OxG Hybrids Research Articles

Ablation reduces androgyny and improves flowering and bunch production in palms of Coarí x La Mé hybrid (Elaeis oleifera x Elaeis guineensis)

The first inflorescence in OxG hybrids after transplant to the field is often androgynous and should be removed to stimulate the initial vegetative growth of palms. The objective of this study was to evaluate the effects of early inflorescence ablation on later inflorescence emission and normal bunch development. The experimental design was completely randomized with two treatments (with early ablation and without ablation), four replicates, and 16 palms per replicate. The emission of female, male, and androgynous inflorescences, the number of leaflets, leaf area and dry weight of leaf 17, number of normal bunches formed, and annual production were estimated. The emission of normal female inflorescences increased with total ablation, while androgynous inflorescences increased without ablation. Ablated palms increased their leaf area, leaf dry weight, and annual bunch production.

Evidence of sustainable intensification in the production of palm oil from crops planted with Elaeis oleifera x Elaeis guineensis in Colombia

Cultivars from crossings between Elaeis oleífera x Elaeis guineensis (OxG hybrids) have proven to have partial resistance to Bud Rot (BR), the most challenging disease for the Colombian palm oil agroindustry. Therefore, OxG hybrids were planted in areas that have experienced BR outbreaks since 2007. Soon, it was discovered that OxG hybrid female inflorescences required to be pollinated with pollen from E. guineensis to improve bunch formation. Researchers from Cenipalma noted that OxG hybrid bunches have a greater proportion of partenocarpic fruits. The latter generated a line of research that yielded artificial pollination in 2018. Artificial pollination consists of applying naphtaleneacetic acid (NAA) to female inflorescences in order to promote the formation of partenocarpic fruits. If artificial pollination was to be scaled up, many questions needed an answer such as, what was labor productivity, the stage at which bunches should be harvested and even, if it was profitable. This paper synthesizes the results of studies carried out by Cenipalma together with managers from oil palm plantations. These research studies were undertaken by means of time and motion studies, optimal harvesting time studies and cost–benefit analysis. Results come from plantations located at all the zones that have planted OxG cultivars that have planted the most common OxG hybrids. Our results indicate that an artificial pollination worker may be asked between 188 and 249 inflorescences per workday depending upon inflorescences density (inflorescences per hectare). We also found that by implementing criteria on optimal harvest time one may increase the oil extraction rate from 6 to 29.7%. Finally, it was found that artificial pollination is more costly than using only E. guineensis pollen, but the increase in yields at the field and the increase in the amount of oil extracted offset this extra cost and provide greater profitability to oil palm growers. This is a sample of how, by using the same natural resources, implementing artificial pollination, and harvesting at the proper stage; one can have greater yields and have a more resilient business. In other words, this is an example of sustainable intensification.

Nitrogen Use Efficiency in Oil Palm Seedlings: Unraveling the Untapped Potential of Elevated External Ammonium Supply.

Ammonium (NH4+) is an essential nitrogen source for plants, but excessive exposure can trigger stress responses that vary among and within different plant species. This study investigated the phenotypic variations in response to ammonium nutrition in five oil palm genotypes seedlings. Nitrate nutrition was used as a reference for a non-stressful condition, and three different nitrogen concentrations (5, 10, and 15 mM) were examined. Control groups without external nitrogen application were included for each genotype. Several parameters were analyzed, including plant growth, root length, gas exchange, fluorescence, chlorophyll, reducing sugars, amino acids, proteins, and nitrogen uptake. The results revealed a significant genotype effect, particularly between the interspecific OxG hybrid and the Elaeis guinensis genotypes. Ammonium nutrition increased shoot growth in all genotypes compared to nitrate nutrition. Additionally, there was a trend towards increased primary root length, amino acids, proteins, and nitrogen uptake under ammonium supply. These findings are promising, particularly considering the recommendation to use ammonium with inhibitors for environmental sustainability.

Light Interception, Photosynthetic Performance, and Yield of Oil Palm Interspecific OxG Hybrid (Elaeis oleifera (Kunth) Cortés x Elaeis guineensis Jacq.) under Three Planting Densities.

