Phenology of ‘Magallanes’ Pummelo (Citrus maxima) Trees and Its Growth and Development as Influenced by Potassium Nutrition

Main Article Content

Alminda Magbalot-Fernandez
Constancio C. De Guzman


This study aimed to determine the influence of potassium (K) fertilization on the vegetative growth, flowering and fruit development of 13-year old ‘Magallanes’ pummelo [Citrus maxima (Burm. Ex Rumph.) Merr.] trees. The experiment was conducted at South Davao Corporation (SODACO) farm, Davao city for 12-months duration. Five treatments were observed with increasing K levels were applied per tree: control (no fertilization), without K, 150 g K basal (recommended rate based on soil analysis), 225 g K basal, and 225 g K basal + foliar application. The critical stage of tree growth coincided with the months of May and August. Peak leaf flushing occurred in June and peak flowering with fruit set in April. The crucial stage of fruit development was noted two months after fruit set. Thus, optimum fertilization must be applied during these stages for maximum growth and production in ‘Magallanes’ pummelo. The vegetative growth of pummelo was not affected by increasing K rates. The recommended rate (150g K basal per tree) significantly increased canopy diameter by 76% but higher K rates did not increase tree height, due to the effect of fruit load and nutrient competition. On the other hand, increasing K rates to 50% higher than the recommended rate (225 g K per tree) increased the number of flushes by 36-100%. Flowering, fruit set and yield of ‘Magallanes’ pummelo were also enhanced by higher K rates. Flowering was increased by 4 times, fruit set by 86-100%, fruit number by 7 times, weight per fruit by 22-26%, and yields up to 9 times on trees composted with 225 g K rates.  The fruit size (diameter and length), however, did not increase by increasing the K level.

Citrus, development, flowering, fruit, growth, potassium

Article Details

How to Cite
Magbalot-Fernandez, A., & Guzman, C. C. D. (2019). Phenology of ‘Magallanes’ Pummelo (Citrus maxima) Trees and Its Growth and Development as Influenced by Potassium Nutrition. Asian Journal of Research in Agriculture and Forestry, 3(4), 1-18.
Original Research Article


Magat SS, Mantiquilla JA. Citrus Crop nutrition and fertilization management of selected tropical fruit crops. PCARRD Los Baños, Laguna. 2005;228.

Tsai HI, Chang SKC, Chang SJ. Antioxidant content and free radical scavenging ability of fresh red pummelo [Citrus grandis (L.) Osbeck] Juice and Freeze-Dried Products. Journal of Agricultural Food Chemistry. 2007;55(8): 2867-2872.
DOI: 10.1021/jf0633847S0021-8561(06)03 384-X

Smith SN. What is a pummelo. Wisegeek article; 2009

Benavente-Garcia O, Castillo J, Marin FR, Orturo A, Del Rio JA. Uses and properties of citrus flavonoids. Journal of Agricultural Food Chemistry. 1997;45:4505-4515.

Guthrie N, Morley K, Hasegawa S, Manners GD, Vandernberg T. Inhibition of human breast cancer cells by citrus limonoids. 2000;164-174.

Middleton E, Kandaswami C. Potential health promoting properties of citrus flavonoids. Food Technology. 1994;48:115-119.

Njoroge SM, Koaze H, Karanja PN, Sawamura M. Volatile constituents of redblush grapefruit (Citrus paradisi) and pummelo (Citrus grandis) peel essential oils from Kenya. Journal of Agricultural and Food Chemistry. 2005;53(25):9790-9794.

Reische DW, Lillard DA, Eitenmiller RR. In: Ahoh CC, Min DB (Eds.), Chemistry, nutrition and biotechnology. Marcel Dekker, New York. 1998;423-448.

The National RDE Network for Fruit Crops. Fruits: The national research, development and extension agenda and program for fruit crops. Quezon City: BAR. 2002;44.

