نشریه علوم و تحقیقات بذر ایران
سال دوم شماره 2 (پاییز و زمستان 1394)

Hydrotime is a method to describe the relationship between water potential and seed germination rates and percentages. Hydrotime analysis quantifies the germination rate (θH), germination tolerance to water stress (Ψb) and uniformity of germination (σb) in a seed sample which are major indicators for seed vigor. In order to investigate the possibility of hydrotime model application (based on Inverse-normal distribution) to predict the seedling emergence of barley in field, experiments were conducted on seven spring barley (Karoon, Zahak, Nimrooz, Hull-less, Jonoob, Reyhaneh and Behrokh) in seed technology laboratory and research farm of Ramin Agriculture and Natural Resources of Khuzestan. For this, the effect of reduced water potential on seed germination of barley varieties was described using the hydrotime model. Then, correlations among the output parameters of the hydrotime model and seedling emergence of barley varieties in field were investigated. Results showed that there were no significant differences among varieties in terms of standard germination percentage (P=0.2719), but seedling emergence percent in field significantly affect by variety type (P<.0001). There were significant negative correlation between field emergences of barley varieties with scale (σ; with a correlation coefficient of -0.5709), mean (with a correlation coefficient of -0.8768), median (Ψb(50); with a correlation coefficient of -0.8769) and mode (with a correlation coefficient of -0.7039) of basic water potential (Ψb(g)) distribution (P<0.01). According to the results, the seedling emergences of barley varieties in field increased with more germination uniformity in osmotic stress levels and higher tolerance of varieties to this stress. Therefore, this model is recommended as one of the seed vigor tests to distinguish strong and weak varieties of barley.

Seed qualitative characteristics and their effects on seed germination are affected by genotype and soil moisture conditions in the field and the time after harvesting. The experiment was carried out as factorial split-plot design in randomized complete with three replicates in laboratory condition. The main plots were combination of 4 different irrigation regimes (I1, I2, I3= eight, six and four hours every other day, respectively and I4 = four hours per day) and 4 different genotypes [Danial (V1), Line6 (V2), Champa (V3), Red Anbori (V4)]. Five post-harvest interval times (0, 20, 40, 60 and 80 days) were considered as subplots. The results showed that high yielding genotypes were superior in comparison with local genotypes because of less shell percentage, higher 1000 seeds weight and bigger embryo. Seed qualitative characteristics affected by genotype, irrigation regimes and the time after harvesting. IR2 was the best treatments in the germination percentage (77%), length of shoot (8.9cm) and seedling dry weight (34mg). Line 6 had the highest seed germination (82%), root length (8.7cm) and seedling dry weight (43.6mg). The highest shoot length (9cm) grew up 60 days after harvesting. By applying every irrigation regimes, line 6 after the 80-day time after harvesting had the highest seed germination.

This experiment was conducted in order to investigate the effect of seed coating with micronutrients on germination characteristics of Marigold, and carried out  as complete randomized design (CRD) with four replications at agronomy laboratory in faculty of Agricultural Science, University of Guilan was performed in 2014. Experimental Treatments were including seed without coating, seed coating without micronutrients, seed coating with micronutrients (Fe, Mn, Cu), seed coating with micronutrients (Mo, Zn, B), and seed coating with micronutrients (Fe, Mn, Cu, Mo, Zn, B). Germination percentage, root length, shoot length, root dry weight, shoot dry weight, seedling length, fresh and dry weight of seedlings, seed vigor, vigor length l index, Allometric coefficient, seedling tissue water content , uniformity of germination, D10, D50 and D90, respectively, for the time they reach 10, 50 and 90%, amylase enzyme activity was studied in this experiment. Coating marigold seeds with micro-nutrients, significantly increased multiple parameters such as germination percentage, seed vigor index, root and shoot length and amylase activity in comparison with control treatment . Among the elements used in this experiment, 3 elements iron, manganese and copper had the greatest influence on the germination process.

Effect of harvest time on seed quality of cow pea cultivar Kamran was evaluated in a field experiment to determine the best time of harvest for achieving high quality seeds. The experiment was carried out based on RCBD in three replications. The treatment was the time of harvesting from mother plant in which seed were harvested at 9 stages in four-day intervals. Seed quality indicators including seed germination percentage, seedling dry weight, 1000-grain weight, electrical conductivity of seed lot and seed moisture content were determined for assessing seed quality. Results revealed that harvest time affected seed quality traits where with increasing harvest time and completing essential structures, seed germination, 1000-grain weight and seedling dry weight increased and EC and moisture content decreased. The highest seed quality was attained at 32 days after flowering which stayed constant until 38 days after flowering. However, regarding seed moisture content, 38 days after flowering was better harvest time, since at the time of 32 days after flowering, seeds had high moisture content which may result in mechanical damage to seeds. Therefore, because of high seed quality and low moisture content of seeds, at 38 days after flowering the highest seed quality can be achieved.

In order to effect of seed priming on oil, grain yield of Safflower under irrigation deficit conditions a split plot experiment based on randomized complete block design was conducted with three replications in 2012-2013 growing seasons in research farm of Payame-Noor University of Zabol. Irrigation in three levels  included; I1= Irrigation in all growth stages (rosset, stem elongation, heading, flowering, and grain filling), I2=Irrigation interruption in rosset, stem elongation, heading and irrigation in flowering, and grain filling), I3=Irrigation in growth stages rosset, stem elongation, heading and interruption irrigation in flowering, and grain filling were main plot and seed priming  in five levels included; P1=Non- Primed (control), P2=Hydropriming, P3=Primed with 1% ZnSO4 P4=Primed with 1% KNO3 P5=Primed with 2% KNO3 were sub plots. The results showed that  number head in plant, grain in head, 1000 grain weight ,oil and grain yield in I2 and I3 treatments decreased as soil available moisture was reduced. Rate decreased grain yield in treatments was 20 and 45 %, respectively. The oil percentage and grain yield was higher in seeds osmopriming with 1% ZnSO4 and 2% KNO3 compared to non prime 19 and 14 %, respectively. Based on results in spring plant of  safflower must be take irrigation in all of growth stages and seeds priming than to non prime seed to be superior.

The effect of arbuscular mycorrhizal (AM), Species Glomus intraradices and plant growth promoting (PGPR), Species Pseudomonas fluorescens strain41and  Pseudomonas fluorescens strain 187, On the aloe vera plant in a pot experiment under greenhouse conditions was studied. Main objective of this study was to increase nutritional quality in Alo vera by applying biofertilizers are mediated by enhanced antioxidant potentials and secondary metabolite accumulation. The experiment, based on  randomized complete block design with eight treatments and three replication were performed. Treatments consisted of: 1- Control plants. 2- inoculation with the intradices.3- Inoculated with Pseudomonas strains 41. 4- Inoculated with Pseudomonas strains 181. 5- Combining intradices and Pseudomonas strains 41. 6- Combining intradices and Pseudomonas strains 187. 7- Combining the two strains of Pseudomonas. 8- Combining the two strains of Pseudomonas and intradices. Statistical analysis of the data showed that microorganisms were used in this study,  had significant effect on indicators such as fresh and dry weight, root dry weight, root volume, leaf uptake NPK, chlorophyll content, total phenol, flavonoids and antioxidant activity of Aloe vera. The  results of this study showed that combination  application of arbuscular mycorrhiza and plant growth-promoting bacteria is more effective than their own on physiological and morphological characteristics of the aloe vera plant.