Environmental conditions are crucial for crops’ growth, development, and productivity. One of the most important physiological factors associated with the production of crops is the use of solar radiation for the photosynthesis process, which determines the amount of assimilates available for crop growth and yield. Three age classes (4, 6, and 14 years) and three planting densities (143, 128, and 115 palms ha−1) were evaluated in a commercial interspecific Elaeis Oleifera x Elaeis guineensis hybrid Coari x La Mé. The light interception patterns and the photosynthetic performance were determined. Measurements were taken of the leaf area, the number of leaves, and incident and photosynthetically transmitted active radiation. Also, photosynthetic rates, light, and yield were measured. The canopy extinction coefficient (Kc) was estimated using the Monsi and Saeki model. Under the evaluated conditions, the average Kc value for 4-year-old palms was 0.44; for the 6-year-old group of palms, the average value was 0.40, and 0.32 for the 14-year-old palms, with coefficients of determination (R2) greater than 0.8. A pattern associated with the age of the crop was observed, where the Kc decreased in groups of adult palms. The results showed increased Kc as the planting density decreased. No statistically significant differences were observed between planting densities or ages in the light and CO2 curves regarding photosynthesis. The leaf level in which the measurement was made influenced photosynthesis. Thus, the highest values of the photosynthesis parameters were observed in leaf 17. The crop yield tended to stabilize 8 years after planting under 143 and 128 palms per hectare, but 14 years after planting, the Fresh fruit bunch (FFB) production was still growing under 115 palms per hectare. The results showed that, up to year 14 after planting, the highest cumulative yield was achieved with 115 palms per hectare. This was partly caused by a sharp decline in production observed under 128 palms per hectare, which could indicate that in the long production cycle of the OxG hybrids, the 115-palms-per-hectare planting density would result in higher cumulative FFB production. Furthermore, the results showed that the optimum planting density for the hybrids of the present study would be 120 palms ha−1, corresponding to a planting distance of 9.8 m between plants.

Application of naphthalene acetic acid and gibberellic acid favours fruit induction and development in oil palm hybrid (Elaeis oleiferaxElaeis guineensis)

SummaryThe OxG hybrid bunches contain more parthenocarpic fruits (PF) than normal fruits (NF) and present problems of development and ripening due to either an asynchronous opening of flowers or insufficient pollination. The objective of this study was to compare the effect of α-naphthaleneacetic acid (NAA) and gibberellic acid (GA3) in the induction and development of PF and NF, the fatty acid profile (FAP), and the oil potential in the ‘Coari x La Mé’ oil palm hybrid. NAA and GA3induced parthenocarpy in the fruits and did not alter the FAP of the mesocarp oil. The commercial dose of pollen (0.9 g talc + 0.1 g pollen) resulted in increased bunch weight (BW) (20.8 kg) and lower percentage of PF in the bunch (65.4%). The most effective hormonal doses to induce the formation of PF in the bunch were NAA 300 and 600 mg L-1. GA3alone or in mixture with NAA increased the percentage of PF but did not increase the BW, indicating that GA3had no synergistic effect on BW. The NAA applications represent alternatives to complement assisted pollination of OxG hybrids to increase bunch production and oil yield.

High-Oleic Palm Oil (HOPO) Production from Parthenocarpic Fruits in Oil Palm Interspecific Hybrids Using Naphthalene Acetic Acid

Interspecific OxG hybrids of African palm Elaeis guineensis Jacq. and the American palm Elaeis oleifera Cortes produce high-oleic palm oil (HOPO) with low saturated fatty acid content. OxG hybrids are highly productive, grow slowly, and are resistant to bud rot disease. However, OxG hybrid pollen presents low viability and germinability, so assisted pollination is a must. Hybrids can produce parthenocarpic or seedless fruits, with the exogenous application of plant growth regulators. Thus, naphthalene acetic acid (NAA) effects on parthenocarpic fruits induction, bunch formation, and oil quality were evaluated. The OxG hybrid Coari x La Mé was used. NAA doses, frequency, number of applications, and the phenological stages for the treatments were defined. A total dose of 1200 mg L−1 NAA applied three or four times produced bunches with better fruit set, similar average bunch weight, and oil to dry mesocarp than those obtained with assisted pollination. At a semi-commercial scale, 1200 mg L−1 NAA induced bunches that consisted of 93% or more of seedless fruits. Bunch number (2208 ± 84 versus 1690 ± 129) and oil to bunch (32.2 ± 0.7 versus 25.3 ± 0.8) were higher in the NAA induced bunches than in the assisted pollination. However, the average bunch weight was lower (12.2 ± 0.4 versus 14.9 ± 0.6). NAA increased oil to bunch in 36% (8.7 ± 0.1 versus 6.4 ± 0.3). Thus, with this technology, it is plausible to reach more than 10 tons per hectare per year of HOPO. Potentially, without increasing the planted oil palm area, OxG hybrids and NAA applications could alone meet the world’s fats and oil demands.

