Crop Regulation In Guava: A Review

Guava (Psidium guajava L) is a tropical fruit that belongs to the Myrtaceae family, which contains about 150 species. It is grown in the terai, inner terai, and hilly regions of Nepal, with the highest-producing districts being Kailali, Jhapa, Dhading, Taplejung, and Khotang. Guavas grow in the leaf axils during the present season and yield solitary white flowers or in cymes of two to three flowers. Guavas are primarily self-pollinated, with the major pollinator being honey bees. Guavas often flower twice or three times a year, with the rainy and winter seasons seeing the most blooming. Crop regulation is the manipulation of the natural flowering and fruiting of guava in the desired season of the year so as to increase fruit yield, quality, and profitability. Crop regulation can be carried out in guavas through various techniques, including withholding irrigation, pruning, root pruning and root exposure, bending of shoots, hand thinning, nutrient application, de-blossoming by hand, and using different plant growth regulators and chemicals. Stoppage of irrigation after harvest of winter crops (December–June) and applying fertilizer and irrigation in June creates profuse flowering and production in the winter season. Another method of crop regulation in guava is terminal pruning, which involves cutting the plant 20 to 30 cm in April to prevent rainy season crops and promote winter season flowering. Exposing the roots to the sun by removing 7–10 cm of soil around the tree, creating water stress by withholding irrigation for a month or two before flowering, and covering the roots one month before desired flowering with soil. In order to avoid rainy season crops and have a good winter harvest of guava, FYM and prompt irrigation are helpful. In guava, bending shoots between August and September promotes increased flowering and fruit set, as well as an increase in the CN ratio. In leaves, barks, and fruits, bending has also been shown to raise the amounts of pectin, tryptophan, proline, polyphenol oxidase, catalase, and peroxidase. Hand or chemical thinning in March and April reduces crop yields during the rainy season and increases winter fruit set and good flowering. Furthermore, fertilizer time and dose can be changed to promote greater vegetative development and boost winter season yields. De-blossoming is done manually, with PGRs, or with chemicals to enhance the amount of winter-season crops in guava and prevent any rainy-season crops. In conclusion, guava crop regulation can be accomplished successfully by a variety of chemical and cultural techniques that control summer flowering and winter fruit production.