Scielo RSS <![CDATA[Chilean journal of agricultural research]]> vol. 81 num. 4 lang. es <![CDATA[SciELO Logo]]> <![CDATA[Sowing date as a response to ecological conditions in maize seed production]]> ABSTRACT The environment protection, energy, and resources preservation are especially pronounced under present climate changes. In agriculture, these changes are recognised as drought, high temperatures, occurrence of stormy winds and hail. The aim of this study was to determine variations in seed morphology that are a result of different sowing dates in relation with agro- ecological conditions of maize (Zea mays L.) cultivation. The material used for the study encompassed three inbred lines (G1, G2, G3) sown every 10 d on five sowing dates (T1, T2, T3, T4, T5) starting from 1 April to 10 May, during 2 yr (Y1: 2018, Y2: 2019). The following physical properties of seeds were estimated: width (W), length (L), thickness (Tk), ratio of small (SF) to large fraction (LF) and grain yield (GY). The width was the highest in all three inbreeds on T4 (1.00, 1.03, 0.99 cm, respectively); T5 was the least favourable date for L (1.09, 1.12, 1.09 cm, respectively) while Tk was the lowest in G1 (0.51 cm) and G2 (0.51 cm) sown on T1. The most significant differences in the formation of physical properties occurred in seeds sown on T5 (p ≤ 0.05). The highest differences were observed in width between T5-T4 (-0.223 cm), in length between T5-T2 (-0.309 cm) and in thickness between T5-T3 (-0.129 cm). Later sowing dates favoured LF (85.2%) in comparison to SF (14.7%). Seed size variability participated with 50% in yield formation (R2 ≥ 0.5). <![CDATA[Leaf water potential for surface and subsurface drip irrigated bell pepper under various deficit irrigation strategies]]> ABSTRACT Increased water scarcity necessitates the implementation of water-conserving irrigation management practices to sustain crop production, especially in water-limited areas. Field experiments were conducted to evaluate midday leaf water potential (LWP) of bell pepper (Capsicum annuum L. var. annuum) irrigated differentially using surface drip (DI) and subsurface drip irrigation (SDI) systems during 2016 and 2017 growing seasons in the eastern Mediterranean environmental conditions. The treatments considered were deficit irrigations (I50, I75), regulated deficit irrigation (RDI), partial root-zone drying (PRD50) and full irrigation (I100) under DI and SDI systems. The experimental design was completely randomized in a split-plot system with four replicates per treatment. Deficit irrigation treatments of I75 and I50 received 75% and 50% I100, respectively; RDI was supplied with 50% I100 during vegetative growth stage until flowering, then received 100% of crop water requirement; PRD50 plots received 50% I100. Bell pepper plant water status was estimated by LWP. Higher LWP values were determined in I100 for two drip systems than the I75, I50, and PRD50; LWP correlated significantly (P &lt; 0.01) and negatively with fresh pepper yield, DM yield, leaf area index (LAI), and mean soil water content and all these relations are best described with the curvilinear equations. In conclusion, bell pepper should be irrigated at mean LWP values between -0.89 and -0.95 MPa without any yield reduction. It is also concluded that RDI and I75 treatments appear to be good alternatives to I100 for sustainable bell pepper production under the Mediterranean environmental conditions. <![CDATA[Comparison of nutritional and nutraceutical properties of <em>Chenopodium quinoa</em> cultivated in Mexico and Ecuador]]> ABSTRACT Quinoa (Chenopodium quinoa Willd.) is considered a superfood due to its nutritional qualities and potential health benefits. In this work, the nutritional and nutraceutical properties were compared for white Ecuador quinoa seeds (WEQ) and red Ecuador quinoa seeds (REQ) with respect to the white Mexican quinoa seeds (WMxQ). Quinoa seeds from Peru have been introduced and adapted to the geographic and climatic conditions by the State of Morelos, Mexico, improved by mass selection in field to obtain plants with desirable phenotypic characteristics. The nutritional properties of seeds were evaluated through a proximate analysis, mineral content, amino acids profile, and fatty acid profile of quinoa oil. The