Scielo RSS <![CDATA[Chilean journal of agricultural research]]> http://www.scielo.cl/rss.php?pid=0718-583920150001&lang=en vol. 75 num. 1 lang. en <![CDATA[SciELO Logo]]> http://www.scielo.cl/img/en/fbpelogp.gif http://www.scielo.cl <![CDATA[<b>Relationships between phenotypic variation in osmotic adjustment, water-use efficiency, and drought tolerance of seven cultivars of <i>Lotus corniculatus</i> L.</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392015000100001&lng=en&nrm=iso&tlng=en Lotus corniculatus L. is a perennial forage legume species highly-adapted to growth under drought conditions. However, the genetic and physiological mechanisms involved in its adaptive capacity have not been elucidated. The role of osmotic adjustment (OA) and water-use efficiency (WUE) on the drought tolerance of L. corniculatus was studied in a greenhouse experiment. Seven cultivars of different origin were subjected to two contrasting treatments of available soil water: No water stress (NWS) and with water stress (WWS). Xylem water potential (Ψx), osmotic potential (Ψπ), pressure potential (Ψp), relative water content (RWC), stomatal conductance (g s), shoot DM production, water transpiration (T), and WUE (shoot DM/T) were measured. Water treatments significantly (P < 0.05) affected plant water status, which was reflected in reduced Ψx, RWC, g s, and transpiration rate in the WWS treatment compared with the NWS treatment. All cultivars showed a high capacity for OA under WWS treatment because Ψπ decreased by approximately 60% and Ψp increased by approximately 30%, compared with the NWS treatment. Cultivars with a higher solute accumulation (low Ψπ value) had the lowest DM production under WWS treatment. In contrast, WUE varied greatly among cultivars and was positively associated (R² = 0.88; P < 0.01) with DM production under drought conditions. <![CDATA[<b>Seed quality and water use characteristics of maize landraces compared with selected commercial hybrids</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392015000100002&lng=en&nrm=iso&tlng=en Understanding seed quality and water use characteristics of maize (Zea mays L.) landraces will improve food security among subsistence farmers who still cultivate them. The objective of this study was to evaluate seed quality and water use characteristics of two maize landraces (GQ1 and GQ2) compared with two commercial hybrids (SC701 and PAN53). Seed quality was determined by the standard germination, electrical conductivity, and tetrazolium tests. A controlled environment study was conducted in which the landraces were compared with hybrids across three water treatments (30% ETc; 50% ETc, and 80% ETc). Although landrace GQ2 performed at par with the hybrids, overall, seed quality tests showed that hybrids had superior seed quality than landraces. This was also confirmed by highly significant emergence results (P < 0.001) from pot trials where SC701 and PAN53 had higher emergence (100% and 94.44%, respectively) compared with GQ2 (86.11%) and GQ1 (61.11%). Subjecting landraces and hybrids to water stress (50% and 30% ETc) resulted in shorter plants with fewer leaves and earlier tasselling compared with non-stressed plants (80% ETc). Plant height for the 30% ETc water treatment was 156.1 cm compared with 175.8 cm for the 80% ETc water treatment, while plants under the 30% ETc water treatment tasseled at 105.4 d compared with 129.5 d for the 80% ETc water treatment. The GQ2 landrace continued to perform similar to, and often better, than the hybrid varieties, especially under stress conditions. Yield was poor under controlled conditions. Performance of the GQ2 landrace for both seed quality tests and under controlled conditions shows that landraces remain an important germplasm resource. <![CDATA[<b>Effects of different potting growing media for <i>Petunia grandiflora</i> and <i>Nicotiana alata</i> Link & Otto on photosynthetic capacity, leaf area, and flowering potential</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392015000100003&lng=en&nrm=iso&tlng=en Petunia grandiflora Juss. and Nicotiana alata Link & Otto are two of the most widely spread plants on the market for annual potted ornamental plants. In order to identify the most adequate substrate formula we analyzed the effects of different potting growing media used for P. hybrida grandiflora 'Bravo' and N. alata 'Dinamo' on their photosynthetic capacity, leaf area, and flowering potential. Optimization of growing media formula for petunia and ornamental tobacco was performed by preparing four growing media mixing fallow soil (FS), Biolan peat (BP), acid peat (AP), leaf