Scielo RSS <![CDATA[Chilean journal of agricultural research]]> vol. 75 num. 4 lang. en <![CDATA[SciELO Logo]]> <![CDATA[<b>Genetic characterization and cotyledon color in lentil</b>]]> Genetic characterization of lentil (Lens culinaris Medik.) cultivars is important for lentil breeding. Therefore, random amplified polymorphic DNA (RAPD) and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis were carried out to evaluate genetic diversity in 13 Turkish lentil cultivars. A total of eight RAPD primers were used in this study; 61 bands were produced and 55 of them were polymorphic (89.78%). The RAPD primers OPA-10, OPB-11, and OPI-13 had the highest polymorphism ratio (100%). As a result of SDS-PAGE analysis, variations in the seed protein pattern were observed among the lentil cultivars being studied. The SDS-PAGE similarity matrices indicated higher genetic similarity estimates among the lentil cultivars than RAPD. In addition, principal components analysis (PCA) was performed for both SDS-PAGE and RAPD where the first three components accounted for 75.760% and 68.121% of the total variation for SDS-PAGE and RAPD analysis, respectively. It was noted that the lentil cultivars with factor loadings greater than 0.5 for each principal component (PC) were also grouped together in the SDS-PAGE and RAPD dendrogram. In addition to genetic diversity, cotyledon color (an important market criterion) values were measured for lightness (L*), redness (a*), and yellowness (b*). As for cotyledon color, values for brightness, redness, and yellowness varied significantly among lentil cultivars. Among the red lentil cultivars, &rsquo;Cagil&rsquo; and &rsquo;Yerli Kirmizi&rsquo; had the highest cotyledon L* values of 70.83 and 70.74, respectively. The results of both genetic diversity analyses and cotyledon color of lentil cultivars would help in planning future breeding programs to improve high yielding marketable lentil cultivars. <![CDATA[<b>Evaluation of genetic effect on physiochemical properties changes of <i>Wx</i> near isogenic lines of Y58S in rice</b>]]> The Wx gene primarily influences the physiochemical properties changes of rice (Oryza sativa L.) To improve the grain qualities of the cv. Y58S with low amylose content (AC) value, the genetic effect of Wx gene was explored on quality traits. With the BC3F2 genetic population of Y58S line associated with different AC value as the materials, this study reported the genetic effect of three different Wx alleles (Wxª, Wx in, Wx b) under near-isogenic background. It was shown that Wx had major effects on the quality traits, and the genetic effect value was in the order Wxª &gt; Wx in &gt; Wx b. In addition, during the course of physiochemical properties changes of higher AC rice cultivars determined by Wxª or Wx in allele, accompanied by the increasing of AC, gel consistency and head milled rice recovery would be decreased in combination with the rising of chalky traits, all of which resulted in substantial fluctuations on quality traits (p < 0.01). However, the genetic law was not evident for Wx b allele. Therefore, except for the major gene Wx, the minor genes in the regulative network of starch-synthesis might be utilized for quality improvement. <![CDATA[<b>Estimates of heterosis parameters in elephant grass <i>(Pennisetum purpureum</i> Schumach.) for bioenergy production</b>]]> With a high growth rate and a DM yield of up to 80 t ha-1 yr¹, elephant grass (Pennisetum purpureum Schumach.) has been utilized as an alternative source of energy. However, genotypes adapted to and productive in the different regions of Brazil need to be developed. Thus, the objectives of the present study were to estimate and evaluate heterotic effects in elephant-grass hybrids obtained in a partial diallel cross (5 x 5), with the aim of assisting the superior hybrids selection for bioenergy production. The experiment was conducted in Campos dos Goytacazes, Rio de Janeiro, Brazil. The following traits were evaluated: plant height (HGT), stem diameter (SD), leaf blade width (LBW), number of tillers per linear meter (NT), percentage of DM (%DM), and DM yield (DMY). The experiment was conducted in a randomized block design, with 35 treatments (five female parents, five male parents, and 25 hybrid combinations) and three replicates. The adopted statistical model was that of Miranda Filho and Geraldi, in an adaptation of Gardner and Eberhart. Significant heterosis was observed for most traits in the rainy and dry seasons. Hybrid combinations H1 (&rsquo;Cubano Pinda&rsquo; x &rsquo;Mercker&rsquo;), H7 (&rsquo;Cameroon-Piracicaba&rsquo; x &rsquo;Três Rios&rsquo;), H8 (&rsquo;Cameroon-Piracicaba&rsquo; x &rsquo;Mercker 86-Mexico&rsquo;), H17 (&rsquo;IAC-Campinas&rsquo; x &rsquo;Três Rios&rsquo;), H18 (&rsquo;IAC-Campinas&rsquo; x &rsquo;Mercker 86-Mexico&rsquo;), and H25 (&rsquo;Guacu/IZ.2&rsquo; x &rsquo;Roxo&rsquo;) showed potential for use in breeding programs that aiming at develop clones with a energy biomass production capacity high. <![CDATA[<b>Fruit size QTLs affect in a major proportion the yield in tomato</b>]]> Yield is a complex trait that is affected by several genetic and environmental factors. Yield is defined as the amount of the part of interest that is harvested from a crop plant in a given area. We investigated the genetic basis of yield in an F2 population derived from a cross between Solatium lycopersicum L. and its most closely related wild species S. pimpinellifolium L. We found that average fruit weight, fruit diameter, and fruit length had a strong effect on yield. In addition, small effects on yield due to soluble solids content and locule number were also observed. A total of 25 different significant quantitative trait locus (QTLs) were detected for six traits (fruit length and diameter, fruit weight, yield, locule number, and Brix degrees). The percentage of phenotypic variation associated with single QTLs ranged from 4.19% to 12.67%. A strong co-location of QTLs among yield and fruit size traits was observed, suggesting that these QTLs play a role in the same expression process controlling yield. We also realized that the effects of soluble solids content on yield could be due to direct effects of fruit size QTLs linked to genes controlling soluble solids content. This result then may suggest that yield in tomato is mainly formed by fruit size QTLs, whereas the remaining factors may play a complementary role in the expression of tomato yield. <![CDATA[<b>Predicting ratoon rice growth rhythmbased on NDVI at key growth stages of main rice</b>]]> The growth of ratoon rice (Oryza sativa L.) is affected by growth of main rice, so it could be evaluated by determining growing condition of main rice. Objective of the study was to find regression model for predicting ratoon rice growth rhythm through establishing the quantitative relationship between growth rhythm in ratoon rice and normalized difference vegetation index (NDVI) after heading of main rice. NDVI at key growth stages of main rice was measured using active spectrometry for 12 varieties in 2008 and for 23 varieties in 2009, and compared the physiological indexes of main and ratoon rice. There was an exponential correlation (P < 0.05) between the NDVI after heading of the main rice and biomass, N concentration of green leaves and stems or leaf area index (LAI) after heading of the ratoon rice for all the 12 varieties in 2008. The regression models from the rice variety experiment in 2008 were used to calculate predicted values with NDVI after heading of main rice in 2009. The results showed that the predicted values of biomass, N uptake, and LAI in ratoon rice were significantly different to measured values. However, there were exponential and significantly positive correlation (p < 0.05) between biomass and N uptake and LAI in ratoon rice and NDVI after heading of main rice in 2009. Therefore, it suggested that regression models were not perfect, and need to be improved adding more parameters about spectral characteristic of main and ratoon rice. <![CDATA[<b>Determination of genetic coefficients of three spring wheat varieties under a Mediterranean environment applying the DSSAT model</b>]]> The impact of climate change requires developing and validating models that help to project possible scenarios that must adapt to new varieties. This study seeks to validate and calibrate the Decision Support System for Agrotechnology Transfer (DSSAT) model as a tool that facilitates the characterization of the behavior of new varieties in the face of new scenarios generated by climate change. The determination of genetic coefficients of three bread wheat (Triticum aestivum L.) varieties was considered in the methodology; this was done with the database of the historical records of the Instituto de Investigaciones Agropecuarias (INIA) Wheat Breeding Program for the 2000 to 2011 period. Once the adjustment level of the model was dealt with, it was feasible to obtain genetic coefficients of three spring wheat varieties (Pandora-INIA, Kipa-INIA, and Millan-INIA); days from planting to anthesis variable exhibited RMSE values fluctuating between 3.5 and 9.7 depending on the variety. For total duration of days to maturity, &rsquo;Millan-INIA&rsquo; exhibited a very good adjustment (RMSE = 0.25) as