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Crop rotation in agriculture can lead to increased crop productivity in the rotation and improved soil fertility as a result of residue incorporation. Unfortunately, residue incorporation is not a common practice in crop production systems under the Mediterranean regime, largely due to the lack of information on the effect of the follow-up crops. Therefore, this study was conducted with six biannual rotations (bread wheat–canola, bread wheat–bean, durum wheat–canola, durum wheat–bean, corn–canola and corn–bean) using four residue incorporation levels (0, 50, 100 and 200%) in an Andisol in south central Chile. Grain yield and residue production were evaluated in the canola and bean crops 5 years after initiating crop rotation. The previous crop affected canola grain yield and residue production, which were both higher after corn. Meanwhile, the residue incorporation level had a slight effect on residue production after bread wheat. Only bean grain yield was affected by the previous crop, which was higher after the durum wheat and corn crops. The residue incorporation has marginally affected residue production after bread wheat. Finally, residue incorporation at different levels under the conditions of the present experiment had a minimal effect on bean and canola residue production following the bread wheat crop. The best crop rotation for canola grain yield was corn–canola, which produced 0.54 Mg/ha (18.3%) higher yield than the average of the other two rotations. The best crop rotation for achieving higher bean grain yield was corn–bean, which yielded 0.52 Mg/ha (12.3%) higher than the average of the other two rotations.

Under intense breeding, modern wheats, such as durum (Triticum turgidum L. ssp. durum), are believed to have lost nutritional quality and protein content while increasing productivity. Emmer (Triticum turgidum ssp. dicoccum Thell) and wild emmer (Triticum turgidum ssp. dicoccoides) are alternative resources for breeding programs by offering favorable alleles to be introgressed into modern materials and thus broadening their genetic diversity. Studies conducted so far have shown that durum wheat has better performance in agronomical qualities and protein quality than T. dicoccum and T. dicoccoides. However, its grain protein content (GPC) and Fe/Zn concentrations are lower. Several QTL for yield, GPC, and nutrient content in T. dicoccoides have been described, demonstrating its potential for transfer of important genes such as Gpc-B1 into modern cultivars. The Gpc-B1 gene increased the grain protein and Fe and Zn contents, but the agronomic performance of some of the modern recipients was reduced. Understanding the correlations and relationships between agronomic, chemical, and nutritional qualities would simplify selection through breeding for a single trait. Combining this knowledge with conventional breeding, MAS, and new breeding techniques would facilitate the QTL studies in these ancestral wheats and the development of new durum cultivars while retaining the agronomic qualities. In this review, we compare some grain parameters of T. durum, T. dicoccum, and T. dicoccoides wheats, including Fe and Zn content and their genetic aspects, and the existing information is analyzed and integrated for the future prospects of durum wheat improvement.

Background and Aims. The study aims to explore the impact of advancements in wheat genetics on root structure and rhizosphere biology, which are still not fully understood. Specifically, we investigated various factors including the exudation of carboxylates, colonization by arbuscular mycorrhizal fungi, microbial activity, and root architecture in winter wheat varieties that have been released between 1965 and 2020. Methods. To conduct our study, we sowed fourteen different winter wheat varieties with four replicates on acidic Andisol at field conditions. Complete root systems and soil samples were extracted using a tractor-mounted hydraulic sampler tube of 3.5 cm diameter, which reached a depth of 60 cm. Results. In this sense, succinate showed a significant increase by 21%. Mycorrhizal colonization was inversely proportional to P concentrations and all varieties showed higher microbial activity at anthesis. The longest roots were found in varieties released after the year 2000, but no significant differences were found in other root architecture parameters. There was no clear pattern observed in root architecture or biological activity as a function of the year of release. Plant genetics moderated root architecture, carboxylate exudation, microbial activity, and mycorrhizal colonization, all of which are affected by high P concentrations. Conclusions. This study investigated plant-microorganism interactions, often overlooked due to root system analysis challenges. Older wheat varieties showed higher carboxylate exudation. We identified wheat varieties with potential for improved root systems and crop efficiency.

This study aims to evaluate the medium-term effect of two biannual rotations and four residue rate incorporation on durum wheat production and its nutritional composition and nutrient extraction. The effects of two biannual rotations of canola (Brassica napus L.) durum wheat (Triticum turgidum L.) and bean (Phaseolus vulgaris L.)-durum wheat and four incorporation rates (0%, 50%, 100%, and 200%) of residues of each preceding crop were evaluated after four seasons on durum wheat production and on its nutritional composition and nutrient extraction, in a volcanic soil in south-central Chile. Results indicated that the highest grain yield and residue production of durum wheat was obtained after bean (7.40 and 7.92 Mg ha−1, respectively). In the grain were obtained lower N and P concentrations after bean, and higher K, Ca, and Mg concentrations in the residue. The extraction of most durum wheat grain and residue nutrients was higher after bean. Nutrient distribution in the durum wheat plant concentrated in the grain was 79.9 to 80.7% N, 91.3 to 92.1% P, 27.1 to 27.4% K, 16.8 to 18.8% Ca, 68.3 to 70.4% Mg, and 56.3 to 57.4% S. In the residue, nutrient distribution was 19.3 to 20.4% N, 7.9 to 8.7% P, 72.6 to 72.9% K, 81.2 to 83.2%, Ca, 29.6 to 31.7% Mg, and 42.6 to 43.7% S. The highest grain and residue production of durum wheat was obtained after bean crop and also the extraction of most nutrients.

