Influence of soil moisture levels and cytokinin application on the formation of hardseeds in mungbean (Vigna radiata L.) variety ‘Harsha’

Hardseededness in mung bean (Vigna radiata L.) leads to poor cooking quality and uneven germination, creating challenges for both consumers and growers, respectively. The exact cause of hard seed formation is still unclear, though it is believed to be due to environmental stresses such as lack of soil moisture, and could be reversed through hormone application. Hence, this study aimed to investigate the effects of soil moisture stress and cytokinin (kinetin) application on hardseed formation in the mung bean variety ‘Harsha’. The experiment was conducted as a two-factor factorial completely randomised design with ten replicates per treatment. Plants were grown in pots, either with or without cytokinin (150 or 0 mgL−1 kinetin) application as a foliar spray after flowering, and at 70–80% or 40–50% field capacity (FC) imposed after flowering. Measurements included percentage of hardseeds, yield components, leaf area, photosynthetic rate, and stomatal conductance. Cytokinin reduced the percentage of hardseeds compared to the untreated control (P < 0.05), and this effect was more pronounced at 40–50% FC than at 70–80% FC (P < 0.05). However, cytokinin had no significant effect on stomatal conductance, photosynthetic rate, pod number per pot, flowers per pot, good and deformed seeds per pot, or 100-seed weight (P > 0.05). However, these variables differed significantly with soil moisture (P < 0.05), with 70–80% FC producing greater values (P < 0.05). Therefore, the effect of cytokinin in reducing hardseed formation is independent from yield components and associated physiological processes, while the effects of moisture stress on tested variables were interconnected.