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• Alternating temperature enhanced seed germination in four cultivars of aubergine. • The most effective treatment tested was a temperature regime of 35/20°C at 16/8 h. • Endogenous hormone analysis showed decreased ABA in seeds with higher germination. • Increased germination and emergence correlated well with increase lipase levels. • There was a corresponding increase observed in SOD with increased germination. High seed quality is important for obtaining high quality seedlings for commercial vegetable production. The rate of seed germination affects seedling quality since seeds which tend to germinate more slowly generally result in low-quality seedlings, especially in aubergine seeds. Alternating temperatures play a crucial role in determining the rate of seed germination in many plant species. This study investigated the effect of alternating temperatures on aubergine seed germination, emergence rates, and physiological changes regulating dormancy. Seeds from four open-pollinated aubergine cultivars were incubated for 14 days under the following temperature regimes: 35/20°C-24/24h, 35/20°C-16/8h, 35/20°C-8/16h, 30/20°C-24/24h, 30/20°C-16/8h, 30/20°C-8/16h, or at constant 25°C. The highest mean germination was 92%, with a corresponding highest mean emergence of 88%, which was found with the 35/20°C-16/8h treatment. All alternating temperature treatments displayed faster germination and emergence compared to the control (25°C), as well as high catalase, superoxide dismutase and ascorbate peroxidase antioxidant enzyme activities, and high auxin and salicylic acid levels. In contrast, lipase enzyme activity, abscisic acid and jasmonic acid content decreased. In conclusion, these findings showed that alternating temperatures improved aubergine seed germination rate, and seedling emergence, and also demonstrated positive correlations with enzymatic and hormonal fluctuations within the seeds. [ABSTRACT FROM AUTHOR]

The study aimed to test various vigour tests to correlate them with seedling emergence in two field sowing dates and two different sowing depths in controlled room emergence of ten dill seed lots. Mean germination time, accelerated aging; for 24 hours, 48 hours, and 72 hours, electrical conductivity readings at 16 hours and 24 hours, and EC readings after AA test were used as vigour tests, and results were correlated with seedling emergence percentages. Seedling emergence was tested in two sowing dates in the field and two different sowing depths in controlled room conditions. Controlled room seedling emergence values (80-95% in 2 cm, 76-92% in 4 cm) were higher than those of field emergence values (67-85% in the first sowing and 60-80% in the second sowing). Most of the vigour tests were significantly correlated with emergence potential. The highest correlation values were observed in EC16h and EC24h tests, significance between emergence and these two vigour tests were at P<0.001 three out of four sowings. The results indicated that EC16h can be a fast, practical and easy method of seed vigour discrimination in dill seed lots. [ABSTRACT FROM AUTHOR]

The work was carried out to test the seed vigour test to correlate seedling emergence potential of rocket seed lots in the field conditions. Standard laboratory germination percentages of the 12 seed lots were ranged between 87 and 93%. Radicle emergence (2 mm) percentages after 18 (RE18h), 24 (RE24h), 36 (RE36h) and 48 (RE48h) during standard germination test, accelerated ageing test (AA, 45 °C, 100% RH, 24h, 48h), electrical conductivity (20 °C, 40 ml, 50 seeds) of 8h, 16h and 24h readings were used as vigour tests. Seeds were sown in two occasions in the field and vigour test results were correlated with seedling emergence percentages. Even though all seed vigour tests were significantly correlated with emergence at various levels EC24h and RE24h showed the highest correlation (p<0.001) with seedling emergence percentages in both sowing times. Correlation values were 0.824 and 0.844 in EC24h, 0.860 and 0.874 in RE24h.The lowest correlations were seen in standard laboratory germination test as 0.640 and 0.654 (p<0.05). Results indicated that EC24h and RE24h are practical and fast vigour tests that can be related to seedling emergence potential in rocket seed lots. [ABSTRACT FROM AUTHOR]

This study was carried out to determine seed longevity in organic and conventionally produced pepper seeds from four different pepper cultivars. Seeds were stored at 20±2 °C with 7.5±0.5 seed moisture over 48 months. Longevity of seeds were evaluated with Ki (initial seed quality), P50 (half-viability period), σ (standard deviation of distribution of seed deaths in time), and regression coefficient values. The highest longevity was observed in 'Corbaci' and 'Yaglik' cultivars, while 'Surmeli' and 'K. Dolma' were found to have shorter longevity. P50 was 43.4 and 40.2 months for 'Corbacı' and 34.9 and 39.7 months for 'Yaglık' organic and conventional cultivars, respectively, whereas it was about 21.4 and 23.7 months in 'K. Dolma' and 'Surmeli' cultivars. Similarly, the highest σ and regression coefficient values were observed for 'Corbaci' and the lowest for 'Surmeli' cultivars. Organic and conventional pepper seed longevity was not different in the same species. Regression coefficient values were 0.043 in organic and 0.046 in conventional seeds for 'Corbaci'. Very close values were found between the two production systems for the other cultivars too. Results indicate that organic seeds had similar longevity to conventional ones. The main differences originated from the cultivars, not from the production system. [ABSTRACT FROM AUTHOR]

