959). These root cuttings often give off new shoots which can eventually be transplanted (Hamilton & Seagrave-Smith, 1959). Bud grafted trees will bear fruit approximately 6 months after they have been transplanted (Menzel, 1985). Trees will likely bear fruit heavily for 15-20 years before declining (Orwa et al, 2009).
Growth and Plant Requirements
The guava tree is considered to be a very hardy fruit tree and can adapt to numerous growing conditions which makes it a good contender against climate change especially with rising temperatures and unpredictable weather. It requires a range of 1000-2000 mm of annual rainfall; the lower range makes it one of the most drought resistant fruit trees (Orwa et al, 2009). Ideal temperatures range from 23-28 C which provide higher yields, but the guava tree can produce fruit within a temperature range of 15-45 C (Orwa et al, 2009). A total of 3.5-6 months of mean temperatures above 16 C allow trees to produce fruit successfully which usually occurs during the summer (Menzel, 1985). They can also withstand periods of frost throughout the subtropics and has been known to recover from frost damage and flooding (Menzel, 1985).
The ideal soil type would be rich clay loams, although guava trees can grow on a range of soils including poor soils, and temporarily waterlogged soils (Menzel, 1985). It can also tolerate soils that range from a pH of 4.5-8.5, therefore slightly to strongly acidic soils (Menzel, 1985). Recommended fertilizer required per tree are: 0.583 kg of nitrogen, 0.271 kg of phosphorus, and 0.399 kg of potassium which should be applied post-flowering for highest production (XiaoPing & XinTao, 2000). Recommended tree spacing is 10 m apart and pruning should be practiced, specifically on the suckers around the base (Morton, 1987). Guava trees can grow in altitudes of 0-2000 m and produce fruit up to altitudes of 1500 m (Orwa et al, 2009). In contrast to other tree crops, the guava tree’s production is not affected by excessive vegetative growth, or weeds, therefore it requires little to no weeding making it a manageable crop for smallholder women farmers (Menzel, 1985). It has also performed well when intercropped with maize, sorghum, and cowpeas (Orwa et al, 2009).
Other Benefits of Growing a Guava Tree
Guava is commonly consumed as a whole ripe fruit but there are many other ways of utilizing the fruit as well as different parts of the tree itself. Firstly, the tree can be used for fuel. The wood is abundant and naturally propagates, and hence can be used as firewood (Orwa et al, 2009). Similarly, the wood can be used to make simple tools or fence posts as it is quite durable (Orwa et al, 2009). Secondly, the leaves and bark of the tree are rich in tannins which can be used or sold to dye different materials (Morton, 1987). Lastly, the roots, bark, leaves and young fruits all contain medicinal properties. Leaf decoction and fruit juice are commonly used throughout the tropics to cure digestive tract ailments, colds, and even high blood pressure (Orwa et al, 2009). Leaf decoction is also used to treat pain and headaches by placing it in a hot compress or gargling it to treat a sore throat (Orwa et al, 2009). The clear fruit juice can also be consumed to treat hepatitis, and gonorrhea (Orwa et al, 2009). A decoction of the leaves or bark can be used topically for numerous skin ailments including ringworm, ulcers, and wounds (Orwa et al, 2009). Overall, it is evident that not only is the fruit a source of food, but the tree has many other uses that could be beneficial to smallholder farmers.
Post-harvest Value Addition
Post-harvest value addition could provide smallholder farmers with more profit and decreased product loss associated with over-ripening and poor storage. Essentially there is more profit in post-harvest processing than there from primary production. If smallholder farmers obtain simple equipment and supplies to process guava, they may be able to have larger profit margins. Some common recipes that utilize guavas are juices, cakes, puddings, sauces, ice cream, jam, cheese, pastes, pies and much more (Morton, 1987). For example, juava juice requires simple processing which may be attainable by smallholder farmers. It is made by boiling sliced guavas and then straining the juice, requiring fuel, pots, water, and a strainer (Morton, 1987). Another simple value addition could be grinding dehydrated guavas into powder, requiring a knife to slice fruit, fuel to bake fruit and some sort of mortar and pestle to grind the dried fruit into a powder (Morton, 1987). The powder can then be sold as is or used to flavour other dishes (Morton, 1987).
