Category Archives: InPress

DEVELOPMENT OF NEW OIL PALM CULTIVARS IN MALAYSIA

At the beginning of the oil palm industry at the turn of the 20th century, commercial plantations utilised the thick-shell thin-mesocarp dura planting materials. The breeds were unconsciously and informally selected from the ‘best-looking’ palms and fruits in the African palm groves or in subsequent decorative avenues elsewhere. Discovery of the single gene inheritance for shell thickness led to the use of the thinner- shell thicker oil-bearing mesocarp dura x pisifera (DxP) cultivated variety (cultivar). However, oil palm breeding populations had been derived from few ancestral palms, which hindered selection progress. The basic population of the maternal line in breeding programmes is almost exclusively the Deli dura. Improvements of tenera/pisifera paternal lines were mainly the AVROS, La Me and Yangambi populations. Malaysian oil palm breeders widely practiced the modified recurrent selection (MRS) in improvement programmes. Subsequent parental inbred lines developed in recurrent selections, crossed and progeny tested exploiting heterosis had boosted bunch and oil yields. The MRS allows incorporation of new genes into the parental lines; and coupled with the need to widen the genetic pool, wild Elaeis guineensis and E. oleifera germplasms were prospected in centres of origin and diversity in Africa and Latin America, respectively. Besides breeding for bunch and oil yields, secondary traits such as dwarfism, oil quality and phytonutrient contents are incorporated in developing PS series new varieties for niche purposes. A notable cultivar is PS1 characterised by short palm height. It takes more than 20 years from collection in the wild to the release of new cultivar. To speed up selection and release of cultivar, the preliminarily selected breeding materials are shared among local industry breeders for further breeding and improvements. In addition to quantitative genetics, further strides in cultivar development are supported by tissue culture, biotechnology and genomics. New varieties are registered based on the Test Guidelines for new, distinct, uniform and stable (DUS) of the International Union for the Protection of New Varieties of Plants (UPOV). Commercial production and sale of oil palm planting materials in Malaysia are regulated by law. Oil palm seed producers must be a registered company, financially sound and has a competent breeder. Seeds and seedlings for commercial sale must fulfill the requirements of Malaysian Standard MS157 (seeds) or MS2099 (clones) and subscribe to relevant certification schemes. Companies must obtain the license to produce, store, shipping and handling of the planting materials. Field performance of commercial oil palm planting materials are regularly evaluated in comparative trials.

ANALYSIS OF MULTISPECTRAL IMAGERY FROM UNMANNED AERIAL VEHICLE (UAV) USING OBJECT-BASED IMAGE ANALYSIS FOR DETECTION OF Ganoderma DISEASE IN OIL PALM

Ganoderma disease that affects oil palms has caused huge losses to the palm oil industry in Malaysia. To curb widespread infection and mitigate further losses, attempts have been made to detect infected oil palms automatically so that they can be treated or destroyed. The multispectral remote sensing technology can be employed to this effect efficiently. From the aerial images, infected oil palms can be detected and classified according to the Ganoderma Disease Severity Index (GDSI). In this study, object-based image analysis (OBIA) was performed to classify oil palms in a selected area into three classes namely; healthy (T0), moderately infected (T2) and severely infected (T3). It would be desirable if lightly infected oil palms could also be categorised as a class. However, it was extremely difficult to discriminate lightly infected oil palms from the healthy ones just by analysing the aerial images since symptoms of early infection were not evident in the fronds yet. Images of each individual band as well as those obtained by combining two, three or four bands of the available spectra were analysed. The OBIA was conducted using example-based feature extraction procedure and various OBIA settings were tested to achieve a number of classification results. The accuracies of the results are quantified by comparing the results with the ground truth data. The results suggest that the combination of Edge-based segmentation and merge algorithm using Full-Lambda Schedule (FLS), Support Vector Machine (SVM) classifier and three-band data of (G_R_NIR) scores the highest accuracy of (91.8%). When data of individual bands were tested using the same algorithm and classifier, they obtained moderate accuracies ranging from 65.5%-76.2%. However, when data of two, three and four bands were combined, better results with classification accuracies from 70%-90% were recorded. These results show that the OBIA can be used to analyse multispectral images of oil palms to detect moderate and severe infection of Ganoderma disease. Detection of early infection of Ganoderma is feasible if more advanced algorithms and classifiers can be used with multispectral and hyperspectral aerial images.

