Influence of storage environment and packing materials on seed germination and viability of Desmodium gangeticum (L.) DC. and Indigofera tinctoria (L.)

Abstract

Desmodium gangeticum and Indigofera tinctoria are valuable medicinal plants frequently used in the Indian System of Medicine. These crops are propagated through seeds. Seeds of these crops lose viability within 3-4 months after extraction under normal conditions. In order to get optimum plant population, uniform germination has to be assured. For that it is necessary to store the seeds at appropriate environmental conditions. By modifying the storage environment and by using apt packing materials storage life of seeds can be enhanced. The present investigation “Influence of storage environment and packing materials on seed germination and viability of Desmodium gangeticum (L.) DC. and Indigofera tinctoria (L.)” was carried out at the Academy of Climate Change Education and Research, Vellanikkara and All India Coordinated Research Project on Medicinal, Aromatic Plants and Betelvines (AICRP on MAP & B), College of Horticulture, Vellanikkara during the year 2016-2017. The experiment was laid out in a completely randomized design with 18 treatments replicated twice. Observations on micrometeorological and seed quality parameters (1000 seed weight, seed moisture content, germination percentage, seedling root length, seedling shoot length, seedling fresh weight and seedling dry weight) were recorded at weekly intervals. All the seed quality parameters were significantly influenced by the individual treatments of moisture levels, packing materials and storage environments and by the combined interaction of these three factors except seedling fresh weight, seedling dry weight and 1000 seed weight at some weeks after storage. Seeds of 8% moisture content recorded higher germination percentage for both crops, higher seedling root length and shoot length for Indigofera tinctoria. Among the packing materials, polythene bag stored seeds of Desmodium gangeticum showed higher 1000 seed weight, germination and seedling shoot length at the same time cloth bag stored Indigofera tinctoria seeds recorded higher 1000 seed weight, germination and seedling root length. Seeds stored under refrigerated condition showed higher 1000 seed weight, germination percentage, seedling root length and seedling shoot length for both crops. Significant positive and negative relationships were observed due to the influence of weather parameters (maximum temperature, minimum temperature and relative humidity) on seed quality. Maximum temperature and relative humidity showed a positive relationship with majority of the seed quality parameters except seedling fresh weight of Indigofera tinctoria and seed moisture content of Desmodium gangeticum. Most of the seed quality parameters (1000 seed weight, seed moisture content, germination percentage, seedling shoot length and seedling fresh weight) were negatively influenced by minimum temperature. Results of the investigation implies that, to enhance the germination of seeds over a period of 12 weeks of storage it is better to dry the seeds to 8% moisture content and pack in polythene bags for Desmodium gangeticum seeds , cloth bags for Indigofera tinctoria seeds and store under refrigerated environment.