Interrelationships among agro-morphological characteristics of Iranian safflower germplasm under cold and rain-fed conditions

Abstract

Safflower is a promising oilseed crop for semi-arid regions like Iran, however, conventional yield analysis frequently encounters difficulties due to interrelated variables. This study utilized sequential path analysis to examine these relationships across 31 safflower genotypes under cold, rain-fed conditions in Iran during 2019–2020. Conducted at the Dryland Research Station of Maragheh, Iran using a randomized complete block design (RCBD) with three replications, the research identified significant correlations between safflower seed yield and key traits: plant height (0.65∗∗), the number of seeds per head (0.63∗∗), and capitula number (0.51∗∗). Biological yield (0.927∗∗) and harvest index (0.222∗∗) directly positively influenced seed yield, while seed weight had a negative direct effect (−0.084∗∗). Taller plants enhanced biomass production (0.718∗∗), though heavier seeds negatively affected biological yield (−0.316∗∗). Lower branching height correlated with a higher harvest index (−0.477∗), suggesting resource allocation toward seed production. Kernel weight was strongly driven by husk weight (0.846∗∗), emphasizing its role in determining seed weight. These findings highlight how different factors work together to affect crop yield suggest that optimizing husk weight could improve seed yield. The study emphasized that biologically nonsensical pathways, such as seed weight indirectly affecting biological yield via plant height, were excluded to ensure the model's validity. Sequential path analysis proved effective in unraveling these complex interactions, offering insights to enhance safflower productivity sustainably in arid and semi-arid regions, thereby supporting global food security and agricultural resilience.