CREA Journals (Consiglio per la ricerca in agricoltura e l’analisi dell’economia agraria)
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Effect of humic acid foliar application on growth and quantity of corn in irrigation withholding at different growth stages
Get PDFIn order to study effect of humic acid foliar application and limited irrigation on growth and quantitative character¬istics of corn an experiment was conducted in research field of Varamin in Iran during 2012 growing season. The experimental design was laid out in a randomized complete block with a split plots arrangement of treatments in three replications. Main plots included three different levels of irrigation (complete irrigation, irrigation withhold¬ing at 8-leaf stage and irrigation withholding at staminate inflorescence) and four different concentration of humic acid foliar application (0, 150,300 and 450 ppm) was allocated to subplots were. The results showed that irrigation withholding conditions in different growth stages significantly decreased plant height, yield components, seed yield, biological yield and harvest index. Humic acid foliar application in irrigation with holding in different growth stages had positive effect on all attributes in this experiment. In general, the results of the present study indicate that usage of humic acid reduces the harmful effects of water deficit stress and increases resistance to drought stress in corn plant
Ozone dynamics in a Mediterranean Holm oak forest: comparison among transition periods characterized by different amounts of precipitation
Get PDFTropospheric ozone (O3) is one of the most toxic compounds for plants in the atmosphere. The large amount of anthropogenic O3 precursors in the urban areas promote O3 formation, thus making Mediterranean forests located in periurban areas particularly vulnerable to this pollutant. O3 flux measurements have been carried out using the Eddy Covariance technique over a Holm oak forest located 25 Km from Rome downtown, inside the Presidential Estate of Castelporziano (Italy).Two transition periods - early Spring and late Fall - in two consecutive years were examined. The uncommon low precipitation recorded in both transition periods in 2012 allowed to evaluate the influence of water availability on O3 fluxes during seasons which are not commonly affected by drought stress.Overall, the forest canopy showed to be a net sink of O3, with peak values of mean daily O3 fluxes of -8.9 nmol m-2s-1 at the beginning of flowering season and -4.6 nmol m-2s-1 at the end of Fall.O3 fluxes were partitioned between stomatal and non stomatal sinks using the evaporative/resistive method based on canopy transpiration in analogy with an Ohm circuit. By comparison of the two years, water availability showed to be an important limiting factor during Spring, since in this season plants are more photosynthetically active and more sensitive to water availability, while in Fall, under conditions of low stomatal conductance, the dependence on water availability was less appreciated
Correlation and combining ability analysis of physiological traits and some agronomic traits in maize
Get PDFCombining ability information on the physiological traits in maize (Zea mays L) and the relationship between physi¬ological traits and biomass, grain yield (GY) and yield components (YC) can help maize breeders design experi¬ments for improving inbred lines and/or developing hybrids with improved GY or YC (GYYC). A six-parent diallel experiment (Griffing method 3) was conducted for combining ability and correlation analyses. The objectives of this study were to 1) study the correlation between physiological traits and biomass at seedling stage; 2) study which physiological traits at seedling stage have significant correlation with biomasses at both seedling and later growth stages and GYYCs; 3) evaluate combining ability of the physiological traits that are significantly correlated with either GY or one of the YCs. Results showed plant heights at 20 day, 40 day, and leaf area were highly corre¬lated with both dry weights of shoots and roots. All chlorophyll-related organelles were significantly correlated with only dry weights of shoots. However, dry matter at seedling stage seemed not to be related to dry matter in later growth stages. Five physiological traits (stomatal conductance, transpiration rate, net photosynthetic rate, two quantum yield related traits) at seedling stage were identified to greatly impact dry matter at later growth stages. Results also showed that 13 out of 35 physiological traits studied were significantly correlated with GYYCs. Differ¬ent germplasms for improving GYYCs could be used based on both correlation between the 13 traits and GYYCs and combining ability effects of each line for the 13 selected traits
Assessment of ethanol yield associated characters in sweet sorghum
