Effects of Seed Priming on Morph-physiological Traits of Three Ecotypes of Astragalus squarrosus Bunge Grown in Iran

Astragalus squarrosus Bunge is one of the native and compatible range species in the dry lands of Iran. It is of great importance in terms of tolerance to specific ecological conditions as well as high nutritional value and soil conservation. In order to study the effects of seed priming on some morph-physiological traits, an experiment was conducted in form of split plots based on a completely randomized block design with five replications in Torud Research Farm in Semnan Province, Iran in 2017. Seed samples were collected from their natural habitats in Yazd, Kashan and Semnan in Iran. Seeds of three A. squarrosus ecotypes were treated by hydropriming (distilled water), hormonal priming (gibberellic acid: with concentrations of 125 and 250 ppm), (Salicylic acid: 100 and 200 mg/l), (Ascorbic acid: 100 and 200 mM) osmopriming (potassium nitrate: 0.3 and 0.2%) and control (without priming). The primed seeds and controls were sown in the field. No seeds were germinated for control and gibberellic acid (250 ppm). The results showed that the effect of priming was significant on leaf carbohydrate content, vegetation cover, dry matter (DM), yield and plant height (p<0.01). According to the results, the highest DM yield and plant height with average values of 82 (g/m2) and 34 cm, respectively, were related to the ecotype of Yazd treated with salicylic acid 100 mg/l. The highest vegetation cover with an average value of 34.6% was observed in Kashan ecotype by applying salicylic acid 100 mg/l. For carbohydrate content, the highest value of 36 (g/100gFW) was obtained in Semnan ecotype using 100 mg/l salicylic acid. The highest rate of proline with a value of 3.39 (Mm/gFW) was obtained in Semnan ecotype using 125 ppm gibberellic acid. It was concluded that application of hormonal seed priming of A. squarrosus could be useful for direct seeding of this species for rehabilitation of degraded arid rangelands of Iran.