compared to &rsquo;Pandora-INIA&rsquo; (RMSE = 1.35) and &rsquo;Kipa-INIA&rsquo; (12.22). Furthermore, the coefficient of determination of the genetic coefficients indicates that the varieties have minimum vernalization requirements; these are similar to the photoperiod between &rsquo;Pandora-INIA&rsquo; and &rsquo;Millan-INIA&rsquo; and lower in the case of &rsquo;Kipa-INIA&rsquo;. Thermal requirements for grain filling, biomass production, and plant height did not exhibit any important differences among varieties. Finally, the methodology allowed calibrating the DSSAT model and achieving a good predictive level of yields for the three varieties. The plant development parameters must be studied in greater detail because of the low association between simulated and observed values. <![CDATA[<b>Systems to establish bioclimatic analogies to predict the area of adaptability of plant species to new environments</b>: <b>The case of <i>Moringa oleifera</i> Lam. in Chile</b>]]> Adaptability of a species to new territories is generally assessed by costly trial and error in situ experiments distributed throughout different agroclimatic environments. Nowadays climatic data are available to allow the construction of climatic maps based on data provided through world or local networks of climatic weather stations. The objective of this work was to establish a bioclimatic protocol, based on current and available sources of climate information, to make rapid surveys of suitability for plant species in a given environment. Moringa oleifera Lam. species, native from India, was chosen considering its rusticity and the increasing interest on this species due to its multiple uses, nutritional value, and medicinal properties. The first phase of this work was a compilation of data from climatic downscaling (WorldClim), University of East Anglia database (CRU), FAO database, and an historic datasets from Chilean meteorological stations. This information was used to test two different models to compare bioclimatic profiles, considering relevant climatic variables for plant adaptation: maximum and minimum temperatures, accumulated degree days, frost regime, and air humidity. The first approach, based on climatic analogy, was to compare each of these variables between Chilean and foreign localities, and the second, based on bioclimatic suitability, focus on the degree of meeting the minimum bioclimatic requirements by the species in each locality. This paper provides some tools to make this kind of comparisons. Both approaches were tested using M. oleifera as target. Both approaches were complementary and prove to be useful for identifying potential areas where the species could be cultivated. The use of these approaches suggested the existence of some bioclimatic suitability for this species in the coastal areas with mild winters and frosts, from 27° to 37° S lat. <![CDATA[<b>Spatio-temporal variability of NDVI and land surface temperature in the Maule and Biobío Regions (2000-2012)</b>]]> The Intergovernmental Panel on Climate Change (IPCC, Geneva, Switzerland) reports that climatic zoning requires new methodologies to discriminate homogeneous areas due to new scenarios generating global climatic change. The objective of this study was to perform climatic zoning by analyzing spatial and temporal variability of land surface temperature (LST) and the normalized difference vegetation index (NDVI). The 20-yr sequence of MODIS (LST and NDVI) images was analyzed by harmonic analysis, empirical orthogonal functions (EOFs), and continuous wavelet cross-correlation functions. Annual harmonic analysis identified agroclimatic zones from amplitude and phase, this result was valid for the two first EOF modes that account for 74% of the annual signal. Wavelet cross-correlations between the NDVI and LST temporal series showed a wideband high-power spectrum associated with the annual cycle. Finally, the methodologies applied to LST and NDVI images allowed the identification of agroclimatic zones. The study area included different dryland zones (coastal, interior, and foothill), irrigated valleys, and forests. <![CDATA[<b>Physiologic specialization of <i>Puccinia triticina</i> Erikss. and effectiveness of <i>Lr</i>-genes in the south of Ukraine during 2013-2014</b>]]> Leaf rust is the most widespread and frequently occurring fungal disease of wheat (Triticum aestivum L.) in Ukraine and worldwide. The information about the effectiveness of Lr-genes and also the consequent monitoring of virulence dynamics is necessary for the successful wheat breeding for leaf rust resistance. In 2013-2014 pathotype composition and virulence