RESUMEN 'Chevignon' es una variedad de trigo de invierno, creada por la empresa ASUR Plant Breeding de Francia e introducida a Chile por el Programa de Mejoramiento de Trigo de INIA Carillanca. Es un trigo de altura mediana, ciclo intermedio, resistente a polvillo estriado (Puccinia striiformis West. f. sp. tritici Erikss) y oidio (Blumeria graminis D.C. f. sp. tritici Marchal), moderadamente resistente a polvillo de la hoja (Puccinia triticina f. sp. tritici Erikss y Henn) y muy buena tolerancia a septoria (Mycosphaerella graminicola (Fuckel) Sand). Es una variedad de alto rendimiento, con buenas características de calidad para panificación directa. Es de hábito de desarrollo invernal, de crecimiento rastrero al estado de plántula y de buena macolla terminal. Sus hojas son de color verde pálido, con hoja bandera semi curvada. La espiga es de color blanco, semi erecta, forma paralela, densidad alta y sin barbas. El grano es de forma redondeada, tamaño mediano, color rojo, pudiendo presentar ocasionalmente ciertos cambios de pigmentación en el endosperma. La altura de planta adulta varía entre 105 y 110 cm, con un promedio de 105 cm, y con una moderada resistencia a la tendedura. Su período vegetativo desde siembra a espigadura es más tardío que 'Maxwell' en alrededor de cinco días y más precoz que 'Bicentenario INIA' y 'Kiron INIA' en aproximadamente 8 a 10 días, respectivamente.

Crop rotations and residue management contribute to the sustainability of the soil and environment and reduction of fertiliser use. However, appropriate crop and residue level combinations have yet...

Water deficit is the most limiting factor for wheat production, so wheat-breeding programmes are currently focused on developing high-performance genotypes under such conditions. Carbon isotope dis...

Conservation agriculture using crop rotations and residue management is increasingly accepted in conventional agricultural systems. However, the effects on crop productivity and soil properties of different rotations, levels of use, and residue management have yet to be fully understood. Our study considered the effect of three previous crops (bread wheat, durum wheat, and corn) and four levels of residue incorporation (0%, 50%, 100%, and 200%) in a split plot design with four replicates on canola production parameters and soil chemical properties at the end of this crop. Production parameters and soil chemical properties were mostly affected by the previous crop and less by the residue incorporation rates under the conditions of this experiment; however, neither of these factors affected grain yield (ranging from 4.0 to 4.8 Mg ha−1). Canola residue production was higher (9.7%) after the corn crop, regardless of the residue incorporation rate, but the harvest index was lower after this crop. Most of the soil chemical properties were also affected, revealing increased organic matter and exchangeable K when the previous crop was corn and decreased concentrations of the cations with basic reaction when the previous crop was durum wheat.

Residue incorporation in agriculture associated with crop rotation, benefits the environment, soil fertility, and crop production. However, the benefits of conservation agriculture practices in soi...

Grain protein composition is important in wheat quality and may influence the amino acidic sequence of bioactive peptides obtained from this feedstock. However, the genetic basis modulating the amino acid profile in durum wheat is not well-understood. Therefore, strong and weak gluten strength durum wheat genotypes were evaluated for their amino acid composition along grain filling. Strong gluten strength lines showed higher expression levels of low-molecular-weight glutenin-related genes between 21 and 35 days post-anthesis (DPA) and exhibited up to 43.5% more alanine than the weak lines at 42 DPA, which was supported by the higher expression levels of putative alanine amino transferase genes in strong genotypes. Therefore, with the involvement of chemistry and molecular biology, the results present here may influence the science of wheat.

Conservation agriculture using crop rotation benefits the environment, soil fertility, and crop production. A biannual rotation experiment during a period of 2 years was conducted in volcanic soil in south-central Chile in a production system under conservation agriculture. The experiment considered two previous crops, canola (Brassica napus L.) and bean (Phaseolus vulgaris L.), and four levels of residue incorporation (0%, 50%, 100%, and 200% of generated residue). Grain yield (0.41 Mg ha−1), grain sedimentation value (5.5%), grain K (0.031%) and Ca (0.006%) concentrations, and residue K concentration (0.159%) were higher when the previous crop was bean. The Ca concentration (0.037%) in wheat residue increased after the canola crop. The different applied residue levels of the previous crop had no effect on any of the evaluated parameters in wheat. There was a very consistent negative correlation between the grain S concentration and the residue P (− 0.55), K (− 0.55), Mg (− 0.61), and S (− 0.63) concentrations in wheat when it was cultivated after bean. A larger number of study cycles are required to obtain more consistent results about the effect of the different residue levels on these two biannual rotations.

