Drying of seeds from common wheat (Triticum aestivum L.) by using Silica gel for ex situ storage

P. Chamurlyisky, N. Tsenov, S. Stoyanova
Abstract. One of the most widely used methods for maintenance of the biodiversity of the cultural plant species is their preservation under ex situ conditions. This major approach is related to storage of accessions at organism level in genetic stock centers by reducing the metabolite activity of the seeds as a result of low moisture content and low temperature. Seed moisture is one of the main indices for the storage ability of seeds. When working with a small number of samples in long term storage collections, a suitable method for reduction of moisture is the use of desiccant Silica Gel. The aim of this study was to develop a practically applicable system for drying winter wheat seeds by using Silica Gel for the purposes of an ex situ working collection of common wheat, following the variations of moisture throughout the entire process of dehydration. Seeds from three contemporary cultivars of DAI were used, Aglika, Enola and Pryaspa, which were grown in 2012. The experiment was designed at three different volumes of grain:desiccant ratios: 1 part grain to 0.5 parts silica gel (1:0.5), 1 part grain to 1 part silica gel (1:1), and 1 part grain to 1.5 parts silica gel. Each cultivar was involved in the above design, in three replications for each variant. Moisture content in seeds was determined by a weight method. The first reading was done on the 30th day, the second and third – at 20 day intervals. Two-factor dispersion analysis and variation analysis were applied for statistical processing of the data with the help of the software XLSTAT Pro ver. 7.5.2.
The lowest moisture content at the end of the experiment was determined for cultivar Enola: 5.2 % at ratio 1:1.5 grain seeds/silica gel. It was found that at variant 1:1.5 seeds/silica gel the lowest moisture levels were reached and moisture reduction was the fastest. A practically applicable and economically efficient methodology was developed for drying according to which the variant 1:0.5 was the most suitable for the purposes of long-term storage of winter wheat.