Effect of delayed cob drying on maize (Zea mays L.) seed vigor

Maize seed vigor was affected by its processing stage. The process must be continue from one stage to another. Delayed one stage in seed processing will affect its vigor. The research aims to study effect of delayed cob drying to maize seed vigor. The research was carried out in Bajeng Experimental Farm and seed laboratory of Indonesian Cereal Research Institute, from February 2018 until April 2019. Bisma and Provit A1 of OPV was used and after harvest, the unhusk cob were store in the processing warehouse and treated by, 0 (immediately drying), 8, 12, 16, 20, 24 days delayed drying. After drying, seeds were store in the room temperature (26-32 degrees C) for one year with observation period every two months. The treatments were arranged using completely randomized design with three factors; varieties, duration of delayed cob drying, and duration of seeds store. Observation were recorded data of seed moisture content, germination, germination rate dry weight, root and shoot length, root and shoot dry weight, electrical conductivity of seed soaking water. The results showed that delayed cob drying significantly affect its seed moisture content, germination percentage, germination rate, root length, shoot length, electrical conductivity of seed soaking water. Delayed cob drying until 24 days were significantly decrease its seed moisture content by 17.5% on Bisma and decreased 17.6% on Provit A1. Delayed cob drying until 12 days could maintain high vigor seeds in term of conductivity leakage value which lower than 25 mu S cm(-1)g(-1).