Category Archives: 1999 Vol 11 No 2

Agronomic performance and genetic variability of Dura x Pisifera progenies

Wide variations for bunch yields, bunch quality components and morphophysiological traits were noted among 52 dura x pisifera (DxP) progenies derived from a North Carolina Model I mating design. Exceptional fresh fruit bunch yields were achieved by progenies producing high bunch number of moderate sized bunches. Progenies producing bunches of high fruit (F/B), mesocarp (M/B) and kernel (K/B) contents achieved out-standing production of total economic products (TEP). Tall progenies, on average, had higher TEP attributed to the higher ratio of bunch dry matter to vegetative dry matter. Correlations among the economically important component traits were generally meaningful  and any significant change in yield involved an increase in the number of bunches. Analysis of variance for yield and bunch quality components showed substantial genetic variation with several traits showing male effects, indicating additive gene action. The results suggested  that palm height is inherited through the male parent. However, further introgression of the pisifera parent is required to improve the economic yield of its shorter progenies. Estimates of genetical variance components of data pooled over replications were higher than those of the individual replications, with the highest estimates from data pooled over years. Pooling of data reduced the error variances, suggesting seasonal effects and, therefore, more years of data are necessary for efficient selection programmes. The Serdang pisiferas, 20A/112 and 20A/8, introgressed with AVROS pisifera generated DxP progenies with high kernel yield, while those arising from AVROS x S27B pisiferas produced high oil yields. The mean performance and genetic structure of the materials suggested that the potential parental genotypes for high overall oil yields are the duras of Ulu Remis, Banting, intracrosses of the Elmina, and the pisiferas of Lever Cameroon, Lever Nigeria and introgressed Serdang x AVROS.

Impact of Metarhizium anisopliae (Deuteromycotina:Hyphomycetes) applied by wet and dry inoculum on oil palm rhinoceros beetles, Oryctes rhinoceros (Coleoptera:Scarabaeidae)

Four local isolates of Metarhizium anisopliae (Bp, Mo, Ma and Ml) were bioassayed against larvae of Oryctes rhinoceros in the laboratory. The larvae were surface-sterilized in 0.3% sodium hypochlorite and dipped into spore suspensions containing 108 conidia ml-1. Of the four isolates, two long-spored isolates (Bp and Mo) were highly pathogenic against the beetles. Both isolates caused 100% mortality within 12 days of treatment and caused 71% to 75% mycosis. The times required to kill 50% (LT50) of Oryctes larvae for isolates Bp (LT50 = 9.1 days) and Mo (LT50 = 8.9 days) were shorter than short-spored isolates Ma (LT50) = 10.0 days) and Ml (LT50 = 14.0 days). The mortality rates (regression slopes) showed that isolate Bp (5.32) killed Oryctes larvae slightly faster than isolate Mo (5.17); therefore, isolate Bp was selected for a field experiment.

A field trial was conducted in seven-month-old heaps of chipped oil palm trunks, using a single application of wet and dry inoculum. Using wet inoculum, each plot was drenched separately with 10 litres plot-1 of water containing 108, 109 and 1010 conidia. For dry inoculum, the plots were broadcasted with inoculated maize at 3 and 6 kg plot-1. In the field, Metarhizium infects adults, pupae and all larval stages of Oryctes beetles. At three months after treatment, pooled mortality for all stages of Oryctes beetles at the highest application rate was between 37% (dry inoculum) and 51% (wet inoculum). A great impact of Metarhizium was found only on third instar larvae, where it was able to reduce the number to about 5.5-5.8 larvae / sampling plot. This was significantly lower than the control which had 34.8 larvae / sampling plot.

The densities of viable spores in plots treated with wet inoculum at 1010 conidia (158.6 cfu) and dry at 6 kg (169.0 cfu) inoculum were significantly higher than the other application rates, especially at 3-month of treatment. A higher density of viable spores in breeding materials enhanced the disease development and subsequently reduced the beetle population. Wet inoculum had more advantages over dry inoculum had more advantages over dry inoculum. It was easily prepared using water from readily available sources such as field drains, river and extin mining pools. This study showed that wet inoculum was effective for control of Oryctes beetle and was more economical to apply than dry inoculum.

