Spanish Journal of Agricultural Research
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Emergence and morphophysiology of Sunki mandarin and other citrus genotypes seedlings under saline stress
No full textThe scarcity of good quality water is a limiting factor for irrigated agriculture, especially in arid and semiarid regions, where water sources generally contain high concentrations of ions. In such conditions, it is essential to cultivate genotypes with economic potential and tolerance to salinity. Considering the importance of citrus and the need to identify genetic materials that adapt to saline stress, this study evaluates the salinity tolerance of 10 genotypes with rootstock potential. For the irrigation water, five levels of electrical conductivity (ECw: 0.8, 1.6, 2.4, 3.2 and 4.0 dS/m at 25 °C) were used in a randomized block design with three replications, and seed germination and growth variables, as well as physiological plant parameters, were evaluated. The germination rate of the hybrid TSKC × CTARG – 019 was the best under salt conditions, as it was the genotype with the highest tolerance to salinity in the germination stage. Salinity reduced the growth of the citrus genotypes, with the possibility of using water with EC of up to 1.6 dS/m in the rootstock formation stage. Salt stress affected the photosynthetic rate of the genotypes ‘San Diego’ citrandarin and TSKC × CTSW – 018 by reducing the stomatal conductance, restricting the diffusion of CO2 into the substomatal camera. The genotypes TSKC × CTARG – 019, TSKC × CTTR – 012 and TSKC × TRBK – 007 have the greatest potential for growth and photosynthetic apparatus efficiency when subjected to salinity
Effects of two commercial feeds with high and low crude protein content on the performance of white shrimp Litopenaeus vannamei raised in an integrated biofloc system with the seaweed Gracilaria birdiae
No full text A trial was conducted for 42 days to evaluate the effects of two commercial feeds with high and low crude protein content on the performance of white shrimp Litopenaeus vannamei cultivated in an integrated biofloc system with the seaweed Gracilaria birdiae. The experiment had a 2 × 2 factorial design (a biofloc monoculture or an integrated system with 32% (low) or 40% (high) crude protein content) with the following treatments: IS32 (an integrated system using low protein commercial feed); IS40 (an integrated system using high protein commercial feed); M32 (a monoculture system using low protein commercial feed); and M40 (a monoculture system using high protein commercial feed), all in triplicate. Shrimp individuals (0.23 ± 0.04 g) were stocked at a density of 500 shrimp/m3 and no water exchange was carried out during the experimental period. No significant influence (p > 0.05) was found to be caused by the integrated system or the crude protein levels on water quality. However, a significant influence (p < 0.05) was found for final weight (3.21–4.12 g), weight gain (2.97–3.89 g), yield (1.39–1.96 kg/m3) and feed conversion ratio (1.47–1.74). Growth was similar in IS32, M40 and IS40, indicating that crude protein levels can be reduced with no adverse effect on shrimp performance variables in integrated biofloc systems with G. birdiae
Short communication: Gender and heat stress effects on hypothalamic gene expression and feed intake in broilers
No full textOur study aims to evaluate gender and heat stress effects on animal performance and on the expression of five hypothalamic genes related to feed consumption: neuropeptide Y (NPY), ghrelin (GHRL), pro-opiomelanocortin (POMC), AMP-activated protein kinase (AMPKα-1), and liver kinase B1 (LKB1). To assay these effects, 42-day-old male and female broilers were maintained in thermal comfort or were subjected to heat stress (HS, 38°C for 24 hours). All animals were fed with diets formulated to meet their nutritional requirements. Broilers subjected to HS showed lower weight gain (p=0.0065) and tended to have lower feed intake (p=0.0687) than broilers kept in comfortable conditions. We observed gender and heat stress interaction effects on NPY (p=0.0225), AMPKα-1 (p=0.0398), and POMC expression (p=0.0072). The highest NPY gene expression was observed in male broilers from the thermal comfort group. Male broilers exposed to HS showed the highest AMPKα-1 gene expression levels. Comparing POMC expression between males and females at the comfortable temperature, we observed that females showed higher POMC expression levels than male broilers. A gender effect was also observed on LKB1 and AMPKα-1 gene expression (p=0.0256 and p=0.0001, respectively); increased expression was observed in male broilers. Our results indicate that the expression of some hypothalamic genes related to food consumption may contribute to the observed differences in voluntary feed intake between animals of different gender exposed to different environmental conditions
Influence of spunbond degradable floating row covers on microclimate modification and yield of field cucumber
