Effects of Static Magnetic Field Pretreatment on Mung Bean Traits Across Multiple Developmental Stages

Mung bean (Vigna radiata (L.) Wilczek) seed pretreatment commonly involves biological and chemical methods, whereas physical pretreatments such as static magnetic field pretreatment (SMFP) have attracted attention because they are noncontact and offer adjustable treatment parameters. To clarify the effects of SMFP on multiple traits of mung bean across several developmental stages, seeds were exposed to magnetic flux densities of 5 and 10 mT for magnetic treatment durations of 10, 20, and 30 min. Laboratory germination tests and field experiments showed that, under the tested conditions, most SMFP combinations at these low magnetic flux densities resulted in a higher germination rate (GR) than the control. Responses of basal stem diameter (BSD), straw dry weight (SDW), straw-to-grain ratio (SGR), and harvest index (HI) varied among traits and were nonmonotonic. Mean relative chlorophyll content (RCC) fluctuated across observation weeks, and treatment differences were observed for some combinations of observation week and canopy position. No magnetic treatment significantly increased grain yield per unit area (GY) or grain component yields per unit area (GCY) relative to the control. Grain starch content (SC) generally increased, whereas crude protein content (CPC) decreased in most treatments. The interaction between magnetic flux density and magnetic treatment duration significantly affected the maximum shear force of the basal stem (MSFB) and the maximum bending force of the basal stem (MBFB). For paired measurements obtained from individual plants, BSD was positively associated with both maximum force values. Overall, the effects of SMFP on mung bean traits differed among traits, depended on the treatment parameters, and were nonmonotonic; no single treatment combination was suitable for all indicators. These exploratory findings provide a basis for further research across multiple cultivars, locations, and growing seasons.