Effect of glucose concentration on the formation of terminal inflorescences and rigid shoots in oil palm cultures

Oil palm cultures respond to external factors such as high osmoticum. It was observed that a high concentration of glucose (0.55 M to 0.82 M or 10% to 15% w / v) induced terminal inflorescences (TI) and rigidity in vitro shoots. The occurrence of TI  and rigid shoots varied from clone to clone. TI and rigid shoots also differed in their morphology within the same flask . This indicated that cultures responded differently in their development to glucose treatment. Thus, sensitivity of the cultures to high concentrations of glucose has potential to be used as a  technique for in vitro indexing of the stability of oil palm clonal materials.

Interactions between Malaysian and Indonesian palm oil industries : Stimulating the impact of liberalization of imports of CPO from Indonesia

The presence of excess refining capacity in the refining sub-sector of the Malaysian palm oil industry is one of the challenges facing the industry. Market driven adjustments within the refining sub-sector that have taken place in the last few years (e.g. cessation of refining operations) have incurred significant costs to the industry. These costs would have been avoided if greater supply of crude palm oil (CPO) were made available either through increase in domestic production or imports. However, expansion of domestic production of CPO has been constrained by land and labour shortage. This paper investigates the impact on the industry from the liberalization of imports of CPO from Indonesia. A structural econometric model of the Malaysian palm oil industry will be used to simulate the effect of import liberalization. It is argued that import liberalization not only improves capacity utilization within the refining sub-sector, but also that the higher supply of CPO would help sustain the development of domestic downstream activities in the long run. As palm oil has been identified by the Industrial Master Plan (1985) as one of the resource-based industries to be developed, the simulation results would be useful to palm oil producers, policy makers and investors. However, import liberalization would require a more liberal trading stance to be adopted by both countries. As such, collaborative efforts would be beneficial to both sides given the fact that the market for fats and oils is a growing market.

Method for the determination of paraquat residue in oil matrix

Two experiments were carried out using the method developed by Imperial Chemical Industry (ICI) to determine paraquat residue in grains and crops. The aim of these experiments was to evaluate the feasibility of the method in determining paraquat residue in palm oil and palm oil products. Paraquat free RBD palm olein was used in the study. The method involved three steps: extraction of residue from the oil, clean up procedure using two types of equivalent resin, Duolite and Amberlite, spectrophotometric determintion of the purified material. In Experiment I, in which the resin Duolite was used, the percentage recoveries were adequate ranging from 50%-83%. The percentage recoveries increased with increasing concentration of paraquat. The  estimated limit of detection based on recovery data of this experiment was 0.01 μg g-1. In experiment II, using Amberlite, the percentage recoveries were greater than 90% for both the 0.05 μg ml-1 and 0.50 μg ml-1 level of concentration. Results from the two experiments showed that the ICI method can be applied for determination of paraquat residue in palm oil and palm oil products, and that the method with the use of Amberlite resin in the clean up step can give better recoveries of the analyte.

Quantification of oil palm biomass and nutrient value in a mature plantation. II. Below-ground biomass

The below-ground biomass of oil palm in a mature plantation was sampled and its nutrient contents and values estimated. Root biomass in this study was quantified by using core sampling and excavation method. The estimated root biomass amounted to about 16 t ha-1 and the below-ground portions of trunk contributed little to the nutrient content of the stand. The total nutrient stocks from root biomass projected on per hectare basis were 65 kg N, 8 kg P, 128 kg K, 15 kg Mg and 12 kg Ca, in terms of monetary value worth about RM 278 ha-1. The results show that oil palm roots provide significant amounts of nutrient which can be recycled in the plantation ecosystem at replanting.

Mineralization of soil organic carbon and nitrogen in relation to residue management following replanting of an oil palm plantation

During oil palm replanting, substantial amounts of the above-ground oil palm residues were available which contributed about 577 kg N ha-1 and 40 t C ha-1 and the root materials produced about 65 kg N ha-1 and 8 t C ha-1. These materials were the main sources of C and N which would affect the mineralization of C and N in the soil. In this study, the potential mineralizable of N, the mineralization of organic C through soil respiration and CO2evolution with different residues management practices were estimated.

The results of C mineralization study showed that the carbon fluxes due to crop residues inputs contributed about 7.7 t CO2 ha-1 yr-1 which was mineralized from the soil. However, the mineralization rate of C from the light fraction organic matter which accumulated on the top soil surface was found to be about 20 times higher than that in the soil under the organic layer. The CO2  fluxes might largely reflect microbial activity from different residue treatments.

