Effect of fertilization and flower bud dormancy breaker on yield and fruit quality of crystal guava (Psidium guajava L.)

Guava (Psidium guajava L.) crystal variety or often called crystal guava is a type of fruit that has recently become increasingly popular in the community and is highly favored by consumers. The advantages of this guava compared to other guavas are fast fruiting (8 months after planting has started production), small habitus so that the population per hectare is high, the fruit is large with thick pulp, tastes good, fresh, and crunchy, very few seeds only 4-6 per fruit, even many are seedless (seddless), and the appearance of the fruit is attractive. With its various advantages, the crystal guava population in Bali has grown very rapidly since the last 5 years, but farmers complain that although certified superior seeds are used, the production, quality and continuity of the fruit produced are not as expected. The continuity of fruit harvest is not sustainable because many naturally induced flower buds do not develop into flowers due to dormancy. The aim of this study was to increase the production and quality of crystal guava fruit through fertilization and the application of flower bud dormancy breakers.

The research was conducted in Semanik Village, Petang District, Badung from January to July 2024. The experiment was arranged in a 2-factor factorial with 9 replications, using a group randomized design. The first factor was fertilization consisting of 3 levels; fertilization as the farmer's way/control (P1), fertilization with N, P, K, and Ca (P2), and fertilization with N, P, K, Ca and microfertilizers Zn, and Cu (P3), while the second factor was the application of flower bud dormancy breaker type consisting of 3 levels; without dormancy breaker/control (Dt), Ethreel dormancy breaker (De), and KNO3 dormancy breaker (Dk). The results showed that fertilization level P2, namely the provision of urea, TSP, KCl and calcium fertilizer in the form of gypsum (CaSO4.2H2O) at a dose of 250 g, 300 g, 300 g, and 1,250 g/plant respectively and fertilization level P3, namely the provision of urea, TSP, KCl and gypsum at a dose of 250 g, 300 g, 300 g, and 1,250 g/plant coupled with the provision of micro-fertilizers ZnSO4 and CuSO4 tend to increase the growth, production and quality of crystal guava fruit. Similarly, the application of Ethreel and KNO3 flower bud dormancy breakers tended to increase the number of new buds per plant, number of fruits per plant, weight of fruits per plant and percentage of grade A fruits.