Get PDFSweet sorghum is a crop close to sugarcane in respect to its sucrose accumulation, and the juicy composition of the stem offers an excellent alternative feedstock apart from others such as sugar beets. In the present inves¬tigation nine sweet sorghum cultivars were grown in the field, IARI, New Delhi; all the ethanol yield associated morphological characters were recorded, sorghum cultivars samples were analyzed at harvesting. The association analysis had clearly brought out that among the inherent genotypic characteristics stem girth, number of inter¬nodes per plant, juice content of sorghum were very important for increase in juice yield. Among the other associ¬ated characters, green cane yield and consequently percent juice recovery with higher total soluble sugar content were important parameters for ethanol yield in sorghum. It is therefore, suggested that these inherent genotypic characteristics could be exploited in identifying suitable cultivars for the purpose of ethanol production
Combining ability of white corn genotypes with two commercial hybrids
Get PDFWhite corn is a special type of corn used to make «canjica», a dish appreciated in many regions in Brazil. However, there is a shortage of scientific information, genetic statistical estimates for breeding programs and white corn cultivars for producers to produce grits. The objectives of the present study were to assess two groups of white corn genotypes in a partial diallel cross for the main agronomic traits, estimate the combining ability of the parents and identify promising white corn hybrids for yield and grits quality. The fourteen topcross hybrids obtained from a partial Diallel (2 x 7), using seven genotypes and two commercial testers of the white maize (IPR 119 e IPR 127). The resulting hybrids and the two commercial controls were assessed in the 2011/2012 in the experimental center Agronomic Institute in Campinas (IAC) in growing season at the in Campinas and Tatuí, São Paulo state, Brazil. A randomized block design was used with four replications. The traits assessed were male flowering (MF), female flowering (FF), plant height (PH), ear height (EH), percentage of broken and lodged plants (Ld + Br) and grain yield (GY). There were two treatments for all the traits assessed in the two locations and some hybrids presented higher mean production than the commercial controls. The P7, P1, P3, and P2 genotypes presented the best general com¬bining ability for all the traits assessed. The best estimates for specific combining ability were observed in the P6 x P9, P2 x P9, and P7 x P8 hybrids, indicating dominant loci systems in the genetic control of the traits PH, EH and GY
Exploring soil water budget of a pristine oak wood in peri-urban Rome, central Italy
Get PDFExploring soil water budget of a pristine oak wood in peri-urban Rome, central Italy. The water budget in bounded and fenced areas was assessed by analyzing pedo-climatic conditions and the soil moisture content. Water content in the soil was measured using a Theta Probe Soil Moisture sensor (ML2x by Delta-T-Devices) with a direct read-out device that provides soil moisture estimates as percent volume. The correlation between the experimental values obtained by the gravimetricmethod and thevalues directly measured by Theta Probe was found significant. Soil moisture at 100 cm depth indicates soil water as permanently available for plants through the year except during exceptionally dry summer periods. Therefore, oaks experienced no water deficiency with normal rainfall rates, possibly suffering root asphyxia during rainy years. Results are collected in fenced areas, sheltered by the action of the local fauna
A Gis-based cost distance approach to analyse the spread of Matsucoccus feytaudi in Tuscany, Italy (Coccoidea Matsucoccidae)
Get PDFThe Maritime pine bast scale Matsucoccus feytaudi Ducasse was introduced into south-eastern France from the Atlantic regions and since then has moved eastward to reach Tuscany, Italy, causing decay and death of thousands of hectares of pine stands. Monitoring of the pine bast scale by pheromone traps in Tuscany since 2000 has allowed us to obtain yearly data on the pest’s diffusion. The data were processed by means of the Thiessen polygons algorithm to obtain the distribution of the insect. A GIS cost distance model was adopted to simulate the spread of M. feytaudi infestation: dominant winds were used in the least accumulative distance calculation, together with Pinus pinaster presence as secondary factor. The overall accuracy of the model calculated for the years 2003 to 2008 ranged between 70.0% and 81.8%; user’s and producer’s accuracy showed greater variability, but with good performances in the majority of cases. The use of pheromone traps and spatial analysis enabled to produce annual maps for the Tuscany, with the identification of the Maritime pine forests more susceptible to M. feytaudi colonization. This cartography was an important tool for regional offices in the identification of areas requiring direct forestry management
