Category Archives: 1994 Vol 6 No 2

Genetic control of polymorphism for kernel-to-fruit ratio in the oil palm (Elaeis guineensis Jacq.)

A study to clarify the genetic control of polymorphism in kernel-to-fruit ratio in the oil palm Elaeis guineensis Jacq. was carried out on the basis of the following crosses from the NIFOR oil palm breeding programme – 45 tenera (T) x tenera; 24 tenera (T) selfings; 33 dura (D) x tenera; and 29 tenera (T) x dura (D).

The mean kernel-to-fruit ratio (%K/F) for the dura and tenera fruit forms and the tenera:dura (T:D) ratio of %K/F were determined for each of the segregating progenies. Estimates of correlation coefficient (r) and narrow-sense heritability (h2) derived from parent-offspring regression analysis for the T:D ratio of %K/F were obtained for each type of cross. Dura and tenera fruit forms showed distinct differences in their mean %K/F, thus confirming that the oil palm exhibits polymorphisms in its kernel size, with the dura progeny having a higher mean %K/F than the tenera in all the segregating crosses.

The coefficient of correlation between the %K/F of the tenera parent and the tenera:dura ratio of %K/F of selfed offspring was highly significant (r = 0.52**). The comparison between the female tenera parent T:D ratio of %K/F and that of the TxT offspring was highly significant (r= 0,44**) with a high narrow-sense heritability estimate (h2 = 67%). A similar comparison with the male tenera parent was not significant (r = 0.18NS) and had a low heritability estimate (h2 = 25%). In DxT and TxD crosses the estimates of the correlation coefficient of the tenera parent to T:D ratio of %K/F and the offspring values were not significant (r = 0.17NS and 0.20NS respectively).

This indicated that tenera parents carry a certain kernel inhibiting factor (or factors) that reduces the kernel size of the tenera offspring relative to their dura sibs. This factor(s) was transmitted to the tenera offspring especially when tenera was the female parent. The kernel in-hibiting factor(s) is proposed to be closely linked with the recessive allele of the gene controlling shell thickness. The implication of this for the kernel size and fertility of pisifera palms is discussed.

Status report on the use of Bacillus thuringiensis in the control of some of oil palm pests

Progress in the use of B. thuringiensis in the control of bunch moth (pyralidae), nettle caterpillars (Limacodidae) and bagworms (Psychidae) is reviewed. Bacillus thuringiensis Berliner (Thuricide) was more effective than diflubenzuron, cyfluthrin and endosulfan in the control of the bunch moth. Few field trials on the use of B. thuiringiensis against nettle caterpillars have been reported to date. In all reported instances except one, it was found to be ineffective.

The performance of B. thuringiensis against bagworms is similar to that against nettle caterpillars: there has been no field success. Laboratory investigations with the bagworm, Metisa plana, revealed that of the eight products tested (Bactospeine, Thuricide, BCBT II, Florbac, Foray, Dipel, Biobit FC and CGA-BT-237218), only Florbac showed some potential in control, causing 80% mortality of the fourth instars after seven days. The mortality values with the other products, as well as with Florbac against second instars, were generally less than 60 per cent.

Investigations on concentration-mortality responses revealed that a high concentration would be required to effect a 75% kill, the level regarded as acceptable for biocontrol agents. Subsequently, various suggestions are made on how to overcome the lack of potency of B. thuringiensis against the larvae of M.plana.

Common/spear rot crown disease in oil palm (Elaeis guineensis Jacq.) : Anatomy of the affected tissue

Bent rachises in palms with symptoms of “crown disease” had fibres with thinner and less lignified cell walls than normal cells. Also, vascular bundles were less numerous, thinner, and had fewer fibres than healthy tissue. The first symptom observed before necrosis in leaflets was the collapse of the hypodermal cells. Fungal mycelium was found intercellularly in some preparations. The structural changes observed explain, in part, the softness of these tissues, which causes the bending of the rachises that characterizes the disease. Glyphosate applied to young palms caused anatomical changes similar to those observed in palms affected by crown disease.