This study aims to determine the effect of solid matrix priming (SMP) treatment with an air composition of O2, N2, air, vacuum on four leek (Allium ampeloprasum L.) seed lots of various ages, in terms of enhancing germination, mean germination time, electrical conductivity of solute leakage and catalase activity. Untreated seeds were used as control. Solid matrix priming at a seed: vermiculite: water ratio of 2.5:1.25:3.75 (w/w/w) was applied at 20 °C for 24 hours in the dark. Solid matrix priming with O2 was found to give the highest germination, lowest mean germination time, lowest electrical conductivity (reduced solute leakage) and the highest catalase activity among all treatments and lots. SMP treatment with air provided positive response, while N2 and vacuum treatments were found to be less effective. The advantages of solid matrix priming were more pronounced in lower quality lot than in the higher quality ones. The results indicated that oxygen enrichment in SMP may enhance leek seed quality. [ABSTRACT FROM AUTHOR]

An experiment was made to test the potential for radicle emergence (RE), and predict the germination percentage of normal seedlings both at constant (25 °C) and fluctuating (20/30 °C, 16 h/8 h) temperatures for 23 commercially available Thiram treated and untreated aubergine (Solanum melongena L.) seed lots. Frequent counts of RE at 96, 104, 112, 120, 128 and 136 hours in two different temperature regimes (constant and alternating) consistently predicted final normal germination after 14 days. The R2 values at fluctuating temperatures (R2=0.69 and 0.88, p < 0.001) were generally higher than those at a constant (R2=0.60-0.63, p < 0.01) temperature. Among the 23 seed lots, nine were Thiram threated. The R2 relationship in both temperature regimes were reduced (for Thiram-threated seed lots ranging between R2=0.60-0.79 at 25 °C and 20/30 °C respectively, and for untreated lots ranging between R2=0.68-0.91 at 25 °C and 20/30 °C, respectively). Cumulative germination was slightly higher in the lots kept at fluctuating temperatures than in those kept at a constant temperature. The results showed that the RE test (i.e. 104 h count) can be used to make quick and repeatable predictions of the percentage of normal seedlings in aubergine lots. Moreover it was also significantly related to mean germination time (MGT) values at constant (R2= 0.769, p < 0.001) and alternating temperatures (R2= 0.861, p < 0.001). [ABSTRACT FROM AUTHOR]

This work tested the effect of after-ripening on seed germination of thirteen commercial seed lots from four open pollinated cultivars (Aydın Siyahı, Kemer, Pala and Topan) of aubergine (Solanum melongena L.). Seeds were stored (after-ripened) at 5 °C with at 9% seed moisture content over 14 days in the dark in hermetic conditions. After-ripened seeds were tested at 25 °C and 20/30 °C (16/8 h) together with a control at 20/30 °C for 14 days in petri dishes. Results indicated that after-ripening significantly (p < 0.05) increased total germination in six lots and normal germination in eight lots out of thirteen when germination was tested at 25 °C. Increases were also observed eleven lots in total and thirteen in normal germination percentages out of thirteen when seeds were tested at 20/30 °C. Cumulative germination showed that after-ripened seeds germinated faster than control either germinated at 25 or 20/30 °C. Results indicated that aubergine seed germination can be increased through after- ripening treatment which shows the presence of seed dormancy in this species. [ABSTRACT FROM AUTHOR]

This study was conducted to test the effect of a priming combination on the seed germination percentage and seedling emergence performance of purslane under climate chamber and field conditions. Four purslane seed lots were treated according five different methods, which were T1: Seeds kept at a hundred percent relative humidity for four hours at 20 °C; T2: Seeds kept at a hundred percent relative humidity for four hours at 20 °C, and then soaked in distilled water for 8 hours at 5 °C; T3: Seeds kept at a hundred percent relative humidity for four hours at 20 °C, and then soaked in distilled water for 8 hours at 20 °C; T4: Seeds soaked in distilled water for 8 hours at 5 °C; T5: Seeds soaked in distilled water for 8 hours at 20 °C; and C: Control (untreated). Seed germination was calculated for 14 days at 20 °C, seedling emergence percentages were calculated in the climatically-controlled chamber for 21 days at 22 °C, and in the field for 35 days at 15-25 °C. The highest seed germination (94%) and seedling emergence in the climatically-controlled chamber (87%) and field (82%) were obtained from seeds that had been kept at a hundred percent relative humidity for four hours at 20 °C, then soaked in distilled water for eight hours at 5 °C. Results indicated that farm-priming, can be an efficient priming method in purslane seeds. [ABSTRACT FROM AUTHOR]