Evaluation of genetic parameters of different rapeseed traits using diallel analysis

Bilateral diallel crosses of eight rapeseed genotypes were used to graphically analyze and estimate of genetic parameters for agronomic and physiological characteristics. F1 along with their parents (64 genetypes) were planted in a randomized complete block design with three replications at Gorgan Agriculture Research Station, in 2019-2020. The results of analysis of variance showed that a and b components were significant for all traits. The results of the Jinks-Hayman test indicated that hypothesis of the genetic analysis were satisfied for pod length, number of pod per lateral branches, number of pods per plant and 1000-grain weight traits. Analysis revealed significant values for D and H1 estimation for all traits, which indicated the existence of both additive and non-additive effects on genetic control of these traits. While the proportion of non-additive variance was higher than the additive effects for all traits, which was in agreement with high mean levels of the degree of dominance. The positive and significant sign of F confirmed that there are much more dominant alleles than recessive alleles in parents, regardless of whether they have a negative or positive effect. Based on Hayman graphical analysis, 1000-grain weight was influenced by the dominance of genes. Narrow-sense inheritance levels were low for all traits, which could indicate a greater impact of environmental and non-additive effects on their genetic control. The results showed that selection-based methods were not very effective in canola yield improving and production of hybrids and exploiting the effects of gene dominance is necessary.