Abundance and biodiversity of soil arthropods in one conventional and two organic fields of maize in stockless arable systems
Get PDFSoil arthropod community was evaluated, in three different farming systems in Central Italy, in the context of a long-term experimental stockless arable system (MOLTE). The soil arthropodofauna was recorded in two organic agrosystems of different age (16-year old organic, named OldO; 6-year young organic, named YngO) and in one conventional (Co), at a fixed time on maize. Arthropods, extracted by Berlese-Tullgren funnels, were counted and identified at order or suborder taxonomic level. In the three maize fields, the farming system affected both abundance and biodiversity of arthropods. The arthropod density ranged from about 20,000 individuals/m2 in OldO to about 45,000 in YngO. The number of oribatid mites was higher in Co than in OldO, while YngO showed the highest density of collembolans. The mite/collembolan ratio was the highest in Co (6.43), the lowest in YngO (1.95). Both biodiversity indices adopted – V, synthetic index of degree of diversity change of ecological systems and QBS, index of biological soil quality – showed the highest values for YngO. On the whole, differences in the arthropod community were higher in the YngO-OldO comparison than in OldO-Co. The soil arthropod community tended to be characterized by lower density of specimens and lower number of taxa in the OldO organic system than in the YngO
Evaluation of different Bacillus thuringiensis sv kurstaki formulations against Lymantria dispar and Malacosoma neustria larvae infesting Quercus suber trees
Get PDFLepidopteran defoliators such as Lymantria dispar and Malacosoma neustria represent a major concern for cork oak forest, especially during population outbreaks. To contain their infestations over large areas, the use of entomopathogenic microorganisms such as Bacillus thuringiensis serovar kurstaki (Btk) is one of the available option. However, the features of the microbial control agent formulations represent a key factor for the success of application programs. The results of two years efficacy trials with different formulations of Btk, conducted in 2012 and 2013 in a cork oak forest in North-Western Sardinia, are reported. In the first year, trials were carried out on a M. neustria population, while in the second year a mixed population of L. dispar and M. neustria was involved. Trials included two formulations of Btk strain EG 2348 (Rapax® and Rapax Experimental) in comparison with two other commercial formulations (Foray 48B® and Delfin®). Both formulations of Btk strain EG 2348 proved to be effective in controlling the two pest species, showing a forest protection potential comparable to that of the reference products, Foray 48B® and Delfin®, containing spores and insecticidal Cry proteins of strains HD-1 and SA-11, respectively. Also the defoliation levels were significantly higher in untreated control trees than in treated ones
Selecting maize for rapid kernel drydown: timing of moisture measurement
Get PDFPrevious studies have shown that maize ear moisture measured using a modified Electrophics Moisture Meter model MT808 was highly correlated to kernel moisture and could be used as a selection tool in breeding maize genotypes with faster rates of kernel drydown. Such a tool would need to be standardized for practical and routine use in a breeding program with large numbers of plants. The objective of this study was to determine the opti¬mum time for measuring ear moisture using this meter. In a split-plot design with three replicates in 2007, 2008 and 2009, ear moisture of six inbred lines and eight F1 hybrids were measured weekly from one to eight weeks post-silking using a modified MT808 moisture meter. To determine if multiple ear moisture readings (EMRs) could be made on the same ear, an additional treatment was added so that all eight readings were made on the same ear. There was a positive correlation between weekly EMRs readings done on separate ears and those done on the same ear, indicating that repeated readings, if desired, could be made on the same ear. Significant genotypic differences in EMRs were found five to eight weeks post-silking. The EMRs at week one, five, and eight could be used to calculate a daily drydown rate (DDR). Maize genotypes (hybrids and inbreds) could be divided into four groups based on their DDRs during development as: high-high, high-low, low-high, and low-low DDRs from weeks one to five and five to eight, respectively. Genotypes with higher DDRs from weeks one to five tended to have overall higher DDRs by eight weeks post-silking. Inbred lines with higher DDRs at either stage expressed this trait in their hybrid crosses. This non-destructive method will improve selection for fast kernel drydown in maize breed¬ing programs, especially in short-season areas