Variability of Sap Yield in Kaong (Arenga pinnata (Wurmb) Merr.) in the Philippines

Abstract

The study aimed to find the extent to which sap yield in kaong
(Arenga pinnata (Wurmb) Merr.), a potential source of
bioethanol and sugar with low glycemic index, varies from one
tree to another within the same locality and from one locality to
another. The study was carried out using randomly selected
trees from six natural stands located in different parts of the
Philippines: Makiling Forest, College, Laguna; Cavinti,
Laguna; Santor, Tanauan, Batangas; Cavite State University,
Indang, Cavite; Sigma, Capiz; and Binaton, Digos, Davao del
Sur. One inflorescence was tapped from each of the trees used
in the study. The results showed that within the same locality,
significant tree to tree variations exist in terms of tapping
duration (total number of days a tree exudes sap) and in terms of
average daily sap yield. Significant differences were also
observed between morning (AM) and afternoon (PM) sap yields.
PM yields were consistently higher, presumably because
photosynthesis occurs at daytime.

Trees differed widely in terms of tapping duration (range: 24 to
604 days; mean: 150 days). Average daily sap yield varied from
one location to another. The highest yields were found for Mt.
Makiling and Binaton. In all localities studied, tree to tree
variation in sap yield was high. Yields of eight liters or more per
day were recorded for some trees in Binaton, Indang, Sigma and
Makiling. Sap yield showed no significant correlations with
elevation, dry season length, soil pH and N and P content. The
highly significant variations in sap yield among trees within the
same locality indicate the possibility of raising high sap yielding
plantations by obtaining planting materials from high yielding
trees. This is just speculation though, since has not yet
established the role of genetics in sap yield variability among
kaong trees.