فصلنامه پژوهش های تولید گیاهی
سال شانزدهم شماره 2 (تابستان 1388)

Turmeric (cucurma longa) has been used as an antioxidant agent in medical as well as health sciences some years ago. However, it has not been applied in tissue culture till now. Browning tissues is result of tissue damages caused by polyphenoloxidase enzyme. In order to study this problem and reduce browning, explants are cultured in culture media containing antioxidants including citric acid, ascorbic acid 1,4 dithiotheritol, mercapto ethanol. In this study turmeric (cucurma longa) is used as an antioxidant. In order to investigate the antixidantal characteristics of turmeric, an experiment has been undertaken on elm browning callus, comprising comparison of turmeric with two standard antioxidants, active coal and ascorbic acid. Initial callus divided and sub-cultured in MS medium containing 25% coconut milk and 0.8% agar. Treatments were active coal, turmeric and ascorbic acid in concentrations of 0.1%, 0.5% and 1% respectively. Totally 9 treatments were used. Statistical analysis of data at 95% confidence level showed that increasing of callus growth was significant in treatments, containing ascorbic acid with concentration of 1% and turmeric with concentration of 0.1%. Medium containing active coal with concentrations of 0.5%, 1% and turmeric 0.5% concentration showed significant decrease of browning in comparison with other treatments.

Cerato-ulmin is the most important toxin of fungal causal agents of Dutch elm disease and its content is one of the most important factors to distinguish two species Ophiostoma ulmi and O. novo-ulmi. With attention to the Ophiostoma novo-ulmi is more pathogenicity than O. ulmi, this research was carried out to discuss the role of Cerato-ulmin on pathogenicity of causal agent using measurement of Cerato-ulmin content of isolates of casual agent and their comparison with pathogenicity and spore germination ability in moisture stress conditions. For these aim, content of Cerato-ulmin toxin was calculated as Cerato-ulmin Production Index (CPI) using spectrophotometer at 400 nm. The spore germination was also calculated in moisture stress conditions (5, 10 and 15 days-old). The results showed that O. novo-ulmi isolates able to produce the higher Cerato-ulmin toxin than O. ulmi, however was not observed clear relationship between rate of defoliation and wilting of Ulmus glabra Huds. seedlings and toxin production but there was completely significant positive correlation between rate of spore germination in moisture stress conditions and toxin production by fungal isolates of Dutch elm disease. The involvement of Cerato-ulmin on pathogenicity of causal agents of Dutch elm disease is intricate.

Licorice, Glycyrrhiza glabra (Fabaceae), is one of the herbal medicines. Glycyrrhizin is the importance content through compounds exiting in licorice, which is 50 times sweeter than sucrose. Glycyrrhizin used as the primary matter in pharmacy and used to remedy of many diseases, and also, used in tobacco, confectionary and beverage industries. Since Glycyrrhizin in the phases of growth received at maximum and then decreased; and also to consider of root diameter and harvest time effect on active substance content, This study done for determine the best harvest time and suitable root diameter to obtain the greatest Glycyrrhizin in this plant. For this study, root of Glycyrrhiza glabra were collected in four times (Nov, Dec, Jan and Feb) and in three root diameter (<1 Cm, 1-2 Cm and >2 Cm) from gorgan (Araghi mahalle agricultural station). Variant of measurement in this study were including fresh weight, dry weight (for determination of percentage of humidity) and glycyrrhizin content. Extraction of glycyrrhizin was done with methanol and its measurement done with used hight performance liquid chromatography (HPLC). The result showed that the least root diameter were containing the least humidity percentage (32.46%) and the greatest of glycyrrhizin (1.187%), the root were harvested in Jan., in comparison with other harvest time, were containing the least humidity percentage (22.26%) and the greatest amount of glycyrrhizin (1.112%).

