Information on seed viability and understanding of the specific nutritional requirements for asymbiotic seed germination of orchid species are essential for successful production of plantlets for either conservation or commercial breeding programmes. We compared seed viability and in vitro seed germination of three rare and threatened neotropical epiphytic orchid species from the Lycaste genus . Viability was assessed using a Tetrazolium test (TTC) and in vitro germination was evaluated on three culture media [Murashige and Skoog (MS), Knudson C (KC) and basic culture media 1 (BM-1)]. All species exhibited high seed viability (above 70%) but relatively low germination (below 30%) across all media tested. Although seeds germinated on all media tested, MS media showed the highest germination and high-quality plantlets. However, the fact that seed germination did not reach the highest potential, as indicated by the TTC viability test, signifies that further optimisation of in vitro germination media is required. We discuss the reasons behind the gap between viability and germination and suggest avenues for future research. These findings highlight the need for species-specific media optimisation to bridge the gap between seed viability and germination, and to establish effective conservation protocols for these threatened orchids.

Looking back on 2025, a total of 37 research papers have been published in Seed Science and Technology. The research that has been reported in this volume has been carried out all over the world and covers topics including dormancy and germination, new technologies in seed testing, vigour testing and enhancement, and seed storage. The range of species which researchers have focused on is diverse and has included major staple food crops, forages, trees and orchids.

Potential seed storage longevity is influenced by environment during seed development and maturation but postharvest processing may also affect longevity, particularly in accessions with variable maturity or seed shedding. The impact of sequential harvesting and post-harvest processing was examined in durum wheat (Triticum turgidum subsp. durum) and its wild relatives, Triticum turgidum subsp. dicoccoides and T. monococcum subsp. boeoticum. Spikes were collected in sequential harvests as they matured and either processed immediately (fumigated, threshed, cleaned, dried) or delayed (remaining in the field until all plots were harvested). A separate study with durum wheat assessed seed quality throughout development and maturation and the effects of initial post-harvest drying temperatures. Delayed processing resulted in equal or greater seed longevity than immediate processing across all accessions. In durum wheat, longevity improved considerably between 21 and 41 days after heading but declined thereafter. Initial seed drying temperature affected longevity: 30°C was optimal for the earliest harvests, whereas 15°C was superior at harvest maturity and beyond. These findings demonstrate that immature seeds can continue to develop in quality ex planta under warm, dry conditions, challenging conventional recommendations for immediate post-harvest processing and suggesting a potential role for delayed processing in optimising seed longevity.

This study was conducted to assess the analytical quality of commercial rice seed lots in the Nigerian seed industry and to identify the weed seeds associated with the seed lots. Fifty seeds samples of commercially produced lowland and upland rice varieties from 50 seed companies spread across 25 states of Nigeria were tested for the presence of weed seeds that are considered as constraints to agricultural production in Nigeria. The results show that the average percentage pure seeds was 97.95% (approximately 98.0%), while the percentage of other seeds and inert matter were 1.10% and 0.95% respectively. The seeds of Oryza glaberrima were more common compared with other weed seeds that were identified. It is also apparent that seeds of O. longistaminata, Rottboellia cochinchinensis and Lithospermum spp. were identifiable after conditioning and could be categorised as noxious and prohibited weeds. These results underscore the need for more innovative research-based weed control management strategies in the Nigerian seed quality assurance scheme to control trans-border transfer of quarantine weeds seeds. Such efforts would boost trust in the seed trade.

Many forage species exhibit seed dormancy, which prevents germination and poses challenges for seed growers and analysts. Various methods have been developed to overcome dormancy in different forage species, but their effectiveness varies depending on the species and environmental conditions during seed development and storage. The seeds of Chamaecytisus proliferus exhibit dormancy due to a hard seed coat and lens covering the embryo. To overcome this dormancy, we evaluated physical, mechanical and chemical scarification methods. Among the treatments, excised embryos achieved the highest germination proportion (0.95). Hot water treatment for 15, 20 and 25 minutes effectively broke dormancy, resulting in proportions of 0.89, 0.92 and 0.89 germinated seeds, respectively. Treatment with 0.1 or 0.2% KNO3 also enhanced germination, whereas a 0.3% solution led to lower germination (0.73). Exposure to concentrated H2SO4 increased germination but caused a high proportion of dead seeds and abnormal seedlings. Similarly, mechanical scarification using a scalpel blade resulted in low germination (0.70) and a high proportion of seedling abnormalities (0.3). All pre-treatments reduced mean germination time, with excised embryos germinating fastest. In conclusion, excised embryos and hot water treatment (15-25 minutes) effectively break dormancy and enhance germination in Chamaecytisus proliferus.

