Genetic diversity assessment among 18 elite cashew tree genotypes (Anacardium occidentale L) selected in Western Burkina Faso

Abstract

The development of cashew orchards increased in recent years in Burkina Faso, due to high nut demand on international markets. However, little activities have been oriented toward cashew cultivar development, and farmers often use seed plants with little or no information about genetic characteristics of the material at hand. Therefore, a description of cashew diversity is needed to provide guidance to farmers and identify elite material for the crop improvement. In this study, phenotypic attributes of cashew accessions collected in Western Burkina Faso were recorded. Then, Gower’s distance was used to show phenotypic relationship among accessions. Furthermore, four microsatellite markers were used to assess the genetic diversity of accessions, based on amplicon sequences. Sequence patterns across samples were converted into 75 binary alleles, combining sequence length and nucleotide polymorphisms. The 75 binary markers were 100% polymorphic and provided high average alleles per primer of 18.75. The polymorphic information content (PIC) varied between 0.003 and 0.895, averaging 0.534 per primer. Gower’s distance between cultivars varied between 0.151 and 0.894. Dendrograms based on Nei’s distance and Gower’s distance revealed three main clusters each, although group compositions were different. These results were discussed with an outlook on future cashew tree breeding in Burkina Faso. Key words: horticulture, breeding, molecular markers, phenotype, nut.