analysis was studied both on the standard differential set and on the North American System of Nomenclature. According to the standard differential set, 12 phenotypes were identified, of which the most common were 77 (75%) and 144 (6%). A total of 40 phenotypes were identified on the North American Nomenclature. Phenotypes TGTT (24%) and TJTT (8%) were the most frequent, TRTT (1.5%) and TSTT (1.5%) were within the broadest spectrum of virulence among the isolates found in the south of Ukraine. For virulence analysis we used wheat lines of &rsquo;Thatcher&rsquo; that are near-isogenic for 24 leaf rust resistance genes and additionally four cultivars/lines. No virulence to Lr19 was found, whereas increasing virulence to Lr9 was detected (13%). Low frequency of virulence was observed to Lr29 (11%) and Lr47 (21%), high level of virulence was detected to other genes. The effectiveness of 53 known Lr-genes was studied at the seedling and the adult plant stages. Most of them were not effective against leaf rust. Genes Lr9, Lr19, Lr29, and Lr47 were highly effective both at the seedling stage and at adult plant stage. Genes Lr24, Lr42, Lr50, Lr51, and Lr56 were effective only at the adult plant stage. <![CDATA[<b>Resistance in alfalfa to <i>Aphis craccivora</i> Koch</b>]]> The cowpea aphid, Aphis craccivora Koch (Aphididae), is considered to be one of the major pests in the semiarid Pampas of Argentina and in other alfalfa (Medicago sativa L.) growing areas of the world. In the present study the antibiotic, antixenotic, and tolerance resistance of eight alfalfa cultivars to A. craccivora, were investigated under laboratory conditions at 24 ± 1 °C, 65 ± 10% relative humidity, and 14:10 h photoperiod. Antibiosis experiments showed significant differences in the developmental time and adult longevity of the cowpea aphid among the alfalfa cultivars. Intrinsic rate of natural increase (rm) for apterous aphids varied significantly with alfalfa cultivars on which aphids were reared. This value ranged from 0.04 to 0.16 females female-1 d-1, which was the lowest on &rsquo;Medina&rsquo;. Additionally, the estimated net reproductive rate (Ro) and finite rate of increase (X) for apterous aphids were the lowest on &rsquo;Medina&rsquo;. For the antixenosis experiment significant difference was found in aphid&rsquo;s preference to the alfalfa cultivars. &rsquo;Carmina&rsquo; and &rsquo;Victoria&rsquo; were the least preferred by the apterous aphids. For the tolerance experiment &rsquo;Carmina&rsquo;, &rsquo;Monarca&rsquo;, &rsquo;SPS6550&rsquo; and &rsquo;Victoria&rsquo; were more tolerant than the other cultivars to A. craccivora. Therefore, our results demonstrated that among the investigated cultivars &rsquo;Medina&rsquo; displayed antibiosis to A. craccivora, &rsquo;Carmina&rsquo; and &rsquo;Victoria&rsquo; expressed antixenosis and tolerance, and &rsquo;Monarca&rsquo; and &rsquo;SPS6550&rsquo; were tolerant to this aphid pest. <![CDATA[<b>Effect of nitrogen and water deficit type on the yield gap between the potential and attainable wheat yield</b>]]> Water deficit and N fertilizer are the two primary limiting factors for wheat yield in the North China plain, the most important winter wheat (Triticum aestivum L.) production area in China. Analyzing the yield gap between the potential yield and the attainable yield can quantify the potential for increasing wheat production and exploring the limiting factors to yield gap in the high-yielding farming region of North China Plain. The Decision Support System for Agrotechnology Transfer (DSSAT) model was used to identify methods to increase the grain yield and decrease the gap. In order to explore the impact of N and cultivars on wheat yield in the different drought types, the climate conditions during 1981 to 2011 growing seasons was categorized into low, moderate, and severe water deficit classes according to the anomaly percentage of the water deficit rate during the entire wheat growing season. There are differences (P < 0.0001) in the variations of the potential yields among three cultivars over 30 yr. For all three water deficit types, the more recent cultivars Jimai22 and Shijiazhuang8 had higher yields compared to the older &rsquo;Jinan17&rsquo;. As the N fertilizer rate increased, the yield gap decreased more substantially during the low water deficit years because of the significant increase in attainable yield. Overall, the yield gaps were smaller with less water stress. Replacement of cultivars and appropriate N fertilizer application based on the forecasted drought types can narrow the yield gap effectively. <![CDATA[<b>Soil carbon mineralization