nutraceutical properties were determined quantifying total phenols, total betalains and antioxidant capacity. The results evidenced that WEQ seeds had the highest protein content (16.59 g 100 g-1 dw). The P, Ca, and Mg contents were high in WMxQ (424.6, 60.3, and 152.3 mg 100 g-1 in dw respectively). Arginine, glutamic acid, and alanine were the most abundant amino acids in the three cultivars. In all quinoas, unsaturated fatty acids were most predominant (73.6% to 78.0%). The Mexican quinoa seeds showed the highest total phenolic content (2.9 mg gallic acid equivalent g-1 in fw). The concentration of betalains in the REQ was 83.3 mg 100 g-1 fw. The results demonstrate that nutritional and phenolic contents varies according to the color seeds and region. Quinoa of Mexico is high in phenolic compounds and may be used as a source of natural antioxidants. <![CDATA[Pre-breeding for waxy proso millet by phenotyping and marker-assisted selection]]> ABSTRACT Proso millet (Panicum miliaceum L.) is important in some Kazakhstan food, this research objective was to develop pre- breeding waxy proso millet resource for breeding new varieties by using phenotyping and marker-assisted selection. The amylose content of the endosperm starch in a collection of 18 proso millet cultivars widely used in northern Kazakhstan were evaluated and ranged from 14.6% to 34.8%. The introduced glutinous millet accessions of PI436626 (Lung Shu 18), PI436625 (Lung Shu 16) were selected to cross with local cultivars (Saratovskoe 6 and Pamyati Bersieva). The potassium iodide (KI) staining method and PCR analysis using the 9bF/15delRB primer were used to identify the waxy trait for selection of the F2-F3 generation. Seeds staining dark blue to black were scored as wild type, while waxy seeds were stained as pinkish or amber to reddish-brown color. The hybridological analysis of inheritance of the “waxy” trait suggested that the segregation ratios for waxy endosperm in the F2 and F3 populations was close to 15:1 of the caryopses with blue and brown colors. PCR analysis with the 9bF/15delRB primer confirmed that this specific primer flanks a 123 bp fragment in amylose samples, while in glutinous samples, this primer promotes the amplification of 108 bp long PCR product (15 nucleotides deletion). Finally, the waxy lines were obtained and could be used for further testing. <![CDATA[Effect of L-proline and L-glutamic acid on productivity of winter rapeseed]]> ABSTRACT A higher level of fertilizers can have negative effects on the environment; therefore, selection of environmentally friendly preparations to increase plant productivity is very important. The aim of this study was to evaluate the effect of exogenously applied amino acids L-proline (30 mM L-1) and L-glutamic acid (1.5 M L-1) on the productivity of winter rapeseed (Brassica napus L. subsp. oleifera (Delile) Sinskaya) measuring number of siliques per plant, number of seeds per silique, 1000-seed weight, seed yield, crude fat content and crude fiber content. Treatments were applied at one or two growth stages of rapeseed. Higher 1000-seed weight and seed yield were obtained with L-glutamic acid in autumn and spring, while the higher number of siliques per plant was observed without amino acid application. Application of both amino acids led to an increase in seed yield of winter rapeseed from 3.5% to 11.8%. Principal component analysis showed that the first factor was highly and positively correlated with seed yield, 1000-seed weight, and crude fat and negatively with crude fiber, while the second factor was highly and positively correlated with silique per plant and negatively with seeds per silique. Higher values of crude fat content, seed yield, and 1000-seed weight were associated with application of glutamic acid on winter rapeseed, while crude fiber content was related to the application of proline. The study showed that higher 1000-seed, seed yield weight and crude fat content in seeds of winter rapeseed (P &lt; 0.05) were obtained spraying plants with 1.5 M L-1 L-glutamic acid solution in autumn and spring. <![CDATA[Hormesis effect of 2,4-D choline salt on soybean biometric variables]]> ABSTRACT Auxin-based herbicides, such as 2,4-dichlorophenoxyacetic acid (2,4-D), are lethal to plants at higher doses, but can enhance plant