Quality and quantity are the keywords that put an industry ahead of its competitors. Though there is increased demand for durian (Durio Zibethinus) in the world markets – due largely to its rich and exotic taste – the country has been unable to tap this opportunity for export earnings as the local industry is hampered by limited production of high-quality durian.
durian fruitThe durian production industry has been incurring losses due largely to a physiological disorder appearing in the fruits. Known as uneven fruit ripening (UFR), this disease is characterized by a hardened leathery aril, and a whitish color, odorless and tasteless pulp. It normally occurs when the fruits are about to ripen and remains invisible until the fruits are opened.
Efforts have been made to arrest the occurrence of this disease. One such effort has been the initiation of the study on the “Uneven Fruit Ripening and other Physiological Disorder in Durian”by the Bureau of Plant Industry (BPI) and Davao National Crop Research and Development Center, with the support of the Bureau of Agricultural Research in the conduct of a study. The study aimed at determining the causal agents of UFR in durian fruits and controlling the occurrence of the said disease in maturing and ripening stage of durian.
Results of the study revealed that mulching significantly minimized the incidence of UFR and wet core in durian. Mulching is the principle of covering the soil surface of the plant’s base with materials such as rice straws and plastic sheets to reduce the infiltration rate of water into the soil and minimize the absorption of water into the roots. It was observed that the excessive water uptake by plant is the major cause of UFR and wet core. Wet core is somewhat similar to UFR by the fact that it affects the flesh or pulp of durian giving its pulp a watery and dull taste.
One significant observation obtained from the study is the amount of rain as the major causal agent of UFR in durian. It was concluded that high rainfall at 200 mm and above during maturity period of durian incurred the highest incidence of UFR and wet core. Results of the study showed that rainfall triggers the growth of shoots that compete for the nutrients needed by the fruit to attain full maturity and development.
Moreover, the study recommends to apply mulching using plastic sheets one month before maturity or harvesting especially during rainy season.
For more information, please contact Mr. Virgilio L. Loquias, Davao National Crop Research and Development Center (DNCRDC), BPI Bago Ushiro, Davao City) or call at tel. no. 087-227-9838)
By: Mary Charlotte O. Fresco, BAR Digest, July-September 2000 Issue (Vol. 2 No. 3)