Molecular Characterisation of Traditional Cashew (Anacardium occidentale L.) Populations from Nachingwea and Newala Districts in Tanzania

Abstract

This study assessed the genetic diversity of 120 selected cashew plants from Nachingwea and Newala traditional cashew populations, comprising of 60 cashew plants from each population. Eight Simple Sequence Repeats (SSR) makers were used to ascertain the extent of genetic variation within and between the two traditional cashew populations. Genomic DNA extraction and Polymerase Chain Reaction (PCR) were performed using standard protocols. The results showed that all SSR markers were polymorphic. Average Polymorphic Information Content (PIC), heterozygosity, number of alleles per locus, allelic frequency and Shannon’s Index were 0.540, 0.721, 3.391, 0.666 and 0.649, respectively. Analysis of molecular variance results showed that genetic variation within populations was 88% while genetic variation between populations was 12%, implying gene flow between the populations. The results further showed that the two cashew populations are genetically diverse and that Nachingwea traditional cashew population was genetically more diverse than Newala population. High genetic variation observed in the cashew populations shows that they are suitable for use in cashew breeding programmes. Thus, conservation of traditional cashew populations is recommended.