Water scarcity is a significant constraint on agricultural practices, particularly in Colombia, where numerous palm cultivators rely on rainfed systems for their plantations. Identifying drought-tolerant cultivars becomes pivotal to mitigating the detrimental impacts of water stress on growth and productivity. This study scrutinizes the variability in drought responses of growth, physiological, and biochemical variables integral to selecting drought-tolerant oil palm cultivars in the nursery. A comprehensive dataset was compiled by subjecting seedlings of eleven cultivars to four soil water potentials (−0.05 MPa, −0.5 MPa, −1 MPa, and −2 MPa) over 60 days. This dataset encompasses growth attributes, photosynthetic parameters like maximum quantum yield and electron transfer rate, gas exchange (photosynthesis, transpiration, and water use efficiency), levels of osmolytes (proline and sugars), abscisic acid (ABA) content, as well as antioxidant-related enzymes, including peroxidase, catalase, ascorbate peroxidase, glutathione reductase, and superoxide dismutase. Principal Component Analysis (PCA) elucidated two principal components that account for approximately 65% of the cumulative variance. Noteworthy enzyme activity was detected for glutathione reductase and ascorbate peroxidase. When juxtaposed with the other evaluated cultivars, one of the cultivars (IRHO 7001) exhibited the most robust response to water deficit. The six characteristics evaluated (photosynthesis, predawn water potential, proline, transpiration, catalase activity, sugars) were determined to be the most discriminant when selecting palm oil cultivars with tolerance to water deficit.

Oil palm (Elaeis guineensis Jacq.) is a highly productive crop economically significant for food, cosmetics, and biofuels. Abiotic stresses such as low water availability, salt accumulation, and high temperatures severely impact oil palm growth, physiology, and yield by restricting water flux among soil, plants, and the environment. While drought stress’s physiological and biochemical effects on oil palm have been extensively studied, the molecular mechanisms underlying drought stress tolerance remain unclear. Under water deficit conditions, this study investigates two commercial E. guineensis cultivars, IRHO 7001 and IRHO 2501. Water deficit adversely affected the physiology of both cultivars, with IRHO 2501 being more severely impacted. After several days of water deficit, there was a 40% reduction in photosynthetic rate (A) for IRHO 7001 and a 58% decrease in IRHO 2501. Further into the drought conditions, there was a 75% reduction in A for IRHO 7001 and a 91% drop in IRHO 2501. Both cultivars reacted to the drought stress conditions by closing stomata and reducing the transpiration rate. Despite these differences, no significant variations were observed between the cultivars in stomatal conductance, transpiration, or instantaneous leaf-level water use efficiency. This indicates that IRHO 7001 is more tolerant to drought stress than IRHO 2501. A differential gene expression and network analysis was conducted to elucidate the differential responses of the cultivars. The DESeq2 algorithm identified 502 differentially expressed genes (DEGs). The gene coexpression network for IRHO 7001 comprised 274 DEGs and 46 predicted HUB genes, whereas IRHO 2501’s network included 249 DEGs and 3 HUB genes. RT-qPCR validation of 15 DEGs confirmed the RNA-Seq data. The transcriptomic profiles and gene coexpression network analysis revealed a set of DEGs and HUB genes associated with regulatory and transcriptional functions. Notably, the zinc finger protein ZAT11 and linoleate 13S-lipoxygenase 2-1 (LOX2.1) were overexpressed in IRHO 2501 but under-expressed in IRHO 7001. Additionally, phytohormone crosstalk was identified as a central component in the response and adaptation of oil palm to drought stress.

En los siguientes apartes se presentan aspectos generales sobre la ecofisiología de palmas híbrido OxG (Elaeis oleifera x Elaeis guineensis) y de Elaeis oleifera. Estos resultados son una aproximación que permite mostrar la respuesta diferencial de genotipos a las condiciones climáticas existentes y a su vez deja ver que se hace necesario continuar la investigación en la ecofisiología del híbrido OxG y de la palma americana.

Los modelos de cultivo basados en procesos, como PALMSIM, constituyen herramientas valiosas para estimar los rendimientos potenciales de la palma de aceite, pero su aplicación directa en diversas regiones genera discrepancias significativas. En Colombia, se calibraron múltiples componentes de PALMSIM en nueve cruzamientos genéticos con diferentes antecedentes genéticos. A partir de datos del observatorio de cultivares comerciales establecido en el Campo Experimental Palmar de la Vizcaína (Barrancabermeja, Colombia), que proporcionó observaciones a largo plazo bajo condiciones óptimas de manejo, se calibraron cuatro mecanismos fisiológicos del modelo: respuesta fotosintética, peso potencial de racimo, tasa de emisión foliar y número potencial de racimos. La calibración de la respuesta fotosintética reveló diferencias fundamentales entre palmas colombianas y del sudeste asiático. En particular, las palmas colombianas presentaron una tasa fotosintética máxima 16 % menor que la de las palmas del sudeste asiático (410 frente a 490 μg CH2O m-²s-¹) y requirieron casi el doble de radiación para alcanzar la saturación. La calibración por cruzamiento de las funciones de peso potencial del racimo mostró valores máximos asintóticos entre 20,7 y 38,5 kg, sustancialmente inferiores a las predicciones del modelo original. Las tasas de emisión foliar variaron entre 21,8 y 24,8 hojas palma−1 año−1, mientras que los parámetros del número potencial de racimos mostraron patrones reproductivos distintivos entre los cruzamientos. El modelo completamente calibrado redujo los errores de predicción en aproximadamente un 60 % respecto a la versión original.