In oil palm, three types of fruit forms are present, viz., dura, pisifera and tenera. These three palms morphologically look similar but differ in their fruit form.
Fruit of Oil Palm is a sessile drupe. It consists of a pericarp, (exocarp or skin), mesocarp, and endocarp (shell) usually surrounding one, but sometimes upto four kernels. The kernel consists of a testa (skin) and a solid endosperm and embryo.
The presence or absence of the shell is genetically controlled. Dura has dominant Sh+ Sh+ allele, pisifera has recessive sh-sh- allele, where as tenera has Sh+sh- alleles. Tenera is a hybrid produced by cross between dura and pisifera, hence having each allele from both the parents.
On selfing or inter-crossing, the hybrid fruit forms segregate into 25% dura: 50% tenera: 25% pisifera. The flow chart showing the crossing and hybridization in oil palm given below. Selfing or crossing of tenera produces dura, pisifera and tenera fruit forms.
Oil palm fruit forms and tenera hybrid formation
In dura the percentage of mesocarp to fruit ranges from 35-50 and the shell is 2-8 mm thick and the kernel is usually large. Pisifera is characterised by the absence of shell and hence there is a high ratio of mesocarp to fruit. Tenera has a mesocarp percentage ranging from 60 to 96% with a shell thickness of 0.5 mm to 4 mm with comparatively smaller kernel and more oil yield.
Pisifera palms are broadly classified into three classes based on fruit setting. Fertile Pisiferas are characterised by normal fruit setting, semi-fertile fruits may have varying degrees of fruit set and sterile palms produce abortive bunches. Fertility is under simple genetic control
Kalyana Babu*, P. Anitha
ICAR-Indian Institute of Oil Palm Research, Pedavegi-534 450, West Godavari (Dt), Andhra Pradesh