compost (C), and perlite (P) in different proportions. The physiological potential of petunia and ornamental tobacco was investigated by photosynthesis and respiration rate and chlorophyll pigments in leaves, while the vegetative and flowering phenological stages were evaluated by number of leaves per plant, leaf area, number of flowers per plant and leaf area/flowers ratio. These measurements were significantly influenced by the different potting growing media used in this study. In the flowering stage, the highest photosynthesis rates (8.612 μmol CO2 m-2 s-1) as well as leaf area (1.766 dm²) of petunias were obtained on growing media with 60% biolan peat, 30% acid peat and 10% perlite (BP60-AP30-P10). Flowering responses to growing conditions vary greatly among plants and the biggest number of ornamental tobacco flowers (22 flowers plant-1) was registered as an effect of BP60-AP30-P10 media. Growing media with the BP60-AP30-P10 formula seem to be the most adequate growth substrate to develop profitable crops for petunias and ornamental tobacco with high decorative value. <![CDATA[<b>Performance of faba bean genotypes with <i>Orobanche foetida</i> Poir. and <i>Orobanche crenata</i> Forsk. infestation in Tunisia</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392015000100004&lng=en&nrm=iso&tlng=en Orobanche foetida Poir. and O. crenata Forsk. are major constraints to faba bean (Vicia faba L.) cultivation in Tunisia. To evalúate the different levels of resistance of seven small-seeded faba bean genotypes to these parasitic weed species, three trials were conducted in fields infested and non-infested with O. foetida in the Oued Beja Agricultural Experimental Unit and O. crenata in an experimental field at Ariana of the National Institute of Agricultural Research during three cropping seasons. Compared to the susceptible cv. Bad'i, the seven genotypes showed moderate to high levels of resistance to both Orobanche species. The number and dry weight of emerged broomrapes and underground tubercles recorded on the new improved genotypes were lower than those recorded on released and resistant 'Najeh' and 'Baraca'. The parasitism index on the new genotypes varied from 2-6 times less than susceptible 'Bad'i' in both Oued-Beja and Ariana. Yield reduction due to O.foetida infection varied from 13.5% on genotype XAR-VF00.13-89-2-1-1-1-1 to 59.7% on 'Baraca', whereas the yield loss was about 92% on the susceptible control. Parasitic infection did not affect dry grain protein accumulation in the tested genotypes. <![CDATA[<b>Effects of ridge tillage on photosynthesis and root characters of rice</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392015000100005&lng=en&nrm=iso&tlng=en Rice (Oryza sativa L.) is an important crop and breeding has not been able to improve yield. Root characteristics of hybrid rice 'Zhuliangyou 02' under conventional tillage and ridge tillage were studied in a Calcisols in Huaihua, China, from 2011 to 2013 to find better tillage methods to resolve massive water consumption, improve yield, and enhance productivity of agricultural labor for rice cultivation. Results showed ridge tillage increased photosynthetic parameters such as photosynthetic rate (P N), stomatal conductance (g s), and water use efficiency (WUE). It also significantly enhanced rice root number, root activity, and antioxidant enzyme activities; it also increased effective panicle number and actual yield by 22.12% and 15.18%, respectively, and enhanced aerenchymae during the early growth stage. Overall, ridge tillage could promote hybrid rice yields by enhancing root absorption, gas exchange, and reducing water consumption. It could be widely used in rice cultivation. <![CDATA[<b>Content of nitrates in potato tubers depending on the organic matter, soil fertilizer, cultivation simplifications applied and storage</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392015000100006&lng=en&nrm=iso&tlng=en Nitrates naturally occur in plant-based food. Nitrates content in consumable plant organs is small and should not raise concern provided that the recommended fertilization and harvest terms of the original plants are observed. The aim was to determine the effect of the application of various organic matter of soil fertilizer and simplifications in growing potato (Solanum tuberosum L.) on the content of nitrates in the tubers of mid-early cultivar 'Satina' after harvest and after 6-mo of storage. Introducing cultivation simplification involves limiting mineral fertilization by 50% as well as chemical protection limitation. The soil fertilizer was used: 0.6 (autumn), 0.3 (spring), and 0.3 L ha-1 (during the vegetation period). The content of nitrates, was determined with the use of the ion-selective method (multi-purpose computer device CX-721, Elmetron). The lowest amount of nitrates was recorded in the tubers from the plots without the application of organic matter with a 50% rate of mineral fertilization with soil fertilizer (120.5 mg kg-1 FW). The use of varied organic matter resulted in a significant increase in the content of nitrates in tubers and the lowest effect on their accumulation was reported for straw. The soil fertilizer used significantly decreased the content of nitrates in tubers by 15% for 100% NPK and 10.4% for 50% NPK. After 6-mo storage, irrespective of the experiment factors, the content of nitrates decreased in the fertilization experiment by 26% and in the experiment with a limited protection - by 19.9%. <![CDATA[<b>Monitoring levels of deoxynivalenol in wheat flour of Brazilian varieties</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392015000100007&lng=en&nrm=iso&tlng=en Deoxynivalenol (DON) is a mycotoxin produced by Fusarium graminearum and its intake represents a severe risk to human and animal health. The objective of this study was to evaluate levels of DON in wheat (Triticum aestivum L.) flour from two representative locations of south Brazil. Experiments were carried out in Pato Branco (Paraná) and Coxilha (Rio Grande do Sul) in a randomized complete block design with three replicates. Levels of DON were measured by high-performance liquid chromatography coupled with mass spectrometry (HPLC-MS/MS). This mycotoxin was detected in 97% of samples, ranging from 200 to 4140 u,g kg-1. Only 17% of samples presented DON beyond of the maximum allowed by the Brazilian Health Surveillance Agency up to the year 2012; even though, Fusarium head blight (FHB) epidemics were slight low in the growing season that the study was performed. According to our knowledge, this is the first report showing genetic variability of Brazilian cultivars to DON contamination and some genotypes have potential to be exploited as a source of low accumulation of this toxin. <![CDATA[<b>Modeling codling moth (Lepidoptera: Tortricidae) phenology and predicting egg hatch in apple orchards of the Maule Region, Chile</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392015000100008&lng=en&nrm=iso&tlng=en Studies were conducted in the Maule Region to characterize the phenology of the codling moth, Cydia pomonella (L.) The Predictive Extension Timing Estimator (PETE) and a logistic phenological model were validated with eight data sets of cumulative moth catches in sex pheromone (PH) and kairomone-baited traps and the cumulative occurrence of fruit injuries from apple (Malus domestica Borkh.) orchards during the 2009-2011 seasons. Second, the start of egg hatch was predicted from the first sustained male and female moth catches (biofix) in traps baited with pear ester (PE), PE+acetic acid (AA), PE+PH, and PH alone. Both phenological models fit data well except that the logistic provided a better fit than the PETE model of the phenology of egg hatch of the codling moth in the first generation, with a difference of 11 d between models in the prediction of 50% egg hatch. No significant difference was found between biofix dates established for males using either PH or PE+PH lures or for the biofix date based on female catches with PE+AA or PH+PE. The biofix established with the sustained female catch occurred nearly 11 d later than the male-based biofix. The use of a female biofix provided on average a 4-d improvement in the prediction of first egg hatch compared with the traditional use of a male biofix, but this difference was not significant. The use of PE+AA lures increased the proportion of cases when a female-based biofix could be established compared with the use of the PH+PE lure. <![CDATA[<b>Múltiple natural enemies do not improve two spotted spider mite and flower western thrips control in strawberry tunnels</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392015000100009&lng=en&nrm=iso&tlng=en Biological control techniques are commonly used in many horticultural crops in Spain, however the application of these techniques to Spanish strawberries are relatively recent. In this study the effectiveness of augmentative biological control techniques to control the two main strawberry (Fragaria xananassa Duchesne) pest: the two-spotted spider mite (TSSM), Tetranychus urticae Koch (Acari: Tetranychidae), and the western flower thrips (WFT), Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), through releases of the predatory