Oil Palm - Genomics of Cultivated Palms - page 28

Plate 3.1 Dura-the thick shelled form of oil palm.
Plate 3.2 Pisifera-the thin shelled form of oil palm.
formation in the region where the shell is formed. Pisifera palms are usually female
sterile and are difficult to propagate by seeds.
The endocarp cells of oil palm fruit become lignified to a hard shell, while the
mesocarp tissue remains fibrous during shell formation. A transition zone made up
of fibrous units was also visible beneath the shell. The role of ferulic acid and the
three enzymes (phenylalanine ammonia lyase [PAL], cinnamyl alcohol-NADPH-
dehydrogenase [CAD], and peroxidase [POD]) is crucial in lignin synthesis [12] .
Hence, the quantification of activity of these lignin biosynthetic enzymes is also used
to discriminate the seedlings as dura, pisifera, and tenera [12,13] .
3.2.1 Markers and Genes for Shell Thickness
Molecular markers associated with shell thickness can aid in identification of fruit
form at the seedling stage of oil palm. They were identified using RAPD [14,15] ,
AFLP [16] , RFLP [17] , and SSR [18,19] marker systems. RAPD bands specific
to pisifera (P12-600, P10-700, P6-650, P19-800), dura (P7-700, P10-1000), and