Scielo RSS <![CDATA[Chilean journal of agricultural research]]> vol. 77 num. 3 lang. en <![CDATA[SciELO Logo]]> <![CDATA[Mexican native tomatoes as rootstocks to increase fruit yield]]> ABSTRACT Tomato (Solanum lycopersicum L.) is one of the most economically important vegetables in the world. Mexico is considered as its center of domestication and there is a large genetic diversity. Grafting in tomato has grown for various purposes including the increase of yield. An alternative use of native tomato genotypes is as rootstocks for grafting improved tomato. The objective of this work was to evaluate native accessions of tomato as rootstocks to identify outstanding genotypes for their potential to be used as rootstocks in tomato production. An experiment was conducted for two cropping cycles (2014 and 2015) in greenhouse and hydroponic conditions, in a randomized complete block design (RCBD) with three replicates and 10 plants per experimental unit. Treatments were formed by a combination of nine native tomatoes and two commercial rootstocks with two hybrids used as scions. Twelve traits were recorded and most of the treatments were significantly different (P &lt; 0.05) from each other for these traits. The accessions LOR-22, LOR-77, LOR-81, LOR-84, LOR-95 and LOR-100 with the hybrid ‘El Cid’, and LOR-81, LOR-84 and LOR-100 with the hybrid ‘Sun 7705’, increased significantly yield by 19% and 22%, respectively, compared to ungrafted control. Moreover, characteristics related to fruit quality were preserved with grafting. The best combination scion/rootstock (‘Cid’/100) yielded 30% higher than hybrid ‘El Cid’ without grafting and 16% higher than the commercial rootstock ‘Multifort’. This allowed identifying genotypes of Mexican native tomatoes with great potential to be used as rootstocks or as source of germplasm for rootstock development. <![CDATA[Alterations in volatile metabolites profile of fresh tomatoes in response to <em>Alternaria alternata</em> (Fr.) Keissl. 1912 infection]]> ABSTRACT Alternaria alternata (Fr.) Keissl. 1912 is one of the main fungal pathogens that infect tomato (Solanum lycopersicum L.) during cold storage affecting postharvest quality and marketing. During fungal infections, fruits and fungi release specific volatile metabolites (VM) that could alter the fruit aroma, or could mediate resistance response in the fruit, or they also could suggest the possible status of fungal attack. The detection of the VM released during the tomato-Alternaria interaction could contribute to the development of ecofriendly and harmless strategies for its control. In this study, the profile of VM of fresh tomatoes inoculated with A. alternata, were analyzed by solid phase microextraction and gas chromatography-mass spectrometry (SPME-GC-MS) during storage at 15 and 20 °C for 48 h, respectively. Changes in the profile of VM were observed between control and inoculated fruit since the first few hour post-inoculation. Some VM (3-methyl-2-butenal, dimethyl disulfide, 1-butenol, hexanol, 2-methyl-1-butanol acetate, among others) were only detected in inoculated fruit, so they appear to be synthesized by the presence of the pathogen. Also, a marked increase of 3-methyl-1-butanol and 6-methyl-5-hepten-1-one were observed in inoculated fruit, and they were progressive over time particularly at 20 °C. In conclusion, A. alternata induced changes in the profile of volatile metabolites released by tomato fruit. Some of the VM released during tomato-A. alternata interaction, were synthesized or stimulated by the fungal attack. These results contribute to the current knowledge about the profile of VM released during the fruit-pathogen interaction. <![CDATA[Significant associations between single nucleotide polymorphisms and photosynthetic parameters and grain yield in maize]]> ABSTRACT Photosynthesis is the basis of maize (Zea mays L.) grain formation. To further understand the genetic basis of maize photosynthetic parameters and clarify the relationship between maize photosynthetic parameters and grain yield (GY), identifying quantitative trait loci (QTLs) underlying photosynthetic parameters and GY plays an important role in improving maize yield. In this study, a set of 260 maize accessions from different geographic origins were evaluated across three developmental stages in 2 yr to identify QTLs for photosynthetic parameters and grain yield using 2824 single-nucleotide polymorphisms (SNPs) via genome-wide association analysis. The analysis revealed that maize photosynthetic parameters are substantially correlated with GY at different developmental stages. Fourteen SNPs associated with photosynthetic parameters and GY were detected at the threshold of P ≤ 0.001 in 2 yr as well as over years. Moreover, PZE-102116144 and SYN35048 associated