No full textIn recent years, there has been an increase in interest in innovative plastic materials for use in horticulture. The aim of this study was to examine the effects of (bio)degradable floating covers (polylactide nonwoven ‒ PLA, and oxo-degradable polypropylene nonwoven with 0.1% iron stearate ‒ PP photo, both 20 g/m2) compared to the conventional PP nonwoven (control, 20 g/m2) on microclimate modification and yield of field-grown cucumber. The greatest PAR transmittance was recorded for the control nonwoven (83%), while the degradable materials transmitted 8% less radiation. Maximum soil surface temperatures were the highest under the PLA nonwoven, but minimum temperatures ‒ under the oxo-degradable fleece. The mean temperature under the oxo-degradable material was comparable to the control, while PLA increased the soil temperature by 1.8 °C, on average. The yield from cucumber plants covered with degradable materials was similar to that from the plants cultivated under the conventional oil-based nonwoven fleece. There were no significant changes in dry weight and soluble sugar content in cucumber fruits in 2013; however, the degradable nonwovens decreased these parameters in 2012. The lifespan of the oxo-degradable nonwoven was limited only to one growing season, thus the durability of the polymer must be increased. Polylactide nonwoven can be a sustainable ecological alternative to conventional non-degradable PP covers
Molecular characterization of the cucumber (Cucumis sativus L.) accessions held at the COMAV’s genebank
No full textThe cucumber (Cucumis sativus L.) is an important crop worldwide. In the present study, the molecular genetic diversity of 131 Spanish accessions was analyzed using 23 simple sequence repeat (SSRs). Eighteen of these SSRs were polymorphic; the mean number of alleles, mean observed heterozygosity and mean polymorphic information content were 3.2, 0.065 and 0.229, respectively. Seven SSRs showed a polymorphic information content (PIC) ranging from 0.31 to 0.44, therefore they were reasonably informative. Around 60% of the alleles showed a frequency higher than 0.05, and only one allele in the SSR31399 showed a frequency lower than 0.01. In addition, three accession-specific alleles were found. A high proportion of variation among accessions was obtained. In no case all plants of any accession showed the same genotype and only 18 of 131 Spanish accessions had at least two plants with the same genotype. A cluster analysis did not show any relation with morphological types or geographical area. Therefore, these results demonstrated that molecular diversity of the cucumber did not reflect its phenotypic variability. Finally, this study provided information for the rationalization of the cucumber collection of the COMAV. Morphological traits, origin and molecular data were taken into account to select 47 accessions, six belonging to ‘French’ type, 15 to ‘Long’ type, and 24 to ‘Short’ type. Phenotypic and molecular variability contained in the complete collection was conserved in the selected accessions
Effects of antioxidant activity of black maize in corn borer larval survival and growth
No full textAntioxidant activity (AA) of black maize kernels attributed mainly to polyphenols has potential effects on health and possible defense functions against pests. Our objective was to evaluate the effects of maize polyphenols and AA in survival and growth of larvae of the corn borer Sesamia nonagrioides. We carried out two bioassays with S. nonagrioides larvae grown in artificial diet with white and black maize flour and control. AA was tested spectrophotometrically on each of the diets using four methods. The different measurements of AA were strongly correlated, indicating that these measurements were highly reliable. The control diet, the white-maize-diet and black-maize-diet with vitamin C and without H2O2 had the highest antioxidant activity. The processing of the maize flour altered the AA of the polyphenols. The control treatment had the highest AA, and vitamin C had stronger AA than polyphenols. AA of vitamin C hides that of polyphenols probably due to environmental effects, dilution of polyphenols, or interactions with other substances. Larvae grew more in the control diet and the addition of H2O2 had not significant effects on weight. There was a weak rank correlation between AA and larval weight. Mortality was lowest for the control diet with or without H2O2 followed by white maize with or without H2O2 and black maize without H2O2. Effects of polyphenols depend on other substances that might interact with them. The results indicate that antioxidant activity has insecticide effects on young larvae and, as the larvae grow, antioxidants have positive effects on larvae
Non-phytate phosphorus requirement for male broilers subjected to two calcium supply regimens from 8 to 21 days of age under thermoneutral environment conditions
No full textThe purpose of this study was to determine the non-phytate phosphorus (nPP) requirement for male broiler subjected to two calcium supply regimens from 8 to 21 d of age, based on performance and bone mineralization. Birds were distributed in a complete randomized 4 × 2 factorial design with four nPP concentrations: 0.25, 0.35, 0.45 and 0.55%, and two Ca supply regimens: Ca fixed at 9.0 g/kg of diet (CaF) or varying together with the nPP concentrations tested keeping a fixed Ca:nPP ratio (CaV), with 8 battery cages/treatment and 9 birds/battery cage. Feed intake (FI), body weight gain (BWG) and Ca:P ratio deposited in the dry defatted tibia (TibCa:TibP) were quadraticaly increased by the increasing nPP concentrations, regardless of the Ca supply regimen adopted (p<0.01). The nPP levels tested also influenced FCR and TibAsh, which presented a quadratic and linear response when CaF and CaV diets were used, respectively, and TibP and TibCa, which presented a quadratic response with both Ca supply regimen, CaF and CaV diets. Also, CaV diets provided a 2.86 and 5.02% higher FCR (p<0.05) and TibCa (p<0.01), respectively, when compared to CaF diets. Therefore, nPP nutritional requirement for male broilers reared at thermoneutral conditions from 8 to 21 d of age that provided better performance and bone mineralization were, respectively, 0.480 and 0.459% with CaF and 0.550% with CaV diets, indicating that, under thermoneutral conditions, CaV diets negatively affected growth performance of broilers, while positively affecting bone mineralization especially when low nPP levels are applied
