Evaluation of Genetic Variability and Multivariate Analysis of Major Agro-morphological traits in Sorghum (Sorghum bicolor (L.) Moench) Germplasm

Abstract

For germplasm to be effectively conserved and utilised, the characterisation and evaluation of phenotypic traits are crucial for enabling future breeding efforts. The trial was carried out at Bako Agricultural Research Center, Ethiopia, during the 2020/21 and 2021/22 main cropping seasons. The aim of this study was to determine the extent and nature of phenotypic variability and character associations among 185 accessions of Ethiopian sorghum germplasm. The trial was laid out in a 37 × 5 incomplete block design arranged in a row × column configuration with two replications, and each plot consisted of a single 5 m row with inter- and intra-row spacings of 0.75 and 0.20 m, respectively. Sixteen quantitative traits and anthracnose severity were assessed to evaluate phenotypic variability. Mean squares revealed highly significant (P < 0.01) differences among sorghum accessions for the tested quantitative traits due to genotype, season, and their interaction, indicating substantial genetic variability. The highest estimates of genotypic coefficient of variation (GCV) and phenotypic coefficient of variation (PCV) were observed for panicle weight, leaf width, flag leaf width, above-ground fresh biomass, and mean grain yield ha⁻¹. High heritability and genetic gain, expressed as a percentage of the mean, were observed for panicle weight, panicle length, leaf length, and days to flowering. PCA identified days to physiological maturity, leaf length, and leaf count per plant as significant factors contributing to the observed variability. While anthracnose had a significant negative correlation (-0.34) with grain yield, leaf length, leaf width, flag leaf width, and panicle width showed significant positive correlations with grain yield. Leaf and panicle characteristics were identified as important yield-related factors, indicating that direct selection for these traits could enhance yield. The genotypes ETSL100474, ETSL100072, ETSL100032, ETSL100235, and ETSL100100, which were identified as superior accessions for anthracnose tolerance, grain yield, and yield-related traits, may be exploited by breeders.