Imbibition Treatments on the Germination of White Winged Bean (Psophocarpus tetragonolobus) Seeds

Abstract

Winged bean seeds require imbibition treatment to ensure fast and uniform germination. Seed soaking has been commonly used; however, it is unclear if this is a safe method for winged bean seeds. Solid matrix priming (SMP) is an imbibition treatment that combines seeds, a matrix and water in a specific ratio. It allows seeds to imbibe under controlled water uptake. We investigated the effect of imbibition treatments on seed germination of white winged bean. Soaked seeds had significantly reduced germination and emergence as a result of imbibition injury due to rapid imbibition. SMP at a seed: vermiculite: water ratio of 7:12:9 (w/w/w) was the most effective treatment that allowed seeds to imbibe slowly without the occurrence of imbibition injury. SMP significantly reduced the mean germination time from 4.63 days to 2.01 days, and mean emergence time from 7.21 days to 5.78 days, compared to the control, as well as having a high germination rate of 98% and uniform emergence. The fast imbibition rate of white winged bean seeds was likely the result of cracks present on the permeable seed coat.