with stomatal conductance (gs), and PZE-101152541 associated with photosynthetic rate (PN), were identified at different developmental stages. Four loci were co-associated with two or more traits, such as PZE-101152541 was significantly co-associated with GY and PN (at 25 and 35 d after pollination [DAP]), PZE-102116144 with GY, gs (at 15 and 25 DAP), and PN (at 25 DAP), PZE-109061997 with intercellular CO2 concentration (Ci) (at 25 DAP) and transpiration rate (Tr) (at 25 DAP), PZE-110019199 with gs (at 25 DAP) and GY. Based on functional annotations, two genes were considered as potential candidate genes for the identified SNPs (PZE-101152541 and PZE-109016787). The SNPs and candidate genes identified in this study might provide instrumental information for understanding the genetic mechanism of maize photosynthetic parameters and yield. <![CDATA[Assessment of Genotype × Trait × Environment interactions of silage maize genotypes through GGE Biplot]]> ABSTRACT In yield experiments conducted at different environments, assessment of Genotype × Environment interactions for investigated traits is a quite significant issue for both agronomists and breeders. GGE biplot analysis was employed in this study to assess the Genotype × Trait, Environment × Trait and Trait Association × Environment of five different traits (silage yield [SY], stem diameter [SD], green leaf weight ratio &amp;91;GLWR], green stem weight ratio [GSWR], green corn cob ratio [GCCR] and plant height [PH]) of 25 silage maize (Zea mays L.) genotypes grown in six environments. The biplot graphs created in this study to assess Genotype × Trait, Environment × Trait and Environment × Trait correlation interactions were able to explain respectively 86%, 92%, and 83% of total variation of experiments. Current findings revealed that the genotype G18 (Safak), with the greatest silage yield in Genotype Trait biplot (GT biplot) also had the greatest SD; DIY14 (DIYARBAKIR-2014) with the greatest distance from the origin over Environment Trait (ET-biplot) graph was the most distinctive environment; SD with the greatest vector length was the most distinctive trait; DIY14 and DIY15 environments were the best environments for PH, GSWR, SY and SD. It was concluded that GGE biplot method with different perspectives could reliably be used in assessment of silage characteristics of maize genotypes grown in different environments. <![CDATA[NIR-Prediction of water-soluble carbohydrate in white clover and its genetic relationship with cold tolerance]]> ABSTRACT In temperate climates, cold stress constrains productivity of white clover (Trifolium repens L.), the most important perennial forage legume in intensive grazing systems for ruminants. Metabolism of water sugar carbohydrate (WSC) has been proposed as an important trait conferring cold tolerance to white clover. Conventional methodologies for WSC determination are considered high-cost and time-consuming. Near-infrared (NIR) spectroscopy is a robust, reliable, and high-throughput methodology to estimate chemical composition of forage species. The objectives of this work were to determine the accuracy of NIR spectroscopy for predicting WSC in stolon samples of white clover, and to evaluate the genetic relationship between WSC and cold tolerance. A white clover association mapping (WCAM) population was stablished in three location that represent a winter low temperature gradient associated with altitude. Dry matter production and some morphological traits were evaluated during three growing seasons. Samples for WSC determination were collected three time during a winter period. Samples were scanned with a NIR system, and a prediction model for WSC was fitted using partial least squares (PLS) regression. The adjusted prediction model achieved suitable predictive ability (R2 &gt; 0.85). The WSC per se did not show significant genetic relationship with morphological and agronomically important traits. However, the WSC degradation rate (WSCdr) across the winter period showed significant genetic correlation with DM production during spring (rg = 0.64), which is the result of genetic/physiological mechanism expressed during the cold period. The NIR spectroscopy is a reliable and high-throughput methodology to predict WSC in stolon samples of white clover. The metabolism of WSC, evaluated as WSCdr, is involved in the cold tolerance of the WCAM population. The methodology implemented in this work is suitable to be applied in a plant breeding program routine. <![CDATA[Decrease in artificial radiation with netting reduces stress and improves rabbit-eye blueberry ( <em>Vaccinium virgatum</em> Aiton) ‘Ochlockonee’ productivity]]> ABSTRACT Blueberry production under netting has increased in recent years to mitigate the adverse effects of climate