نشریه علوم و تحقیقات بذر ایران
سال چهارم شماره 4 (زمستان 1396)

This study aimed to select the most suitable chemical and physical treatment for germination and breaking seed dormancy of Crataegus pontica. The experiment was set up in a completely randomized with 5 replications and 12 treatments in laboratory conditions. In this study, each replication involved 30 seeds. Treatments were hot water - sulfuric acid, sulfuric acid for 15 and 20 minutes, gibberellic acid for 24 and 48 hours, scarification, chilling wet seeds (-20 °C for for 2 weeks), freezing seeds in water (-20 °C for for 2 weeks), nitric acid for 20 and 25 minutes, hot water and cold water and control. In this study, characteristics such as germination rate, germination value, speed of germination and Kotowski's coefficient of velocity, germination vigour, mean daily germination and mean germination time were measured. According to the ANOVA, significant differences were detected between treatments in term of mean germination time, Kotowski coefficient of velocity, speed of germination, mean daily germination, germination rate and germination vigour. The highest amount of germination rate, germination value, speed of germination, germination vigour, mean daily germination and mean germination time was related to hot water - sulfuric acid treatment while the lowest one was related to control treatment.

This study aims at investigating the effect of herd trampling on soil in Darrehshar town pasture in a complete random survey.Regarding to this study the amountcof germination of soil seed bank wil be investigated.Treatment of the study involves trampled soil by herd, and the soil without herds’ trace on repeated three times.In order to compare the means (averages), . The indices of Simpson and Shannon-Wiener and richness indices were studied and Menhing.The obtained results of the research indicated that grazing livestock stomping had a direct effect on the germination of borried seeds in seed bank soil in both 0-5 cm and 5-10 cm soil depth, so that stamping of Livestock on the amount of indexes of species diversity and richness in the soil free from livestoch sings and effects was more them livestoch stamping. The results of variance analysis showed that there is a significant difference between the values of Margalof enrichmentindices and Manhing, and also between Shanoun- winner variety indices and Simpson ( P .(05>The value of Margalof enrichmentindices and Manhing was 29/6 and 8/62, respectively. And the value of Shanoun- winner variety indices and Simpson was 51/66 and 25/27, respectively, showed that in the soil without herds’ trace on was greater than trampled soil. Understanding these changes can be an appropriate guideline in interpretation of plantcoverchanges and how to manage it in future.

Low soil moisture content is one of the major problems in arid and semi-arid regions that leads to weak and nonsynchronous seedling emergence and establishment, finally resulting in the yield lose. Seed hydropriming mitigates somewhat these adverse drought effects. Therefore, in current study the effective factors in seed hydropriming such as time and temperature are evaluated on physiological quality of seed and seedling of a rainfed wheat (Var Kouhdasht) under drought stress. Pot experiment was carried out as factorial with three replications in base of the RCBD under drought stress conditions in Lorestan University. Drought levels were 25, 50 and 75% field capacity. Hydropriming time and temperature levels were 12, 18, 24 h and 15, 20, 25 ° C, respectively. Percent and speed of seedling emergence, seedling growth rate, leaf area index, chlorophyll index and number of root branches were studied. Results showed that the most of traits decreased by drought progress. Also, hydropriming temperature affected emergence percent and speed, seedling growth rate and chlorophyll index. Maximum of these traits was obtained when the seed primed at 25 ◦C. Interaction of drought and hydropriming time was significant for seedling emergence percentage and there was an interaction between priming temperature and priming time for LAI. Seed priming for 12 h was the best time for increasing seedling emergence at mild drought stress. But there was no difference between priming times at sever stress. According to importance of seedling emergence and speed, seed hydropriming of this cultivar for 12 hour at 20 or 25 ◦C is suggestibel.

