نشریه علوم کشاورزی و منابع طبیعی
سال پانزدهم شماره 5 (پیاپی 67، آذر و دی 1387)

Production of Reactive Oxygen Species (ROS) has an important role in gene expression and metabolism at cellular levels. High concentrations of ROS lead to phytotoxicity, and may oxidase biological molecules such as DNA, proteins and lipids. In this study, the biochemical links and gene expression between senescence and ROS levels was investigated during senescence and in response to stress in Brassica napus. Experimental treatments (oxidative treatments) were 3-Amino 1, 2, 4-Triazole (3-AT), Silver Nitrate (AgNO3) and Ultraviolet-B (UV-B) radiation as well as three combined treatments: pre-treatment of Ascorbic-Acid followed by the each of the above treatments. The results showed, the effect of oxidative treatments both in detrimental effects on physical appearance and in changes in chlorophyll and TBARM (indicating oxidative levels in cell) was reduced by pre-treating the tissues with ascorbic acid. According to northern blot analysis results, it was similar to changes in senescence-enhanced and defence gene expression, indicating that oxidative treatments induced gene expression by increasing ROS levels. This result implies the importance of ROS in genetic signal pathways.

In order to investigate the effects of water saltiness of irrigation on the features of the agronomy in two lines (Maya&Tou2) of wheat, an examination was performed in Faculty of The University of Agriculture Science and Natural Resources of Gorgan in 1382. This examination was done by applying irrigation water: 0.67 (witness), 2 and 4 dS/m in three periods (booting, milky and mild doughy). The examination was performed by factorial in form of Complete Randomized Blocks three times. Results indicated that, plant height, 1000 grain weight, total number of head, harvest index and grain yield in two lines of wheat weren’t significant in comparison with witness. In milky phase, the whole dry matter in Tou2 line decreased after using saline water. Increase in the salinity in the third level (4 dS/m), increased the number of spike let per spike in line Maya. Salinity increased the number of spike let per spike of Tou2 line in second level of salinity. The number of spike let per spike, the number of grain per spike, total dry matter, and grain yield and harvest index were much more in Maya line, but total number of head and 1000 grain weight increased. The grain yield in Maya line was more than 30/51 % that in Tou2 line.

In order to evaluation of grain yield and its relation with grain yield components, changing harvest index and biological yield in barley, an experiment was conducted during 2005-2006 growing season in field experimental of Gorgan Agricultural Science and Nature Resource in randomized complete block design with 4 replication by 10 barley genotypes treatment. The genotypes were: Bomi, Torkaman, Eize, Siah, Sahra, 1-yeknavakht, 14G, 11G, 5G and 15G, that recommended by Golestan Agricultural Center. Results showed the higher grain yield is related to 14G that is from modern genotype of this region. The lower grain yield is related to Torkaman that is one of the oldest genotype. These genotypes showed significant difference in considerate of biological yield and harvest index. Correlation between biological yield with yield and yield components was positive. The highest harvest index (HI) is related to modern and modified genotypes that they category in high yield genotype group. Positive correlation between grain yield and harvest index and its improvement in modern genotype could be one reason for increasing high yield.

In order to determine the best planting date and plant density on forage yield of Foxtial millet,an experiment was conducted using a factorial experiment in Randomized Complete Block Design with 4 replications at research station of Gorgan in 2005. First factor included different three planting dates (Jun.22th, Jul.7th, and Jul.22th) and second factor plant densities (30, 45 and 60 plant per m2). Results showed that forage yield increased with increasing of plant density. The highest forage yield obtained in 60 plants/m2 (fresh forage= 35628kg/hac, dry forage= 13494 kg/hac). Forage yield decreased with delaying of planting date, as highest density forage yield (fresh forage=37011kg/hac, dry forage=12833 kg/hac) obtained in first planting date (Jun.22th). Interaction of planting date and plant density wasnt significant. Total dry matter, CGR, LAI and LAR increased with increasing of plant densities. Also total dry matter, CGR, LAI and LAR increased with delay in planting date.