Mitigation of salinity stress in canola plants by sodium nitroprusside application
No full textSalinity is a global issue threatening land productivity and food production. The present study aimed to examine the role of sodium nitroprusside (SNP) on the alleviation of NaCl stress on different parameters of canola (Brassica napus L.) plant growth, yield as well as its physiological and anatomical characteristics. Canola plants were grown under greenhouse conditions in plastic pots and were exposed to 100 mM NaCl. At 50 and 70 days from sown, plants were sprayed with SNP (50 and 100 µM) solutions under normal or salinity condition. Growth and yield characters as well as some biochemical and anatomical changes were investigated under the experimental conditions. Salinity stress caused an extremely vital decline in plant growth and yield components. A significant increase was found in membrane permeability, lipid peroxidation, hydrogen peroxide, sodium, chloride, proline, soluble sugars, ascorbic and phenol in canola plants under salinity stress. Under normal conditions, SNP application significantly increased all studies characters, except sodium, chloride, hydrogen peroxide, lipid peroxidation, membrane permeability that markedly reduced. Application of SNP to salt-affected plants mitigated the injuries of salinity on plant growth, yield, and improved anatomical changes. The present investigation demonstrated that SNP has the potential to alleviate the salinity injurious on canola plants
Identification of epiphytic yeasts and bacteria with potential for biocontrol of grey mold disease on table grapes caused by Botrytis cinerea
No full textThe objective of this study was to identify grapevine epiphytic yeasts and bacteria for biocontrol of Botrytis cinerea on grapes. Antagonistic yeasts and bacteria were isolated from the epiphytic flora associated with grape berries and leaves cv. ‘Thompson seedless’ from vineyards in Iran and identified by sequencing the conserved genomic regions. A total of 130 yeast and bacterial isolates from the surface of grapevine were screened in vitro for determining their antagonistic effect against B. cinerea and used to control postharvest gray mold. Among the 130 isolates, five yeasts and four bacterial isolates showed the greatest antagonistic activity in vitro against B. cinerea. Two yeasts species including Meyerozyma guilliermondii and Candida membranifaciens had high antagonistic capability against the pathogen. Also, 4 bacterial isolates belonging to Bacillus sp. and Ralstonia sp. showed significant biocontrol effect against B. cinerea. The isolates were capable of producing volatile and non-volatile substances, which suppressed the pathogen growth. The antagonistic activity of selected yeasts and bacteria against the pathogen was investigated on wounded berries of ‘Thompson seedless’. On small clusters with intact berries, all of the antagonistic isolates considerably reduced the decay on grape berries and inhibition of gray mold incidence on fruits treated by these isolates was less than 50%, except for the isolate N1, which had higher capability in inhibiting the disease incidence. These results suggest that antagonist yeasts and bacteria with potential to control B. cinerea on grape can be found in the microflora of grape berries and leaves
The profitability of value-added products in dairy farm diversification initiatives
No full textA more open and competitive dairy market has encouraged certain dairy farms to adopt value-adding strategies in order to achieve a higher profitability, which may be important for farms’ survival. This paper investigated the role of some product characteristics in the profitability of value-added products in these farms. For this purpose, we used a unique database of 265 different products commercialized by 49 Spanish dairy farms that offers information on nine attributes of each product. Using hedonic models as a baseline, we examined the influence of these attributes on the margin per liter (ML) of the products. The results of the regression indicated that cheese and yogurt generated 0.688 and 1.518 € more of margin per liter than liquid milk. Similarly, we found a set of attributes that have a positive influence on ML, including possession of a certificate of protected designation of origin (PDO), the milk-type composition (proportion of sheep milk), a longer expiration period, and involvement in direct marketing strategies (DMS). However, other recognized attributes such as organic labeling, maturation period, size of the sales unit and returnable packaging did not have a significant influence on ML. Our findings also showed that firms producing more elaborated products as cheese and yogurt need a lower percentage of their production to cover the fixed costs associated to transformation and commercialization. Overall, our results revealed that the elaboration of value-added dairy products improves the profitability of dairy farms