TRANSCRIPTOMICS OF MICRODISSECTED STAMINODES AND EARLY DEVELOPING CARPELS FROM FEMALE INFLORESCENCES OF Elaeis guineensis

In an abnormal female inflorescence from a mantled clonal palm, the male reproductive organs develop into pseudocarpels. Transcriptomes of microdissected male and female reproductive organs in a normal inflorescence were thus compared to identify genes that were differentially expressed during the normal development of these two reproductive organs. Besides the increased expression of stamen identity MADS- box genes EgDEF1, EgGLO1 and EgGLO2 in male reproductive organs, NAC and homeodomain leucine- zipper type of transcription factors were also upregulated. Male reproductive organ development may be associated with increased ethylene and decreased bioactive gibberellin levels inferred from the increased expression levels of ACC OXIDASE and GA 2-OXIDASE genes. This expression pattern may be important for the impending developmental arrest of the staminodes as they do not develop into stamens. Early carpel development occurred in conjunction with increased expression of the floral meristem identity LEAFY and organ boundary specification CUP-SHAPED COTYLEDON 2 (CUC2) genes. Hence, genes important for male reproductive organ development and early carpel development were identified using precise isolation of specific reproductive organs.

INDICATION OF OIL PALM (Elaeis guineensis Jacq.) RESISTANCE TO Curvularia LEAF SPOT DISEASE BY PR-PROTEINS PRODUCING ABILITY

Curvularia leaf spot disease of oil palm seedlings caused by Curvularia oryzae is an important disease and widespread in South-east Asia. In this study, the resistance of oil palm C. oryzae was indicated after treatment with 106 spores ml-1 of C. oryzae NK1. The PR-proteins (chitinase and β-1,3-glucanase) were detected within 24 hr. From the inoculated oil palm seedlings, lines 129 and 187 were indicated as susceptible and resistant lines, respectively based on activities of the pathogenesis-related (PR)-proteins. The chitinase and β-1,3-glucanase activities of line 187 were 14.03 ± 0.87 and 13.51 ± 1.04 U ml-1, while the respective activities of line 129 were much lower at 3.76 ± 0.41 and 4.31 ± 0.83 U ml-1 and not significantly different from control plant. The sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) analysis showed accumulation of 22, 25 and 33 kDa in inoculated line 187, whereas protein bands of line 129 were not visible. The disease symptoms in the susceptible line appeared approximately on 10% of the leaf area after 72 hr of fungal inoculation while no leaf spot symptoms were visible in the resistant line. Thus, the resistance of oil palm against Curvularia leaf spot disease was successfully indicated based on PR-protein producing ability, prior to testing with inoculation.

TRANSCRIPTOME ANALYSIS ACROSS VARIOUS MESOCARP DEVELOPMENTAL STAGES OF MPOB-ANGOLA Dura

Angolan germplasm materials are being evaluated for their potential use in oil palm breeding programmes. Large fruits characteristic of some Angola dura palms have provided breeders with a source of favourable traits for introgression into the current planting materials. With the aim of understanding molecular regulation during mesocarp development, maturation and ripening of Angola dura palms, efforts were initiated to profile the expression of transcripts across nine different developmental stages of mesocarp tissues. A 36 675 total gene set was identified from ribonucleic acid (RNA)-Sequencing with 24 226 transcripts successfully annotated with the Plant Reference Sequence (RefSeq) Database using BLASTX, while 12 449 transcripts had no hit to any known genes. Pairwise T-test was performed using TIGR Multiexperiment Viewer and a total of 21 261 transcripts were identified as significant across all the pairwise comparisons. BLAST2GO analysis resulted in the annotation of 13 996 unigenes with various gene ontology (GO) terms. Transcripts associated with lipid metabolic process were highly expressed during lag phase preceding the lipid biosynthesis [10 to 12 weeks after anthesis (WAA)] and fruit maturation (18 to 20 WAA) stages. Further annotation of the unigenes with Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway resulted in the identification of 279, 757 and 142 transcripts related to lipid metabolism, carbohydrate metabolism and hormone metabolism, respectively. Detailed analysis of the expression data revealed that certain transcripts such as KAS I, FATA, DGAT, WRI1 and bZIP showed unique expression profiles in the MPOB-Angola dura as compared to the published data. The availability of these transcriptome datasets gives an insight into the transcriptional mechanisms controlling the Angolan dura fruit development, maturation and ripening.