Cadmium (Cd) is a metalloid present in agricultural soils and harmful for human health. A large part of the Cd entering into the soil can be fixed, while another portion can contribute to increasing availability indices of this element (residual effect). The present study evaluated Cd residual effect and Cd fixation derived from anthropic applications at four locations in Chile during two seasons. Three crop rotations were used, which included white lupine (Lupinus albus L.), narrow-leafed lupine (Lupinus angustifolius L.), and durum wheat (Triticum turgidum L. var. durum) as the first crop and durum wheat as the second crop. Results indicated that the anthropic application of Cd to the soil, in the three crop rotations and at the four locations under study, exhibited a low residual effect in the next season and null effect two seasons after its application. Among the three preceding crops of each rotation, the highest effect on Cd residuality in both seasons was achieved using both lupines, especially narrow-leafed lupine. The Cd fixation coefficient in the upper 0.2 m of soil in the three crop rotations and at the four locations was very high, and it was greater than 99.9% in all cases.

RESUMEN Lasana-INIA es una variedad de trigo harinero (Triticum aestivum L.) de primavera que proviene de un cruzamiento efectuado en el Proyecto de Fitomejoramiento de Trigo del Instituto de Investigaciones Agropecuarias (INIA), en el Centro Regional de Investigación Quilamapu, Chillán, el año 1996. Es una variedad de hábito primaveral, de crecimiento semi-rastrero al estado de plántula. La altura de la planta adulta se considera mediana, y varía entre 85 y 100 cm. La espiga es de color blanco, con barbas largas presentes en toda su extensión. El grano es de color rojo, aspecto vítreo, y forma elíptica. El peso de 1.000 semillas varía entre de 42 a 49 g. Sembrado a mediados de agosto en el Campo Experimental Santa Rosa (36°31' S; 71°54' O), Chillán, la emisión de espigas ocurre 95 a 100 días después de la siembra. En las localidades de riego, Yungay y Human, 'Lasana-INIA' alcanzó, en promedio, un rendimiento 0,5% y 3,1% mayor que la variedad testigo Pandora -INIA. En la localidad de Chillán, en promedio de los cinco años presentó un rendimiento inferior a Pandora-INIA en 4,1%, pero con diferencias entre años. En suelos de secano húmedo, localidades de Carillanca y Purranque, alcanzó un rendimiento superior en un 9,5% y 4,2% respectivamente, respecto de 'Pandora-INIA. 'Lasana-INIA' es un trigo de buen peso del hectolitro y de textura dura. Las cifras de sedimentación de Zeleny (cc), glúten húmedo (%) y de proteína (%) lo clasifican como trigo fuerte. Presenta un valor de fuerza de trabajo W alto, y una buena relación P/L.

Phytoene synthase 1 (Psy1) and lipoxygenase 1 (Lpx-1) are key genes involved in the synthesis and catalysis of carotenoid pigments in durum wheat, regulating the increase and decrease in these compounds, respectively, resulting in the distinct yellow color of semolina and pasta. Here, we reported new haplotype variants and/or allele combinations of these two genes significantly affecting yellow pigment content in grain and semolina through their effect on carotenoid pigments. To reach the purpose of this work, three complementary approaches were undertaken: the identification of QTLs associated to carotenoid content on a recombinant inbred line (RIL) population, the characterization of a Mediterranean panel of accessions for Psy1 and Lpx-1 genes, and monitoring the expression of Psy1 and Lpx-1 genes during grain filling on two genotypes with contrasting yellow pigments. Our data suggest that Psy1 plays a major role during grain development, contributing to semolina yellowness, and Lpx-1 appears to be more predominant at post-harvest stages and during pasta making.

Refereed/Peer-reviewed It is well known that phosphorus (P) addition helps mitigate the adverse effects of water deficit stress on plants. However, the efficiency of spring wheat genotypes in the use of both components has not been addressed. The objective of this study was to evaluate the combined effect of P and water limiting conditions over phosphorus use efficiency (PUE) and water use efficiency (WUE) to categorize different spring wheat genotypes. Eight spring wheat genotypes were selected based on their yield tolerance index score (YTI) obtained from a previous screening of 384 wheat genotypes. They were evaluated for their ability to use P and water. Plants were grown under semi-controlled conditions on an Andisol with soil P-concentration of 3.4 mg P kg−1 (-P), which was enriched to 30 mg P kg−1 (+P). Irrigation was applied at two levels: well-watered (+W) and 30% +W (water-stressed, -W). Wheat was grown until the end of its phenological cycle. The P and water scarcity produced a delay in wheat development, especially in the first vegetative stages. Genotypic differences in growth, development, P accumulation, and yield were observed in response to P and water limiting conditions. The lowest performance in plant growth and grain yield was regarded when the P and water restrictions were applied. However, differences were observed in terms of PUE and WUE. In this sense, spring wheat genotypes were grouped into three and four classes for PUE and WUE, respectively. The most efficient genotype for all the conditions was “QUP2418”, which obtained the highest score in the consolidated PUE and WUE ranking. On the contrary, “FONTAGRO 92″ and “F6CL091337″ were the most inefficient genotypes. Strong correlations were observed between PUE components and WUE, enabling the future selection of co-adapted wheat genotypes efficient in the use of P and water.