The main objective of this study was using of canonical correlation analysis (CCA) to find relations between 15 different variables of seed emergence and seedling growth related characteristics of seven important crop that were classified in three groups. The studied groups of variables were included physical characteristics (seed weight, seed length, seed density, water absorption and water content), seed germination characteristics (germination percentage, germination rate, uniformity of germination, wet and dry weight of petridish grown seedling) and seed emergence characteristics (emergence percentage, emergence rate, uniformity of emergence, wet and dry weight of field grown seedlings) and crops were included of wheat, barley, soybean, cotton, rapeseed, sunflower and safflower. The CCA revealed two considerable associations between physical characteristics and seed and seedling characteristics grown in petridish. The first pair of canonical variables had a correlation coefficient of 0.99. The physical and growth related characteristics of seedlings grown in petridish most consistently correlated with the first pair of canonical variables respectively were seed density, water absorption, water content, germination percentage, wet and dry weight of petridish grown seedlings. The second pair of canonical variables between physical characteristics and seed and seedling characteristics grown in petridish had a correlation coefficient of 0.73. The CCA indicated that there are three important pairs of canonical variables between physical characteristics and seed and seedling characteristics grown in field with correlations of 0.92, 0.86 and 0.8, respectively. Also there was one considerable pair of canonical variables between seed and seedling characteristics grown in field and grown in petridish with correlation of 0.78. Careful evaluation of distribution of each measured variables in the obtained canonical variables revealed that there was considerable relationship between seedling weight and germination with water content or absorption of seeds; seed size with seedling weight; and biomass production with growth in petridish. Finally, the results showed that CCA could be use for evaluation of association between seed physical characteristics, germination and seedling growth.

In this study six genotypes of upland cotton (G. hirsutum L.) were crossed in a half diallel (6×6) mating fashion. The parents and F1s were planted in a complete randomized block design with three replications at the Hashemabad Cotton Research Station (Gorgan) in 2005. Cotton yield and some agronomic traits were evaluated. Analysis of variance showed that differences due to genotypes were significant (P≤0.05) for yield, plant height, boll weight, monopodial branch number and maturity coefficient (earliness). Also, the correlation coefficients between cotton yield and above indicated traits were significant. The diallel analysis results showed that plant height, monopodial branch numbers and earliness exhibited additive gene effects. Both additive and non-additive gene effects were important in controlling of cotton yield and boll weight. The parental genotypes of Cok. 349, V.S.O and No: 200 genetyp exhibited significant General combining Ability (GCA) for yield and boll weight. Bolgar539 exhibited significant GCA for earliness. The Cok. 349 × NO: 200 and Asland × NO: 200 have exhibited higher and positive specific combining ability (SCA) for yield. Dominance and recessive allele frequencies were not in equilibrium with respect to traits studied. The average degree of dominance value was greater than 1 (d>1) for all studied traits. Frequencies of dominant alleles were more than recessive alleles in parental genotypes. According to our data, increase of cotton yield is obtained by exploitation of both additive and non-additive gene effects. For this purpose, recurrent selection in order to accumulate desirable additive genes, as well as exploiting of dominance variance through hybrid production would be more appropriate in future cotton breeding programs.

In recent years, symptoms of virus diseases on stone fruits have been observed in wide range in Golestan province. In order to study the important viruses on stone fruits, cherry, plum, nectarine, peach and apricot trees with symptoms such as mosaic, chlorosis, ring spot, shot hole, pale margins in leaves and dwarf in trees, Sampling was done during 2005. Putative infected plants were tested by DAS-ELISA kits respected to PNRSV (Prunus necrotic ring spot virus), PPV (Plum pox virus), PDV (Prune dwarf virus), CLRV (Cherry leaf roll virus) and ArMV (Arabis mosaic virus). Positive results were obtained for PNRSV in peach, nectarine and plum, but not in cherry and apricot. The most infected regions were Aliabad and Gonbad with the highest infection rate in foreign cultivar peach (6.55%) and red gold nectarine (3.22%).

