Genetic diversity and relationships among populations of jackfruit, an underutilized nutrient-rich climate-smart fruit tree crop in Kenya and Uganda

Abstract

Jackfruit (Artocarpus heterophyllus Lam.) is an underutilized fruit tree crop in East Africa. Despite its importance for food and nutritional security, only limited information exists on the extent of genetic variability among Ugandan and Kenyan jackfruit populations. This study was aimed at analyzing the extent of genetic diversity in jackfruit germplasm from selected regions of Kenya and Uganda. A total of 30 mature fruit samples were collected randomly from three districts (Kampala, Wakiso and Mbale) in Uganda and five counties (Siaya, Kwale, Mombasa, Busia, and Murang’a) in Kenya. Genetic characterization was using six simple sequence repeat (SSR) and nine sequence-related amplified polymorphism (SRAP) markers. The results revealed that 62.50% of the loci for SSR and 82.14% for SRAP markers were polymorphic. The average polymorphism information contentwas 0.48 for SSR and 0.56 for SRAP markers. The Jaccard’s similarity coefficient ranged from 0.55 to 1.0 for SSR and from 0.33 to 0.93 for SRAP markers, indicating considerable genetic diversity among jackfruit germplasm. Based on combined SSR and SRAP data, analysis of molecular variance revealed greater genetic diversity within the populations (76%) than among the eight populations (24%). Dendrogram and principal coordinate analysis separated the germplasm into two clusters, with several intermediates. The germplasm distribution among the clusters and sub-clusters was not associated with the geographical region. The significant genetic variability existing in Ugandan and Kenyan jackfruit germplasm can be used to improve jackfruit through breeding. The substantial genetic diversity should enable jackfruit breeders to develop high-yielding varieties with improved quality traits.