mites Phytoseiulus persimilis Athias-Henriot, Neoseiulus californicus (McGregor), Amblyseius swirskii Athias-Henriot (Acari: Phytoseiidae), and Orius laevigatus (Fieber) (Heteroptera: Anthocoridae) were tested. Two-year results on the performance of treatments using combinations of these biocontrol agents are presented. In both years, all treatments resulted in the reduction of TSSM numbers; but no treatment was better than the release of P. persimilis alone (P < 0.05). TSSM suppression varied among crop phases being greater early in the season. None of the treatments reduced significantly WFT numbers (P < 0.05), and the established economic injury level (EIL) was surpassed from March to late April in both years. However, EIL was surpassed less times when treatment included O. laevigatus (2009: 20.7%; 2010: 22.7% of samples). No effect of A. swirskii was observed when this mite was released. Results corroborate that biological control techniques for TSSM and WFT are feasible for high-plastic tunnel strawberries. Under the conditions in our study no additive effects were observed, and there was not advantage in the release of multiple natural enemies. <![CDATA[<b>Survival of <i>Bemisia tabaci</i> and activity of plant defense-related enzymes in genotypes of <i>Capsicum annuum</i> L.</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392015000100010&lng=en&nrm=iso&tlng=en The whitefly Bemisia tabaci (Gennadius, 1889) is a major plant pest of horticultural crops from the families Solanaceae, Fabaceae and Cucurbitaceae in Neotropical areas. The exploration of host plant resistance and their biochemical mechanisms offers an excellent alternative to better understand factors affecting the interaction between phytophagous insect and host plant. We evaluated the survival of B. tabaci in landrace genotypes of Capsicum annuum L., and the activity of plant defense-related enzymes (chitinase, polyphenoloxidase, and peroxidase). The landrace genotypes Amaxito, Tabaquero, and Simojovel showed resistance to B. tabaci, as we observed more than 50% nymphal mortality, while in the commercial susceptible genotype Jalapeño mortality of B. tabaci nymphs was not higher than 20%. The activities of plant defense-related enzymes were significantly different among pepper genotypes (P < 0.05). Basal activities of chitinase, polyphenoloxidase and peroxidase were significantly lower or equal in landrace genotypes than that of the commercial genotype Jalapeño. The activity of plant enzymes was differential among pepper genotypes (P < 0.05). For example, the activity of chitinase enzyme generally was higher in non-infested plants with B. tabaci than those infested. Instead polyphenoloxidase ('Amaxito' and 'Simojovel') and peroxidase enzymes activities ('Tabaquero') increased in infested plants (P < 0.05). We conclude that basal activities of plant defense-related enzymes could be act through other mechanism plant induction, since plant defense-related enzymes showed a different induction response to B. tabaci. We underlined the role of polyphenoloxidase as plant defense in the pepper genotype Simojovel related to B. tabaci. <![CDATA[<b>Distribution and prevalence of crown rot pathogens affecting wheat crops in southern Chile</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392015000100011&lng=en&nrm=iso&tlng=en Crown rot pathogens are associated with higher losses for wheat crop farmers, but information about the distribution and prevalence of these pathogens in Chile is inadequate. Distribution and prevalence of wheat (Triticum aestivum L.) crown rot pathogens were examined in a survey of 48 commercial fields from December 2011 to February 2012 in southern Chile. These fields were located between Collipulli (37°56'00" S; 72°26'39" W) and Purranque (40°50'30" S; 73°22'03" W). Severity of crown rot disease was determined through visual assessment of the first internode of 20 tillers obtained from each field. Incidence of crown rot pathogens per field was determined by plating the 20 tillers on Petri plates with 20% potato dextrose agar amended with lactic acid (aPDA) medium. Resulting fungal colonies from monoxenic culture were identified by morphological or molecular-assisted identification. Severity of crown rot varied between 11.3% and 80% for individual fields. Culture plate analysis showed 72.2% of stems were infected with some fungus. Fusarium avenaceum, F. graminearum, and F. culmorum, pathogens associated with Fusarium crown rot disease were isolated from 13.5% of tillers. Gaeumannomyces graminis, causal agent of take-all disease in cereals, was isolated from 11.1% of culms. Phaeosphaeria