Assessment of genetic diversity in Fusarium wilt tolerant and susceptible oil palm (Elaeis guineensis Jacq) progenies in Nigeria using inter- simple sequence repeat (ISSR) molecular markers

Background Improving oil palm in Nigeria for food security and subsequent export requires a better understanding of the genetic diversity among oil palm progenies tolerant and susceptible to Fusarium wilt disease. In view of the limitations of the orthodox method used in screening this disease, and the advantages of molecular markers, fourteen (14) Inter-simple sequence repeat (ISSR) DNA markers were applied to evaluate the genetic diversity, population structure and cluster resolutions of alleles responsible for tolerance of 560 Elaeis guineensis Jacq palms representing 8 different progenies distributed across NigeriaResults The amplification product revealed a moderately high level of genetic diversity with a total of 46 alleles identified, resulting in an average of 4.9091 alleles per locus detected between the oil palm progenies. Polymorphic information content (PIC) values varied between 0.3706-0.7861, with a mean value of 0.6829. The genetic diversity values ranged from 0.4063-0.8125 with a mean of 0.7216, while the major allele frequency ranged from 0.2500- 0.7500 with a mean value of 0.3750. Shannon's information index (I), Nei's gene diversity (H), and the effective number of alleles (Ne) had values of 0.6931, 0.5000, and 2.000, respectively. The genetic diversity was highest in progeny 3023, and lowest in progeny 4189. Mean values of the total gene diversity (Ht), gene diversity within the population (Hs) of the progenies, coefficient of gene differentiation among the progenies (Gst) and level of gene flow (Nm) were 0.4899, 0.3520, 0.2815 and 1.2764, respectively. The dendrogram clustered the progenies into six major clusters, while Principal Component Analysis (PCA) grouped the progenies into five clusters. PCA further identified the coordinate positions of tolerant and susceptible alleles of oil palm progeniesConclusion This study confirmed the identification of the coordinate positions of tolerant alleles in the gene loci, which could be exploited by breeders to developing tolerant oil palm seedlings.