Seed moisture is a crucial aspect of seed quality which reflects the physiological status of the seed tissues. The International Seed Testing Association (ISTA) currently requires seed moisture to be reported as the percentage – by weight – of the sample that is water, most often determined using the constant temperature oven method. The introduction of water activity (aw) as an alternative method is being evaluated, hence in this study, we determined the moisture relations of film-coated or pelleted vegetable seeds to see whether aw measurement is a reliable method to assess seed moisture status. The film coating used on these seeds did not significantly change the relationship between seed moisture content (MC; % fresh weight) and aw for carrot and endive seeds. There were some differences in the relationship between control (non-coated) and film-coated lettuce seeds. The sowing unit of pelleted seeds of lettuce (primed seeds) and chicory showed very much lower moisture contents, suggesting that the pellet material had very different moisture relations compared with the seeds themselves. Moisture history, including priming, is an important consideration when reporting aw results.

Effective management of seed collections in genebanks requires knowledge of seed storage behaviour and species-specific longevity under conventional air-dry storage. This knowledge is lacking for traditional African vegetable (TAV) crops compared to cereals and conventional vegetables. This review aimed to assess the published literature until December 2023. The findings will guide post-harvest seed processing (cleaning and drying), storage (containers, storage parameters), viability monitoring and regeneration intervals, and to identify further research gaps that will inform data needs from the genebanks conserving TAV seeds. Our findings show that, compared to cereals and legumes, there is limited information available on vegetable crops and more acutely on TAVs. While conventional vegetable seeds benefited from research on their storage behaviour and longevity, there was significant neglect of TAV crops, which represented only 17% of the studies reviewed. Overall, genebanks involved in TAV germplasm conservation should invest more time and resources to investigate seed physiology and generate data that will inform on the storage behaviour and longevity of these crops under medium and long-term storage conditions. Such data are important to establish crop-specific knowledge on optimal conditions for high post-harvest seed quality, and for genebanks to plan seed regeneration.

The detection of seed viability is an important step in seed production, as well as in conservation and restoration practice. Due to random natural events, the quality and viability of seeds of wild flowering species vary substantially, and hence a quick and reliable method for seed viability assessment is desirable. X-rays provide information about the internal structures of a seed and therefore show promise for detection of viability and even germination capacity. Seeds of 207 accessions of 176 wild flowering plant species were x-rayed and the viability results were compared with combined germination-TZ test results. Of special interest was whether there are certain plant families for which x-ray is an appropriate method for viability detection, considering correlations with seed internal morphology, seed mass and/or shape. The comparison revealed a strong correspondence between viability determination by combined germination-TZ tests and by x-ray analysis. According to taxonomy and seed type, two main groups could be distinguished, that differed significantly in viability detection by x-ray and combined germination-TZ test. Whereas the evaluation of little/non-endospermic seeds gave approximately identical results, there was greater discrepancy for of endospermic seeds. Seeds of different sizes and shapes were evaluated similarly with both methods. Especially for little/non-endospermic seeds, x-ray can provide a useful and quick tool for viability detection, whereas for endospermic seeds, further research is needed. For the commercial seed industry, viability detection via x-ray should be the first step before further vigour testing is performed.

This study was carried out to determine the use of single counts of radicle emergence to test seed vigour and estimate seedling field emergence of soybean (Glycine max) seed lots. Results of radicle emergence (RE) (production of 2 mm radicle) at 20°C for 48 hours and 25°C for 24 hours, mean germination time (MGT), tetrazo lium vigour test (TZ) and field emergence (FE) were compared using nine soybean seed lots with standard germination above 80%. The single counts of RE performed at 20 and 25°C were significantly correlated with the MGT at the same temperature (R2 = 0.82 and 0.89, respectively) and with the TZ vigour (R2 = 0.96 and 0.93, respectively). The RE counts at both temperatures also estimated the field emergence of the seed lots (R2 = 0.74 at 20°C and 0.68 at 25°C). The TZ vigour results had a significant correlation with the seedling field emergence (R2 = 0.70). Results indicate that a single count of radicle emergence after 48 hours at 20°C or 24 hours at 25°C is an efficient option for soybean seed vigour assessment.

Cynanchum forrestii is an over-harvested medicinal plant species in China. At present, wild resources of this species urgently need to be conserved and cultivated to meet the demand of the pharmaceutical industry. However, information on reproduction and propagation is not available. Here, different treatments were assessed to develop an effective protocol for facilitating seed germination of this species. Once seeds were released from physiological dormancy, using 25/15°C with a 12-hour light period promoted germination. Seeds cold stratified at 4°C for 90 days and 120 days germinated to 87 and 91%, respectively, and mean germination time was 11.53 and 10.52 days, respectively. The combination of 60 days cold stratification and 200 mg L-1 GA3 significantly increased germination from 11% (fresh seeds) to 87%. Among four concentrations used, 200 mg L -1 GA3 was the most effective for promoting germination of 90-day dry-stored seeds. Taken together, cold stratification for 90 days or more is recommended as a practical measure to break innate dormancy of this species.