SEED RESEARCH (JOURNAL OF SEED SCIENCE AND TECHNOLOGY)
Year:2012 | Volume:1 | Issue:1 (1)|Papers Count:8

This experiment was conducted to evaluate seed size (large, medium and small) and salinity (0, 30 and 60mM and 0, 9×10-4 and 18×10-4pa) effects and their interactions on germination traits and seedling growth of soybean cv. KATUL. It was done as factorial experiments in the base of completely randomized design with three replications in seed physiology and technology laboratory of Mohaghegh Ardabili University in 2011. In this experiment coefficient of velocity of germination (CVG) and germination percentage, homogeneity, seedling dry weight, reserve mobilization and its efficiency were examined. According to results, by increasing seed size, germination uniformity decrease significantly. Salinity decreased seedling dry weight, mobilized reserves and its efficiency, significantly. But it didn't have any significant effect on germination percentage, uniformity and CVG. Furthermore, interaction effect of salinity and seed size had significant effect on germination uniformity, seedling dry weight, mobilized reserves and its efficiency. This experiment showed that small seeds had better germination uniformity and getting reserves more and faster than larger ones to seedlings.

Post harvesting processes such as cleaning, washing, handling, weighing and complementary and conversion processes carried out base of mechanical and physical properties of product. In this research determined dimensional characteristics and components such as arithmetic diameter, geometric diameter, sphericity, bulk density and angle of repose of six varieties of cotton seed. Studied varieties included Sahel, Sephid, Golestan, Armaghan, 43200 and B-557. The data was analyzed by JMP software in CRD, and the graphs were drawn by Excel software. The largest and the smallest arithmetic and geometric diameter were belonged to 43200 and Armaghan respectively. Armaghan cultivar had a biggest sphericity (0.63). Golestan cultivar had the thickest skin, and the highest density was belonged to 43200. Maximum angle of repose (22o) was shown in Sephid cultivar, and the lowest angle of repose (18o) was measured in Armaghan cultivar.

Salinity is one of the most important osmotic stresses that limits growth and production of crop via changing ion and osmotic balance. For studying salinity stress effects on germination, vegetative and some germination indices an experiment conducted by factorial based on completely randomized block designs with four replications in 2010 in the department of agriculture of Urmia Payame Noor. The factors were wheat genotypes with eight genotypes (Shahriar, Sardari, Sardari 39, Sardari 101, Zarin, Arvand, fgs and Azar 2) and B factor with Six levels salinity (0, 2, 4, 8, 12, 16) ds/m from NaCl. The variance analysis results showed that different levels of salinity had significantly effects on germination uniformity, stress tolerance index, germination rate index, meantime of germination, mean rate of germination, mean coefficient of Velocity of Germination, germination rate index. With increasing salinity stress germination rate decreased. The genotypes respond differently to salinity levels. It seems genotypes of Zarin, Arvand and Sardari have more tolerance to salinity conditions. Genotypes of Sardari 101 and Azar 2 were identified sensitive to salinity stress.

In order to the effect the effects of osmopriming on seed germination of rice cultivars Fajr View Post factorial experiment in randomized design with three replicates in the laboratory of Agriculture and Natural Resources Research Center of Mazandaran province in 2010 was conducted. Treatments include polyethylene glycol (PEG) with various concentrations of 5 and 10 %, potassium nitrate (KNO3) with concentrations of 1 and 2 %, pure water and control the priming period of 5, 10 and 15 hours. Results showed that maximum shoot length of treated and PEG priming and KNO3 concentrations of 5 and 2% respectively and 10 and 15 hours respectively, at least during the seedling with the Prime was observed by witnesses. More than root and shoot length (R/S) at the time was 5 hours. Maximum and minimum germination rate of 5% concentration of PEG in the Prime Time 10 and 15 hours. The lowest and highest index Vigor1 for control of the Prime Vigor2 with PEG and KNO3 concentrations of 5 and 2% were obtained. The best solution for priming and PEG 5% concentration and duration of 15 hours is recommended.

In early stages of seedling development, heterotrophic seedling growth has been made of two portions: 1) the weight of mobilized seed reserve and 2) the conversion efficiency of mobilized seed reserve to seedling tissue. This research was carried out to evaluate germination and seedling growth of aged seeds of soybean (cv. DPX). Seed deterioration treatments were 12, 24, 36, 48, 60, 72, 96 and 120 hour at 41oC. After seed deterioration, standard germination test and seedling growth test were performed. Results showed that by seed deterioration treatments, amount of germination rate and accumulated germination percentage decrease considerably but "germination uniformity" and "germination beginning and ending time" increased. Also, seedling dry weight decreased linearly with 0.0002 mg/hour significantly when exposed to 41oC. Seed reserve utilization increased meaningfully, while conversation efficiency of mobilized seed reserve decreased considerably. It causes seedling dry weight decreased and finally seed growth power reduced.

Seed germination is one essential process in plant development, which is often affected by environmental stresses. To study germination characteristics of Secale montanum in water stress and different temperature conditions two experiments were conducted at separate laboratories. The experiments wereg conducted in completely randomized design with four replications in university of Tehran for water stress and different temperatures. The treatment, for water stress was five osmotic potential (0, -4, -8, -12 and -16 bar) of PEG and five of different temperatures (5, 10, 15, 20 and 25oC). Results of two experiments showed that increasing water stress and decreasing temperature significantly decreased germination rate, germination percentage, plumule and radicle length and normal seedling percentage (P<0.01). The best osmotic potential for this montanum rye germination test was non-stress conditions (77.5 %), and the best temperature was 20oC (77.5%). Pearson correlation among traits in both conditions showed the highest correlation between the percentage of germination and the normality seedling percentage (p≤0.01, r=0.99).

Understanding the seed germination response of cultivated genotypes to temperature is important, agronomically. The genotypes that germinate in lower temperatures could be useful for situations where temperatures are low in germination stage. Therefore, this experiment was conducted to study the cardinal temperatures, response to sub- and supra-optimal temperatures and thermal tolerance of seed germination in 15 rice cultivars from the north of Iran. The effects of seven constant temperatures between 12, 16, 20, 25, 27, 30, 33, 36 and 40oc on the seed germination characteristics were also evaluated. The base (Tb), optimum (To) and maximum or ceiling (Tc) temperature for germination changed from 10.06 to 11.69oc, 30.42 to 32.97oc and 40.15 to 43.84oc, respectively. The analysis of variance revealed no significant differences between cultivars for cardinal temperatures. The effect of cultivar on thermal tolerance was not also significant, but differences between cultivars for thermal tolerance in supra-optimal temperatures were more than sub-optimal temperatures. Generally, all cultivars were more responsive to supra-optimal temperatures than sub-optimal temperatures. In the other hand, the slope of regression line of germination rate (GR) versus supra-optimal temperatures was more than that of sub-optimal temperatures.

Seed priming improves germination characteristics and seedling stabilishment and resulted in better seed performance under environment stress conditions. In order to evaluate the effects of gibberellic acid (GA) and salicylic acid (SA) pretreatments on enhancement of seed germination of Agropyron elongatom under cold stress an experiment was conducted at the Seed Lab, University of Tehran in 2010. The experimental design was factorial based on a completely randomized design with four replications. Seeds were primed for12 and 24 hours at two temperatures (10 and 20oC) with GA (25, 50 and 100 ppm) and SA (25, 50 and 100 ppm).The result showed that all seed priming treatments significantly affected all of germination properties. However, priming in 25 ppm with GA and 50 ppm SA were the best treatments. The beneficial effects of GA and SA could be used for improving seed germination performance under cold stress and unstress condition.