Spanish Journal of Agricultural Research
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Effect of tillage system on the structure of weed infestation of winter wheat
No full textThe study aimed to evaluate the structure of weed infestation of winter wheat grown in different weeding systems: conventional tillage (CT), reduced tillage (RT), and herbicide treatment (HT). In CT system, shallow ploughing and pre-sow ploughing were conducted after the harvest of the previous crop. In RT system, shallow ploughing was replaced by cultivator tillage, whereas pre-sow ploughing by a tillage set. In HT system, shallow ploughing was replaced by spraying with glyphosate and pre-sow ploughing by cultivator tillage. At the tillering stage (22-23 in BBCH scale), species composition and number of weeds/m2 were determined with the botanical-gravimetric method, whereas at the stage of waxy maturity of wheat (82-83 BBCH) analyses were conducted for species composition as well as density, air-dry weight, and weed distribution in crop levels. The Shannon-Wiener’s diversity index (H’) and degrees of phytosociological constancy (S) of weeds were determined as well. The study showed that more weeds occurred in RT and HT systems than in the CT system and they produced higher biomass in RT than in CT and HT systems. The tillage system affected weed distribution in crop levels. In CT system, the highest weed density was identified in the ground and lower levels, whereas in RT and HT systems in the ground and middle levels. Values of the species diversity index (H’) indicate a similar diversity of weed species composition between weeding systems and more diverse between study years
Evaluation of a local goat population for fertility traits aiming at the improvement of its economic sustainability through genetic selection
No full textThe study aims to determine the environmental and genetic components for the reproductive performance of a Tunisian local goat population to set up the basis for the future improvement of this important component of efficient production. The reproductive traits considered were kidding interval (KI) and litter size at birth (LSB). Records of 462 kiddings belonging to 185 dams and 11 sires were collected over a period of 22 years in the caprine herd of the Arid Areas Institute of Médenine. Significance of environmental effects was tested with ANOVA techniques. Genetic parameters were estimated using restricted maximum likelihood fitting an animal mixed model. Mean KI and LSB were 13.85 ± 5.20 months and 1.33 ± 0.49 kids, respectively. The effect of parity number and the interaction between year and month of kidding were significant for LSB and KI. Trait LSB increased with parity number up to the fifth parity while KI decreased with parity number indicating that young females show compromised reproductive performance probably because of growth requirements and scarcity of food resources. A detrimental effect for kiddings occurring during winter (matings in summer) was observed from estimates of the year by month of kidding effect. Heritability estimates for KI and LSB were 0.13 and 0.08, respectively. A moderate repeatability estimate of 0.31 was obtained for LSB while 0.17 was obtained for KI. The low estimates of heritability obtained for reproductive traits indicated that accurate selection based on the doe’s own performance will require large amounts of data. However, the estimated genetic variability was substantial, providing the grounds for the genetic improvement of the reproductive parameters in this population
Ovule senescence and unusual pollen tube growth in the ovary of sweet cherry as affected by pistilar genotype and temperature
No full textThe study of ovule senescence in the ovaries of four sweet cherry cultivars (‘Karina᾿, ‘Kordia᾿, ‘Regina᾿ and ‘Summit᾿) in the environmental conditions of West Serbia was carried out. Monitoring of ovaries was performed using the fluorescence microscopy method, on emasculated and pollinated flowers (cross-pollination variant), non-emasculated open-pollinated flowers (open pollination variant), and emasculated unpollinated flowers (unpollinated variant). In cross- and open pollination variants, the rate of unusual pollen tube growth in the ovary, fertilization percentage and fruit set were determined. The tendency in the appearance of fluorescence, as an indicator of ovule senescence, showed strong genotypic dependence ‒ it was the most and the least pronounced in the ovaries of ‘Kordia’ and ‘Regina’, respectively, in all the flower categories. Investigation of unusual pollen tube growth, fertilization percentage and fruit set, considered from the aspect of ovule senescence and cultivars’ behaviour as female (pollinated), pointed to their specific relations and complex dependence on the air temperature before and during the flowering. Flower emasculation and pollination also influenced ovule senescence, and this impact was unequal by genotypes, i.e. those having better ovule vitality in general, had also better ovule vitality in the conditions of emasculation, and pollination absence. The results imply different adaptation of cultivars to higher temperatures before and during the flowering, pointing to the further investigation related to the good adaptability of genotypes to air temperatures in reproductive sense, which is a basic indicator of good adaptability in general
A biotic strategy to sequester carbon in the ornamental containerized bedding plant production: A review