RESUMEN Maxwell es un cultivar de trigo (Triticum aestivum L.) de invierno, introducido a Chile en el año 2004 por el Instituto de Investigaciones Agropecuarias (INIA) en colaboración con la Empresa Saaten Union Research de Francia, y liberado comercialmente el año 2012. Maxwell fue evaluado por el Programa de Mejoramiento de Trigo del INIA de Chile. Esta investigación se realizó con el fin de evaluar su comportamiento agronómico en el área nacional más importante de producción de trigo, bajo diferentes condiciones de suelo y clima. En base a los resultados obtenidos se pudo establecer que para el hábito de crecimiento, altura de la planta, precocidad, sanidad, rendimiento y calidad industrial, el cultivar Maxwell se destacó por sobre los testigos comerciales y mostró gran adaptabilidad para siembras tempranas, en zonas de inviernos largos y primaveras húmedas. La planta alcanza una altura promedio de 90 cm, siendo clasificado como un trigo enano a semienano. Su rendimiento promedio, en diferentes localidades y varios años de evaluación, fue 1,06 t ha-1, superior al testigo, siendo clasificado desde el punto de vista industrial como un trigo de calidad intermedia.

RESUMEN 'Kiron INIA' es un nuevo cultivar de trigo (Triticum aestivum L.) obtenido en el Programa Nacional de Trigo, Centro Regional de Investigación (CRI) Carillanca, del Instituto de Investigaciones Agropecuarias (INIA). Es un trigo de altura mediana, de ciclo tardío, resistente al polvillo estriado (Puccinia striiformis West. f. sp. tritici Erikss) y al oidio (Blumeriagraminis D.C. f. sp. tritici Marchal), y moderadamente sensible al polvillo de la hoja (Puccinia triticina. f. sp. tritici Erikss y Henn) y septoria (Mycosphaerella graminicola (Fuckel) Sand). Es un cultivar invernal de alto rendimiento, con buenas características de calidad para panificación directa, que heredó un alelo de tolerancia a la acidez del suelo de un parental. Sus hojas son de color verde ligeramente pálido, con hoja bandera semi erecta, de abundante cerosidad (glauescencia) en el haz. La espiga es de color blanco, decumbente, forma paralela, densidad alta, compacta y con barbas en todo su longitud. El grano es de forma redondeada, tamaño mediano, y color rojo pálido. La altura de la planta adulta varía entre 95 cm y 105 cm, con un promedio de 100 cm, y con un tallo de muy buena resistencia a la tendedura. Es un trigo de alto rendimiento (12,9 t ha1), superando incluso al testigo comercial en diferentes localidades y estaciones.

Phytoene synthase 1 ( Psy-1 ) is an essential synthesis gene influencing semolina yellowness while catalase ( Cat3-A ) is a catabolic enzyme that causes color loss. The main objective of this study was to evaluate the expression of Psy-A1 , Psy-B1 and Cat3-A as candidate genes for semolina yellowness, using a panel of 94 durum wheat genotypes differing in yellowness. Real Time-qPCR experiments of a subset of 12 genotypes showed greater expression of Psy-A1 , which specifically peaked at 35 days post-anthesis (DPA). At this time, Psy-A1 was 21-fold higher expressed in the high-yellowness relative to the low-yellowness genotypes. Psy-B1 and Cat3-A peaked at 21 DPA, suggesting different timing of expression of these genes during grain filling. The contribution of Psy-B1 was relatively higher in the genotypes showing low semolina yellowness than those with high semolina yellowness. Cat3-A did not exhibit clear differences in transcript accumulation throughout grain filling. We conclude that Psy-A1 has a major role in determining semolina yellowness, particularly in genotypes with high levels for this trait.

Phytoene synthase (Psy) is a key gene influencing semolina yellowness. Specific molecular markers have been developed to identify some of the known allelic variants of Psy1-A1 (Psy1-A1a, Psy1-A1l, Psy1-A1o) and Psy1-B1 (Psy1-B1a, Psy1-B1b) associated to semolina yellow color. This study was undertaken to assess the genetic variability existing for Psy1, and to evaluate the relationship between genotype and phenotype, in two contrasting durum wheat panels formed mostly by American breeding lines (BL panel), and a collection that included 155 Mediterranean landraces and 20 modern cultivars (M panel). The BL panel showed h 2 values over 0.93 for two indicators of yellowness [i.e. semolina yellow pigments absorbance, and b* values that were strongly correlated (r = 0.95, P

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.