In order to investigate genetic correlation and path analysis between grain yield and yield components, fifteen early maturing hybrids of grain corn (Zea. mays) using a randomized complete block design with 4 replications were evaluated in Khoramabad agricultural research center, Iran. The data were collected and analyzed for ear emergence date, anthesis date, maturity date, plant height, ear height, plant stand, ear cover, grain number per row, row number per ear, grain depth, 1000- grain weight, plant value, cob percent, grain yield, stay green, stem and leaf resistante to disease. The results showed grain yield was positively correlated with plant height, ear height, grain depth, row number per ear, grain number per row, but negatively with 1000-grain weight, ear cover, cob percent and stay green. Between emergence date and maturity date and It was observed significant negative correlation stay green and leaf disease and positive significant correlation with ear height, grain depth and ear cover, suggested that late maturing hybrids with higher productivity were more resistante to diseases. The results of regression and path analysis showed that 1000-grain weigh and cob percent were correlated with yield negatively, and grain depth, plant height and plant stand were positively (R2=0.52) and had higher effects on grain yield.

In order to study the effects of four concentrations (check, 5, 10 and 15%) of hull extracts on growth of 10 iranian rice cultivars, two experiments were conducted in completely randomized block design with factorial arrangement and three replications at two sites, laboratory and greenhouse. Laboratory study showed that same rice hull extracts had stimulat effects and the others had inhibitory effects on seedling growth of the same cultivar. Behnam Chalos cultivar showed the highest stimulation on germination percentage, root length and total dry weight of seedlings. The rice hull extract of nemat and tabesh exhibited the most stimulation on shoot length and germination rate of the same seedlings, respectively (P≤0.01). The result of greenhouse research suggested that rice hull extract of nemat cultivar had the greatest stimulatory on shoot length and root dry weight of the same seedling. Root length in tabesh cultivar, germination rate and total dry weight in gerdeh cultivar and shoot dry weight in zarak cultivar were more stimulated than other cultivars (P≤0.01). The results suggest that various allelopathic effects (inhibition and stimulation) exist in rice hull extract of different cultivars. Rice hull extract from breeding cultivar contrary to native cultivars had the greatest stimulatory on seedling growth. Enhanc of aqueous extract concentration increased stimulation effects on seedling traits in breeding cultivars. Length and dry weight of seedling root was decreased in rice native cultivars under rice hull extract (P≤0.01).

Cabbage aphid (Brevicoryne brassicae L.) is a important pest of canola (Brassica napus L.) throughout the world, and as the host plant resistance is considered as a useful method to control the pest, therefore twenty one genotypes of canola were evaluated from the view point of their resistance to cabbage aphid infestation in a randomized complete block design with three replications and under natural infestation conditions in Urumia during 2007-8. To evaluate the infestation rate of the genotypes, an infestation index indicator of the percentage of infested plants, the number of aphids per centimeter of stem length and the average length of the infested stems was used. The infestation to the aphid began in the mid May and continued till canola harvest time in mid-late June. In the last sampling synchronized to the maturity of canola seeds, the level of infestation was reduced. The different sampling dates indicated significant differences in the levels of infestation to aphid. Also from the stand point of the level of cabbage aphid infestation, canola genotypes were classified in four groups of resistant (including Sahara, Opera, Arc-2, Sintara, okapi and Sunday), semi-resistant (including SLM046, Modena, Milena, Arg-91004 and Regent Cobra), semi-sensitive (including Arc-5, Orient, Elite, Dexter and Licord), and sensitive (including Geronimo, Olpro, Ebonite, Talent and Celisius).