No full textIdentifying options of climate change mitigation is of global interest to researchers. Whereas wide range of techniques of reducing greenhouse gas (GHG) emissions and carbon sequestration have been studied in row crops and forest systems, little research has been done on the ornamental horticulture. The ornamental industrial sector has indeed some negative impacts on the global environment, but also presents opportunities to reduce GHG emissions and increase C sequestration. Thus the objective of this study was to synthesize the potential contributions of some substrates used in the horticultural sector to carbon sequestration. The specific focus of the review is on the possible use of compost, vermicompost and biochar as soilless substrate substitutes for containerized ornamental plants production. Around 11 million kilograms of sphagnum peat moss are used annually in the world for horticultural production. Therefore, the potential of using compost, vermicompost and biochar as growing media is assessed on the basis of data from greenhouse studies. Peat-based substrate can be substituted up to 30% to 35% by compost or vermicompost and up to 20% to 25% by biochar. Some examples from field studies are included to conduct the life cycle assessment of using these growth media. An estimate of C storage on the long-term basis in soil indicates up to 3 million tons of CO2 equivalent as the maximum C potential storage per year in the global productive sector if the peat-based growing media are substituted by compost/vermicompost and biochar at the ratios mentioned above. Finally, synergies between compost vermicompost and biochar are discussed when these materials are combined as growing media additives and research gaps in this area of activity have been identified for further research
Pathogenic and biological characterization of Phytophthora capsici isolates from zucchini and pepper in Southeast Spain
No full textIn this work, isolates from pepper and zucchini were tested for pathogenicity on crops commonly cultivated in Mediterranean greenhouses. Also, morphological and growing features and mating types have been studied to find any differences linked with the plant origin and pathogenicity of each isolate. Three isolates were highly pathogenic on all cucurbitaceous and solanaceous hosts tested and caused root rot and wilting. Eggplant and pepper were moderately susceptible, while zucchini, tomato and cucumber were highly susceptible. No root rot symptoms occurred on the fabaceous plants inoculated with Phytophthora capsici, including bean and pea. Moreover, the pathogen was never reisolated from the roots of fabaceous plants. Other isolate of P. capsici was less pathogenic on cucurbitaceous and solanaceous crops, causing only slight root damages. None of the isolates tested produced chlamydospores, and all belonged to A1 mating type. These findings suggest that beans or peas may be a feasible alternative crop for those Mediterranean greenhouses with a history of root rot due to P. capsici
Characterization of the antifungal activity of three rhizobacterial strains against Rhizoctonia solani
No full text In this study, three rhizobacterial strains were characterized by their ability to inhibit Rhizoctonia solani and tested in chili (Capsicum annuum L.) seedlings. Strains A46 and P61 were identified as Pseudomonas tolaasii, and S108 as Rhanella aquatilis. In the dual culture tests, all the strains inhibited the radial growth of R. solani. None of the three strains produced chitinases or volatile compounds, but they were found to produce siderophores. However, this last characteristic was not responsible for the rhizobacterial inhibitory effect on the growth of R. solani, other bacterial metabolites were possibly involved. The bacterial filtrates added to the potato dextrose agar medium (PDA) in a 3:7 ratio had significant antifungal activity, being the filtrate from strain S108 the one that showed the highest effect, with 56% fungal inhibition. The co-culture of strain A46 with the phytopathogenic fungi in potato dextrose broth (PDB) increased the antifungal activity of the rhizobacterial filtrate. The application of the rhizobacterial strains to Serrano chili decreased the R. solani-related mortality rate in seedlings; particularly, S108 had the greatest effect, which was similar to the fungicide effect. This study showed that the S108 strain has potential as a biofungicide to control R. solani in chili seedlings
Improvement of cryopreservation protocol in both purebred horses including Spanish horses
No full textThere is a widely held belief that the semen of Purebred Spanish Horses (PRE) is of generally poorer quality than that of other breeds, and survives cryopreservation less well. To determine whether this is the case, sperm concentration, viability and morphological abnormalities were examined in a total 610 fresh ejaculates from 64 healthy PRE (N=47) and non-PRE stallions (N=17). Sperm concentration and viability were then re-examined after pre-freezing centrifugation, and once again after freezing-thawing. No differences were observed between the PRE and non-PRE stallions in terms of any sperm quality variable at any observation point. When considering all PRE and non-PRE samples together, differences in sperm viability were observed between fresh and fresh-centrifuged sperm viability (70.1±12.5% compared to 76.3±10.9%; p<0.01). After centrifugation the samples were also more homogeneous in terms of the total number of recovered sperm cells. Centrifugation also improved frozen-thawed sperm viability, reducing differences in sperm quality between individual stallions. For all centrifugations, a sperm:extender ratio of 1:5 was used. This would appear to provide better final results than those reported in the literature for the 1:1 ratio commonly used for PRE stallion sperm cryopreservation. In conclusion, obtained results show that the quality and frozen/thawed results of PRE stallion sperm are not lower than that of non-PRE breeds. In addition, using a 1:5 sperm:extender dilution ratio when selecting sperms by centrifugation prior to freezing, seems to provide better results than those usually reported when using a 1:1 ratio