Durum wheat (Triticum turgidum L. var durum) is a species that accumulates cadmium (Cd). Durum wheat cultivars differ in their absorption ability of Cd; therefore, identifying and selecting genetic material with low Cd accumulation reduces human exposure to this toxic element. In the present study, Cd concentration was evaluated in three Chilean durum wheat cultivars (Llareta- INIA, Corcolén-INIA, and Lleuque-INIA) grown in four Chilean locations with varying concentrations of Cd in soils. The objective of this study was to evaluate the response of these durum wheat cultivars to different doses of cadmium in terms of grain yield; Cd concentration in different plant tissues (grain, straw, roots); soil Cd concentration was also evaluated. Results show that grain yield was not affected by soil Cd; differences in Cd concentration in plant tissues were generally associated with location, cultivar, and soil Cd concentration. Grain Cd concentration in all three cultivars was classified in the low accumulation category for this metal; ‘Lleuque-INIA’ noted as having a very low accumulation.

There is a worldwide increase of heavy metal or potentially toxic element (PTE), contamination in agricultural soils caused mainly by human and industrial action, which leads to food contamination in crops such as in maize. Cadmium (Cd) is a PTE often found in soils and it is ingested through food. It is necessary to determine the bioabsorption, distribution, and accumulation levels in maize to reduce or prevent food chain contamination. Cadmium absorption and accumulation in three maize cultivars were evaluated in three agricultural environments in Chile by increasing CdCl2 rates (0, 1, and 2 mg kg-1). Evaluation included Cd accumulation and distribution in different plant tissues, bioaccumulation factor (BAF), bioconcentration factor (BCF), translocation factor (TF), and tolerance index (TI). Cadmium whole-plant uptake was only affected by the CdCl2 rate; the highest uptake was obtained with 2 mg kg-1 CdCl2 (34.4 g ha-1) (p < 0.05). Cadmium distribution in the maize plant usually exhibited the highest accumulation in the straw (p < 0.05), independently of the environment, Cd rate, and evaluated cultivar. Given the results for TF (TF > 2) and BAF (BAF > 1), the Los Tilos and Chillán environments were classified as having a high capacity to contaminate the food chain for all evaluated cultivars. © 2017 by the authors. Licensee MDPI, Basel, Switzerland.

Anthropogenic soil contamination with heavy metals has received much attention in recent years, especially cadmium (Cd), which is a very toxic element for human health and is exposure is mainly through contaminated food. Maize (Zea mays L.) is one of the most important cereals in the human diet that is characterized as species whose cultivars differ in Cd accumulation. Therefore, identifying and selecting low Cd-accumulating genetic material will contribute to reducing its ingestion. Among the agricultural crops that are important for Cd in the human diet is maize. Cadmium contents in three maize cultivars were grown under different environments conditions in Chile where soils were enriched with increasing Cd rates, were evaluated. Grain yield, Cd concentration in different plant tissues, and soil post-harvest, were evaluated. Results showed that grain yield was not affected by soil Cd; however, plant tissues generally exhibited differences in Cd concentration associated with the environment, La Serena showed the highest grain Cd accumulation (30 µg kg-1; P < 0.05). In addition, among cultivars, Pioneer showed the highest grain Cd concentration (19.5 µg kg-1; P < 0.05). Grain Cd concentration of the three maize cultivars were within the range cited in the bibliography as not toxic. © 2017, Sociedad Chilena de la Ciencia del Suelo. All rights reserved.

Phenotyping, via remote and proximal sensing techniques, of the agronomic and physiological traits associated with yield potential and drought adaptation could contribute to improvements in breeding programs. In the present study, 384 genotypes of wheat (Triticum aestivum L.) were tested under fully irrigated (FI) and water stress (WS) conditions. The following traits were evaluated and assessed via spectral reflectance: Grain yield (GY), spikes per square meter (SM2), kernels per spike (KPS), thousand-kernel weight (TKW), chlorophyll content (SPAD), stem water soluble carbohydrate concentration and content (WSC and WSCC, respectively), carbon isotope discrimination (Δ13C), and leaf area index (LAI). The performances of spectral reflectance indices (SRIs), four regression algorithms (PCR, PLSR, ridge regression RR, and SVR), and three classification methods (PCA-LDA, PLS-DA, and kNN) were evaluated for the prediction of each trait. For the classification approaches, two classes were established for each trait: The lower 80% of the trait variability range (Class 1) and the remaining 20% (Class 2 or elite genotypes). Both the SRIs and regression methods performed better when data from FI and WS were combined. The traits that were best estimated by SRIs and regression methods were GY and Δ13C. For most traits and conditions, the estimations provided by RR and SVR were the same, or better than, those provided by the SRIs. PLS-DA showed the best performance among the categorical methods and, unlike the SRI and regression models, most traits were relatively well-classified within a specific hydric condition (FI or WS), proving that classification approach is an effective tool to be explored in future studies related to genotype selection.