sp., an endophyte and possibly a non-pathogenic fungus, was isolated from 13.9% of tillers. Pathogenic fungi such as Rhizoctonia spp. and Microdochium nivale, other saprophyte, and several unidentified non-sporulating fungi were isolated at frequencies lower than 3% of the total. Fusarium crown rot and take-all were the most prevalent and distributed crown rot diseases present in wheat crops in southern Chile. <![CDATA[<b>Recovery of root growth and physiological characters in cotton after salt stress relief</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392015000100012&lng=en&nrm=iso&tlng=en Crop growth in a saline environment depends on its tolerance to salt stress and capacity to recover after salt stress relief. To evalúate recovery mechanisms in cotton after salt stress relief, the changes of plants growth, root vigor, lipid peroxidation, antioxidant enzymes activity, organic solutes in root after salt stress relief were studied for two cotton (Gossypium hirsutum L.) cultivars (Lumianyan 37 and Sumian 22) grown under control (salt content of soil grown cotton was maintained at 0.2%), salt stressed (salt content of soil grown cotton was maintained at 0.5%) and salt recovered (salt content of soil grown cotton was reduced from 0.5% to 0.2% level at the 57 d after seeding) conditions. The results showed that root and shoot growth rate and root vigor significantly increased after salt stress relief, and the increase in growth rate and root vigor was more pronounced in 'Lumianyan 37'. In salt-recovered root, malondialdehyde (MDA) content decrease, the activities of superoxide dismutase (SOD) and peroxidase (POD) decreased, but catalase (CAT) activity increased compared with those in the salt-stressed root. For salt-recovered root, MDA content and POD activity of 'Lumianyan 37' was lower, while the SOD and CAT activities were higher. Salt-recovered cotton root showed a decrease in soluble sugar and free amino acid content compared with the salt-stressed root, especially in 'Lumianyan 37'. The results indicated that growth and root metabolism of cotton plants gradually recovered after salt stress relief, and the high capacity of cotton plants to recover after salt stress relief may be related to the high capacity of antioxidative system and the high utilization capacity of organic solutes as important nutritional components in root. <![CDATA[<b>Nitrogen fertilizer influence on wheat yield and use efficiency under different environmental conditions</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392015000100013&lng=en&nrm=iso&tlng=en Managing N inputs in wheat production systems is an important issue in order to achieve máximum profitable production, and minimum negative environmental impact. The aim of this investigation carried out in dry land farming in the Vojvodina province (Serbia) was to estimate the effects of different N fertilization levels (0, 75, and 150 kg N ha-1) on some quantitative traits, rain-use efficiency (RUE), N agronomic efficiency (NAE), and N use efficiency (NUE) in two Serbian winter wheat (Triticum aestivum L.) cultivars 'Pobeda' and 'Renesansa'. 'Pobeda' had higher grain yield (4437 kg ha-1) and RUE (8.32 kg ha-1 mm-1) than 'Renesansa' (4265 kg ha-1 and 8 kg ha-1 mm-1, respectively). Grain yield (4652 kg ha-1) and NUE (31.46 kg kg-1 N) were higher in the 2010-2011 season (favorable weather conditions) than in the 2011-2012 (4050 kg ha-1 and 27.59 kg kg-1 N, respectively). The highly significant effect on grain yield (4396 and 4494 kg ha-1), RUE (8.24 and 8.45 kg ha-1 mm-1), NAE (3.11 and 2.21 kg kg-1 N) and NUE (58.62 and 29.96 kg kg-1 N) had levels of 75 and 150 kg N ha-1. NAE and NUE declined at high N rates. Based on the results of this study, farmers should be advised that the use of large amounts of N increases production costs and reduce the economic benefits. The increase in wheat production is possible by selecting adapted genotypes with improved NUE. <![CDATA[<b>Relationship between mineralized nitrogen during anaerobic incubations and residual effect of nitrogen fertilization in two rice paddy soils in Chile</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392015000100014&lng=en&nrm=iso&tlng=en An important N source for rice (Oryza sativa L.) is mineralization of the organic forms of N present in the soil. The correct N determination will help to optimize the amount of fertilizer used. Our objective was to calculate an index that relates crop N uptake from previous N fertilization and N mineralized in rice paddy soils. To do so, we used two rice paddy soils, Alfisol and Vertisol, in Chile under different