Effect of the application of plant hormones on the formation of parthenocarpic fruits and oil production in oil palm interspecific hybrids (Elaeis oleifera Cortes x Elaeis guineensis Jacq.)

ABSTRACT Oil palm is the most important oil crop globally, accounting for almost 40% of fats and oil consumption worldwide. The OxG interspecific hybrid results from the crossing of African oil palm Elaeis guineensis Jacq. and the American oil palm Elaeis oleifera Cortes. It is a promising genotype for its high productivity, oil quality, and partial resistance to some diseases. These hybrids require assisted pollination, an activity that is time-consuming and expensive. Oil production in the OxG hybrids depends on the formation of normal (fertile) fruits and seedless (parthenocarpic) fruits. Thus, it is appealing to stimulate parthenocarpic fruits without assisted pollination. This research evaluated artificial methods of inducing parthenocarpy by applying plant hormones, and the effect on bunch formation and oil quality and its potential implementation at an industrial scale. The study was carried out in a 6-year-old hybrid (OxG) Coari x La Mé. The effects of the plant hormones indoleacetic acid (IAA), 2,4-dichlorophenoxyacetic acid (2,4-D), naphthalene acetic acid (NAA), and an ethylene precursor (ethephon) were evaluated. IAA and ethephon did not result in consistent bunch production of parthenocarpic fruits. The plants presented abnormal fruit growth, low-weight bunches, and high abortion rates. 2,4-D and NAA promoted proper parthenocarpic fruit development with oil-to-bunch (O/B) values similar to those obtained with assisted pollination. Thus, NAA and 2,4-D are an excellent alternative for oil production in the OxG hybrids that can be implemented in the African oil palm, with particular relevance that pollinators are endangered, and highly female genotypes are widely used.

Genome-wide association study (GWAS) for morphological and yield-related traits in an oil palm hybrid (Elaeis oleifera x Elaeis guineensis) population

BackgroundThe genus Elaeis has two species of economic importance for the oil palm agroindustry: Elaeis oleifera (O), native to the Americas, and Elaeis guineensis (G), native to Africa. This work provides to our knowledge, the first association mapping study in an interspecific OxG oil palm population, which shows tolerance to pests and diseases, high oil quality, and acceptable fruit bunch production.ResultsUsing genotyping-by-sequencing (GBS), we identified a total of 3776 single nucleotide polymorphisms (SNPs) that were used to perform a genome-wide association analysis (GWAS) in 378 OxG hybrid population for 10 agronomic traits. Twelve genomic regions (SNPs) were located near candidate genes implicated in multiple functional categories, such as tissue growth, cellular trafficking, and physiological processes.ConclusionsWe provide new insights on genomic regions that mapped on candidate genes involved in plant architecture and yield. These potential candidate genes need to be confirmed for future targeted functional analyses. Associated markers to the traits of interest may be valuable resources for the development of marker-assisted selection in oil palm breeding.

Physiological and agronomic behavior of commercial cultivars of oil palm (Elaeis guineensis) and OxG hybrids (Elaeis oleifera x Elaeis guineensis) at rainy and dry seasons

Oil palm is the most productive and efficient oilseed crop in the world. Oil palm is planted in various geographical areas, where the frequency of extreme weather events is expected to increase because of climate change. The characterization of the response of oil palm cultivars to climatic conditions will allow identifying sources of tolerance to different types of stress caused by climate change, leading to the determination of the best genotype x environment relationships. The physiological responses, oil quality and yield of 11, six-year-old commercial oil palm cultivars with different origins were evaluated in two periods of contrasting climate conditions (rainy and dry seasons between the years 2008 and 2010). We found that the first impact of a period with water deficit was the reduction on gas exchange of all cultivars. Photosynthesis fell between 25% to 40% and transpiration decreased between 10% and 50%. During the dry season, leaf sugar concentration increased respect to the rainy season between 14% to 114%, and certain cultivars showed up to 27% higher photosynthetic water use efficiency. This variation could be due to the genetics of different cultivars. No significant differences were observed between the seasons in terms of oil quality. In general, changes in oil palm physiology observed in response to water deficit were related to the ability of the palm to adapt and survive periods of drought stress. The cultivars evaluated showed a good response to dry periods, with the IRHO being the most outstanding at each evaluated season .

