Population structure analysis of cashew (Anacardium occidentale L.) in Kerala -the region of introduction in india

Cashew (anacardium occidentale) entered the Malabar Coast of Kerala in 16^th century along with the Portuguese. More than five centuries of existence in this area has acclimatized this crop to this region. The present study reveals the population genetic structure of cashew in Kerala through AFLP marker analysis. The germplasm accessions specific to the locality were used for the study. AFLP analysis gave moderately high Gst (0.23) and Fst (0.31) values which showed moderate to high genetic diversity. Genetic load developed by the cross pollination and use of non descript seeds have widened the genetic variation in addition to the few introductions. Population structure analysis confirmed the uniqueness of the Kannoore population of cashew in the northern districts of Kerala near the port of entry of the initial introductions. This study shows that moderate to high genetic diversity observed in cashew populations of Kerala has raised this region of introduction to the status of secondary centre of origin of cashew.