In order to study of plant density (planting pattern) of pea garden (Pisum Sativum var. Shamshiri choruk) on seed green yield, components of seed yield and morphological characteristics a field experiment was carried out at Gonbad Agricultural Faculty Research Station, (Golestan Province) Iran. The experiment was designed factorial in randomized complete block design with four replications. In this investigation were used three row spaces (30, 45 and 60 cm) and three plant to plant distances (5, 7.5 and 10 cm). The harvest was done when all the pods were green and seeds were soft. At the harvest time, 10 plants of each plot were selected randomly and used for determination of yield components including number of pods per plant and number of seed per pod moreover some selected morphological characteristics. These characteristics included plant height and number of branches. The results indicated that the effects of plant density had no significant effect on yield and components of yield. Plant to plant distance showed a significant (p< 0/05) effect on lateral branches and the maximum numbers of branches were observed on 10 cm row spacing. The highest seed green yield obtained from 30 cm row spacing with 10 cm plant to plant distance that was 12.1 Ton /ha.

In the developing countries, there are increasing demands for timely and effective meteorological information for many agricultural decisions and farm management but many farmers for applying these information constrained by limiting factors such as shortage of money or credit, unavailability of seeds, lack of education and advice, or shortage of farming equipment. These constraints reduce effectiveness of atmospheric forecasts. The purpose of this study was to appoint the limiting factors of effectiveness of atmospheric forecasts from farmer's point of view in Golestan province. The methodological approach was a descriptive and survey type. The target population in the study consisted total farmers in Golestan province, Iran (N=130000).Using multistage cluster and simple random sampling techniques 322 farmers were chosen. Data were collected through a questionnaire and were analyzed using SPSS, V.11. Content and face validity of the instrument were obtained by the faculty members of agricultural extension and meteorology specialist. The reliability analysis was conducted with completing 30 questionnaires and Cronbach's alpha value was 0/80. The results obtained from analytic statistics indicated that there are significant and positive relationships between independent variables namely lack of credits, lack of inputs, farmer inaccessibility to extension worker, lack of enough education to make use of meteorology information, illiteracy and non-acquaintance of meteorologist language (99%) and significant and negative relationships between independent variables namely farmers, point of view about inaccessibility to agricultural instruments (95%) and dependent variable namely farmers, point of view about limiting factors of effectiveness of atmospheric forecasts in Golestan province. This study has suggested providing inputs such as fertilizer, poison, credits, instruments and equipments by responsible organizations for effectiveness use of atmospheric forecasts by farmers.

Brow spot disease is one of the most important seedborne diseases of rice, which is found in all stages of its growth from nursery to farm. Bipolaris victoriae was the most abundant species in Guilan province, and the species B. oryzae, B. bicolor, and B. indica were the subsequent species, respectively. Technique RAPD-PCR has been employed for study of genetic diversity of fungus. In order to conducting it, two groups of primers were applied, as six primers between them which did the best, were used in all the tests. As a result, segments of DNA by the size of 0.2- 4 kb were multiplied. On the basis of cluster analysis by using the UPGMA method, four DNA fingerprinting groups were determined in relation to B. victoriae, B. oryzae, B. bicolor and B. indica with the abundance of 85%, 10%, 3% and 2% respectively. Further analysis and molecular variance analysis revealed that there was more diversity within each population than between populations. Levels of polymorphism was observed between DNA of different isolates as this polymorphism was observed either between or within species. The pattern of RAPD bands couldn’t show the direct correlation between polymorphism and climates or geographical areas.

