Genetic delineation of oil palm populations using phenotypic traits and simple sequence repeat markers for parental selection and breeding

Well-characterized genetic resources are vital for effective selection and new breeding populations development in crop improvement programs. The objective of this study was to assess the genetic diversity of 96 oil palm ( Elaeis guineensis Jacq.) populations representing Dura, Pisifera and Tenera fruit types using key agronomic traits and eight selected diagnostic simple sequence repeat (SSR) markers to guide parental selection and breeding. The phenotypic data were analyzed using multivariate approaches, while molecular data were subjected to genetic diversity and population structure analyses. Highly significant ( p  < 0.000) phenotypic differences were detected for the assessed phenotypic traits. Genotype variation significantly influenced most phenotypic traits. The SSR markers revealed genetic polymorphisms, with a mean of 7.75 alleles per locus and a mean polymorphic information content of 0.66. The observed (0.70) and expected (0.71) heterozygosity values were comparable, indicating high within-population genetic variation. The analysis of molecular variance showed a higher genetic variation primarily attributable to differences among individuals ( p  < 0.05). Both phenotypic and molecular markers distinguished the Dura, Pisifera and Tenera fruit types, providing complementary evidence of variation among the sampled palms. Based on phenotypic and SSR analyses, individuals designated as 116 T, 016 T, 246D and 117 T were identified as potential parental candidates based on their distinctive genetic relationships and desirable phenotypic traits. The selected palms represent promising candidate breeding materials for further evaluation and validation for the development of high-yielding, resilient oil palm cultivars adapted to diverse agro-ecological conditions of Tanzania or similar climatic conditions.