Wheat yields in Chile have increased significantly during the last four decades as a consequence of plant improvement and better crop husbandry. Central Chile is characterised by high-yield Mediterranean conditions, where precipitation received by the crop in most years does not represent a major limitation to productivity. This study assesses the changes in agronomic and physiological traits of spring cultivars released in the country between 1920 and 2000. A total of 95 spring bread wheat accessions, representing 20 old and 75 modern cultivars (released before and after 1960, respectively) were tested in a humid Mediterranean-type climate, with irrigation. Modern genotypes exhibited higher grain yield, harvest index, number of grains per ear and sedimentation values and lower height, test weight, wet gluten content and hardness index. No differences were found for days to heading, and ear length, whereas kernel weight decreased with the Green Revolution. Principal component (PC) analysis using ten agronomic traits clearly separated modern from old cultivars. Grain yield, a trait not included in PC analysis, was highly correlated with the first PC ( r = 0.80, P

In crop breeding, the interest of predicting the performance of candidate cultivars in the field has increased due to recent advances in molecular breeding technologies. However, the complexity of the wheat genome presents some challenges for applying new technologies in molecular marker identification with next-generation sequencing. We applied genotyping-by-sequencing, a recently developed method to identify single-nucleotide polymorphisms, in the genomes of 384 wheat (Triticum aestivum) genotypes that were field tested under three different water regimes in Mediterranean climatic conditions: rain-fed only, mild water stress, and fully irrigated. We identified 102,324 single-nucleotide polymorphisms in these genotypes, and the phenotypic data were used to train and test genomic selection models intended to predict yield, thousand-kernel weight, number of kernels per spike, and heading date. Phenotypic data showed marked spatial variation. Therefore, different models were tested to correct the trends observed in the field. A mixed-model using moving-means as a covariate was found to best fit the data. When we applied the genomic selection models, the accuracy of predicted traits increased with spatial adjustment. Multiple genomic selection models were tested, and a Gaussian kernel model was determined to give the highest accuracy. The best predictions between environments were obtained when data from different years were used to train the model. Our results confirm that genotyping-by-sequencing is an effective tool to obtain genome-wide information for crops with complex genomes, that these data are efficient for predicting traits, and that correction of spatial variation is a crucial ingredient to increase prediction accuracy in genomic selection models.

Pasta color is considered an important quality trait, which is determined by intrinsic color characteristics of the semolina obtained from durum wheat (Triticum turgidum L. var. durum) grains. Eighteen genotypes of durum wheat were tested in thirteen environments under the Chilean Mediterranean conditions. In addition to grain yield (GY), three semolina color-associated traits were studied: the semolina yellow pigment absorbance (SYPA), the b* value and the brown index (BI). The main objective of this study is to decompose the phenotypic values of these traits using Chilean germplasm grown under local environmental conditions. Additionally, the thousand kernel weight (TKW) and the test weight (TW), were measured to study their relationships with these traits. The ANOVA combined over environments showed highly significant effects of genotypes (G), environments (E) and their interaction (G×E) on SYPA, b* value, BI and GY. Narrow sense heritabilities (h2) were 0.82, 0.82, 0.48 and 0.07 for SYPA, b* value, BI and GY, respectively. Comparisons between two water managements, irrigated and rainfed conditions, and between southern and northern production zones showed significant effects on GY and at least on two of the color-associated traits. Possible causes of these environmental effects are inferred and discussed. Most of the G×E component was of cross-over type, but the changes on the genotype rankings expected for SYPA and the b* values were not abrupt, which would facilitate the development of cultivars with stable yellow color potential. Much more abrupt changes on the genotype rankings would occur for BI and GY. The specific local adaptation pattern identified showing high GY, TW and semolina yellowness, plus the lack of correlation between semolina yellowness and GY or TW, and the high h2 of semolina yellowness, will enable to improve the potential color of pasta without causing detrimental effects on the production and the industrial quality in the future.