growth at nontoxic concentrations. The stimulating effect of low doses of a substance considered toxic is known as hormesis. This study used dose-response curves to assess the hormesis effect of low doses of 2,4-D choline salt herbicide on soybean (Glycine max (L.) Merr.) biometric variables with distinct growth habits at different phenological stages. A completely randomized experimental design with seven replicates was used, and the treatments consisted of six fractions of the average dose indicated on the label of 2,4-D choline salt formulation: 0 (control), 0.068, 0.684, 6.84, 68.4 and 684 g ae ha-1 applied at the plant’s phenological stages second node with fully developed leaves (V2) or fifth node with fully developed leaves (V5). The plants were assessed for their main biometric parameters. The results were analyzed by ANOVA and, when significant, the hormesis model was tested. The maximum effect of hormesis on the main biometric parameters of soybean plants was estimated for doses between 0.20 and 36.01 g ae ha-1 of the herbicide and varies depending on the evaluated phenological stage of the plants. Low doses of 2,4-D choline salt herbicide may increase shoots, roots and total DM when applied at stages V2 and V5 of soybean with determinate growth habit and V2 of indeterminate growth habit. There was no adjustment of the hormesis model for the soybean plant with indeterminate growth habit at stage V5. <![CDATA[Pungency and fruit quality in Mexican landraces of piquín pepper (<em>Capsicum annuum</em> var. <em>glabriusculum</em>) as affected by plant growth environment and postharvest handling]]> ABSTRACT The variability in fruit pungency, size and quality was analyzed in 31 landraces of piquín pepper (Capsicum annuum L. var. glabriusculum (Dunal) Heiser &amp; Pickersgill) collected from 10 Mexican states. The response of fruits collected in situ and harvested in greenhouse was compared. Pungency was estimated by measuring capsaicinoids content with HPLC. Additionally, pungency was recorded along fruit maturity stages in greenhouse-grown fruits. On average, greenhouse- produced fruits were markedly more pungent than fruit collected from field locations (29 485 vs. 6114 SHU). Field- collected fruits averaged 5017 μg mL-1 capsaicin content, while dihydrocapsaicin averaged 7618 μg mL-1. In contrast, greenhouse-harvested fruits contained substantially more capsaicin and dihydrocapsaicin (34 762 and 26 174 μg mL-1, respectively), while the capsaicin:dihydrocapsaicin ratio inverted. The three most pungent field-collected landraces averaged 35% of the pungency measured in the three most pungent greenhouse-grown fruits. Pungency increased as maturity stage advanced: green (14 813 SHU) &lt; intermediate (24 767 SHU) &lt; red (29 485 SHU). The fruits collected from 31 field locations had lower titratable acidity, higher content of total soluble solids, and higher maturity index than fruits harvested in greenhouse. Greenhouse harvested fruits were larger and heavier than those collected in the field. <![CDATA[Principal component analysis and comprehensive evaluation on drought tolerance difference of canola cultivars at germination and emergence stages]]> ABSTRACT Drought stress in autumn is an important factor restricting canola (Brassica napus L.) germination and emergence in the Yangtze River basin in China. Screening drought tolerance varieties in canola is a cost-effective and practical way. The objective of this study was to explore the methods of drought tolerance evaluation and to screen canola varieties with drought tolerance at germination and emergence stages. The experiments were conducted with 53 cultivars under drought treatment and non-stress control. In this research, 16 investigated indicators were synthesized into six independent indices which could represent 87.5% characters information related to drought resistance of canola varieties. With this analysis and evaluation, 53 varieties could be classified into three categories: five varieties as YY10, JLYT, LY9, ZS11, and YY50 owned drought-resistant; 16 varieties as ZY589, QZ7 and DAZ600 and so on, were moderately drought-resistant; and the other 32 varieties belonged to non-drought-resistant. The study proved that there were six indices as mean germination time, germination