Evaluation of some physiological and biochemical characteristics of pot marigold (Calendula officinalis) genotypes affected by irrigation regimes

This study was conducted to evulate the effect of water stress on soluble carbohydrates, root and leaf proline, photosynthetic pigments, petal and seed yield of pot marigold genotypes. It was performed as split plots in randomized complete block design with three replications. Three irrigation regimes (35%, 60% and 85% of available soil water depletion) designed as main plot and nine pot marigold genotypes (Ahvaz, Tehran, Isfahan1, Isfahan2, Candy-man, Gitana, Zen-Gold, Isfahan3, Isfahan4) were evaluated as sub-plot in Ahvaz in 1394-95 growing seasen. The results showed the effect of irrigation regimes and genotype were significant on studied traits, petal and seed yield. Due to drought stress, the content of carbohydrates, root and leaf proline increased but RWC, carotenoid, chlorophyll a, b and a + b, petal and seed yield of genotypes decreased significantly. The results showed high correlation between soluble carbohydrate and leaf proline content with RWC and drought sensitivity index. Resistant genotypes had a highest content of soluble carbohydrates, leaf proline and carotenoid. Based on drought sensitivity index, "Ahvaz", "Isfahan2" and "Isfahan1" genotypes divided in drought resistant group, "Tehran", "Candy-man", "Gitana" in moderately resistant group and " Isfahan4", "Zen-gold" And "Isfahan3" in sensitive group. "Candy-man" and "Ahwaz" genotype produced the highest petal and seed yield, respectively, at all drought levels.