Collection, morphological characterization and diversity analyses of sweet potato (Ipomoea batatas (L.) Lam.) landraces in Agusan del Norte (Philippines)

Genetic resources of sweet potato have long been ignored in the province of Agusan del Norte [Philippines]. Historically, no related studies were made and no formal conservation efforts were done leaving the local sweet potato gene pool dependent on farmers' variety preferences. To address this problem, this study was conducted to i)collect local sweet potato landraces in different areas in the province of Agusan del Norte; ii)characterize the accessions collected based on morphological descriptors, and iii)assess the diversity of the collected sweet potato accessions using Shannon-Weaver's diversity index and cluster analysis using Ward's method. A total of 33 sweet potato accessions were collected in five cities/municipalities of the province from December 2018 to January 2019. Collection sites were marked using a Global Positioning System and passport data of accessions were gathered using the germplasm collecting from of the National Plant Genetic Resources Laboratory (NPGRL). Provisional ex situ conservation for the collections was established at the Caraga State University Organic Agriculture field for morphological characterization, Eighteen stem and leaf, 3 inflorescence, and 6 storage root characteristics were recorded for each accession and were subjected to diversity analyses. Shannon-Weaver's diversity index showed 21 out of 27 phenotypic traits are highly diverse. Cluster analysis using Ward's method revealed two major groupings, wherein only three accessions belong to group A, while the remaining 30 belongs to group B. At least four accessions were identified to be promising in terms of storage root characteristics, namely, Acc. 5, Acc. 16, Acc. 17, and Acc. 21. The data generated from this study will be useful for subsequent genetic studies and the accessions will be used as primary gene pool for sweet potato varietal improvement.