Controlled Deterioration Test to Estimate Soybean Seed Storability.

Abstract

Physiologycal quality of soybean seed was easily deteriorated during storage. It was caused by high protein content, permeable seed coat and high humidity in storage condition. Therefore, it was important to maintain the soybean seed quality to fulfill the increasing requirement of soybean seed. Estimation of the seed storability could be done by carrying out the laboratory tests. One of the testing method is controlled deterioration test. The objectives of the research were to determine seed moisture content and period at the controlled deterioration treatment which could be used to evaluate soybean seed viability, and to find the appropriate controlled deterioration test for estimating storability of soybean seed. The research was conducted at the Horticulture Crops Quality Control Laboratory and the seed storage warehouse PT. BISI International, Tbk, Kediri since October 2012 until February 2013. The research consists of three experiments, i.e. controlled deterioration test for soybean seed, controlled deterioration test by time series pattern and soybean seed storage at room temperature. Wilis and Detam-1 variety seeds were used as experimental material. The first experiment was arranged in a Completely Randomized Design with two factors and four replications. Three levels of moisture content (15%, 17.5% and 20%) and four levels of controlled deterioration test period (0 hour, 8 hours, 16 hours and 24 hours) were used as treatments. The second experiment was arranged in a Completely Randomized Design with one factor and four replications. Sixteen levels of deterioration period (1–16 hours) were used as treatments. The moisture content, germination, vigour index and speed of germination were observed after controlled deterioration test. The third experiment was arranged in a Completely Randomized Design with one factor and four replications. Sixteen levels of actual storage periods (1–16 weeks) were used as treatments. The moisture content, germination, vigour index and speed of germination were observed every week during the sixteen weeks storage periods. The experiment results showed that there were significant differences for germination, vigour index and speed of germination after controlled deterioration test. The results also showed that the proper controlled deterioration test to evaluate Wilis variety seed was at 17.5% moisture content for 16 hours and controlled deterioration test for Detam-1 variety seed was at 15% moisture content for 16 hours. There were significant correlations of physiological quality variables and the actual at 16 weeks storage periods, indicating that controlled deterioration test period could describe storage period. The equation for estimating seed storability vigour (VDS) developed based on the relationship between controlled deterioration period (t) and the storability vigour was - t, where a and b are the constant values. The equation for estimating seed storability (DS) developed based on the relationship between storage periods and germination after controlled deterioration ( det ) was - det , where a and b were the constant values. Verification result showed that the VDS equations could be used to estimate germination and speed of germination. Qualitative verification showed that the actual observed variables were in the simulation interval confidence (1-α 0.95 . These results were confirmed by quantitative verification showed the chi square value lower than chi square table. Different results occured in vigour index variable. The equation could not be used to estimate the vigour index. The majority of actual vigour index values were outside the simulation interval confidence (1-α 0.95 nd it h ve chi- square value higher than chi-square table. Simulation of storability equation results showed that the greater value of seed germination after controlled deterioration the higher seed storability. The validation result showed that the equation could estimate the seed storability of Wilis and Detam-1 varieties stored using aluminum foil package at room condition with 25.1-34.8 °C temperature.