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This study investigated the effect of high temperature and drought (during grain-filling) on the quality and components yield of five winter wheat varieties. Drought and drought + heat were found to have a much greater influence on the yield and quality than heat stress alone. Averaged over the varieties, the yield losses were 57% after drought, 76% after drought + heat, and only 31% after heat stresses. The reductions in the unextractable polymeric protein fraction and glutenin-to-gliadin ratio indicated a poorer grain yield quality, despite the higher protein content. Quality deterioration was observed after drought or drought + heat, while high temperatures alone resulted in no change or in a better ratio of protein components. A significant negative correlation was observed between starch granule size and relative protein content after drought.

Spring barley breeding has been carried out for almost a century in all three Baltic countries. The efforts of breeders have resulted in many new improved varieties released. The goal of our project was to survey the effect of these efforts throughout the century on this crop. The material included in this study consisted of 64 accessions originating from Latvia, Estonia and Lithuania, representing landraces, varieties released from 1927 to 2001, and breeding lines. Six agronomic traits (days to heading, days to maturing, plant height, harvest index, volumetric weight and thousand kernel weight) were recorded during two years (2002 and 2003) at three locations — Priekuli (Latvia), Landskrona (Sweden) and Bjørke (Norway). The differences between spring barley materials of different origin and from different breeding periods were assessed, and variation of their performance in different environments was discussed.

Naked barleys are less yielding than the hulled ones while the reason for this difference has not been definitely clarified. To investigate the effect of the nud gene on yield, a barley doubled haploid (DH, Proctor x Nudinka) population was initially tested in three environments and a QTL study was run on the entire population as well as on two nud/NUD DH subpopulations. Among the agronomic traits studied, a QTL effect was found at nud locus on chromosome 7H only for yield and thousand grain weight (TGW), while a second QTL was found on 6H, although contributed by the naked parent. Other QTLs for TGW were identified on 2H, 3H and 5H. Most QTLs found in the entire population were confirmed by the study on the two groups. No interaction was observed between QTLs. To provide a more accurate evaluation of the effects of the nud gene upon grain yield, its components and other agronomic traits, sixteen naked advanced backcross (AB) BC5F2 lines in the hulled background of cultivar Arda were prepared and evaluated in a replicated yield trial for two years. The only differences found between AB lines and Arda in grain yield and TGW were due to hull weight (11.97% of kernel weight). No differences were observed in other traits such as grains/square m, grains per spike, plant height, heading date and mildew resistance. In conclusion, we think to have clarified that the effect of the nud gene on yield is due to hulls, and we did not find any pleiotropic effect of nud on other traits.

We conducted a field experiment to test the hypothesis that improved phosphorus nutrition occurs in maize plants with rapid arbuscular (AM) mycorrhizae development at early developmental stages and that this also is reflected in dry matter allocation and final yield. A split-split plot design was used with previous crop (Zea mays L.-maize and Brassica napus L.-canola), tillage practices (no-tillage or conventional tillage) and P fertilization (5 levels) as factors chosen to modify mycorrhizae development at early developmental stages of maize. Previous cropping with canola resulted in decreased shoot-P concentration and shoot growth of maize at early stages. No-tillage resulted in higher shoot-P concentration but lower shoot weight than conventional tillage. Greater shoot-P uptake was related to a rapid intraradical development of mycorrhizae (previous crop of maize) or rapid connection to a mycorrhizal mycelium network (no-tillage treatments). Maize yield and harvest index were lower after cropping with canola. The yield for conventional tillage was higher than that for no-tillage but the harvest index was lower. The hypothesis was supported at early stages of maize growth by the effect of previous crop but not by results of tillage, because an unknown factor reduced growth in the no-tillage system. The hypothesis was supported at maturity by increased biomass allocation to grain relative to total shoot weight in treatments with greater shoot-P concentration at early stages.

