LAUSR

ABSTRACT Leaf blight is an important disease of teak which reduces photosynthetic rate and ultimate timber yield in infected trees. Symptomatic leaf samples were randomly collected from three forest reserves, Onigambari, Olokemeji and Omo in Southwest Nigeria. Genomic DNA from the samples was extracted using Cetyl Trimethyl Ammonium Bromide (CTAB) method and amplified with Inter Simple-Sequence Repeat (ISSR) markers to evaluate genetic diversity. Dendrogram analysis using UPMA procedure separated the accessions into 12 major groups with bootstrap values ranging from 51 to 62. The constructed dendogram showed that accessions from Onigambari forest reserve were genetically similar to those from the two other reserves. Principal component analysis (PCA) showed that the first, second and third axes accounted for 79.19%, 85.41%, and 88.11%, respectively, of the total molecular variation. All the four ISSR markers showed 100% polymorphism which induced the amplification of 48 alleles across the 39 teak accessions evaluated. Polymorphic information content (PIC) obtained from ISSR markers ranged from 0.6038 to 0.8886, while genetic diversity varied from 0.6288 to 0.8947. The inter-population genetic diversity and allelic richness observed in the study could be employed in breeding for resistance against leaf blight disease of teak.