Compatibility of insecticides and Elachertus inunctus Nees (Hymenoptera: Eulophidae) for controlling Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) in greenhouse condition

Journal of Plant Diseases and Protection - South American Tomato Pinworm (SATP), Tuta absoluta Meyrick (Lepidoptera: Gelechiidae), is one of the most devastating pests in tomato greenhouses....     

Long-term charcoal-induced changes to soil properties in temperate regions of northern Iran

The long-term performance and benefits of charcoal application on the carbon sequestration and properties of forest soils in temperate or non-tropical regions has not been studied in detail in spite of its important role in global warming. This study was conducted to describe the long-term charcoal-induced changes in organic carbon (OC) content and other soil properties of temperate deciduous forests in Mazandaran province, northern Iran. Three sites were sampled to collect composite soil samples from two depths (0–20 and 20–40 cm) inside and outside of a plot of charcoal-enriched soils surrounding a historical charcoal production site (abandoned for more than 120 years). The presence of charcoal in soils for about 120 years elevated significantly the black carbon, total OC, natural soil OC, total nitrogen, dissolved organic matter, soil OC density, exchangeable bases, saturated hydraulic conductivity, available water capacity and available Fe, Mn and Zn compared to the adjacent reference soils. Cation exchange capacity (CEC) and pH were 15.5 cmolc kg^-1 and 0.5 units, respectively, higher than the adjacent reference soils at 0–20 cm soil depth. However, electrical conductivity (EC), bulk density and available Cu were higher in the adjacent reference soil. The aged charcoal had no significant effect on the microbial respiration rate of studied soils. The results of this study provide new insights and strong support for the long-term benefits of biochar application as a management strategy for improving soil productivity as well as sequestering large quantities of durable carbon in soils of the region and mitigating global warming.     

Comparisons of commercial organic and chemical fertilizer solutions on growth and composition of lettuce

The objective of this experiment was to assess the effects of organic or chemical nutrient solutions on the growth and composition of lettuce (Lactuca sativa L.) in greenhouse production. Hoagland and Arnon nutrient solution, an organic hydroponics solution, and no fertilization were factored with lettuce cultivars of different phenotypes, iceberg, romaine, loose head, and loose leaf. Lettuce growth was higher with Hoagland and Arnon solution than with the organic fertilizer or with no fertilization. The organic fertilizer increased growth above no fertilizer applied. Hoagland and Arnon solution gave the highest concentration of nitrogen, potassium, magnesium, and iron in the lettuce whereas lettuce grown with the organic fertilizer had the highest phosphorus. Plant nutrient accumulation differed slightly among the cultivars. Hoagland and Arnon solution produced high nitrate in leaves. Nitrate concentrations with organic or no fertilization were low. Loose head or loose leaf cultivars had higher nitrate than romaine or iceberg.     

Biomass and nutrient concentration of lettuce grown with organic fertilizers

The responses of lettuce (Lactuca sativa L. ‘Arroyo’) to organic nitrogen (N) fertilizers were investigated in a greenhouse. Fertilizers were blood meal (BLO), feather meal (FM), cottonseed meal, alfalfa meal, sewage sludge, compost, cow manure, a chemical fertilizer, and a treatment without fertilizer. Amounts of N from fertilizers were 100, 200, 400, or 800?mg per pot. Lettuce yield was higher for plants receiving fertilizers than with no fertilizer and increased with increased N applications, but high applications of BLO or FM suppressed yields. Nitrogen and nitrate increased in leaves as N supply increased with all fertilizers. Small changes in leaf nutrient contents other than N occurred among or with increased application of the various fertilizers. The soil carbon dioxide release and ammonia volatilization were high from fertilizers with high N concentrations. Organic fertilizers with high N increased lettuce growth at lower applications than those with low N content.     

Genetic variation,heritability and correlations of agro-morphological traits in tall fescue (<Emphasis Type="Italic">Festuca arundinacea</Emphasis> Schreb.)

To study the genetic variation, heritability and genetic correlations of some agro-morphological traits in tall fescue, 25 parents from a genetically broad-base germplasm were polycrossed and their respective half-sib families were generated. Clonally propagated parents and their half-sib families were grown as spaced single plants using a randomized complete-block design with three replications, and observed for seven traits in 2006 and 2007. The estimates of broad-sense heritability were moderate to high for the traits studied. Narrow-sense heritability estimates from analyses of progenies and from regression of half-sib (HS) progenies on parents suggested that genetic variation for these traits was largely controlled by additive gene action. Association of dry matter yield (DMY) with plant height, number of fertile shoot, curbs width and spring growth was positive and significant. With the exception of number of days to pollination, correlation coefficients of the traits between the parents and offspring were not significant. Based on parent-offspring regression, genetic gain from selection for DMY was high, demonstrating genetic potential for improving this trait. Overall, there was high genetic variation and moderate heritability for most traits in the tall fescue populations evaluated. In conclusion, to improve herbage yield, selection would be more effective based on forage yield components.     