A factorial experiment based randomized complete block was conducted in order to investigation of two rice (Oryza sativa L.) genotypes responses for Na+, K+, Ca2+, Mg2+, Clˉ, Mn2+, P and total soluble sugars accumulation and compartmentation in leaves 3, 4, 5 and 6 to salt stress. In estimation of the simple correlation between traits, dry weight was negatively correlated with Na+ and Clˉ. The observed reduction in seedling growth was higher for IR29 (salt sensitive) than IR651 (salt tolerant). Salinity induced high Na+ and Clˉ accumulation in leaves of both genotypes and in IR29 was more than IR651. The highest Na+ and Clˉ concentrations were in third and fourth leaves of IR29. Total soluble carbohydrates concentration was increased only in leaves 5 and 6 of studied genotypes and had no change in leaves 3 and 4. Obtained results showed that under saline condition, reduction in Ca2+ concentration occurred in IR29 more than IR651, however, was observed in all leaves of both genotypes. There was no regular response of seedlings to salinity in relation to accumulation of Mg2+. Mn2+ and P concentrations had no changes under salinity. Under saline condition, K+/Na+ ratio was decreased in both genotypes but was higher in IR29. IR651 could to preserve high K+/Na+ ratio in sixth leaf than other leaves. Generally, IR651 could to accumulation toxic ions in older leaves for prevent damage to young leaves while high levels of these ions were accumulated in young leaves of IR29. Nacl also caused to imbalance for solutes concentration in leaves of both genotypes.

This experiment was conducted to investigate the genetic diversity, relationship between morphological, agronomic and qualitative traits and to identify components of forage yield using some multivariate statistical methods in local sainfoin populations. The experiment was conducted as randomized complete block design with four replications in Isfahan University of Technology Research Farm. Results indicated that correlation coefficients of dry yield with fresh yield, dry matter percent, crude fiber, stem percent and number of stem per square meter were significantly positive but with leaf percent, crude protein, seedling emergence date and flowering date was significantly negative. Forage yield had no correlation with plant height but plant height was correlated with number of stem. Factor analysis revealed five factors which justified more than 80 percent of the total variation, and classified as “quality of forage”, “plant size”, “forage yield component” “tillering potential” and “emergence rate”, respectively. On the basis of stepwise regression analysis, stem percent, plant height, number of branches and day to 50 percent seedling emergence justified the majority of hay yield variation. Hence, these characters could be use for selecting high yield cultivars. Finally, on the basis of the current result in this research compared with previous findings, it can be concluded that multivariate statistical methods can be useful to find relationships between quantitative and qualitative characters in sainfoin.

Nitrate and ammonium ions are the two major forms of nitrogen that taken up by plants, but they differ in their effects on growth and chemical composition of biochemical levels. In this research we examined the effect of nitrogen sources on growth and senescence of rice leaves in biochemical levels. Our results showed that amounts of fresh and dry weights, total chlorophyll, rate of Hill,s reaction, amount of soluble proteins and specific activity of peroxidase significantly were lower in nitrate-fed plants than ammonium-fed plants. Where as, chlorophyll a and chlorophyll b ratio and specific activity of superoxide dismutase were higher in nitrate-fed plant as compared to ammonium-fed plants. Any changes in lipid peroxidation under different treatments of nitrogen means that nitrogen-fed did not induce oxidative stress and senescence in rice plant, but it can only cause reduction in growth parameters such as fresh and dry weights, amount of chlorophyll and protein in nitrate-fed rice plant.

In recent years, shallow bark canker of walnut (Juglandis regia L.) trees has become fairly widespread in Iran. To determine the distribution of the disease in Golestan, Mazandaran and Gilan provinces, from early summer to mid-fall seasons of 2004, more than one hundred bark samples were collected from walnut trees showing symptoms of shallow bark canker. Sixty strains of bacteria were isolated from the infected tissues. Strains appeared to be more or less similar in phenotypic characteristics. In spite of some differences in their electrophoretic profiles of whole-cell proteins, on the basis of the results of morphological, biochemical and physiological tests the bacterium was identified as Brenneria nigrifluens (Wilson) Hauben et al., 1998. This is the first report of shallow bark canker of walnut trees in Golestan and Gilan provinces.