Determination of viability and vigor using accelerated aging technique and electrical leachate conductivity tests for molave (Vitex parviflora Juss) seeds

The Accelerated Aging Technique (AAT) used to assess seed vigor of three molave (Vitex parviflora Juss) seedlots artificially aged seeds at 40 deg C temperature and 100 percent relative humidity with various aging periods (0, 24, 48, 72, 96, 120, 144, 168, 192, 216, 240 hours). Vigor of seedlots 1 and 3 declined faster than seedlot 2 at increasing periods of AAT. From an initial percent germination of 64.25 percent, it increased to 80.50 percent after 48 hours of AAT. Subsequently, germination decrease to 57.25 percent and was zero at 168 hours for seedlots 1 and 3 and at 192 hours for seedlot 2. Moisture content was observed to increase with aging time. The increase in moisture content of the seeds from 16.57 percent to 22.15 percent seeds after 24 hours could have trigerred some beneficial metabolic processes and advance the germination of seeds. At the latter stage of AAT, high humidity and temperature combinations in AAT created adverse conditions and diverse responses such as proliferation of fungal growth, high solute leakage, which eventually led to the death of seeds. At 96 hours of AAT, vigor among seedlots was distinguished. Seed viability and vigor of three molave seedlots was assessed by the electrical conductivity of the leachates using HACH 44600 TDS/Conductivity Model. This was done by soaking samples of 50 seeds for 24 hours in 100 ml distilled water. Seed leachate conductivity when regressed with viability and vigor was linearly and inversely related. Similarly, significant and high correlations were obtained between viability and vigor on conductivity measurements. The computation of germination value of Djavanshir and Pourbeik method (1976) was observed to be a better index of vigor than the peak values and germination values by Czabator (1962). The results confirm that AAT can be used as an alternative method of assessing vigor of molave seeds. Likewise, quantitative measurements of leachates, using electrical conductivity could also be used to assess seed viability and vigor of molave seedlots