Potential Negative Issues
One of the biggest issues associated with guava is the availability of germplasm. ICRAF and AVRDC do not appear to hold any planting material. This constraint identifies a gap for NGOs, Ministries of Agriculture, CGIAR, and other institutions. This suggests that there is a global commercial opportunity. Locally, smallholder farmers could share or trade root cuttings or seeds or form cooperatives.
Although the guava has many benefits, other issues that farmers, particularly smallholder farmers, may encounter are related to storage and transportation. The fruit bruises easily and is considered highly perishable when ripe (Morton, 1987). For instance, guavas that were kept at room temperature in India became overripe and spoiled in 6 days (Morton, 1987). However, there is a solution, pliofilm (a clear plastic/moisture proof membrane), that preserves fruit for a couple more days (Morton, 1987). To increase preservation further, fruit could be wrapped in pliofilm and refrigerated. Smallholder farmers are unlikely to have access to either of these options. See Post-harvest Value Addition section for possible ways to reduce these issues.
Additional Resources
https://gardeningtips.in/growing-guava-in-pots-from-seeds-and-cuttings
Step by step process of planting guava from seed and cuttings. https://www.agrifarming.in/guava-pests-diseases-and-control-guava-plant-care
Identifying pests and diseases and solutions/tips for dealing with them. http://db.worldagroforestry.org/species/properties/Psidium_guajava
Overall information of guava. https://food.ndtv.com/lists/7-best-guava-recipes-2058972
Recipes and nutritional information on guavas. https://www.youtube.com/watch?v=TLwX4fhY6H4
Video on how to eat guava and why it’s good for you. https://www.youtube.com/watch?v=SBnDE4nMa08
Video on how to plant seeds from a fresh guava. https://bestseedsonline.com/100pcs-guava-seeds/
Detailed article on nutritional and medical properties of guava.
References
1. Hamilton, R. A., & Seagrave-Smith, H. (1959). Growing guava for processing. Honolulu, Hawaii: Agricultural extension Service. Retrieved November 15, 2020, from http://128.171.57.22/bitstream/10125/25517/EB1-63.pdf
2. Menzel, C. M. (1985). Guava: An exotic fruit with potential in Queensland. Queensland Agricultural Journal, 111, 93-98. Retrieved November 15, 2020, from https://www.researchgate.net/profile/Christopher_Menzel3/publication/286781042_Guava_An_exotic_fruit_with_potential_in_Queensland/links/59505bf2aca27248ae439194/Guava-An-exotic-fruit-with-potential-in-Queensland.pdf.
3. Morton, J. F. (1987). Guava. Fruits of Warm Climates,356-363. Retrieved November 15, 2020, from https://hort.purdue.edu/newcrop/morton/guava.html.
4. Orwa, C., Mutua, A., Kindt, R., Jamnadass, R., & Simons, A. (2009). Psidium guajava. Agroforestry Database: A Tree Reference and Selection Guide,1-5. Retrieved November 15, 2020, from http://apps.worldagroforestry.org/treedb2/AFTPDFS/Psidium_guajava.PDF
5. Singh, S. P. (2011). Guava (Psidium guajava L.). In Postharvest Biology and Technology of Tropical and Subtropical Fruits (pp. 213-245). Woodhead Publishing Limited. Retrieved November 15, 2020, from https://www.sciencedirect.com/science/article/pii/B9781845697358500103.
6. XiaoPing, Z., & XinTao, L. (2000). The application of fertilizer for guava trees. South China Fruits,29, 29-31. Retrieved November 15, 2020, from https://www.cabdirect.org/cabdirect/abstract/20013005210.