Selection of palms with high iodine index
In 2005, ASD began a study to identify palms with a high degree of oil unsaturation (high iodine values). The iodine index is a scale used to define the degree of unsaturation of an organic compound that contains double or triple bonds. It is assumed that oils with a higher degree of unsaturation are more suitable from a nutritional point of view. The final purpose of the program is to develop varieties and clones with a high quality oil with regard to unsaturation.
The commercial oil palm varieties (E. guineensis) are characterized by having high contents of palmitic acid (44%), oleic acid (40%) and linoleic acid (10%), and an iodine index between 51 and 55. The American species E oleifera produces oil with a higher content of oleic acid and its iodine index ranges from 70 to 93. The behavior of interspecific hybrids is intermediate for this variable, so the range of iodine indices is between 58 and 71. Consequently, one of the advantages of commercial OxG hybrids is the increase in oil unsaturation.
The iodine index of ASD’s traditional seed varieties ranged between 50 and 55, which is normal for the vast majority of commercial varieties currently available in the market. The Deli x Ghana variety showed an iodine index of 50, which is somewhat lower than the average of 54 found in the rest of the ASD varieties. In the case of the ortets (palms from which compact clones are obtained), an average of 55 was found, but a group of palms with values higher than 58 stood out.
Within the compact palms used as progenitors in the breeding program to improve existing varieties, palms with iodine index values over 60 were found. Palms with this trait and also with high oil content in the bunch, will form the basis of the new generation of parents of compact varieties. The idea is to obtain crosses of a compact material with a high iodine index value (>60) with guineensis pollen lines (iodine index = 53 or 54), so that hybrid offspring have an iodine index between 56 and 58. In addition, ASD is working to obtain commercial DxP crosses, where both parents will be compact and therefore the iodine index would remain at a value between 60 and 62.
The action plan for the next stage of improvement is as follows:
- Evaluation of the descendants of DxD, TxT and DxT of superior palms planted in 2008.
- Execution of a complementary program of crosses in which other compact of the same origin are used to increase the population of parents in the medium term.
- Selection (and possible cloning) of D and P high iodine index palm (some P can be directly evaluated since the rate of fertile P in compact populations is relatively high).
- Use of compact D and P palms in conventional seed production programs (Compact x E. guineensis and Deli x compact).
Working on the iodine index in the laboratory.