change. The objective of the present study was to evaluate the effect of different radiation intensities on rabbit-eye blueberry (Vaccinium virgatum Aiton) ‘Ochlockonee’ photosynthetic efficiency and productive parameters. Four treatments were established: T1 (control), T2, T3, and T4 at 0%, 30%, 60%, and 90% radiation decrease (RD), respectively, with black shedding netting. The following were recorded for each treatment: environmental conditions, photosystem II (PSII) maximum quantum yield (Fv/Fm), photosystem II effective quantum yield , leaf stomatal conductance (gs), quality parameters, and fruit yield. Results showed an increase of 4.6 ºC in mean minimum temperatures for the different netting treatments, which promote development and fruit set, as well as prevent damage at temperatures near 0 ºC. The RD treatments increased between 175% and 325% (P &lt; 0.05) compared to the control. It can be concluded that netting decreased soil temperature between 1 and 3 ºC and increased minimum temperatures between 1 and 6 ºC, which promoted plant development and decreased frost damage during flowering and fruit development. Current direct radiation levels over 1000 µmol m-2 s-1 in V. virgatum inhibited productivity in T1. Netting decreased the degree of photoinhibition and increased photosystem II photochemical efficiency throughout the day, and T4 and T3 exhibited the highest efficiency. <![CDATA[Aroma characterization of grape juice enriched with grapevine by-products using thermomaceration]]> ABSTRACT The need to reuse grapevine (Vitis vinifera L.) by-products avoiding negative environmental impact demands the search for new valorization methods like thermomaceration. The combination of grapevine by-products and grape must may be an alternative to get hold of additional aroma. The objective of this study was to assess the aroma potential of grape pomace, grapevine leaves and canes for País (PA) and Lachryma Christi (LC) cultivars to enrich grape must. Fifty aroma compounds were identified in the samples using stir bar sorptive extraction followed by thermal desorption, gas chromatography and mass spectrometry. ‘País’ must showed high contents of esters with a characteristic fruity odor, while benzenoids prevail in LC must giving a phenolic, balsamic odor. Thermomaceration increased contents of 13 free and bound volatile compounds, as well as new compounds (isoeugenol, phenol, vanillin and 2-ethyl hexanol) appeared in enriched juice (EJ). Cluster analysis showed differences among PA, LC and EJ samples. Principal component analysis was successfully applied to discriminate grape juice samples (p &lt; 0.05) being D-limonene, 5-hydroxymethyl-2-furfural and hexadecanoic acid the compounds that contributed most to the differentiation and increase of free and hydrolyzed aroma compounds after thermomaceration. Both grape-grapevine by-products and juice processing conditions affected the generation and increase of free and bound aroma compounds after thermomaceration of grape must. <![CDATA[Viral and intestinal diseases detected in <em>Apis mellifera</em> in Central and Southern Chile]]> ABSTRACT The honeybee (Apis mellifera L.) is an important pollinator worldwide. Beekeepers have experienced an increasing loss of colonies in recent years and pathologies including viruses and intestinal parasites such as Nosema ceranae are among those held responsible for this decline. The aim of this study was to determine the prevalence and distribution, using the real time PCR method, of six honeybee viruses including Deformed Wing Virus (DWV), Black Queen Cell Virus (BQCV), Sacbrood Virus (SBV), Acute Bee Paralysis Virus (ABPV), Chronic Bee Paralysis Virus (CBPV) and Israeli Acute Paralysis Virus (IAPV) in addition to three intestinal parasites, N. ceranae, N. apis and Lotmaria passim in Chilean beehives distributed between the Metropolitan Region and La Araucanía Region. Among the viruses, BQCV was the most prevalent in the analyzed hives, ranging from 72% to 100%, N. ceranae was detected between 19% to 53% and L. passim showed infections ranging from 45% to 73%. Similarly, BQCV (96%) and N. ceranae (42%) were more prevalent in spring-summer whilst DWV (37%) and L. passim (68%) were more frequents in autumn-winter seasons. Furthermore, mixed infections were also detected, wherein viruses were found along with L. passim or viruses with N. ceranae and L. passim, which proved to be the most prevalent. Of the 467 hives analyzed, 97.2% were infected with one or more of the studied pathogens, indicating that they are widely spread in Chile. <![CDATA[Effect of soil and water characteristics on yield and properties of ‘Spunta’ potatoes]]> ABSTRACT Soil texture and its characteristics besides water characteristics can play an eminent role in potato (Solanum