Abstract

The present study assessed whether seed germination of Peganum harmala L. is related to population size and whether factors that control three and four cotyledons and difference in cotyledon shape are different and whether abnormality of cotyledons is related to genetic drift. The percentage of final seed germination was highest in Dzungarian Gobian population and followed by Trans-Altai Gobian population and lowest was in East Gobian population (Tukey HSD test, p<0.01). Most seedlings of P. harmala have two cotyledons in our study areas but there were abnormal cotyledons which are three, four and different shape dicotyledons. Three and four cotyledons showed low frequency in biggest (limited by river basins) and bigger (limited by oasis) populations and high frequency in small population (limited by well) whereas pattern of different shape dicotyledon frequency does not follow difference of population size. The different shape dicotyledons showed higher frequency in region with lower elevation, as compared to regions with higher elevation. The present results suggest that percentage of seed germination of P. harmala and frequency of more than two cotyledons might depend on population size, while frequency of different shape dicotyledons might be related to habitat difference which is high soil salinity. Also, our results suppose more than two cotyledons might be related to genetic drift.

Key words: Abnormality of cotyledons, genetic drift, population size, seed germination.