anaerobic incubation times and temperatures. We determined both soil mineralization and residual effect of fertilization in the previous season under field and laboratory conditions in an Alfisol and a Vertisol managed with a rice monocrop. Anaerobic incubations were carried out at 20 and 40 °C; and at five different times (0, 7, 14, 21, and 28 d). Our results indicate that residual fertilization affects N mineralization, which increases in both paddy soils when compared with the control without N. In the Alfisol it fluctuates between 6.1 and 13.3 mg N-NH4+ kg-1, whereas in the Vertisol ranged between 18.4 and 28.0 mg N-NH4+ kg-1. Crop N uptake as a residual effect of applied N ranged between 29.3 and 33.9 kg N ha-1 in the Alfisol and 28.3 and 45.8 kg N ha-1 in the Vertisol. Thus, N mineralization is mainly affected by incubation time, temperature, and N fertilization rate of the previous crop season; it can be represented by quadratic models with high determination values, R² = 0.73** and R² = 0.78**, for Alfisol and Vertisol, respectively. Moreover, we found that the best incubation time and temperature were 7 d at 20 °C and 21 d at 40 °C, for the Altisol and Vertisol, respectively. In addition, there are potential savings in the next rice crop season from 0.86 to 0.43 kg N applied for each 1 mg N kg-1 mineralized in the Alfisol and Vertisol, respectively. We conclude that crop N uptake was related to mineralized N and that the equation here developed that relates them is a good predictor to optimize fertilizer use in rice paddy fields. <![CDATA[<b>Variability of mineral nitrogen contents in soil as affected by meat and bone meal used as fertilizer</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392015000100015&lng=en&nrm=iso&tlng=en In recent years, a number of alternative sources of organic matter have been discovered, such as producís made of waste materials and recycled into composts or as meal of meat and bone. Meat and bone meal, a by-product of the meat industry, is rich in N and P and hence it can be a viable alternative to mineral fertilizers. This study determined the direct effect of different doses of meat and bone meal (MBM) used as fertilizer on the content of mineral N in soil. The effect of MBM fertilizer applied at rates of 1.0, 1.5, 2.0, and 2.5 t ha-1 was compared with no fertilization. The experiment was conducted in the years 2007-2009 at the research station in Balcyny, Poland. MBM was applied every year for 3 yr, with the following crop sequence: 2007 winter wheat (T. aestivum), 2008 winter rape (Brassica rapa L. subsp. oleífera (DC.) Metzg.), and 2009 spring wheat. Determination of mineral N (NO3--N and NH4+-N) were taken from the 0-30 cm layer, each year, during the full plant vegetation. The study found that changes in the mineral N content in soil depended on the dose of MBM and the crop species in a sequence. Each 0.5 t of MBM above 1.0 t ha-1 increased the mineral N content by an average of 4 mg. MBM applied every year at 2.0 and 2.5 t ha-1 produced a 2.33- and 2.56-fold increase in the mineral N content compared to unfertilized soil. The rate of release of NO3--N was found to be the highest at those sites in all the years of study, while that of NH4+-N was highest during the first 2 yr of study. The levels of NO3--N lay within the range of very low fertility. A strong correlation was found between NO3--N and NH4+-N content in soil and the N content in winter and spring wheat (Triticum aestivum L.) grain and in winter rapeseed (Brassica rapa L. subsp. oleífera (DC.) Metzg.) The NO3--N and NH4+-N compounds released from MBM were a good source of N for the plants. <![CDATA[<b>Contribution of legumes to the availability of soil nitrogen and its uptake by wheat in Mediterranean environments of central Chile</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392015000100016&lng=en&nrm=iso&tlng=en The absorption and partitioning of N is determined by its availability and demand during the various phenological stages of the crop. In two experiments conducted in rainfed areas of the Mediterranean climate region of central Chile, legume-wheat (Triticum aestivum L.) rotations were compared to oat (Avena sativa L.)