tuberosum L.) production. Therefore, a soil and water quality index (SWQI, %) was derived to investigate the effect of combination of soil and water characteristics (sodium adsorption ratio for water and soil, electric conductivity of water and soil, pH for water and soil, organic matter in the soil, and soil texture index) on yield and properties of ‘Spunta’ potatoes produced under center pivot irrigation system. This index was formed studying separately the effect of irrigation water quality and soil texture on yield, water use efficiency, tuber modulus of elasticity, and tuber shape index of ‘Spunta’ potatoes. Field results demonstrated that the lowest potato yield was approximately 34.12 t ha-1 at SWQI 79.63%, and the highest potato yield was 37.79 t ha-1 at SWQI of 30.93%. The lowest water use efficiency was approximately 6.09 kg m-3 at SWQI 30.93%, and the highest water use efficiency was 6.83 kg m-3 at SWQI 79.63%. The lowest tuber modulus of elasticity was approximately 3.98 N mm-1 at SWQI 21.7%, and the highest tuber modulus of elasticity was 4.74 N mm-1 at SWQI 79.63%. Finally, the tuber shape index was approximately 342% at SWQI 79.63%, 418% at SWQI 21.72%, and 403% at SWQI 30.93%, which belongs to long and very long shapes. The soil and water quality index could be a useful tool to get relationships among water and soil characteristics, yield, and other properties of the potato crop. <![CDATA[Multiple resistance to ACCase and ALS-inhibiting herbicides in <em>Beckmannia syzigachne</em> (Steud.) Fernald without mutations in the target enzymes]]> ABSTRACT American slough grass (Beckmannia syzigachne [Steud.] Fernald) is a worldwide weed and is widely distributed in rice-wheat rotations in China. Fenoxaprop-P-ethyl and mesosulfuron-methyl are two major herbicides used to control B. syzigachne. Resistance has evolved in B. syzigachne under continuous selective pressure from herbicides. This study aimed to establish the cross-resistance pattern of a resistant population and explore the potential non-target-site based resistance mechanisms of B. syzigachne. Sequencing of target enzyme genes (acetyl coenzyme A carboxylase [ACCase] and acetolactate synthase [ALS]) revealed that there were no resistance-endowing amino acid substitutions in the resistant B. syzigachne population (RF1) compared with the sensitive population (SF1), and obtained the purified materials. Furthermore, piperonyl butoxide (PBO) and malathion showed synergistic effects with fenoxaprop-P-ethyl and mesosulfuron-methyl respectively in RF1. Therefore, we speculate that the resistance observed in B. syzigachne was related with metabolic, mostly involving the cytochrome P450 enzymes. Cross resistance patterns showed that the purified resistant B. syzigachne produce high resistance to fenoxaprop-P-ethyl and pyroxsulam; intermediate resistance to flucarbazone-sodium; low resistance to quizalofop-P-ethyl, clodinafop-propargyl, sethoxydim and mesosulfuron-methyl; sensitive to clethodim pinoxaden and isoproturon. <![CDATA[Nutrient content, fat yield and fatty acid profile of winter rapeseed ( <em>Brassica napus</em> L.) grown under different agricultural production systems]]> ABSTRACT Quality features of rapeseeds (Brassica napus L.) and potential for high yielding to a major extent may be defined by improvements in agricultural engineering methods that encompass biological progress. However, this is associated with intense fertilization and application of large amounts of pesticides, which may negatively impact on environment and may decrease quality of produced food. It is thus essential to develop and improve edible oil production systems to satisfy farmer and non-threatening consumer. The aim of this study was to evaluate content of nutrients, fat yield and fatty acid profile of rapeseed grown in 5-yr monoculture and after a 4-yr break in the crop rotation system with three levels of agricultural inputs. Three levels of technologies were used: economically (low-input), moderately intensively (medium-input) and intensively (high-input), varied in N amount and S fertilization as well as protection against pests. The medium- and high-input technologies applied in the monoculture contributed to an increased percentage of oleic acid in rapeseeds (by 5.7% and 5.5%), whereas low-input and high-input technologies resulted in an increased percentage proportion of linoleic (by 11.6% and 2.1%) and linolenic acid (by 6.6% and 5.0%) in the monoculture rapeseeds. The medium-input level generated an increased proportion of arachidic (from 6.9% to 15.0%), octadecanoic (by 4.9%), linoleic (by 7.0%), linolenic (by 5.1%) and eicosadienoic fatty acids (by 17.7%) in rapeseeds cultivated in the crop rotation system. The increase in technological input level significantly changed