Nigeria Journal of Plant Breeding Volume 2(1), pages 1 - 12, September 2025 ISSN: 2814-3531 Copyright © 2025 Harriman et al https://pbanjournal.org/ PLANT BREEDERS ASSOCIATION OF NIGERIA Full Length Research CLUSTER ANALYSIS AND GENOTYPE × ENVIRONMENT (G × E) ASSESSMENT FOR ROOT YIELD IN 35 ORANGE-FLESHED SWEETPOTATO GENOTYPES 1 Harriman, J. C., 1 Okocha, P. I., 1 Nwofia, G.E., 1 Okoronkwo, C.M., 1 Nwadinobi, C.A., 2 Onyeabo, C.N.P., 3 Ogu, C. E., 4 Orji, J.O., 5 I. B. Agboeke, 6 Davids, Emmanuel C.F 1 Department of Agronomy, Michael Okpara University of Agriculture, Umudike, Abia State, Nigeria. 2 Department of Plant Science and Biotechnology, Abia State University, Uturu, Abia State, Nigeria. 3 Department of Agricultural Science, Alvan Ikoku Federal College of Education, Owerri, Imo State, Nigeria. 4 Department of Crop Science, University of Agriculture and Environmental Sciences, Umuagwo, Imo State, Nigeria. 5 Department of Soil Science and Meteorology, Michael Okpara University of Agriculture, Umudike, Abia State, Nigeria. 6 Department of Crop Science and Biotechnology, Faculty of Agriculture, Imo State University Owerri. Received 18th July, 2025; Accepted 28th August, 2025 ABSTRACT: Orange-fleshed sweetpotato (OFSP) is a biofortified food of Beta carotene that fights vitamin A deficiency and promotes nutritional security. The success to select and identify the superior genotype is limited by Genotype and Environment (G×E) interactions. The study was conducted to estimate the magnitude of G×E and to select stable and high yielding OFSP in three locations, and to identify the most discriminating test environments. Similarly, to characterized them according to similarities in traits. These genotypes were subjected to heatmap cluster analysis. The 35 OFSP genotypes were evaluated across 3 environments using a RCBD with three replications. The data were subjected to ANOVA using R package. The AMMI model analysis indicated that genotype (G) and environment(E) had significant effects on root yield and the contribution to the total sum of squares difference was 64.89% and 6.35%, respectively. The remaining 3.87 % of the variation resulted from GxE effects. G24, G35 and G34 exhibited high mean root yield across environments with high degree of stability. These hybrids have the potential for production across the test locations as well as others within the same agro-ecological zones. However, G3, G12 and G30 were not only low yielding but also among the least stable genotypes. The best genotype with respect to location include G15 and G14 which were best for Umudike (E1), while G34 and G4 were the best genotype for Igbariam (E1) area. G24 performed well in FUTO (E3). Among the locations, E1 was the most productive site in distinguishing genotypes and the most representative environment. The Cluster heatmap analysis grouped the 35 genotypes into 4 clusters with distinct features. Cluster I was recommended for high root girth, high root yield performance and high beta carotene content, while clusters II and IV were recommended for high dry matter and high starch. Cluster III was characterized with short vine length. Keywords: G x E interaction, additive main effect and multiplicative interaction (AMMI), stability, heatmap cluster analysis, OFSP. INTRODUCTION The orange-fleshed sweetpotato (Ipomoea batatas) (OFSP) is grown in more than 100 countries (Woolfe, 1992). Among the tuber crops grown in the world, sweetpotato ranks fourth after cassava, yam and cocoyam (Ray and Ravi, 2005). It is grown as a starchy food crop throughout the tropical, sub-tropical and frost-free temperate climate zones in the world (ICAR, 2007, Nedunchezhiyan et al., 2012). The crop is very important in promoting nutritional security particularly in agriculturally backward areas (Srinivas, 2009) with poor soils. It can be * Corresponding Author E-mail; ch.john@mouau.edu.ng, Tel: +234)8060690357 This article remains permanently open access under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.