Anticonvulsant evaluation of safranal and crocin from Crocus sativus in mice

The anticonvulsant activities of Crocus sativus stigma constituents, safranal and crocin, were evaluated in mice using pentylenetetrazole (PTZ)-induced convulsions in mice. Safranal (0.15 and 0.35 ml/kg, i.p.) reduced the seizure duration, delayed the onset of tonic convulsions and protected mice from death. Crocin (200 mg/kg, i.p.) did not show anticonvulsant activity.     

Genotypic-specific responses caused by prolonged drought stress in smooth bromegrass (Bromus inermis): Interactions with mating systems

The consequences of recurrent drought events compared with a single drought, and drought's interaction with deliberate selfing compared with open-pollination on postdrought recovery and persistence of smooth bromegrass, are not clear. This research was conducted to investigate the effects of recurrent drought stresses compared with a single drought on stress response, poststress recovery and persistence of full-sib and half-sib progenies of smooth bromegrass. During this study, 25 selfed (S1) and 25 open-pollinated (OP) progenies of smooth bromegrass created in 2012 were evaluated in the field under normal and recurrent drought stress during 2013–2016. After the first harvest of above-ground biomass in 2016, irrigation was withheld in both environments for 2 months; plants were subsequently re-watered and evaluated. Recurrent drought stress changed the relationships between different traits. Moreover, prolonged drought stress resulted in increased plant productivity (recovery aerial biomass; RABI) of S1 and OP populations in recurrent drought stress compared with normal environment. Mandatory selfing increased persistence of smooth bromegrass genotypes but did not affect recovery after prolonged drought stress. Results revealed that, selecting among S1 families would be more effective than OP ones.     

Functional analysis of walnut polyphenol oxidase gene (JrPPO1) in transgenic tobacco plants and PPO induction in response to walnut bacterial blight

Walnut (Juglans regia) is economically important for both its wood and nut nutritional value, but it is susceptible to diseases such as walnut bacterial blight, caused by Xanthomonas arboricola pv. juglandis (Xaj). Walnuts contain many phenolic compounds, providing a good model on which to study polyphenol oxidase (PPO). We inoculated the detached walnut fruits of cultivars Ford, Chandler, Franquette, Robert Livermore, and Payne with Xaj and measured the induction of PPO activity in infected sites and adjacent to infected sites. Compared to infected and uninfected sites, PPO activity was induced significantly in areas adjacent to infected sites in all cultivars except Ford. Ford and Franquette, presenting the lowest and highest PPO activity, showed the largest and smallest mean diameter spots in response to Xaj, respectively. Polyacrylamide gel electrophoresis confirmed monophenol oxidase activity of walnut PPO in the assessed tissues. Then, we revealed the antipathogenic potential of walnut PPO through Agrobacterium tumefaciens-mediated walnut JrPPO1 gene transfer into tobacco (Nicotiana tabacum). Two transformed tobacco lines overexpressing the JrPPO1 gene were regenerated successfully and challenged with Pseudomonas syringae pv. tabaci. Transgenic lines showed significantly higher PPO activity and lower disease severity to the pathogen compared to the control. However, a significant difference in disease severity and PPO activity level was observed between the two transgenic lines. Our results demonstrate a potential defence-related role of PPO in transgenic tobacco and its induction in areas adjacent to infection sites in walnut cultivars treated with Xaj.     

Study of genetic diversity in safflower genotypes using agro-morphological traits and RAPD markers

This research was conducted to study the genetic diversity in safflower (Carthamus tinctorius L.) using agro-morphological traits and RAPD markers. Sixteen selected lines derived from landraces growing in various agro-climatic regions of Iran along with four exotic genotypes were evaluated in a randomized complete block design with three replications under field conditions. Days to emergence, days to initial flowering, days to flowering, days to maturity, plant height, branches per plant, capitula per plant, seeds per capitulum, 1,000-seed weight, seed yield per plant, seed yield, and reaction to powdery mildew (Leveillula taurica Arnaud) were evaluated in this study. Genetic diversity of the genotypes was assessed by RAPD markers. The results indicated significant differences among genotypes for the agro-morphological traits and clustering based on these traits classified the genotypes into five groups. Analysis of the RAPD markers revealed 15 polymorphic primers out of 50 used primers. Based on RAPD data, the highest genetic similarity was observed between the cultivars of “AC Sunset,” “AC Sterling” from Canada and the lowest relatedness observed between a local breeding line “E₂₄₂₈” and genotype “GE₆₂₉₂₃” from Germany. Cluster analysis based on RAPD markers and 54% coefficient of similarity divided the genotypes into five distinct groups. Comparing the clusters based on agro-morphological traits with those from molecular markers showed slight similarities. The finding of high genetic variation for agro-morphological traits and polymorphism at DNA level reveal that agronomic traits can be improved by selection programs.