To study the effect of gibberellic acid and cold shock on dormancy breaking of potato minitubers Var. Agria, a factorial experiment based on completely randomized design with four replications was used. Studied factors included: 1. Gibberellic acid (1000 ppm and Control) and 2. Cold shock at 2°C (C1: no cold, C2: a week of cold, C3: two weeks of cold, C4: three consecutive weeks of cold, C5: three intermitant weeks of cold). Germination percentage, number of sprouts/minituber, length of sprouts,field establishment of minitubers and yield/unit area were studied. Results showed that GA significantly stimulated minitubers germination. In the case of 1000 ppm GA, the number of sprouts/minituber was the highest in all levels of cold shock, while in the absence of GA, cold shock significantly increased number of sprouts/minituber and this trait significantly reduced by prolonged cold period. GA significantly increased field establishment of minitubers. In the case of GA, number of produced tubers/unit area was not significantly different in cold shock levels while in the absence of GA, this trait significantly increased by prolonged cold shock.

Control plots were accomplished to evaluate seed purity and seed born disease of seed parts that product in country. To evaluate 498 wheat seed parts in three group (breeder, basic and certified seed), seeds cultivated in control plots (24 m2, 24 row, 20cm space and 6 m, 5cm space between plants).To avoidance spike deformation, weed control did manual and without use of herbicide. At the beginning in each plot was selected 20 plants randomized and notated in different growth stage based on Zadox growth stages (some morphological and agricultural traits that they are not under environment conditions). Analyzes was done based on seed different groups (breeder, basic, certified), cultivars (Chamran, Yavaroos, Behrang, Shiroodi, Line A. S-83-3, Nimrooze barely. Bahar, Pishtaz and Bam) and each part. Results show that in all three seed groups have 4 grades that in breeder seeds the most purity plot was CHAMRAN plot one. In basic and certified seed plots the most purity plot were CHAMRAM 2 and SHIROODI 3 Respectively. Between different cultivar the most and the least purity were CHAMRAM and BEHRANG, respectively.

Salinity is one of the most important environmental stresses that can affect crop production. The research aimed to study the genetic diversity of 20 wheat varieties at Islamic Azad university, Ahvaz branch in 2015 in factorial experiment in basis randomized completely blocks design with 3 replications of 20 varieties as the first factor and salinity stress with NaCl at 4 levels of zero (distilled water), 4, 8 and 12 ds/m as the second factor was implemented. The principal components analysis, 11 studied traits is divided into 2 components on the basis of 57% of the data changes can be justified. The first and second components respectively 39.7% and 16.9% of the total variation stated and respectively are tolerant and sensitive to salinity were named. Using cluster analysis of 20 varieties located in three clusters. Varieties of Arg, Listan, Bahar, Maron and Hirmand were in the second cluster and the percent of emergence, length of seedling, dry weight of seedling, seed vigor index, leaf relative water content, K concentration, K/Na ratio, STI based dry weight of seedling and length of seedling were higher than the overall mean and it is worth noting that these characteristics in high salinity conditions are favorable. As well as the ionic leakage and Na concentration less than the overall mean that it is desirable in terms of salinity tolerance. According to this study, the use of this varieties for future breeding programs are recommended for salinity tolerance.

In order to investigate the effect of Azotobacter, Azospirillum and application of urban sewage sludge on some of the qualitative and quantitative characteristics of the Rapeseed (Brassica napus L.), an experiment was carried out in crop years 2014-2015 and 2015-2016 on the lands of Water and Wastewater Company of southern Tehran (Rey city). This experiment was conducted in a factorial way based on random complete block design with three replications. Experimental factors included, inoculation of rapeseed (Without inoculation, inoculation with Azotobacter choroccocum, inoculation with Azospirillum. Brasilense) and use of sewage sludge recovered: without nitrogen fertilizer and without using sewage sludge, using nitrogen fertilizer, 10, 20 and 30 tons of sewage sludge per hectare.The results indicated that the effect of inoculation and sewage sludge on stem dry weight, biological yield, number of pods per plant, number of seeds in pod, 1000 seed weight, seed yield and acid oleic and linoleic percent was significant at (1% level). The results indicated that the highest oil seed canola was obtained at 10 ton sewage sludge and non-inoculation treatment (38.75 %) and the highest oil yield was obtained at 30 ton sewage sludge and inoculation with Azotobacter treatment with amount of 932.77 kilogram per hectare.The results indicated that the urban sewage sludge application was effective on qualitative and quantitative yield of Brassica napus and inoculation with Azotobacter had better effect than Azospirillum on the traits being investigated such as oil and protein yield.