index, seedling emergence time, fresh and dry weight per plant and 1000-grains weight, which could be used as identifying indicators related to crop drought resistance at germination and seedling stage. <![CDATA[Behavioral responses of the woolly whitefly <em>Aleurothrixus floccosus</em> (Hemiptera: Aleyrodidae) to volatile organic compounds emitted from <em>Citrus</em> at laboratory conditions]]> ABSTRACT Insects use biogenic volatile organic compounds (BVOCs) as chemical cues to find their host plants and colonize them. Studies of olfactory responses have reported that BVOCs released by host plants attract whiteflies. The citrus woolly whitefly, Aleurothrixus floccosus (Maskell) (Hemiptera: Aleyrodidae) is a serious foliar pest, infesting citrus orchards at the Pica Oasis, Tarapacá Region, Chile. We studied the attractant behavior of A. floccosus toward BVOCs emitted from lime (Citrus ×aurantiifolia (Christm.) Swingle), mandarin (Citrus reticulata Blanco), and tangelo (Citrus reticulata × Citrus ×paradisi Macfad.) shoots. We collected volatiles from living plants using dynamic headspace technique for 24 h. The BVOCs released by the Citrus species were collected on Porapak Q traps and analyzed by gas chromatography coupled to mass spectrometry (GC-MS). The chemical analysis revealed differences in abundances of monoterpenes, sesquiterpenes and aldehydes; thus, D-limonene (33.44%) was the most abundant compound in lime and significantly higher than mandarin and tangelo. On the other hand, sabinene (12.36%), nonanal (28.06%) and caryophyllene (22.97%) were more abundant in mandarin. Tangelo showed high abundance of β-phellandrene (17.01%), nonanal (17.87%) and caryophyllene (16.01%). In the two-choice bioassays, we found 13.5% and 17.1% more A. floccosus females in lime than in mandarin and tangelo, respectively. Our findings show that the volatile profile of ‘Limón de Pica’, C. aurantiifolia, elicits the strongest attractive behavior of A. floccosus females in the olfactometry experiments. <![CDATA[Agronomic traits and chemical composition of forage sorghum plants fertilized with poultry litter and fermentative profile of silages]]> ABSTRACT It is essential to determine the productive potential and quality of forage sorghum (Sorghum bicolor (L.) Moench) silages using alternative and organic inputs, such as poultry litter (PL), intending to higher efficiency, and sustainable development of animal production systems in the world. Poultry litter fertilization has been widely used in crops for silage production, where it is believed that fertilization with PL can influence the fermentation profile and composition of forage sorghum silages. The objective of this study was to evaluate different levels of fertilization with PL on the agronomic and quality characteristics of forage sorghum silage ‘BRS Ponta Negra’. For determination of agronomic and productive characteristics, randomized blocks design was adopted, the treatments were different PL levels: 5, 10, and 15 Mg ha-1. While for the evaluation of silage characteristics, the design was completely randomized. With fertilizer doses, a linear increase was observed for plant height, stem diameter, leaf length, and consequently for fresh and DM productions. Linear reduction was observed for neutral detergent fiber, while crude protein and pH contents of silages increased linearly with PL levels. Quadratic effect occurred for gas and effluent losses. Poultry litter may be an alternative source to supply the N needs in the production of sorghum for silage under experimental similar conditions. Associating productivity with cultivation efficiency, the PL level 13.46 Mg ha-1 is recommended for presenting the highest N agronomic efficiency and good nutritional quality of the silage. <![CDATA[Effect of maize straw additives on the nutritional quality and bacterial communities of ensiled forage rape for animal feed]]> ABSTRACT The impact of forage rape (Brassica napus L.) with maize (Zea mays L.) straw addition on the changes of nutritional quality and bacterial community was investigated by using high-throughput sequencing analysis of the 16S rRNA. The six ensilage treatments were set based on different mass ratios of forage rape (S) and maize stalk (Y): S1 (forage rape:maize stalk 10:0), S7Y3 (7:3), S6Y4 (6:4), S5Y5 (5:5), S4Y6 (4:6), and S3Y7 (3:7). The results showed that compared with S1, the DM content of S7Y3, S6Y4, S5Y5, S4Y6 and S3Y7 increased by 10.71%, 16.02%, 22.56%, 24.37% and 30.19% after the maize straw addition, respectively. Contents of crude protein (CP), ether extracts (EE) and water-soluble carbohydrate (WSC) contents in S7Y3 were significantly higher than that of other maize straw additive treatments (P &lt; 0.05), which were 11.11% DM, 4.54% DM and 12.50% DM, respectively. On the 60th day of fermentation, the lowest pH value was found in S7Y3, which was 3.56. The V-score of each treatment were above 80. Bacterial Shannon and Chao indices were highest in S7Y3. The dominant bacterial phyla across all silage samples were Firmicutes, Proteobacteria, Cyanobacteria and Actinobacteria. The dominant genera are Lactobacillus and Weissella. Redundancy analysis (RDA) suggested that DM, CP, EE and WSC are the main factors in shaping bacterial communities. This study demonstrated that forage rape with maize straw addition can affect the nutritional quality and bacterial community of silage, and the best mixing ratio of maize straw and forage rape ensilage is 7:3. <![CDATA[Excess aluminum tolerance of the common water-hyacinth (<em>Eichhornia crassipes</em>) under greenhouse conditions]]> ABSTRACT Aluminum is a heavy metal toxic to living organisms and is released into soils with a strong acidic composition. The floating aquatic weed Eichhornia crassipes (Mart.) Solms is reported as the most widespread invasive vascular plant in the world and is distributed all over Colombia ranging from sea level to the cold Andean highlands. As a consequence of the solubility of Al3+ in soils, it flows into fresh water sources where E. crassipes grows as an invasive plant. A greenhouse study was conducted in Tunja, Colombia, with the objective of evaluating the growth of aquatic weed in an aqueous substrate with Al3+ content similar to those recorded in lakes (0.0, 0.2, 0.4, 0.6, and 0.8 mg L-1 Al3+). Biomass production, leaf area, evapotranspiration, water use efficiency, and other allometric variables were evaluated. An increase of 18.2% in the transpiration rate and a reduction between 9.7%-41.8% in the leaf area were found. The latter reduced the value of variables such as the specific leaf area between 9.9%-34.6% and leaf area ratio between 16.7%-40.4%. However, the total dry weight, DM partitioning, root to shoot ratio, leaf weight ratio, and the absolute and relative growth rates did not show significantly different values between treatments. Therefore, Al content found in water sources in Colombia, despite being in the ranges reported as toxic for some aquatic plants, did not significantly affect the growth of E. crassipes due to its phenotypic plasticity and anthropic alteration of water sources but rather favor its growth. <![CDATA[Membrane stability and antioxidant enzyme activity of rice seedlings in response to short-term high temperature treatments]]> ABSTRACT The impact of temperature on plants varies depending on the temperature level and the time of exposure. The aim of this study was evaluating different short-term temperatures to stimulate rice (Oryza sativa L.) seedling growth indicated by some physiological functions. Thus, oxidative stress, membrane stability and antioxidant activity in ‘Dular’, ‘IR64’ and ‘KDML105’ rice seedlings were evaluated in response to 25, 35 and 45 °C for 30 min. At 25 °C, ‘IR64’ showed higher electrolyte leakage (EL) percentages, protein contents and peroxidase (POX) activity but lower hydrogen peroxide (H2O2) content. At 35 °C, the highest H2O2 content was found in ‘KDML105’ followed by ‘IR64’ and ‘Dular’. In all rice seedlings the lowest EL was after 35 °C exposure and activities of catalase (CAT) in ‘IR64’ and ‘KDML105’, ascorbate peroxidase (APX) in ‘Dular’, ‘IR64’ and ‘KDML105’ and glutathione reductase (GR) in ‘Dular’, ‘IR64’ and ‘KDML105’, and superoxide dismutase (SOD) in ‘Dular’ and ‘KDML105’ were stimulated by higher H2O2 production. At 45 °C, all rice seedlings showed pronounced EL increase but reduced H2O2 production, protein content and all antioxidant enzyme activities. These results suggested that short-term temperature at 35 °C was an optimum condition for all rice seedlings as indicated by the least