Evaluation of Relationships between Morphological Traits and Grain Yield in Cumin (Cuminum cyminum L.) under Normal and Drought Conditions

To evaluate relationships between morphological traits affecting grain yield of cumin herb, an experiment was conducted as split plot in a randomized complete block design with two replications in two years (2011-2012) in Shahid Bahonar University of Kerman Research Field. In this study, the main plots were two irrigation regime levels and sub-plots were forty nine cumin ecotypes which they are sub-populations belonged to nine populations from different provinces of Iran. Analysis of Multiple linear regressions showed that in stress condition traits such as number of umbels per plant, number of seeds per umbel and 1000-seed weight had the greatest effects on yield performance and also determine 80% of the yield variation among the studied ecotypes. In normal condition 77% variation of yield were explained by umbels per plant, number of branches and number of seeds per umbel. In order to identify the direct and indirect effects of traits on yield, a path analysis was carried out based on the variables entered into the final regression. Due to a direct effect on the performance of both criteria, number of umbels per plant is determined as the most important part of yield and because of high direct effects on yield in both conditions supposed to be as a proper criterion for considering production ability of cumin genotypes that can be recommended for using in breeding programs.