Effect of Genestein Concentration on Nodulation and Nitrogen Content of Three Annual Medic Species in Low Root Zone Temperature

Effect of different genestein concentrations on nitrogen content and nodulation in annual medics was studied; this research was done under controlled environmental condition at the 20/25 oC day/night air temperatures and 5 oC low root zone temperature. Three annual medics species (Medicago polymorpha, Medicago radiate, Medicago rigidula) adapted to cold and temperate zones and 5 genestein levels (0, 10, 20, 30 and 40 µM) were considered in this study. The experiment was conducted in complete randomize block design, factorially arranged, with 3 replications. M. rigidula and M. polymorpha were superior than M. radiata for all measured traits. The mentioned species produced more nodules than M. radiata at low root zone temperature. Genestein increased nodulation and nitrogen content of annual medics at low root zone temperature. Also 20 µ M genestein had the highest effect on nodulation and nitrogen content at low root zone temperature. Root dry matter, nodule number, nodulation and nitrogen content were increased in annual medics at 5 oC, by genestein application. Interaction between cultivars and genestein concentrations showed that M. polymorpha with 20 µ M genestein application was more efficient in most of measured traits than other species. So, using genestein could be helpful for increasing nodulation and size of nodules in regions with low air and soil temperature in the beginning of growing season.