Effect of Population, Collection Year, After-Ripening and Incubation Condition on Seed Germination of \u3cem\u3eStipa bungeana\u3c/em\u3e

Knowledge of the germination behavior of different populations of a species can be useful in the selection of appropriate seed sources for restoration. The aim of this study was to test the effect of seed population, collection year, after-ripening and incubation conditions on seed dormancy and germination of Stipa bungeana, a perennial grass used for revegetation of degraded grasslands on the Loess Plateau, China. Fresh S. bungeana seeds were collected from eight locally-adapted populations in 2015 and 2016. Dormancy and germination characteristics of fresh and 6-month-old dry-stored seeds were determined by incubating them over a range of alternating temperature regimes in light. Effect of water stress on germination was tested for fresh and 6-month-old dry-stored seeds. Seed dormancy and germination of S. bungeana differed with population and collection year. Six months of dry storage broke seed dormancy, broadened the temperature range for germination and increased among-population differences in germination percentage. The rank order of germination was not consistent in all germination tests, and it varied among populations. Thus, studies on comparing seed dormancy and germination among populations must consider year of collection, seed dormancy states and germination test conditions when selecting seeds for grassland restoration and management

Genetic control of Eucalyptus globulus seed germination

International audienceAbstractKey messageThe maternal genotype has a significant effect on most germination traits ofEucalyptus globulusseeds. These differences can be partly explained by genetic-based differences amongst races, including differences in sensitivity to high temperatures which may be of adaptive significance.ContextSlow and uneven germination of Eucalyptus globulus seeds in commercial nurseries can be a problem which has been linked with periods of high temperature.AimsThis study aimed to determine whether maternal genotype affects the germination of E. globulus seeds.MethodsBy sampling seeds over two seasons from multiple randomised ramets (trees) of maternal genotypes from three races of E. globulus growing in a seed orchard, the extent of genetic control of seed germination responses was assessed at different germination temperatures.ResultsMaternal genotype had a significant effect on most germination traits but a differential response to temperature was more evident for germination proportion than rate traits. Maternal races differed in their rate of seedling development regardless of temperature, but differences in the germination proportion were only detected at high temperatures.ConclusionThe present study highlights the potential adaptive significance of the germination response and the need for seed lot-specific germination testing as both genetics and maternal environment vary