Philippine Statistic Authority [PSA]. Commodity Fact Sheet; 2014.
Available:; retrieved 2018

Erner Y, Artzi B, Tagari E, Hamou M. Potassium affects citrus tree performance. The Volcani Center, Institute of Horticulture, Department of Fruit Trees; 2005.

Davies FS. An overview of climatic effects on citrus flowering and fruit quality in various parts of the world. University of Florida, Gainesville; 1997.

Coronel RE, Verheij EWM (Eds.) Plant resources of South-East Asia. No. 2: Edible fruits and nuts. Prosea Foundation, Bogor, Indonesia; 1992.

Kumar N, Meenakshi N, Suresh J, Nosov V. Effect of potassium nutrition on growth, yield and quality of papaya (Carica papaya L.). Indian Journal of Fertilizers. 2006;2(4): 43-47.

Reese RI, Koo RCJ. Effects of N and K fertilization on internal and external fruit quality of three major Florida orange cultivars. Journal of American Society of Horticulture Science. 1975;100:425-428.

Mimoun M, Ben M, Ghrab M, Ghanem M, Elloum O. Effects of potassium foliar spray on olive, peach and plum. Part 2: Peach and Plum Experiments. E-ifc No. 19; 2009.

Mimoun M, Ben O, Loumi M, Ghrab K, Latiri, Hellali R. Foliar potassium application on pistachio tree. IPI Regional Workshop on Potassium and Fertigation Development in West Asia and North Africa; Rabat, Morocco; 2004.

Obreza TA. Effects of P and K fertilization on young citrus tree growth. University of Florida, Southwest Florida Research and Education Center; 1998.

Wolf DD, Kimbrough EL, Blaser RE. Crop Science. 1976;16:292-94.

Menino MR, Caranca C, De Varennes A, Almeida VVD, Baeta, J. Tree size and flowering intensity as affected by nitrogen fertilization in non-bearing orange trees grown under Mediterranean conditions. Journal of Plant Physiology. 2003;160: 1435-1440.

Guardiola JL. Overview of flower bud induction, flowering and fruit set in citrus. Universidad Politecnica de Valencia, Valencia, Spain; 1997.

Fageria NK, Gheyi HR. Efficient crop production. Campina Grande: Universidade de Paraíba; 1999.

Mengel K, Arneke W. Effect of potassium on the water potential, the pressure potential, the osmotic potential and cell elongation in leaves of Phaseolus vulgaris. Physiology Plant. 1982;54:402-408.

Iglesias D, Cercós M, Colmenero-Flores J, Naranjo M, Ríos G, Carrera E, Ruiz-Rivero O, Lliso I, Morillon R, Tadeo F, Talon M. Physiology of citrus fruiting. Brazilian Journal Plant Physiology. 2007;19(4):333-362.

van Bel AJE, van Erven AJ. A model for proton and potassium co-transport during the uptake of glutamine and sucrose by tomato internode disks. Planta. 1979;145: 77-82.

Perkins-Veazie P, Roberts W. Can potassium application affect the mineral and antioxidant content of horticultural crops? Proceedings of the Symposium on Fertilizing Crops for Functional Food; 2002.

Alva AK, Paramasivam S, Patil B, De Mattos D, Dou H, Sajwan K. Role of potassium on sustainable citrus production. Citrus Production; 2002.

Sites JW, Deszyck EJ. The effect of varying amounts of K on the yield and quality of Valencia and Hamlin oranges. Proceedings of Florida State Horticulture Society. 1952;68:65-72.

Reese RI, Koo RCJ. Responses of ‘Hamlin,' ‘Pineapple,' and ‘Valencia' orange trees to nitrogen and potash applications. Proceedings of Florida State Horticulture Society. 1974;87:1-5.

Reese RI, Koo RCJ. Effects of N and K fertilization on internal and external fruit quality of three major Florida orange cultivars. Journal of American Society of Horticulture Science. 1975;100:425-428.

Boman B. Effectiveness of fall potassium sprays on enhancing grapefruit size. Proc. Fla. State Hort. Soc. 1997;110:1-7.