following biochar addition associated with external nitrogen</b>]]> Biochar has been attracting increasing attention for its potentials of C sequestration and soil amendment. This study aimed to understand the effects of combining biochar with additional external N on soil C mineralization. A typical red soil (Plinthudults) was treated with two biochars made from two types of plantation-tree trunks (soil-biochar treatments), and was also treated with external N (soil-biochar-N treatments). All treatments were incubated for 42 d. The CO2-C released from the treatments was detected periodically. After the incubation, soil properties such as pH, microbial biomass C (MBC), and microbial biomass N (MBN) were measured. The addition of biochar with external N increased the soil pH (4.31-4.33) compared to the soil treated with external N only (4.21). This was not observed in the comparison of soil-biochar treatments (4.75-4.80) to soil only (4.74). Biochar additions (whether or not they were associated with external N) increased soil MBC and MBN, but decreased CO2-C value per unit total C (added biochar C + soil C) according to the model fitting. The total CO2-C released in soil-biochar treatments were enhanced compared to soil only (i.e., 3.15 vs. 2.57 mg and 3.23 vs. 2.45 mg), which was attributed to the labile C fractions in the biochars and through soil microorganism enhancement. However, there were few changes in soil C mineralization in soil-biochar-N treatments. Additionally, the potentially available C per unit total C in soil-biochar-N treatments was lower than that observed in the soil-biochar treatments. Therefore, we believe in the short term, that C mineralization in the soil can be enhanced by biochar addition, but not by adding external N concomitantly. <![CDATA[<b>Effect of adding bulking materials over the composting process of municipal solid biowastes</b>]]> Biowastes (BW), the main raw materials for the composting installations in developing countries, are characterized for containing uncooked food wastes (FW), high moisture content, low porosity, acidic pH, and low C/N ratios which affects the overall composting process (CP). In this study, we evaluated the effect of adding sugarcane bagasse (SCB) and star grass (SG) (Cynodon plectostachyus (K. Schum.) Pilg.) as bulking materials (BM) over the quality of the substrate, progress of the process, and quality of the obtained product. In this sense, two pilot-scale experiments were performed. The first one contained a substrate formed by 78% BW and 22% SCB (pile A). The second experiment contained a substrate formed by 66% BW and 34% SG (pile B). For each experiment, control treatments (piles A&rsquo; and B&rsquo; respectively) were performed by using 100% BW without BM. The results showed that in both cases the adding of BM improved substrate quality (pH, moisture, and total organic C content [TOC]), speeding up the starting step (2-3 d) and reducing the duration of the thermophilic phase of CP (3 d). However, the physico-chemical properties of both BM increased cooling and maturation phases duration (between 15 and 20 d). Obtained products quality was improved in terms of higher TOC, cation-exchange capacity, bulk density, and higher water holding capacity. Application of obtained products A and B could improve some soil properties like major nutrient, water retention, and increasing the organic matter. <![CDATA[<b>Effects of straw mulching on maize photosynthetic characteristics and rhizosphere soil micro-ecological environment</b>]]> Straw mulching is an effective measure to improve soil properties, crop growth, and yield. To further understand the advantage mechanisms of straw mulching, a field experiment with seven straw mulching levels (0 to 18 000 kg ha-1) was conducted to study the effects of straw mulching on maize (Zea mays L.) photosynthesis and rhizosphere soil micro-ecological environment. Results showed that maize chlorophyll content was evidently affected by straw mulching, and the highest chlorophyll content was at 12 000 kg ha-1 (M4). Straw mulching could significantly improve the photosynthetic characteristics of maize, and the difference between M4 and 0 kg ha-1 (M0) was significant. There was as trend change in soil microbe quantity; it first increased and then decreased with increasing straw mulching levels, and the most suitable straw mulching level for different types of microorganisms was 9000 kg ha-1 (M3) or M4. Straw mulching significantly enhanced soil enzyme urease, invertase, dehydrogenase, and protease activities, but when the straw mulching level reached a certain level, the effect of straw mulching