The high emergence and uniform seedling size required for glasshouse production of modular transplants of peppers is not always achieved due to vigour differences among commercial seed lots. The mean germination time (MGT) at 18 and 25°C was determined in laboratory germination tests for 11 lots of the cultivar Demre and found to be related to seedling size (root and hypocotyl length) and variation. The longer the MGT (germination slower and more spread in time) the smaller and more variable the seedlings. MGT at both temperatures was also related to mean emergence time (MET) in transplant modules in two experimental runs. In turn, MET was related to mean seedling weight (R²=0.72, R²=0.75, p<0.001 for fresh weight and R²=0.83, p<0.001; R²=0.68, p<0.01 for dry weight) in both runs. Slow germinating lots (high MGT) were slower to emerge in modules (high MET) and produced smaller seedlings. The MGT at 25°C of five further lots of Demre was related to MET in modules (R²=0.84, p<0.05). MGT and MET were both inversely related to the variation in fresh weight of individual seedlings (MGT: R²=0.79, p<0.05; MET: R²=0.96, p<0.01) and variation in dry weights (MGT: R²=0.74, NS; MET: R²=0.89, p<0.05). Germination after controlled deterioration (CD) for the five lots was inversely related (R²=0.93, p<0.01) to MGT indicating that seed ageing was a cause of low vigour and high MGT. The need for repair of deterioration is discussed as a possible explanation of differences in MGT and performance in modules.

The need for the conservation of plant genetic resources has been widely accepted. Germplasm characterization and evaluation yield information for more efficient utilization of these valuable resources. The aim of the present study was to characterize the pea germplasm conserved at the Aegean Agricultural Research Institute of Turkey using morphological and simple sequence repeat (SSR)-based molecular approaches. Genetic characterization of 30 pea genotypes collected from different regions of Turkey and 10 commercial pea cultivars was performed using the criteria of the International Union for the Protection of New Varieties of Plants (UPOV) (TG 7/9 Pisum sativum), and with 10 SSR markers. We originally tested 15 SSR markers; 10 of these markers were selected on the basis of high polymorphism information content in the molecular assays. Sixty-one alleles were detected at the 10 loci. The number of alleles per SSR locus ranged from 3 (PVSBE2) to 12 (AB53), with a mean of 6.1 alleles. The most informative loci were AB53 (12 alleles), AA355 (9 alleles), AD270 (8 alleles), A9 (7 alleles), AD61 (7 alleles), and AB25 (6 alleles). The UPGMA dendrogram defined by SSR markers revealed genetic relatedness of the pea genotypes. These findings can be used to guide future breeding studies and germplasm management of these pea genotypes.

A study was carried out to test whether a single count of radicle emergence (RE test) would correlate with the storage potential of seed lots of cucurbit (C. maxima × C. moschata) rootstock cultivars. The RE test was performed by counting radicle emergence percentage between 26 and 100 hours of germination. Seed longevity was determined by storage at 75% relative humidity at 35°C over 100 days, with seed survival curves constructed based on normal germination percentages. K_i (estimated initial viability in probits), σ (standard deviation of the normal distribution of seed death in time) and p₅₀ (time for viability to fall to 50%) were determined through probit analysis. Correlation analysis showed that RE counts particularly between 30 and 34 hours were highly (P < 0.01) correlated with normal germination percentage, K_i and p₅₀. It can be concluded that RE tests can be used as an indicator of subsequent seed lot longevity in cucurbit rootstock seed cultivars.

This study was conducted to test the potential of the radicle emergence (RE) test to predict normal germination percentage (NG) in seed lots of watermelon, lettuce and carrot. One seed lot of each species was aged at 100% RH and 45°C for different times to produce 14 aged sub-samples. The RE (≥ 2 mm radicle) was counted during a germination test (ISTA Rules) and NG was assessed at the end of the test. RE counts after 74 (watermelon), 40 (lettuce) and 120 hours (carrot) were significantly (P < 0.001) related to NG (watermelon, R² = 0.81; lettuce, R² = 0.74; carrot, R² = 0.81). RE counts at the same times were significantly related to NG in ten commercial seed lots of watermelon (R² = 0.66, P < 0.01), nine lots of lettuce (R² = 0.94, P < 0.001) and eight lots of carrot (R² = 0.64, P < 0.05). The potential of the RE test to predict NG of both different lots within the same cultivar (watermelon, carrot) and lots from different cultivars (lettuce) is discussed.

This work was conducted on the use of the RE (radicle emergence) test to estimate the seedling emergence (SE) and quality (seedling shoot weight (SSW), seedling root weight (SRW) and seedling height (SH)) of twelve hybrid cucumber seed lots with high germination (>95%) at low temperature conditions, high salt conditions and a combination of the two. The percentages of RE, which is a 2 mm radicle protrusion at 25 °C in the dark, were counted between 18 h and 32 h. The seeds were sown in peat moss in trays and kept at 15 °C (low temperature stress), or salty water was applied as 100 mM NaCl at 25 °C (salt stress) for three days, and both were applied in a combined-stress environment. Seedling emergence and quality parameters were reduced by both stress environments and their combination. SE, SSW, SRW and SH values ranged between: 91–100%, 614–844 mg, 102–143 mg, 6.8–8.8 cm at low temperature; 90–98%, 598–904 mg, 101–154 mg, 6.5–7.8 cm at salt stress; and 76–92%, 464–608 mg, 97–133 mg, 5.8–6.9 cm at their combination. The RE values with great differences seen among the lots (20–28 h) were regressed with seedling emergence and quality values. RE 24 h had the highest R² and significant values in all stress environments as R² = 0.596–0.858, p < 0.05–0.001 at low temperature; R² = 0.620–0.827, p < 0.05–0.001 with salt; and R² = 0.686–0.842, p < 0.05–0.001 with combined stresses. We concluded that RE as a vigour test can be used successfully to estimate the seedling quality of highly germinating hybrid cucumber seed lots. Use of the RE test in hybrid cucumber seeds and its influence on high-quality seedling production were discussed.