the ratio of polyunsaturated fatty acids to linoleic and linolenic acids by 5.1% and 7.4% in both the crop rotation and by 4.2% and 7.9% monoculture systems. In general, the impact of winter rapeseed in crop sequence systems was found to have an insignificant impact on the content of macronutrients and trace elements in seeds. The highest fat yield was generated with the crop rotation system at the highest input level, whereas the lowest yield was recorded in the low-input monoculture technology. <![CDATA[Growth of tropical grasses in Oxisol contaminated by nickel]]> ABSTRACT Soil pollution by heavy metals has increased worldwide and the search for plants that can be used to remediate polluted areas is an interesting alternative. The aim of this study was to evaluate the tolerance of tropical grasses to Ni and its availability for the Mehlich 1, DTPA, and USEPA 3051 and 3052 extraction methods in Ni-contaminated Oxisol. Megathyrsus maximus (Jacq.) B.K. Simon &amp; S.W.L. Jacobs ‘Aruana’ and ‘Tanzania’, Urochloa brizantha (Hochst. ex A. Rich.) R.D. Webster ‘Xaraés’ and ‘Marandu’, and Urochloa decumbens (Stapf) R.D. Webster ‘Basilisk’ were grown for 90 d in a Typic Hapludox (Oxisol) after adding 20, 40, and 120 mg Ni kg-1 to the soil. Tropical grasses showed a positive response to the application of Ni doses. The order of decreasing tolerance of tropical grasses to Ni in the soil was: ‘Basilisk’ &gt; ‘Xaraés’ &gt; ‘Marandu’ &gt; ‘Aruana’ &gt; ‘Tanzania’ based on the critical toxicity dose. Nickel concentration and accumulation increased with increasing soil Ni doses in all the tropical grasses. Mehlich 1, DTPA, USEPA 3051, and USEPA 3052 Ni extraction methods in the soil are efficient to diagnose Ni availability in tropical grasses. <![CDATA[Degradation and adsorption of tebuconazole and tribenuron-methyl in wheat soil, alone and in combination]]> ABSTRACT In practice, pesticides are usually simultaneously applied or one after another for crop protection. This often leads to a coexistence of pesticide mixtures in soil. One of the most important processes influencing the behavior of a pesticide in the environment is its degradation and adsorption in soil. Thus, the degradation and adsorption behaviors of tebuconazole (TEB) and tribenuron-methyl (TBM) alone and combined application in wheat soil (pH 7.28) were studied. The concentrations of TEB and TBM in soil were determined using a quick, easy, cheap, efficient, rugged and safe method (QuEChERS) with ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). Results showed that TEB has longer half-lives compared with TBM in the tested soils when they were applied individually. The degradation of TEB was markedly affected by concentration and soil microorganisms. In the non-sterilized soil, half-lives of 0.8 and 80 mg kg-1 TEB were 16.4 and 69.3 d, respectively, and half-lives of 0.8 and 80 mg kg-1 TEB were 20.4 and 73.5 d in the sterilized soil, respectively. The degradation of TBM was not affected by TEB in both soils; however, TBM could reduce the degradation of TEB. Compared to TEB alone, the rates of degradation of 80 mg kg-1 TEB in presence of 32 mg kg-1 TBM were reduced 15.9% and 18.2% in non-sterilized and sterilized soils, respectively. Soil adsorption affinity of TEB was significantly higher than TBM. When used combined, adsorption capacity of TEB was not affected by TBM. However, the adsorption of TBM was obviously inhibited in presence of TEB. <![CDATA[Comparison of three systems of decomposition of agricultural residues for the production of organic fertilizers]]> ABSTRACT Organic wastes (OW) of diverse nature must be subjected to controlled decomposition processes to avoid risks of contamination and obtain products useful for agriculture. The objective of the present study was to compare over time physical, chemical and enzymatic parameters of OW transformed as vermicomposting (VC), semicomposting (SC) and composting (CP) for elaboration of organic fertilizers. A mixture of bovine manure and sawdust was subjected to each of three systems for 183 d. Temperature, total N (Nt), organic C (OC), C/N ratio, pH, enzymatic urease activity (EUA), germination index (GI) and electrical conductivity (EC) were measured throughout the time of study. The variables evaluated showed significant differences between time and treatment. The temperature ranged between 20 and 34 °C in VC and SC, while in CP between 20 and 61 °C. All three systems reduced the C/N ratio to less than 15/1. The CP product had higher pH, EC, and EUA values than both VC and SC. The VC product had the highest GI values. All the products obtained at 183 d were within the parameters to be considered as organic fertilizers, but the SC product transformed into an organic fertilizer fastest and had least water usage.