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Öğe Determination of seed moisture constants (KE, CW) for the viability equation for watermelon, melon, and cucumber seeds(Ista-Int Seed Testing Assoc, 2011) Demir, I.; Kenanoglu, B. B.; Hay, F.; Mavi, K.; Celikkol, T.The effect of moisture on seed longevity during experimental storage was investigated in cucumber (Cucumis sativus L.), melon (Cucumis melo L.), and watermelon (Citrullus lanatus Matsum and Nakai). Seeds were stored hermetically at various moisture contents between 8.0 and 17.0% (fresh weight basis) at 35 degrees C for up to 215, 366, and 175 days for cucumber, melon, and watermelon, respectively. Normal germination percentages were determined periodically. A one-step approach was taken to analyze the effects of moisture on longevity and to estimate K-E and C-W. K-E and C-W values were found to be 4.86 and 1.59 for watermelon, 6.11 and 2.59 for melon, and 5.35 and 2.03 for cucumber, respectively. Watermelon seeds are the most sensitive to seed storage, whilst melon seeds have the greatest longevity. These constants can be used to predict the viability of these cucurbit seeds under various storage conditions.Öğe Electrical conductivity of seed soak water predicts seedling emergence and seed storage potential in commercial seed lots of radish(Ista-Int Seed Testing Assoc, 2014) Mavi, K.; Mavi, F.; Demir, I.; Matthews, S.Electrical conductivity (EC) measurements of seed soak water after 17 and 24 hours of nine commercially acceptable seed lots (79-100% standard germination) of the salad radish cultivar Findik were positively correlated with the mean time taken to emerge (MET) and negatively with final emergence (%) in sowings in modules and in the field. EC after 17 hours was closely related to both the means of the two sowings (R-2 = 0.877; P < 0.001), and standard germination after 12 months storage (R-2 = 0.868, P < 0.001). Thus increased levels of electrolyte leakage were associated with slower and lower emergence and with poorer storage potential. The mean germination time (MGT) to radicle emergence (RE) during germination at 20 C was similarly correlated with seed performance. The slower seed lots were to RE, the slower and lower was the emergence and the poorer the storage potential. EC after 17 hours was positively related to MGT (R-2 = 0.799; P < 0.01) and negatively related to germination after controlled deterioration, a measure of seed age (R-2 = 0.741; P < 0.01). Seed lots showing high levels of leakage were slower to RE and were more deteriorated. High leakage was associated both with seed lots having high percentages of dead seeds (no RE) and seeds producing abnormal seedlings, and also with lots containing seeds that were slow to produce an emerged radicle. EC is suggested as a potential one-day routine test of physiological seed quality for radish and the overall findings are discussed in relation to the effects of deterioration brought about by seed ageing.Öğe Mean germination time estimates the relative emergence of seed lots of three cucurbit crops under stress conditions(Ista-Int Seed Testing Assoc, 2010) Mavi, K.; Demir, I.; Matthews, S.A wide range of seedling emergence in commercial seed lots of watermelon (10 lots), melon (10 lots) and cucumber (9 lots), all with standard germinations above 98%, was seen in low temperature emergence (LTE). high temperature (HTE) and an 8 cm deep sowing (MSE) in the field and in salt stress conditions (SSE) in trays at 20 degrees C. Final emergence was closely related to both the rate of emergence, measured as mean emergence time (MET; the reciprocal of the rate of emergence), and to the mean germination time (MGT; the reciprocal of the rate of germination) for physiological germination (2 mm radicle) in the laboratory at 25 degrees C. Slower germinating and emerging lots, so-called low vigour lots, had lower levels of emergence in all sowings. Single early counts of physiological germination identified low vigour lots for all three species and are suggested as a quick routine test. The physiological age of the seed lots, determined using accelerated ageing (45 degrees C in 100% relative humidity) and controlled deterioration (45 degrees C and 20 or 24% moisture content), was significantly related to MGT which was higher (i.e. germination was slower) in physiologically older seed. Previous work suggests that cucurbit seeds appear to retain germination capacity over several years although ageing is reflected in a slower rate of germination (high MGT). MGT can also he described as the length of the lag period from the start of imbibition to radicle protrusion. We propose that this period is needed for the repair of the effects of ageing and is therefore longer in aged seeds.Öğe Radicle emergence test predicts longevity (half viability period, p50) of leek seed lots(Ista-Int Seed Testing Assoc, 2017) Ozden, E.; Mavi, K.; Sari, E.; Demir, I.This study was carried out to test whether a single radicle emergence count (RE) can be used for predicting longevity in leek seed lots. Experiments were carried out on eight commercial leek seed lots with normal germination percentages above 75%. Single radicle emergence counts (2 mm) were performed after 120 hours of germination (20 degrees C, dark, between papers). Seed longevity was determined by hermetic storage at 45 degrees C with 20% seed moisture content over 96 'hours. Twelve subsamples were taken out of controlled storage after 8, 16, 24, 32, 40, 48, 56, 64, 72, 80, 88 and 96 hours and seed survival curves were constructed on radicle germination tests. Half viability period, p(50), was calculated for each lot. The RE percentages in leek seed lots ranged between 75 and 94% after 120 hours, while p(50) values ranged from 25.9 to 77.4 hours. Regression between RE of 120 hours and p(50) was found to be highly significant (R-2 = 0.848, P < 0.01). Thus, single radicle emergence counts (120 hours) could be used as an assessment of seed longevity in leek.
