Phenotypic characterisation of sweetpotato genotypes grown in East and Central Africa

Abstract

Identification of genetic variability and interrelationships among germplasm collections is fundamental to select parents with complementary traits for plant breeding programmes. The aim of this study was to characterise and identify breeding parents among 54 sweetpotato genotypes grown in Rwanda, East and Central Africa. Genotypes were field-evaluated using 26 phenotypic traits under a 9 × 6 unbalanced alpha lattice experimental design with three replications at Karama and Rubona stations in Rwanda. There were significant (P < 0.01) genotype by site interaction and genotype and site effects on flowering rate, yields of storage roots and vines, harvest index, weight of the largest root per plant and dry matter content. Genotypes K513261, Kwezikumwe, 8-1038 and 2005-110 showed the highest flowering rates of 44.97%, 20.63%, 19.05% and 14.82%, respectively. Suitable genotypes such as K513261, Purple 297, Kwezikumwe and New Kawogo were identified with high storage root yields at 31.90, 28.60, 28.16 and 27.11 t ha⁻¹, respectively. Genotypes Ukerewe, 2005-103, Meresiyana and Mvugamo showed the highest mean dry matter content at 36.52%, 35.53%, 35.31% and 34.04%, respectively. Overall, genotypes K513261, Kwezikumwe, 2005-020, OTADA 24, SPK004, Ukerewe, 2005-110 and 2005-034 were identified as potential breeding parents with superior storage root yield and dry matter content.

Keywords: Central and East Africa, dry matter content, genetic variation, genotype, phenotypic diversity, storage root, sweetpotato