Quantitative information about response of phenological development to temperature and photoperiod in faba bean is limited. This study was undertaken to examine phenological development of four faba bean cultivars (conducted Barakat, Saraziri, Eraghi, Gavi) under 11 sowing dates. The experiment was conducted in Gorgan during 2005-2006. Various response functions were evaluated for quantifying response flowering rate to temperature and photoperiod. Results indicated that response of faba bean flowering rate is described by beta- segmented (Barakat, Saraziri, Eraghi) and beta- quadratic (Gavi). Using these functions, cardinal temperatures (base, optimum, and ceiling) for flowering and critical photoperiod (the photoperiod below which flowering rate begins to decrease) and photoperiod sensitivity coefficient (slope of the function in response to photoperiod) for flowering rate were determined. Barakat, Saraziri and Eraghi Cultivars showed a qualitative long-day plant (LDP) response to photoperiod and progress towards flowering stopped when photoperiod decreased about 10 h per day. But Gavi cultivar showed a quantitative long-day plant (LDP) response to photoperiod. Critical photoperiod estimated by beta-segmented function for Barakat, Saraziri, Eraghi Cultivars were between 14.5 to 16.1 h and by beta- quadratic function for Gavi Cultivar was 15.3.

To investigate the effect of late sowing date and plant density on canola (RGS-003 cultivar) an experiment was conducted in the research station of Gorgan in growing season of 2005-6. The experiment was a factorial design arranged in a randomized compelet block design with four replications. Four sowing date (13 Nov, 21 Nov, 6 Dec and 21 Dec) and with three densities (80, 100, 120 plant/m2) were randomized to plots. Yield and yield components were negatively affected by late planting date significantly as the number of pods per plant, grain per pods and 1000 grain weight were reduced. Quantitative and qualitative characteristics such as oil yield, biological yield and the harvest index were decreased significantly. Yield and the number of pods per plant decreased by density significantly. Also the density affected biological yield significantly as increasing of density resulted in significant decreasing of biological yield. Planting date and density affected grain yield and biological yield significantly, as the highest grain and biological yield of sowing dates of 13 Nov, 21 Nov and 6 Dec belonged to density of 80 plants/m2 and fourth sowing date belonged to density¬ 120 plants/m2.

In order to compare the competitive ability of eight rapeseed cultivars (two hybrids and six open-pollinated) against wild mustard, an experiment was conducted using a factorial arrangement of treatments in a randomized complete block design with three replications during 2006-2007 growing season at the Research Field of Abouraihan Campus, University of Tehran, Pakdasht. Each cultivar was grown in weed-free conditions or infested with wild mustard. Studied traits were grain yield, plant height, harvest index, AWC (Ability to withstand competition) and WSA (Weed suppressive ability) for rapeseed, and seed yield and biomass for wild mustard. The results indicated that grain yield, harvest index and competitive indices differed significantly among the cultivars. The highest and lowest value of AWC and WSA belonged to Elite and Okapi, respectively. No significant correlation was found between AWC and yield in the weed-free plots. But, significant correlation was observed between AWC and WSA. Wild mustard caused an increase in rapeseed height through reduction of R/FR ratio. The study showed that Elite cultivar having high height and HI, greater LAI and better vertical leaf area distribution to prevent yield loss (tolerance) in weed-infested conditions, and more suppression ability in the presence of wild mustard. These criteria used in breeding programs to screen for more competitive canola cultivars against wild mustard.

This experiment was conducted to evaluate the competition relationship of canola cultivars and wild mustard at the agriculture research station of golestan province during 2006-2007 growing season. The experimental design was a factorial arranged in RCBD with three replications. Experimental factors were canola cultivars (Zarfam, Hayola330, Option500, and Rgs003) and four wild mustard densities (0, 4, 8 and 16 plant/m2). Linear reciprocal and yield loss models were fitted and their coefficients were used to interpret competition relationships of canola cultivars and wild mustard results revealed that Zarfam, cultivar had the lowest coefficient of reciprocal model than other cultivars for both of grain yield and biological yield. Also, result indicated that interspecific competition of canola cultivars was different and the highest value belonged to Zarfam cultivar. Our results based on yield loss models confirmed that biological yield decreased less than grain yield (Grain yield was more susceptible). Comparison of hyperbolic yield loss models showed that relative leaf area model with the highest value of R2, was more capable to predict yield loss of canola cultivars. The relative damage coefficient (q) of relative leaf area model showed that wild mustard was more competitive than canola (q>1).