was no longer apparent and even had some adverse effects at straw mulching levels higher than 15 000 kg ha-1 (M5). Yield in M4 (10 186.84 kg ha-1) was the highest compared with M0 (9365.12 kg ha-1), and yield significantly increased by 8.8%. Correlation analyses indicated that the soil microbe quantity and aforementioned enzyme activities were all significantly and positively correlated with maize chlorophyll content, photosynthetic rate, and yield. Findings suggest that straw mulching can apparently increase soil microbe quantity and enzyme activities and improve crop photosynthesis and yield; the M4 level is the most reasonable straw mulching level in this study under comprehensive consideration, and a straw mulching level that is too high (over M5) will have some negative effects. <![CDATA[<b>Effect of chemical fertilization and green manure on the abundance and community structure of ammonia oxidizers in a paddy soil</b>]]> Ammonia oxidization is a critical step in the soil N cycle and can be affected by the fertilization regimes. Chinese milk-vetch (Astragalus sinicus L., MV) is a major green manure of rice (Oryza sativa L.) fields in southern China, which is recommended as an important agronomic practice to improve soil fertility. Soil chemical properties, abundance and community structures of ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) in a MV-rice rotation field under different fertilization regimes were investigated. The field experiment included six treatments: control, without MV and chemical fertilizer (CK); 100% chemical fertilizer (NPK); 18 000 kg MV ha-1 plus 100% chemical fertilizer (NPKM1); 18 000 kg MV ha-1 plus 40% chemical fertilizer (NPKM2); 18 000 kg MV ha-1 alone (MV); and 18 000 kg MV ha-1 plus 40% chemical fertilizer plus straw (NPKMS). Results showed that NPKMS treatment could improve the soil fertility greatly although the application of 60% chemical fertilizer. The abundance of AOB only in the MV treatment had significant difference with the control; AOA were more abundant than AOB in all corresponding treatments. The NPKMS treatment had the highest AOA abundance (1.19 x 10(8) amoA gene copies g-1) and the lowest abundance was recorded in the CK treatment (3.21 x 10(7) amoA gene copies g-1). The abundance of AOA was significantly positively related to total N, available N, NH4+-N, and NO3--N. The community structure of AOA exhibited little variation among different fertilization regimes, whereas the community structure of AOB was highly responsive. Phylogenetic analysis showed that all AOB sequences were affiliated with Nitrosospira or Nitrosomonas and all AOA denaturing gradient gel electrophoresis (DGGE) bands belonged to the soil and sediment lineage. These findings could be fundamental to improve our understanding of AOB and AOA in the N cycle in the paddy soil. <![CDATA[<b>Development of dominant sequence characterized amplified region (SCAR) marker linked with plume moth (<i>Exelastis atomosa</i> Walsingham 1886) resistance in pigeon-pea</b>]]> The mode of gene action governing resistance to plume moth (Exelastis atomosa Walsingham 1886) derived from pigeon-pea (Cajanus scarabaeoides (L.) Thouars) accession ICPW-94 has been determined and the resistance alleles have been designated as PPM1. The progenies of F2 population and F3 families derived from an interspecific cross C. cajan (L.) Huth (&rsquo;ICP-26&rsquo;) x C. scarabaeoides (accession ICPW-94) revealed monogenic gene action for resistance to plume moth, and the dominant control by single locus or cluster of tightly linked alleles. Bulked segregant analysis (BSA) of 116 F2 progenies by using 143 parental polymorphic RAPD primers could identify a fragment OPA09(910) associated with plume moth resistance in coupling phase of linkage. Further single plant analysis of the 116 F2 mapping population revealed OPA09(910) was linked to PPMi locus conferring host resistance to plume moth with recombination fraction (rf) value of 0.125 (12.7 cM of Kosambi function). The resistance specific fragment OPA09(910) was cloned, sequenced and converted into a sequence characterized amplified region (SCAR) marker, SCOPA09(942), which was also closely associated (10.3 cM) with the locus PPMl with rf value 0.102. BLAST analysis with pigeon-pea genome sequence also confirmed its occurrence in CcLG02 (Scafseq.LG_V5.0fa) and contig 01597 (AFSP01.fsa1). This SCAR marker showed reasonable screening efficiency in the F2, F3, and BC1F1 lines, thus it can be used as genetic handle in marker-assisted introgression of the genomic fragment conferring plume moth resistance and screening of breeding lines in pigeon-pea.