Effects of humic acid and cytokinin on yield, biochemical attributes and nutrient elements of radish (Raphanus sativus L.) cv. Watermelon

Abstract

In this study, the effects of four concentrations of humic acid (0, 0.5, 1, and 1.5 kg ha⁻¹, HA applied to the soil) and kinetin (0, 25, 50, and 75 mg L⁻¹, KT, foliar sprayed) on vegetative growth, yield and biochemical attributes of radish cv. Watermelon, grown in two seasons of spring and autumn, were investigated. Results showed that, the number of leaves per plant, leaf area and chlorophyll content increased with application of HA and KT in both seasons, while the high levels of treatments had no significant effect on leaf number per plant and chlorophyll content in spring season. The root diameter, fresh weight and yield increased significantly with application of HA and KT in both seasons, though, this increase was noticeable in the autumn season. Our results also showed that radish root treated by HA and KT exhibited higher root firmness, vitamin C, anthocyanin content and total soluble solids (TSS), especially in autumn cultivation. Macronutrient contents of root including magnesium (Mg), phosphorus (P), potassium (K), nitrogen (N), and calcium (Ca) were significantly enhanced by HA and KT, however high concentration of KT in combination with high concentration of HA decreased some nutrient contents. Generally, the results of this study demonstrated that cultivation season is one of the most important management tools to minimize the negative effects of high temperature during root development. In addition, the benefits of KT spray combined with HA were inconsistent between both seasons, but showed more in the autumn crops.

Keywords:

• anthocyanin
• cultivation season
• radish root
• vegetative growth
• vitamin C

Disclosure statement

No conflict of interest was reported by the authors.