Response of in vitro obtained oil palm and interspecific OxG hybrids to inoculation with Phytophthora palmivora

AbstractBud rot (BR) disease caused by Phytophthora palmivora is the most devastating disease in oil palm cultivation in America. Oil palms that survived BR epidemics were found in areas highly devastated by the disease; these palms were introduced into Cenipalma's in vitro micropropagation (cloning programme). A severity scale was developed for in vitro palms from five ortets inoculated with two different P. palmivora isolates. Then, eight ortets of Elaeis guineensis and two ortets of the OxG interspecific hybrid were evaluated in two inoculation trials under chamber growth conditions. The clone performance response was consistent with that reported in the field for the corresponding ortets, and two contrasting ortets, one susceptible (ortet 57) and one resistant (ortet 34) were identified. We monitored and compared defence responses to P. palmivora in the contrasting ortets. An increase in reactive oxygen species (ROS) production after inoculation with the pathogen was observed, with higher accumulation of H2O2 in the resistant plants. Catalase (CAT) activity in resistant plants increased after inoculation with the pathogen from 24 hr post‐infection (hpi) and remained high during the observation time. In the susceptible ortets, there was a significant increase on catalase activity only at 48 hpi. Peroxidase (POS) activity increased in clones from both susceptible and resistant ortets, but the increase was much greater in the susceptible ones. Phenylalanine ammonia lyase activity increased in response to inoculation, and these increases were greater in clones of the susceptible ortet than in clones of the resistant ortet.

Physicochemical characterization of bunches from American oil palm (Elaeis oleifera H.B.K. Cortes) and their hybrids with African oil palm (Elaeis guineensis Jacq.)

El objetivo de este estudio fue realizar un análisis comparativo de las características físicas y químicas de racimos de genotipos de Elaeis oleifera y de sus híbridos interespecíficos OxG con Elaeis guineensis, determinando los componentes y el potencial del aceite del racimo, y la calidad de los aceites, analizando el contenido de ácidos grasos, vitamina E y carotenos. En el estudio se utilizaron racimos provenientes de inflorescencias sin polinización asistida con la presencia perimetral de E. guineensis. Se utilizó un diseño experimental completamente al azar con tres unidades experimentales, cada una conformada por tres racimos. Los mayores cuajados del fruto se encontraron en el genotipo de E. oleifera Sinú (76,53 %) y el híbrido OxG II (72,64 %). Los potenciales de extracción de aceite fueron superiores en los materiales híbridos OxG destacándose el II (20,82 %). Las palmas E. oleifera presentaron mejores perfiles de ácidos grasos, destacándose los materiales del genotipo Sinú (79,1 % de ácidos grasos insaturados) y los del híbrido II (70,2 %). Para el contenido de vitamina E se confirmó la alta calidad del aceite de los materiales de E. oleifera, sobresaliendo el genotipo Coarí (1.006,7 ppm) y el híbrido II (1.549,6 ppm); el material del genotipo Sinú registró el mayor contenido de carotenos totales (1.524,7 ppm).

Anin vitroinvestigation of MalaysianPhytophthora palmivoraisolates and pathogenicity study on oil palm

AbstractBud rot disease affecting oil palm in South American countries is reported to be caused byPhytophthora palmivora.P. palmivorais a local pathogen affecting various crops in Malaysia, and this finding caused an alarm, which prompted an investigation of pathogenicity using MalaysianP. palmivorato assess the potentials of this Oomycete to infect oil palm in Malaysia. A total of 11P. palmivoraisolates were obtained from cocoa and durian for the study. Leaf bioassays via artificial inoculation using 50,000 zoospores/ml and mycelial agar disc showed severe necrotic lesions on the infection spot of oil palm (DxP) spear leaves. Mild infection was observed in oil palm spear leaves of OxG hybrids indicating lower susceptibility againstP. palmivorainfection. Phylogenetic analysis using internal transcribed spacer (ITS) data revealed that Malaysian isolates were genetically similar to Colombian isolates supported by significant bootstrap values. The leaf bioassay results revealed that Malaysian oil palm materials are susceptible towards localP. palmivorainfection. The ColombianP. palmivoraisolates causing bud rot incidence may have evolved over a long period of time, undergone sequential genetic shift to become more virulent towards Colombian oil palm planting materials.

Description of four new species of Ochlerini from South America (Hemiptera: Pentatomidae: Discocephalinae).