A consequence of seed deterioration is decreased vegetative growth that causes decreased crop competition, utilization of the environmental resources, and tolerance against the unfavorable conditions and hence decreased yield. One reason of decreased vegetative growth can be disruption in photosynthesis system and one way to investigate this disruption is to evaluate chlorophyll fluorescence that reflects photochemical condition of the plant. In this study, soybean seeds stored at 34ºC for 0, 7, 14, 21, 28, 35, and 42 days, and were then planted in the field. Vegetative growth and parameters of chlorophyll fluorescence were measured during vegetative growth at 32 and 53 days after planting. The results indicated that seed deterioration causes decreased leaf area index and dry matter accumulation, but no decrease was observed in chlorophyll fluorescence parameters, indicating that decreased vegetative growth is not related to photosynthetic system. Therefore, other mechanisms must be investigated in future studies.

The increase in canola (Brassica napus) area under cultivated in the east of Golestan province is indicated the success of plant breeders and agronomists in introduce appropriate varieties to cultivate in the area, and optimum management options to increase seed yield. In order to evaluation the effect of different temperature and moisture regimes on shoot nitrogen amount, nitrogen amount and contribution in remobilization, dry matter production and seed yield of canola a 2-year study was conducted at Agricultural Research Station of Gonbad. The experiment was a randomized complete block design arranged in a split-plot in two conditions, i.e. supplemental irrigation and rainfed. Five sowing dates (6 Nov., 6 Dec., 4 Jan., 5 Feb. and 5 Mar.) were as main plots and 2 cultivars (Hyola 401 and RGS003) were as subplots. The shoot nitrogen amount and remobilization was affected by weather conditions during 2 years of the experiment. With a delay in sowing, shoot nitrogen amount decreased, due to decrease in above-ground dry matter. At physiological maturity, the relationship between seed nitrogen amount with above-ground dry matter and seed yield was positive and very strong, explaining 87 and 96% of the variation for Hyola 401 and 89 and 97% of that for RGS003, respectively. The amount of leaf nitrogen in remobilization ranged from 44.5 to 140.3 kg/ha. Compare to four first sowing dates, at last sowing date, the contribution of stem and leaf remobilization in seed yield increased severely, that associated with severe decrease in harvest index and seed yield of canola. The contribution of stem and leaf remobilization in seed yield was 0.37-3.17% and 2.02-12.38% in 2005-6, and 0.46-13.11% and 3.05-33.45% in 2006-7, respectively. The relationships between shoot nitrogen amount, nitrogen amount and contribution in remobilization with dry matter and seed yield can be used in crop modeling.

Zinc and boron are two elements influencing endogenous auxin in plants which is necessary for the induction of somatic embryogenesis. Somatic embryogenesis for carrot petiols was studied with two concentrations of boron; zero and 0.6 mg/l and three concentrations of zinc; zero, 0.45 and 0.9 mg/l at the presence and absence of auxin in a B5 modified medium using a complete randomized design with ten treatments and four replications. With statistical analysis boron and zinc affect somatic embryogenesis with carrot petiol (P<0.01) and there is an interaction between these two elements. The maximum somatic embryogenesis (P<0.05) were with the B5 basal medium, containing 0.6 mg/l boron with no zinc and also B5 containing exogenous auxin. Zinc is a stress element and discarding zinc from culture media significantly affected somatic embryogenesis by carrot petiol. Eliminating boron from B5 containing 0.45 mg/l zinc increased seedling embryos (P<0.05). Adventives roots were also observed with some sub samples in addition to embryogenesis. Maximum root production was statistically with B5 containing idol acetic acid (P<0.05).