Agronomic practices, climatic variables, and soil conditions are key factors in crop productivity. Although the effects of soil chemical properties and water and agronomic crop management are known, there is little information about effective soil depth and its influence on crop productivity. Since most crop fertilization systems are based on the productive potential associated with climatic conditions and chemical properties of the first 20 cm of soil depth, the objective of this study was to determine the importance of effective depth in terms of increasing fertilization rates on durum wheat (Triticum turgidum L. var. durum) productivity. Two experiments were conducted in the 2006-2007 season in the Santa Rosa Experimental Station (71°54’ S, 36°31’ W, 220 m a.s.l.) of the Instituto de Investigaciones Agropecuarias (INIA) located in south central Chile. We used the hard wheat cvs. Llareta-INIA and Corcolén-INIA because both respond differently to soil physicochemical properties. Each cultivar was sown in sectors with different depths: 1) 0.45 m depth, silt loam on river material and 2) 1.0 m depth, loam on deep sediments. Fertilization was: 1) control without fertilization, 2) basal fertilization (BF) based on P, K, Ca, Mg, S, B, and Zn plus 90 kg N ha-1, and 3) BF plus 210 kg N ha-1. Grain yield, plant height, and number of stems m-2 were positively affected by increasing depth of soil profile. The increasing fertilization rate affected grain yield and plant height. Grain yield for cv. Corcolén-INIA had a greater response than cv. Llareta-INIA when soil depth was increased.

RESUMEN Pionero INIA es la primera variedad de trigo doble propósito liberado por el Programa Nacional de Trigo del INIA Carillanca. Es una variedad de invierno (Triticum aestivum L.) producto de la selección de germoplasma recibido de la Empresa Saaten Union Research de Francia. Mostró excelente adaptabilidad para siembras tempranas, en zonas de inviernos largos y primaveras húmedas. La altura promedio de planta adulta alcanza los 90 cm, siendo clasificado como una variedad de trigo enano a semi enano. El rendimiento promedio, en diferentes localidades y varios años de evaluación, fue significativamente superior al testigo Kumpa INIA, destacándose por su resistencia a enfermedades y tipo agronómico. Sus características de calidad molinera y de almidón permiten utilizarlo en la industria galletera, ganadera y acuícola.

Background Whole-genome genotyping techniques like Genotyping-by-sequencing (GBS) are being used for genetic studies such as Genome-Wide Association (GWAS) and Genomewide Selection (GS), where different strategies for imputation have been developed. Nevertheless, imputation error may lead to poor performance (i.e. smaller power or higher false positive rate) when complete data is not required as it is for GWAS, and each marker is taken at a time. The aim of this study was to compare the performance of GWAS analysis for Quantitative Trait Loci (QTL) of major and minor effect using different imputation methods when no reference panel is available in a wheat GBS panel. Results In this study, we compared the power and false positive rate of dissecting quantitative traits for imputed and not-imputed marker score matrices in: (1) a complete molecular marker barley panel array, and (2) a GBS wheat panel with missing data. We found that there is an ascertainment bias in imputation method comparisons. Simulating over a complete matrix and creating missing data at random proved that imputation methods have a poorer performance. Furthermore, we found that when QTL were simulated with imputed data, the imputation methods performed better than the not-imputed ones. On the other hand, when QTL were simulated with not-imputed data, the not-imputed method and one of the imputation methods performed better for dissecting quantitative traits. Moreover, larger differences between imputation methods were detected for QTL of major effect than QTL of minor effect. We also compared the different marker score matrices for GWAS analysis in a real wheat phenotype dataset, and we found minimal differences indicating that imputation did not improve the GWAS performance when a reference panel was not available. Conclusions Poorer performance was found in GWAS analysis when an imputed marker score matrix was used, no reference panel is available, in a wheat GBS panel. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-3120-5) contains supplementary material, which is available to authorized users.

This study identified single nucleotide polymorphism (SNP) markers associated with 15 complex traits in a breeding population of barley (Hordeum vulgare L.) consisting of 137 recombinant chromosome substitution lines (RCSL), evaluated under contrasting water availability conditions in the Mediterranean climatic region of central Chile. Given that markers showed a very strong segregation distortion, a quantitative trait locus/loci (QTL) mapping mixed model was used to account for the heterogeneity in genetic relatedness between genotypes. Fifty-seven QTL were detected under rain-fed conditions, which accounted for 5–22% of the phenotypic variation. In full irrigation conditions, 84 SNPs were significantly associated with the traits studied, explaining 5–35% of phenotypic variation. Most of the QTL were co-localized on chromosomes 2H and 3H. Environment-specific genomic regions were detected for 12 of the 15 traits scored. Although most QTL-trait associations were environment and trait specific, some important and stable associations were also detected. In full irrigation conditions, a relatively major genomic region was found underlying hectoliter weight (HW), on chromosome 1H, which explained between 27% (SNP 2711-234) and 35% (SNP 1923-265) of the phenotypic variation. Interestingly, the locus 1923-265 was also detected for grain yield at both environmental conditions, accounting for 9 and 18%, in the rain-fed and irrigation conditions, respectively. Analysis of QTL in this breeding population identified significant genomic regions that can be used for marker-assisted selection (MAS) of barley in areas where drought is a significant constraint.