A study of the nature of oil recovered from spent earth obtained from the physical refining of palm oil

The characteristics of oils extracted with solvents from spent earth used to bleach palm oil were investigated. It was found that the total oil extracted from spent earth by petroleum ether (SE-P) followed by chloroform (SE-C) accounts for 26.3% of the total weight of spent earth. The extracted oils were slightly brownish red and brownish respectively. The unsaponifiable matter in SE-P and SE-C amounted to 1.39% and 1.60% respectively. The FFA content of both extracts was high, about 22 per cent. However there was no significant difference in the fatty acid composition or carbon number between palm oil, SE-P and SE-C. The phosphorus contents of SE-P and SE-C were found to be 11.2 ppm and 10.1 ppm respectively, while the iron and copper present in SE-P were found to be at 2.1 ppm and 0.04 ppm respectively.

Studies on the use of fractions from palm oil and palm kernel oil as suppository base materials.

In vitro studies were made of fractions from palm oil and cocoa butter substitute derived from palm kernel oil as suppository base materials. The dissolution of Sulphatizol and salicylic acid from suppositories made with fractions from palm oil and palm kernel oil was investigated and compared with their dissolution from suppositories made of cocoa butter and Witepsol, the two commonly used base materials. It was observed that the dissolution rates of Sulphatizol and salicylic acid from cocoa butter substitute and from a mixture of non-lauric cocoa butter substitute and hydrogenated palm kernel oil were faster than that of the same drugs from cocoa butter and Witepsol. The dissolution rates were increased by the addition of 1% (w/w) Tween 80 to cocoa butter substitute. On storage, the dissolution rate of 1% Sulphatizol from cocoa butter substitute decreased, while that of salicylic acid remained constant.

Blood plasma and liver lipids of rats fed physically refined and re-refined palm oil

Physically-refined palm oil (PRPO) and palm oil after further chemical refining (chemically-refined palm oil, CRPO) were included in the diet of rats and the effects on plasma and liver lipids were studied and compared. No differences in body weight gain or organ weights were observed as between the rats fed the PRPO and the CRPO diets for two months. Differences in plasma total cholesterol, high-density lipoprotein cholesterol and phospholipid content as between the rats fed the PRPO diet and those fed the CRPO diet were not evident. Liver total cholesterol, phospholipid, phosphatidylcholine hydroperoxide, phosphatidylethanolamine hydroperoxide and α-tocopherol contents were also not significantly different as between the rats on the two diets. Liver and plasma triglyceride levels did differ between rats on the two palm oil diets, however. The results show that differences between the dietary effects of PRPO and CRPO on the tissue lipid profiles in the rats were relatively small.

Renewable energy from the palm oil industry

Palm oil mills produce crude palm oil and palm kernel or crude palm kernel oil as their main products. Considerable amounts of co-products, such as fibre (from the mesocarp), shell (from around the kernel), empty fruit bunehes and palm oil mill effluent are also generated by the milling process.

Fibre and shell are the main energy sources for the palm oil mills. In 1992, fibre and shell generated about 650 million kWh to meet the energy demand of 265 palm oil mills in the country. This amounted to 2%-3% of the national energy consumption.

Other co-products like empty ftuit bunches and biogas are very much under-utilized as energy resources. They have the potential of generating 1131 million kWh of electricity which is about 5% of the national energy demand.

Palm oil methyl esters and crude palm oil are being evaluated as diesel substitutes. The palm oil methyl ester mixture (palm diesel) is being run in unmodified diesel engines. So far it has passed all the tests as a diesel substitute in exhaustive field trials. Very positive results have been obtained in terms of engine wear and tear, and reduction in dark smoke, CO, CO2 and SO2 in the exhaust emission. Crude palm oil is run in modified diesel (Elsbett) engines. Its performance is being evaluated.

This paper discusses the potential energy available from the above-mentioned products and co-products from palm oil mills.