membrane damage (EL ≈ 45.04%) and induction of most antioxidant enzymes (CAT, APX, GR and SOD ≈ 48.29 nmol min-1 μg-1 protein, 247.49 ng ascorbic acid min-1 μg-1 protein, 0.16 μM min-1 μg-1 protein and 0.078 unit min-1 μg-1 protein, respectively). This temperature induced higher H2O2 production which plays a significant role in signaling molecules to stimulate protein function and antioxidant enzyme activities. While short-term 45 °C proved to be damaging temperature for all rice seedlings because of membrane damage and decreased reactive oxygen species defense mechanism. <![CDATA[Spatial dynamics and consistency of agroclimatic trends in Chile during 1985-2015 to the Köppen- Geiger climate classification]]> ABSTRACT The Köppen-Geiger classification is one of the most common climate classification systems in the world. It allows classifying ecosystem distribution based on temperature and precipitation, two critical factors in climate, and vegetation cover’s sensitivity. We analyzed the dynamics and spatial consistency of agroclimatic variables in each type of Köppen- Geiger climate present in Chile, visualizing the variables’ behavior throughout the territory. Thus, we computed the trends of different climate and agroclimatic variables in each meteorological station, mapping their slope and statistical significance, and comparing their sense among all those that belong to the same climate zone. Our global trends analysis showed a thermal amplitude decrease in northern and central areas in about 12.03% and 20.3%, respectively, and an increase in south and southern areas in about 13.7% and 26.3%. A generalized increase in frost events (2.90%-16.02%) took place mainly in the country’s northern part. Results showed higher concordance percentages in stations belonging to the Köppen-Geiger type B (dry climate) and C (temperate climate). Thus, an increase in the maximum temperature occurred from north-central to south zones, a decrease in minimum temperature from north to central zone, and an increase in highlands (700-4000 m a.s.l.), central, south, and southern zone of the country. Also, a precipitation decreases and thermal amplitude increased roughly from the Coquimbo Region to the country’s central and southern zone. Variations in the agroclimatic indices’ behavior can affect yield and production of crops; thus, agroclimatic information presented here can support the zoning and selection of the cropping system. <![CDATA[Stages of grassland degradation in subalpine ecosystems of the Central Caucasus, Russia]]> ABSTRACT Overgrazing and grassland degradation are significant environmental problems in the mountain ecosystems of the Central Caucasus. The aim was to define the criteria for the stages of grassland degradation to provide land managers with useful guidelines on evaluating grassland status. We identified four stages of grassland degradation based on a statistical analysis of 23 vegetation and soil parameters at 126 model plots in the subalpine meadows. Main indicators of grassland degradation were grass height, coverage of forage species, coverage of grazing-resistant species, and fresh herbage yield. Grass height decreased significantly (P &lt; 0.05) with each stage of grassland degradation from 31.4 ± 3.6 cm in untransformed grasslands to 3.3 ± 1.7 cm in severely degraded pastures. Fresh herbage yield in untransformed grasslands (120.8 ± 12.5×102 kg ha-1) was 81% higher than in highly degraded pastures. Coverage of forage species decreased in the row of grassland degradation from 72% to 34%, while coverage of grazing-resistant species increased with grazing intensity from 23% to 77%. Critical values of the integral degradation index based on these four parameters are useful for a reliable assessment of grassland status in the field. <![CDATA[Evaluation of pigment, antioxidant capacity and bioactive compounds in microgreens of wheat landraces and cereals]]> ABSTRACT Landraces that adapt to all kinds of stress factors over thousands of years are considered a very important genetic resource. In this study, antioxidant activities, bioactive compounds, and pigment contents of microgreen in Kose and Kirik wheat landraces, which are used extensively in bread making especially in rural areas of Eastern Anatolia, and some cereals, were examined. In the