Different physiological traits have been proposed as key traits associated with yield potential as well as performance under water stress. The aim of this paper is to examine the genotypic variability of leaf chlorophyll, stem water-soluble carbohydrate content and carbon isotope discrimination (Δ(13)C), and their relationship with grain yield (GY) and other agronomical traits, under contrasting water conditions in a Mediterranean environment. The study was performed on a large collection of 384 wheat genotypes grown under water stress (WS, rainfed), mild water stress (MWS, deficit irrigation), and full irrigation (FI). The average GY of two growing seasons was 2.4, 4.8, and 8.9 Mg ha(-1) under WS, MWS, and FI, respectively. Chlorophyll content at anthesis was positively correlated with GY (except under FI in 2011) and the agronomical components kernels per spike (KS) and thousand kernel weight (TKW). The WSC content at anthesis (WSCCa) was negatively correlated with spikes per square meter (SM2), but positively correlated with KS and TKW under WS and FI conditions. As a consequence, the relationships between WSCCa with GY were low or not significant. Therefore, selecting for high stem WSC would not necessary lead to genotypes of GY potential. The relationship between Δ(13)C and GY was positive under FI and MWS but negative under severe WS (in 2011), indicating higher water use under yield potential and MWS conditions.

Wheat (Triticum aestivum L.) is the major crop in terms of planted area and presents the largest distribution in the country covering a wide range of climatic regions. This study assesses the changes of various agronomic traits of winter wheat cultivars released in Chile between 1920 and 2000. A total of 117 winter accessions, representing 45 old and 72 modern cultivars were tested in a humid Mediterranean-type climate, with irrigation, in 2003. Old cultivars were those released before 1960 and modern ones were those released after 1960. Principal component (PC) analysis using 10 agronomic traits clearly separate modern from old cultivars of winter wheat. Comparing modern cultivars with old ones, plant height have been reduced by 25.6%, but others traits have increased, like harvest index (21.1%), number of grains per ear (42.6%), sedimentation value (103%), and grain hardness (32.0%). The variation in plant height was negatively correlated with harvest index (r = -0.30, p < 0.001). Grain yield, a trait not included in PC analysis, was highly correlated with the second PC (r = 0.81, p < 0.0001). Significant (p < 0.01) correlations were found between the year of release of cultivars and agronomic traits: plant height (r = -0.82), harvest index (r = 0.40), number of grain per ear (r = 0.69), sedimentation value (r = 0.64), and kernel weight (r = -0.46). Those correlations were mostly a consequence of absence or presence of dwarfing genes in the germplasm. Finally, the yield progress was calculated from yield data of yield trial with 15-25 cultivars and advanced lines of winter wheat tested almost every year from 1965 to 2001, showed no increase in yield between 1965 and 1975, but an increment of 246 kg ha-1 per year between 1976 and 1998, representing an annual increase of 2.6%.El trigo (Triticum aestivum L.) es el cultivo más importante en Chile en términos de superficie sembrada y áreas geográficas en las cuales se siembra, cubriendo una gran diversidad de condiciones climáticas. Este estudio evaluó los cambios de varias características agronómicas de variedades de trigo de invierno liberadas en el país entre 1920 y 2000. Un total de 117 genotipos de trigos de invierno, que representa 45 cultivares antiguos y 72 cultivares modernos, se evaluaron en un clima húmedo de tipo mediterráneo, en condiciones de riego, en el año 2003. Los cultivares antiguos corresponden a aquellos liberados antes del año 1960 y los modernos a los liberados después del año 1960. Mediante un análisis de componentes principales (CP) usando 10 características agronómicas, permitió separar claramente los cultivares modernos de los antiguos. Al comparar los cultivares modernos con los antiguos se determinó que la altura de la planta se ha reducido un 25,6%, pero en otras características se produjo un aumento, como el índice de cosecha (21,1%), número de granos por espiga (42,6%), valor de sedimentación (103%) y la dureza del grano (32,0%). La variación en la altura de la planta se correlacionó negativamente con el índice de cosecha (r = -0,30, p < 0,001). El rendimiento de grano, una característica no incluida en el análisis de PC, estuvo altamente correlacionado con el segundo PC (r = 0,81, p < 0,0001). Correlaciones significativas (p < 0,01) se encontraron entre el ano de la liberación de los cultivares y las características agronómicas: altura de planta (r = -0,82), índice de cosecha (r = 0,40), número de granos por espiga (0,69), valor de sedimentación (r = 0,64), y peso del grano (r = -0,46). Estas correlaciones fueron en su mayoría una consecuencia de ausencia o presencia de genes de enanismo en el germoplasma. Finalmente el avance en rendimiento, calculado a partir de datos de rendimiento de ensayos en los que se probaron entre 15 y 25 cultivares y líneas avanzadas de trigo de invierno evaluados casi todos los anos entre 1965 y hasta 2001, no mostró ningún aumento en el rendimiento entre 1965 y 1975, pero sí un aumento de 246 kg ha-1 por año entre 1976 y 1998, lo que representa un incremento anual de 2,6%.