The tribe Ochlerini Rolston was proposed in 1981 to house 23 genera of Neotropical pentatomids, most of them containing few species and poorly represented in entomological collections. After a quarter century of accumulated taxonomic knowledge the tribe totals 36 genera and 133 species, but a number of taxa still require revision or remain undescribed. Here we describe and illustrate four new species from South America, Cromata flavida sp. nov., Lincus curvatus sp. nov., Ocellatocoris longirostris sp. nov., and Xynocoris ecuadorensis sp. nov. The specimens of L. curvatus and X. ecuadorensis were collected on oil palms (OxG hybrids, Elaeis oleifera x Elaeis guineensis) affected by the lethal wilt (marchitez sorpresiva) disease.

Pollination in the oil palms Elaeis guineensis, E. oleifera and their hybrids (OxG), in tropical America

ABSTRACT Oil palm (Elaeis guineensis) is very important in the Central and South American economies. Plants suffer from a devastating fungal disease known as "lethal decay" or "pudrición del cogollo", in Spanish. Producer countries in Africa, Asia and tropical America have developed breeding programs that seek the tolerance of this disease by plants. The hybrids Elaeis guineensis x Elaeis oleifera (OxG) are resistant, but show physiological problems that affect commercial productivity. Natural pollination in these hybrids is low and manual pollination has high labor costs. The Coleoptera order is the most numerous and diverse natural pollinator, and the Elaeidobius genus has high efficiency and specificity to oil palm species. Elaeidobius kameronicus, Elaeidobius subvittatus and Mystrops costaricensis are the insects most commonly associated with oil palm inflorescences. Dynamics in insect populations change according to palm species and weather conditions. It is necessary to understand the insect behavior and population dynamics in OxG hybrids. Thus, recent studies on oil palm pollination, insect diversity and distribution in Latin America are discussed in this study.

Use of phenological stages of the fruits and physicochemical characteristics of the oil to determine the optimal harvest time of oil palm interspecific OxG hybrid fruits

Oil palm is the major source of vegetable oil in the world. Traditionally, African oil palm (Elaeis guineensis Jacq.) has been used for industrial production, however, in the last few years the interspecific hybrid OxG, a cross between the E. guineensis and the American oil palm Elaeis oleifera Cortes has emerged as a new alternative for oil palm production, mainly due to the high quality of the oil and the apparent resistance of the hybrid to some of the most problematic diseases. The last is especially true in Latin America where cultivation of oil palm is under pressure from various pests and diseases, particularly the bud rot and lethal wilt, which are a constraint to the sustainability of the crop. However, these interspecific hybrids have problems with fruit filling and ripening due to poor natural pollination and because the flower bud opening is asynchronous. Therefore, it is difficult to determine the optimal harvest time so as to ensure obtaining fruits with the greatest possible amount of oil and with the highest standards of quality. This research identified various physiological, physicochemical and quality parameters to establish the optimal harvest time for fruit bunches. To standardize the optimal harvest time, regardless of the region of cultivation or hybrid used, the different stages of oil palm fruit development were analyzed in accordance with the BBCH phenological scale. The results showed that the optimal harvest time for fruit bunches of OxG interspecific hybrid material (Coari×La Mé) corresponds to the phenological stage 807. The highest values of oil content (21.6%), the lowest free fatty acid values (<1%) and better concentration of phytonutrients were obtained at this stage.

Predicción y control de la cosecha en el híbrido interespecífico Elaeis oleifera x Elaeis guineensis en la zona palmera occidental de Colombia I. I. Determinación del periodo de madurez para obtener racimos con alto contenido de aceite.

El propósito de la investigación fue identificar el periodo de madurez del fruto con mayor acumulación de aceite en los racimos del híbrido OxG (Elaeis oleifera x Elaeis guineensis) Corpoica Elmira en la zona palmera de Tumaco, Colombia. El periodo con mayor acumulación de aceite en los racimos se obtuvo entre 170 y 180 días después de la polinización asistida; dentro de este rango es posible cosechar el mayor número de racimos en punto de madurez óptima. Las variables aceite en pulpa seca de frutos fértiles (AcPSFF), aceite en pulpa seca de frutos partenocárpicos (AcPSFP), aceite en pulpa fresca de frutos partenocárpicos (AcPFFP), aceite en racimo con base en frutos partenocárpicos (AcRFP) y aceite en racimo (AcR) son sensibles a los periodos de maduración.