Sex determination of South Africa's Encephalartos - A conservation perspective

Abstract

Species within Encephalartos Lehm., the largest cycad genus in Africa, face considerable threats from habitat loss and illegal collection. Living collections in botanical gardens play a crucial role in conserving these slow-growing plants, necessitating the presence of both male (microsporangiate) and female (megasporangiate) individuals for successful sexual reproduction. Recent genomic research has identified sex-specific genes in cycads, offering an opportunity for sex determination in ex situ collections. This study tested the utility of the CYCAS_034085 gene, found exclusively in microsporangiate plants, for identifying the sex of Encephalartos individuals using a simple qualitative PCR assay. A total of 88 accessions representing six Encephalartos species were collected from Kirstenbosch National Botanical Garden. The results demonstrated that the developed primer combination effectively differentiated between microsporangiate and megasporangiate plants, achieving an accuracy of 86.3 %. This PCR-based sex determination method represents a valuable tool for cycad conservation management and the establishment of effective ex situ collections.