In order to study the effect of different types and rates of organic and chemical fertilizers on yield and yield components response of corn (Zea mays L.) an experiment was conducted at research farm of Sari Agricultural Sciences and Natural Resources University during 2007. The experiment was arranged in split plot based on complete randomized block design with two factor and three replications. Main plot included 8 fertilizer treatments (consisting of 20 and 40 Mg.ha-1 of compost, vermicompost, and sewage sludge enriched with 50% chemical fertilizer, chemical fertilizer and control). Sub plots were considered as one year or two years application of that fertilizer. Results showed that different types and rates of organic and chemical fertilizers had significant effect on yield parameters such as grain yield, biomass, harvest index, row number, grain number per row and grain number per ear. Meanwhile, one year and two years application of these fertilizers caused significant differences on all mentioned traits expect 100-grain weight and harvest index. Interaction effect of two factors also were significant expect for row number. According to results, the highest grain yield was belonged to two years application of 20 Mg.ha-1 sewage sludge enriched with 50% chemical fertilizers but not significant with two years application of 40 Mg.ha-1 sewage sludge, 20 and 40 Mg.ha-1 vermicompost enriched with 50% chemical fertilizer. Among traits, biomass and number seed per ear had higher correlation with grain yield. Generally, it seems that using of compost could improve corn performance in addition to reduction of environmental pollution.

Kochia (Kochia scoparia L. Schrad) is annual salt-tolerant and drought-tolerant specie, it can be a valuable source of forage using saline water in arid zones. In order to evaluate the effects of limited irrigation on seed yield and seed quality of two local population of Kochia a field experiment was conducted in Research Field of Center of Excellence for Special Plants, Ferdowsi University of Mashhad at 2007. The experiment was arranged in a spilt arrangement based on completely randomized block design with 3 replications. In main plots were four irrigation regimes including: complete irrigation (100%), 80%, 60% and 40% of water requirements and two local populations of kochia including Sabzevar and Borujerd were allocated to subplots. The plant characteristics were studied in terms of 1000 grains weight, seed yield, oil percentage, oil yield, protein percentage, protein yield, germination percentage, mean germination time, seedling length and seedling dry weight. Result showed that the effect of different irrigation regimes imposed a significant effect on all plant characteristics. In 40% treatment a significant reduction in oil percentage (33%) and seedling dry weight (65%) were observed to complete irrigation. Sabzevar's local population represented a better performance on all of above characteristics except protein percentage, mean germination time and seedling length that no significant effect were recorded. There was positive significant correlation between oil percentage and protein percentage. Maximum correlation showed between seed yield and oil yield.

There is a little information about the effects of temperature and water potential on germination of medicinal pumpkin, black cumin and borago. The factors include 9 levels of temperatures (5, 10, 15, 20, 25, 30, 35, 40 and 45oC) and 6 levels of water potentials. Results showed that temperature and water potential have significant effect on germination percentage (GP) and rate (GR). GP and GR decresed in three plants with decresing in water potential in all temperatures. Also, GP and GR increased with temperature increasing up to optimum temperature and decreased after it. Sensitivity of GR to temperature and water potential was more than GP. Also, sensitivity of GP and GR to water potential was more than temperature. Sensivity of black cumin germination to temperature and water potential was more than borago, and this was more than medicinal pumpkin germination.

In order to study the effect of different Genestein concentration on yield and yield components of annual medic varieties under 50C root- zone temperature, an experiment was conducted in Faculty of Agriculture of Tarbiat Modares University in a growth chamber with 20/250C day/ night temperatures with three annual medics containing (Medicago polymorph cv. Santiago, Medicago radiata cv. Radiate, and Medicago rigidula cv. Rigidula) and five Genestein levels including 0, 10, 20, 30 and 40 micromole/lit. Experiment was conducted in factorial arrangement in complete randomized block with three replications. There were differences among varieties for dry matter and yield components and Medicago rigidula in measured parameters had better condition than other species and had more yield. 20 micromole/lit Genestein increased forage yield and yield components of Medicago varieties at 50C root- zone temperature. Medicago rigidula was better than other varieties for most measured traits under Genestein 20 micromole/lit. Thus it may be suitable for cultivation in ley-farming system at cold and temperate zones.