Genetic Variability, Heritability, and Selection Indices for Root Yield Components in Sweet Potato (Ipomoea batatas L.) Germplasm of Southern Malawi

African Journal of Agriculture | Vol. 13, No. 8, August 2026 | pp. 138–145

DOI: 10.46882/2026/AJA/000751

Article Type: Original Research Article

Title: Genetic Variability, Heritability, and Selection Indices for Root Yield Components in Sweet Potato (Ipomoea batatas L.) Germplasm of Southern Malawi

Names of Authors: Memory F. Banda¹, Blessings K. Phiri¹, Charles L. Maliro²

Authors’ Affiliations: ¹Department of Horticulture, Lilongwe University of Agriculture and Natural Resources, Lilongwe, Malawi; ²Bunda College of Agriculture, Crop Sciences Department, Lilongwe, Malawi

Abstract: Breeding high-yielding, beta-carotene-rich sweet potato (Ipomoea batatas L.) requires a precise understanding of genetic variability and genetic advance for targeted root parameters. This study evaluated the genetic components, broad-sense heritability (H²), and selection gains for yield-related traits across 24 sweet potato genotypes under rainfed conditions in southern Malawi. The experiments used a randomized complete block layout with three replications. Morphological markers, including storage root count per plant, average root weight, dry matter content, and total storage root yield, were monitored. Statistical analyses revealed significant variation across all genotypes for all measured traits (p < 0.01). The genotypic coefficient of variation (GCV) for total storage root yield (28.4%) was close to the phenotypic coefficient of variation (32.1%), showing a strong genetic foundation and low environmental interference. Broad-sense heritability estimates were exceptionally high for storage root yield (84.5%) and average root weight (78.2%). Crucially, total storage root yield displayed a high genetic advance as a percentage of the mean (54.2%), indicating that selective breeding can yield substantial improvements. Genotype LUST-26 logged the highest mean storage root yield at 22.45 ± 1.12 t/ha along with an acceptable root dry matter content of 31.4%. Selecting parental lines based on root count and individual root weight will maximize genetic gains in sweet potato improvement programs.

Keywords: Ipomoea batatas, Genotypic coefficient, Heritability, Genetic advance, Root yield, Breeding selection

Manuscript Timeline: Received: June 08, 2026; Revised: July 12, 2026; Accepted: August 04, 2026; Published: August 31, 2026

Citation: Banda, M. F., Phiri, B. K., & Maliro, C. L. (2026). Genetic Variability, Heritability, and Selection Indices for Root Yield Components in Sweet Potato (Ipomoea batatas L.) Germplasm of Southern Malawi. African Journal of Agriculture, 13(8), 138–145. DOI: 10.46882/2026/AJA/000751

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