The commercial oil palm (Elaeis guineensis Jacq.) produces a mesocarp oil (commonly called ‘palm oil’) with approximately equal proportions of saturated and unsaturated fatty acids (FAs). An increase in unsaturated FAs content or iodine value (IV) as a measure of the degree of unsaturation would help to open up new markets for the oil. One way to manipulate the fatty acid composition (FAC) in palm oil is through introgression of favourable alleles from the American oil palm, E. oleifera, which has a more unsaturated oil. In this study, a segregating E. oleifera x E. guineensis (OxG) hybrid population for FAC is used to identify quantitative trait loci (QTLs) linked to IV and various FAs. QTL analysis revealed 10 major and two putative QTLs for IV and six FAs, C14:0, C16:0, C16:1, C18:0, C18:1 and C18:2 distributed across six linkage groups (LGs), OT1, T2, T3, OT4, OT6 and T9. The major QTLs for IV and C16:0 on LGOT1 explained 60.0 – 69.0 % of the phenotypic trait variation and were validated in two independent BC2 populations. The genomic interval contains several key structural genes in the FA and oil biosynthesis pathways such as PATE/FATB, HIBCH, BASS2, LACS4 and DGAT1 and also a relevant transcription factor (TF), WRI1. The literature suggests that some of these genes can exhibit pleiotropic effects in the regulatory networks of these traits. Using the whole genome sequence data, markers tightly linked to the candidate genes were also developed. Clustering trait values according to the allelic forms of these candidate markers revealed significant differences in the IV and FAs of the palms in the mapping and validation crosses. The candidate gene approach described and exploited here is useful to identify the potential causal genes linked to FAC and can be adopted for marker-assisted selection (MAS) in oil palm.

This research was conducted to study the performance of biparental dura × pisifera (D × P) progenies and their parental genetic origins on fruit set and yield components. Twenty-four D × P progenies developed from 10 genetic origins were used for this study. Analysis of variance showed that there was genetic variability based on the evaluation of individual progenies. Deli Ulu Remis × Nigeria of progeny ECPHP500 recorded the highest bunch number (22.91), and fresh fruit bunch (184.62 kg palm⁻¹ year⁻¹) and Deli Banting dura × AVROS pisifera (ECPHP550) had the highest average bunch weight (10.36 kg bunch⁻¹ year⁻¹). Progenies PK4674 (61.12%) and PK4465 (60.93%) had the highest fruit set, and the highest oil yield of 52.66 kg bunch⁻¹ was noticed by progeny PK4674. Estimation of variance components, coefficients of variation, heritability, and genetic gain were calculated to establish the genetic variability. To validate the genetic disparity among the progenies, an unweighted pair-group procedure with arithmetic mean (UPGMA) and principal component was employed based on their quantitative traits. Through the UPGMA and principal component, the 24 progenies were clustered into 7 clusters, whereas cluster V had the highest fruit set (60.62%) and cluster IV had the highest oil yield (43.71 kg palm⁻¹ year⁻¹). For oil palm tissue culture and breeding programs, progeny PK4674 will be more useful for developing planting materials of high oil yielding with stable performance. However, we recommend that future studies incorporate molecular studies with conventional breeding.

This study was conducted to assess the Elaeidobius kamerunicus (EK) population density among the biparental dura × pisifera hybrids’ palms on deep peat-soil. Twenty-four hybrids derived from 10 genetic sources were used. Variance analysis showed that the EK population density varies between different oil palm hybrids, with a more noticeable variation of a low population mean in the male weevil across the hybrids. The highest weevil population mean/spikelet was attained on the third day of anthesis. The maximum monthly population of EK/spikelet (12.81 ± 0.23) and population density of EK (1846.49 ± 60.69) were recorded in January. Accordingly, 41.67% of the hybrids recorded an EK population density greater than the trial means of 973.68 weevils. Hybrid ECPHP550 had the highest mean of EK/spikelet (10.25 ± 0.11) and the highest population density of EK/palm (1241.39 ± 73.74). The parental mean population was 963.24 weevils and parent Deli-Banting × AVROS recorded the highest EK population density (1173.01). The overall results showed a notable disparity in the EK population among the biparental hybrids. Parental Deli-Banting × AVROS and hybrid ECPHP550 could be more useful to optimize the weevil population for pollination improvements in palm plantations. However, we suggest that volatile production should be included as a desirable trait in oil palm selective breeding.

This study investigated oil palm inflorescence sex ratio (ISR) and fruit set (FS) yield among 24 dura × pisifera biparental progenies on fibric peat soil, hybridized from ten genetic origins. Three-month intervals of data collection on ISR and “S-shape” procedure for FS determination were carried out in an independent complete randomized design for one year. Based on the assessment of individual progenies, analysis of variance revealed the existence of genetic heterogeneity. Five of the progenies had the highest ISR above 90%. However, 20.83% of the progenies (PK4841, PK4674, ECPHP415, ECPHP550, and PK4118) had the best normal range of ISR, indicating FS declined being influenced by ISR. Therefore, only 12.50% of the progenies (PK4674, PK4465, and PK4482) were above 60% FS critical level. Correlation analysis verified that ISR depends on the female flower and progeny PK4674 (65.78%) and PK4465 (62.62%) had the best FS and fruit to bunch. Among the parental origins, Deli Serdang × Cameroon was statistically the best for male flower production at 29.40% and ISR at 72.22%. The highest FS was recorded in Deli Banting × AVROS (54.00%) and Angola × AVROS (53.78%). However, molecular research, such as microsatellite molecular markers if concurrently used as a selection criterion with the present conventional study, could present further details to complement the present findings.

One of the most important and widely known plantation crops with high revenue returns is the Elaeis guineensis palm. To date, yield variability in fresh fruit bunches (YFFB) in Malaysian oil palm plantations is one of the key influences in low palm oil yield. Accordingly, an assessment of dura×pisifera progenies and their genetic origins on oil palm yield was investigated. Twenty-four derived progenies from 10 genetic sources were adopted as F1 hybrid-single generation and the standard approach for data collection of the yield and yield traits was followed for three sequential years. Variance analysis showed genetic differences between the progenies and their origins. Amid the progenies analyzed, 45.83% had YFFB above the trial mean. Progeny HPDP500 had the highest YFFB (191.74 kg/palm/year) and the highest bunch number (YBNO) was recorded in PKDP4474 (20.65 bunches/palm/year), and HPDP500 (20.53 bunches/palm/year). In year one and year three, the highest YFFB was reported, while in year one of data collection, the highest YBNO was recorded. Dura-Ulu Remis × Yangambi had the highest YFFB (175.81 kg/palm/year) and Tanzania × Nigeria recorded the highest YBNO (19.06 bunches/palm/year). High heritability and phenotypic coefficient of variation with a moderate genotypic coefficient of variation for all the traits were further revealed. YFFB had a moderate positive YBNO relationship (r = 0.676; df =3, 23; p = 0.0001) and a weak positive average bunch weight correlation (r = 0.378; df = 3, 23; p = 0.0001). For tissue culture and hybridization programs for yield enhancement, progenies and origins with better performance may be used; however, the use of molecular research as a selection criterion seems to be worth further analysis.