-wheat systems (with and without applications of N fertilizer). The objective was to assess the contribution of legumes to the availability of soil N and N uptake by the wheat crop following grain legumes. N mineralization and uptake, N use efficiency (NUE), and N uptake efficiency (NUpE) by wheat were evaluated at different phenological stages in 2010. Synchronization existed between accumulated soil N mineralization and N uptake by the wheat. N uptake by wheat was higher in Experiment II (Andean foothill) than in Experiment I (interior dryland). Grain yields after legumes ranged 60-110% and 72-103% of yields in the fertilized cereal rotation (oat-wheat) in Experiments I and II, respectively. There was high correlation between soil N availability vs. grain yield (R² = 0.84 and 0.64) and N uptake vs. grain yield (R² = 0.55 and 0.64) for Experiments I and II, respectively. Rotations with lupine (Lupinus spp.) and field peas (Pisum sativum L.) showed high NUE and NUpE in Experiment I, and Experiment II in pea. The lowest NUE was after oats with N fertilizers. It is concluded that wheat cultivated in both agro-ecological areas after grain legumes or green manure was more efficient in N uptake and use than cereal, especially when the latter was fertilized. <![CDATA[<b>Genetic variability analysis of faba bean accessions using Inter-simple sequence repeat (ISSR) markers</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392015000100017&lng=en&nrm=iso&tlng=en Faba bean crop (Vicia faba L.) is important in México, it is a legume rich in protein and its market price is higher than those of maize and bean; however, in recent years there has been a significant decline in its performance. The aim of this study was to determine the genetic variability and analyze the relationship between 39 faba bean accessions using inter simple sequence repeats (ISSR) markers. Accessions of faba bean were collected according to their best phenotypic characteristics, later they were molecularly characterized. With the obtained band registration, a binary data matrix was built to perform the corresponding statistical analysis. The utilized ISSR markers produced 142 fixed and repeatable bands, of which 134 were polymorphic. The values of resolution power (Rp), polymorphic information content (PIC), and marker index (MI), respectively indicated that primer 848 was the most efficient to analyze genetic variability with values of 12.8, 0.40, and 8.06, respectively, followed by primers 857 and ISSR2M. Genetic distances oscillated between 0.38 and 0.83, and verified the groupings observed in the dendrogram, which indicates high variability at the level of DNA among the analyzed genotypes, observing six defined groups according to UPGMA analysis. In the analysis of main components the registered groupings were determined by the origin of the gathering. The use of ISSR markers was efficient to characterize at the level of DNA the assessed bean accessions, indicating the existence of variability, the identified contrasting accessions can be utilized in genetic improvement programs aimed at solving the needs of the producers. <![CDATA[<b>Genetic differentiation between 'Araucana' creole and 'Hampshire Down' sheeps in Chile</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392015000100018&lng=en&nrm=iso&tlng=en Genetic diversity studies in domestic animals allow evaluating genetic variation within and among breeds mainly for conservation purposes. In Chile exist isolated recovery programs, conservation and characterization of animal genetic resources, a consequence of which the vast majority of them have not been characterized, poorly used, and some of them have become extinct. The aim of this research was to determine genetic diversity and relationship between 'Araucana' creole and 'Hampshire Down' sheeps based on microsatellite markers; sheep breeds with similar phenotypic characteristics, raised in the south of Chile. A total of 64 'Araucana' sheep ('Araucana' from Freire, AF: 27, 'Araucana' from Padre Las Casas, AP: 10, 'Araucana' from Chol Chol, AC: 15, 'Araucana' from Villarrica, AV: 12) and 43 'Hampshire Down' sheep ('Hampshire' from Marchigue, HM: 18, 'Hampshire' from Valdivia, HV: 11, 'Hampshire' from San José, HS: 14) were analyzed using 17 microsatellite markers for determine the genetic diversity and relationship between breeds. A total of 284 alleles were observed with average polymorphic information content equal to 0.76, showing that the microsatellites panel used was highly informative. Estimated heterozygosity ranged from 0.73 in 'Hampshire Down' to 0.85 in 'Araucana'. The low inbreeding or endogamy coefficient (F IS, 0.022) and total inbreeding estimate (F IT, 0.070) indicated low level of inbreeding within and among breeds. The phylogenetic tree showed a separation between HS and HV, and the other sheep populations. The results indicated high genetic variability, low inbreeding, and low genetic differentiation, except for HV and HS, and were in according with geographical location and breeding practices.