Iranian Journal of Seed Research

The effect of seed rate of alfalfa (Medicago sativa L.) and efficiency of plant growth promoting bacteria (PGPR) that facilitates phosphorus uptake with different doses of phosphate fertilizer was evaluated on seed quality. For this purpose, the germination and seed vigor tests before and after accelerated aging were performed in a split split plot experiment based on randomized complete block design with three replications in 2010 in the field of education and research in the College of Agriculture and Natural Resources, Tehran University, Karaj. Phosphorus factor at 4 levels (0, 30, 60 and 90 kg Phosphorus.ha-1) in main plots, PGPR (Pseudomonas) in three levels (no bacteria, bacterial strains, No. 9 and bacterial strains No. 41) in subplots and rate of seed factors on three levels (2, 6, and 10 kg of seed per hectare) were the sub-subplots. The results showed the highest rate of germination and seed vigor obtained by use of 6 kg seeds per hectare, PGPR No.41 strains with 30 kg Phosphorus per hectare and after accelerated aging. The highest rate of germination and seed vigor at 10 kg of seed per hectare were found for PGPR No.41 strains, with 60 kg Phosphorus ha-1 treatments. After accelerated aging practices to achieve maximum germination index and vigor, seed rates and phosphorus requirement were more than standard conditions. Based on obtained results for the storage conditions, bacterial strains No. 41 had a better effect on increasing seed vigor than bacterial strains No. 9. To produce alfalfa seed with high vigor and obtain better results, use of optimum seed rates and phosphorus (6 and 30 kg.ha-1, respectively) along with PGPR (strain No. 41) could be considered in crop plants.

In order to investigate the effects of priming with a KH2Po4 solution on emergence and heterotrophic growth of black cumin (Nigella sativa L.) seedling, a series of experiments were conducted at the Faculty of Agriculture, Ferdowsi University of Mashhad, Iran, in 2013 and 2014. A field experiment was conducted as factorial layout based on a randomized complete block design with four replications. The fertilizer resources (vermicompost (V)+Tiobacilus (T), micronized Sulfur (S)+T, V+S+T and control) and three levels of phosphorus (0, 30 and 60 kg.ha-1) were the first and second experimental factors, respectively. In the second experiment, selected treatments (in which showed emergence below 60% in the previous experiment) and seed priming (no priming, hydro priming and three levels of phosphorus (P)-priming as 100, 300 and 500 mM KH2Po4) were the first and second experimental treatments, respectively. Based on the results, the resources of soil amendment (V+T and V+S+T) significantly increased the emergence percentage of black seed (by 50 and 54%, respectively). In addition, seed reserve depletion percentage, seed reserve utilization efficiency and emergence percentage significantly increased by 300 mM KH2PO4 (by 9, 143 and 29%, respectively). There was a significant positive relationship between the weight of mobilized seed P and the emergence percentage of black seeds (R2= 0.90 **).