Genetic Variability of Soybean (<i>Glycine Max</i> (L) Merrill) Genotypes Under Moisture Stress Areas of Ethiopia

Abstract

Characterization and evaluation soybean genotypes for different traits of interest is important to facilitate the breeding program. The study was conducted using 25 early maturing soybean genotypes at Mehoni, Humera, Jinka, Tiro-afeta, and Gofa, Ethiopia during 2018 main cropping seasons. The objective of the experiment was to estimate genetic variability of these breeding materials. The genotypes were planted using 5x5 simple lattice design and managed as per the soybean recommended agronomic production practices. Data on important traits like days flowering (DTF), days to maturity (DTM), plant height (PH), number of pod per plant (NPP), number of seed per plant (NSP), hundred seed weight (HSW) and yield per hectare (YLD) was recorded. The pooled analysis of variance revealed highly significant difference among locations (L) and genotypes (G). The maximum yield was recorded from genotype; JIM-ALM/CRFD-15-SA (2.30 t/ha) followed by PI417129B (2.27 t/ha), with the yield advantage of (27% and 37%) and (25% and 36%) relative to the checks varieties; Gazale (1.81t/ha) and Nova (1.67t/ha), respectively. Based on earliness of the genotypes, all the tested genotypes were found early with the rage of 86 to 105 days. High phenotypic (PCV) and high genotypic coefficients of variation (GCV) were recorded for DTF (148.38% and 142.29%), PH (97.64% and 95.13%), NPP (56.68% and 47.63%), NSP (136.52% and 111.43%), HSW (55.92% and 45.45%) and YLD (133.80% and 92.09%), respectively. While, high PCV (20.78%) with moderate GCV (15.90%) was recorded from DTM. However, the difference between PCV with the corresponding GCV values was relatively higher for NSP and YLD, suggesting high influence of the environment on these traits. High heritability estimates was recorded for DTF (91.95%), NPP (70.62%), NSP (66.62%), and HSW (66.07%), while the remaining showed moderate heritability. High genetic advance as percent of mean (GAM) was found for all the traits studied. Whereas, combined high GCV, high heritability and high GAM were recorded for DTF (142.29%, 91.95% and 281.48%), PH (95.23%, 95.23% and 191.62%), NPP (47.63%, 70.62% and 82.57%), NSP (111.43%, 66.43% and 187.63%) and HSW (45.45%, 66.07% and 76.21%), respectively, which means these traits are controlled more of by additive genes. Generally, the existences of sufficient variability among the evaluated materials create immense opportunity to bring considerable improvement through selection and cross breeding in soybean breeding program.