Inter-population variabilities in seed mass and germination of Panicum turgidum and Pennisetum divisum in the desert of Kuwait
摘要：Understanding variability in seed germination among populations is essential for planning an effective germplasm collection for restoration and conservation purposes. The knowledge of germination and dormancy patterns among populations of desert grasses is crucial for determining the potential of the species and populations to be used for restoration and conservation as well as forage production. Variability in seed germination of Panicum turgidum Forssk and Pennisetum divisum (Gmel.) Henr. in the desert of Kuwait was evaluated in different populations in May 2017. Experiment of seed germination (25 seeds and 4 replicates) was conducted for each population at night/day temperatures of 15°C/20°C and 20°C/30°C under the following light condition: continuous darkness or 12 h/12 h light/dark. Results showed that seed masses of both species strongly varied according to their seed provenances, and both species produced heavier seeds in population with a higher soil electrical conductivity. Seed germination percentage considerably varied between two species, and the variation in P. turgidum was greater (17%–49%) than that of P. divisum (72%–93%). Germination percentage in P. turgidum was greater at high temperature (20°C/30°C) than at low temperature (15°C/20°C). However, temperature regimes had no effect on germination percentage of P. divisum seeds. Mean germination time of both species exhibited significant inter-population variability. This result is especially relevant to assure the selection of the best population of each species and the regeneration success of the species. Besides this, inter-population variability also provides valuable information for enhancing our understanding of the mechanisms that regulate seed germination and how they might be related to seed provenance.