The efficiency of crop breeding programs is largely driven by the availability of genetic diversity and the inheritance of desirable traits. Heritability, genetic advance and sequential path analysis were assessed in 26 spring oilseed rape genotypes in a randomized complete block design with three replicates over two crop years 2018-2020 at the experimental field of Moghan Agricultural Research Station, Parsabad, Iran. Several morpho-physiological characteristics were recorded during the experiments. Genetic characteristics, heritability, and genetic advance in oilseed rape genotypes were estimated using the restricted maximum likelihood (REML)/Best Unbiased Linear Prediction (BLUP) method. Significant variations between oilseed rape genotypes were found for all characteristics investigated. This study found greater PCV values than GCV, showing that the environment influenced these traits. Broad-sense heritability ranged from low (8.81% for SPAD) to moderately high (79.09% for SW). The heritability estimate was moderately high for FC, PH, FPH, BN, PL, PT, SNP, SW, and OY. High heritability and genetic advance for OY were also observed in this research. SW, BN, and OY had moderately high heritability in the broad sense with high genetic advance as a percentage of the mean (GAM), demonstrating the existence of additive genes that regulate these characteristics and, thus, selection will be effective in crop improvement. Conventional path analysis showed that several traits, especially those with significant direct effects on OY exhibited substantial collinearity. Sequential path analysis revealed that SY, FP, and SW showed the most significant direct effects on OY. It can be concluded that SW and PL with high broad-sense heritability and GAM are good traits for indirect selection in the breeding program for spring oilseed rape genotypes.

28.4.2023