Asafetida is a medicinal plant belonging to the family of Apiaceae. Gum obtained from this plant has many industrial and pharmaceutical applications. Poor establishment of this plant is of main concern that is mainly attributed to the issues on seed germination and slow initial growth. Hormone priming is aimed to improve seed germination and increase plant establishment. The present study is an attempt to investigate the effects of hormone priming on seed germination in different time and concentration regime. The experiment was planned based on a factorial-completely randomized design with three factors including hormone type at two levels (Giberlic acid and Salicylic acid), priming time duration at 3 levels (6, 12 and 24 hours) and Hormone concentration at three levels (500, 1000 and 1500 ppm) in 4 replications. The results showed that the seeds primed with giberlic acid (500 ppm for 12 hours) and salicylic acid (500 ppm for 6 hours) have made high improvements to Asafetida’s seed germination. As well as to evaluate the effect of different SA concentrations on seed germination was conducted an experiment in a completely randomized design with 6 treatments and 3 replications. Results showed that the concentrations of salicylic acid had inverse relations with germination characteristics.

To study interaction of seed priming with salicylic acid and methanol on germination traits of rapeseed (cultivar Hyola 401) under drought stress, A factorial experiment was carried out in a completely randomized design with three replications. The treatment experiment were included seed priming with salicylic acid at three levels 0, 0.7 and 1.4 mM, and methanol at three levels 0, 3% and 6% volume. Polyethylene glycol 6000 at three levels 0 as control, -0.4 and -0.8 Mpa were used for drought stress. Traits case study in this experiment were including Germination percent, Mean germination time, germination rate, radicle length, plumule length, seedling length, seedling dry weight and seed vigor. results showed that the interaction of salicylic acid and methanol on all rapeseed (cultivar Hyola 401) germination traits was significant except from the radicle length (P

Due to sensitivity of soybean seedlings to cold, in order to study the effect of chilling duration and cultivar on physiological characteristics of soybean seed germination, a factorial trial in random block design with five level of pre-chilling (control, 10, 20, 30, 40 days in 4°C) and three cultivars (JK, Linford and Clean) with three replication was conducted in the seed science and technology laboratory of Mohaghegh Ardebili University in 2014. Traits like the percentage of  germination, germination rate, Sodium (Na) content, Calcium (Ca) content, Potassium (K) content,  Electrical conductivity (EC), soluble sugar content, Catalase and Peroxidase enzyme activity were measured. The interaction of cultivar and pre-chilling was significant on all biochemical traits of seed germination except Peroxidase and Catalase enzyme activity and EC. Highest germination percentage and rate happened in 40 days pre-chilling treatment. The EC of seeds was increased by 27 percent with increase in the duration of chilling from control (no chilling) to 40 days chilling. Cultivar and chilling interaction on inorganic elements Na, K and Ca were significant, the percentage of Na decreased and percentage of K and Ca increased with increase in duration of chilling. 40 days of chilling caused 8.5 percent increase in soluble sugar compare to control (no chilling). The activity of antioxidant enzymes Catalase and Peroxidase, rose with the increase in duration of chilling. The highest activity of Catalase enzyme was gained from the cold resistant cultivar (JK) with 8.507 µM/min*g (fresh weight) and the highest Peroxidase enzyme activity yielded from 40 days chilling treatment with amount of 37.243 µM/min* g (fresh weight). According to the physiological result the 40 days chilling treatment, due to high germination percentage and rate, high antioxidant enzyme activity and soluble sugar, is recommended for sowing and better seedling establishment.