study, chlorophyll (CHLdx), flavonol (FLV), anthocyanin (ANT), and N balance index (NBI) were measured in fresh material with a Dualex device. Also, total antioxidant capacity (TAC), total phenolic content (TPC), total flavonoid content (TFC), ascorbic acid (AAC) content and pigment values such as total chlorophyll (TCHL), chlorophyll a (CHLa), chlorophyll b (CHLb) and carotenoid content (CAR) were determined. It was observed that TAC capacity of wheat landraces was more than twice that of other cereals (except ‘Alparslan’) and their NBI, AAC, ANT and FLV contents were low. Kirik landrace had high TCHL, CHLa, CHLb and CAR content, while Kose landrace had low all pigment values. Besides, NBI content of barley, AAC and FLV content of oat cultivars and ANT content of wheat ‘Alparslan’ were high as a group. The CHLdx values of barley and oats were twice that of wheat. A very important and positive correlation was determined between TCHL with CHLa, CHLb, and CAR contents. Also, correlations between CHLa with CHLb and CAR, and between CHLb with CAR was important and positive. In the study, especially TAC capacities of local wheat varieties were significantly higher. <![CDATA[Silicon induces changes in the antioxidant system of millet cultivated in drought and salinity]]> ABSTRACT In recent years, benefits of silicon in plants grown under stress conditions have been reported. The objective of the research was to evaluate the response at a physiological and biochemical level of millet (Panicum miliaceum L.) to fertilization with Si under controlled stress conditions during vegetative stage, drought, salinity and the control (without stress). After stress, shoot and root length, DM content, peroxidase (POD) and catalase (CAT) activity, proline, H2O2 and Si content, seed yield and germination percentage were measured. Drought and salinity significantly decreased shoot (24%, 21%) and root (30% in drought) development, weight (36%, 29%) and seed number (30%, 21%) per plant. Application of Si significantly increased seed number (289) and seed weight (1.20 g) in the control plants, increased seed weight (0.83 g) in plants under drought and germination percentage (99%) in plants under salinity. Silicon increased 2.1 times POD activity in drought, 1.4 times in salinity and control plants; CAT activity increased 10.6 times in salinity and 1.7 times in control plants. Silicon decreased 10 times proline levels in plants under drought; in salinity and control, proline content increased 1.3 times with Si and H2O2 levels decreased in these treatments. The Si content in plants fertilized with Si under drought, salinity and control was 6%, 3.54% and 5.45% respectively. In conclusion, Si can improve plant stress tolerance by stimulating POD and CAT activity, and regulating proline levels, allowing it to improve the production and physiological seed. <![CDATA[Agricultural sciences in Chile: Institutions, human resources, investment and scientific productivity]]> ABSTRACT Agricultural science in Chile began in 1881 with the establishment of the Agronomic Station of the National Society of Agriculture (SNA). In this article we described the history and evolution of research and development (R+D) and human capital training in this field. The main research institution, in terms of territory coverage and human resources, is the Instituto de Investigaciones Agropecuarias (INIA), along with five regional research centers, specialized in different aspect of agricultural science, and 20 schools of agriculture and 11 doctoral programs associated to different universities. Public investment in agricultural R+D is provided by the Ministry of Agriculture, Ministry of Science and Technology, Ministry of Economy and Regional Governments, reaching around US$200 million in the last decade. The number of researchers in agricultural science is ~ 40 per million of inhabitants (~ 800 in total). An average of 140 projects per year are financed in agriculture R+D by different funding agencies. The scientific productivity was estimated in ~ 0.45 articles (Scopus) per researcher. It is concluded that, although significant progress has been made the last decades, there is still a reduced number of researchers and insufficient investment to face urgent challenges of the agricultural sector in Chile.