Nitrogen mineralization due to the inputs of crop residues could significantly increase the availability  of N to the young palms of which about 421 kg N ha-1 yr-1 were mineralized from the mineral soil and made available to the palms. In contrast, the N mineralization from the plot without crop residue inputs only contributed about 312 kg N ha-1 yr-1  which probably came from decomposed roots of the previous crop. Thus, the fluxes of about 109 kg N ha-1 yr-1  was transferred to the soil as a consequence of leaving crop residue about the ground during replanting of the plantation. A large amount of N was in the labile pool of the light fraction organic matter which accumulated on the top soil surface and which, when mineralized, was six to seven times higher than that in the soil under the organic layer.

Determination of chlorpyrifos in refined palm olein by GC-FPD and GC-ECD

Chlorpyrifos (a pesticide containing phosphorous and chlorine) from oil matrix was determined using gas chromatography (GC) with a flame photometric (FPD) and electron capture (ECD) detectors. In the first experiment, the detector (FPD) used gave recoveries (from palm olein samples spiked with chlorpyrifos at levels of 0.04-0.10 μg ml-1) ranging from 89% to 100% with coefficients of variation from 2.9% to 10.8%. In the second experiment, ECD showed recoveries (from palm olein spiked with chlorpyrifos at levels 0.02-0.10  μg ml-1) of greater than 97% with coefficients of variations ranging from 0.5% to 2%. The results showed that using GC, the ECD and FPD are suitable detectors for quantification of chlorpyrifos in oil matrix.

The oil palm trunk as a carbohydrate reserve

Samples of oil palm trunk tissues were analysed for their contents of soluble sugar (SS), starch and acid-hydrolysable polysaccharides (PS). Starch was found in high concentrations only in samples taken near to the trunk apex of young palms, while SS and PS were present in appreciable amounts throughout the trunk.

The total amounts of carbohydrates present in the trunk of an eight-year-old palm were calculated as being sufficient to sustain the production of up to 38 kg of FFB.

Chromatographic and enzymatic analysis of the carbohydrates showed that sucrose was the main form of SS, followed in descending order by glucose and fructose. Acid hydrolysis of the polysaccharide fraction released mainly glucose together with appreciable proportions of a material with the chromatographic properties of xylose, together with some fructose.

Three trials were conducted to monitor variation in trunk carbohydrates in relation to bunch load, genotype and time of year. In the first trial, trunk carbohydrates levels were  compared in selected low and high yielding tenera palms. High yielding palms had higher SS levels, lower PS levels and a higher proportion of carbohydrate in the form of SS (%S) than low yielding ones. In the second trial, trunk carbohydrate were measured in 20 mature commercial teneras over a period of more than two years. Mean PS levels were again negatively correlated with bunch yield while %S was positively correlated with yield. The third trial made use of infertile pisiferas, and tenera sibling  progenies from the breeding population. Tenera palms had lower PS levels and more of the trunk carbohydrates present in the form of SS than did pisiferas. Infertile pisiferas had higher PS levels and a lower proportion of SS than did fertile pisiferas.

The results are discussed in relation to the possible role of trunk carbohydrates as a source of assimilates during periods of peak bunch production.

Reaction force and energy requirement for cutting oil palm fronds by spring powered sickle cutter

A Study was conducted to investigate the effect of  cutting angle and from maturity  on the specific reaction force (ROCSA) and energy requirement (RENCSA) for cutting oil palm fronds. A spring powered sickle cutter was used in the experiment. The experiment conducted was to determine the magnitude of reaction force that would be transferred to the harvester in the cutting operation. Cutting angles of 90º, 60º, and 45º were tested on the three levels of frond maturity (F1, F2 and F3).

Experiment carried out showed significant effects of cutting angle on the ROCSA and RENCSA but not by frond maturity. Increasing the cutting angle from 45º to 90º  increased the ROCSA to  about 72%. The maximum and minimum values of ROCSA were 24.5 N cm-2   and 10.8 N cm-2  respectively.

The ratio of reaction force to the maximum cutting force (R/Fcmax) was also studied. The ratio gives the percentage of cutting force being transferred to the harvester during the cutting process. It was found that R/Fcmax was significantly affected by the cutting angle and frond maturity. The maximum and minimum ratios were 35% and 14% at cutting angles of  70º and 45º  for cutting F3 a d F1, respectively.