Durante el ciclo primavera-verano de 2013 se evaluó, en la Cañada Oaxaqueña, México, el efecto de nitrógeno (N) en niveles de 0, 50 y 100kgha-1 sobre la evaporación, evapotranspiración, eficiencia en el uso del agua y rendimiento de semilla, fibra y biomasa, así como longitud de pepónide de dos variantes de estropajo (Luffa cylindrica L). Se probó un diseño de bloques completos al azar, cuyos tratamientos fueron los tres niveles de N con tres repeticiones. La relevancia del estrudio radica en la búsqueda de materiales que tengan aplicaciones en la extracción de aceite o utilización de fibra, que se adapten a las condiciones de aridez de la zona, como lo es el estropajo. Los resultados indicaron que la aplicación de 50 y lOOkgha·-1 generó mayor rendimiento de semilla, número de orificios/cm2 y longitud de pepónide. Con el tratamiento de lOOkg·ha-1 aumentaron la cantidad de biomasa, el rendimiento de fibra y la eficiencia en el uso del agua para semilla, fibra y biomasa. La evaporación se ajustó a un modelo cuadrático, mientras que la evapotranspiración se ajustó a un modelo lineal. El N afectó de manera positiva al cultivo de estropajo.

Density and spatial arrangement (rectangularity) effects on the competitive relationships, yield performance, and dynamics in canopy dominance of winter wheat and Italian ryegrass were evaluated using two addition series experiments. In experiment 1, combinations of six densities of each species formed the treatment matrix of addition series. In experiment 2, each species was tested at four densities and three rectangularities (RE) of winter wheat. In monocultures, crop density (plants per square meter) explained 82 to 85% of the total variation in the per-plant biomass of winter wheat in experiment 1. In mixtures of crop and weed, initial wheat density (N1) and initial ryegrass density (N2) and interaction of N1 and N2 explained 74 to 80% of the total variation in the per-plant biomass of winter wheat and 68 to 79% of Italian ryegrass in experiment 1. Intraspecific competition was apparent between 15 and 90 days after emergence (DAE) in winter wheat and between 90 and 170 DAE in Italian ryegrass. In mixtures, RE influenced plant size of Italian ryegrass up to 50 DAE only. Maximum winter wheat intraspecific competition occurred at 170 DAE, but maximum interspecific competition occurred during reproductive stages in mixtures. High RE increased seed yield, seed size, and harvest index of winter wheat and reduced biomass of Italian ryegrass. Grain yield of winter wheat was reduced up to 92% by competition from ryegrass. Even nine ryegrass plants in 100 winter wheat plants m−2 reduced winter wheat grain yield by 33%. However, the extent of loss in winter wheat grain yield was less in RE 16 (wider spacing) than in RE 1 (square planting) or 4 (close row spacing). Winter wheat was the stronger competitor during vegetative stages, but Italian ryegrass became the stronger competitor during the reproductive stages of development. Winter wheat leaves dominated at the top canopy during the vegetative stage, but ryegrass dominated at the top canopy during the reproductive stages. In the top canopy of mixtures at 200 DAE, the leaf area indices (LAI) of ryegrass was 6.6 times greater than winter wheat at RE 1 compared to only 1.6 times at RE 16. Greater LAI of Italian ryegrass in the top canopy reduced photosynthetically active radiation available to winter wheat by 68% at booting stage.

Resumen. La planta de agraz o mortiño es un arbusto que pertenece al género Vaccinium, conocido hoy en día por ser fuente de altos contenidos de antioxidantes en sus frutos, por consiguiente sirve para inhibir la oxidación de las grasas y es usado como nutracéutico en la prevención de enfermedades degenerativas en el humano, aspectos que han favorecido sus posibilidades de transformación y comercialización. En el mercado se observan frutos en diferentes grados de madurez, en detrimento de la calidad final; en parte por carecer de una caracterización fisicoquímica y de un criterio definido para la recolección del fruto. Por lo tanto, se establecieron estados de madurez basados en el color de la epidermis, por medio de los cuales se caracterizó el fruto. En cada estado de madurez, se evaluó el peso promedio, diámetro, pH, sólidos solubles totales (SST), acidez total titulable (ATT), relación de madurez (SST/ATT) y porcentaje de germinación de las semillas. De acuerdo al color del fruto se establecieron seis estados de madurez (0-5), diámetro de 0,8 a 1 cm y peso aproximado de 0,5 g. Los SST presentaron valores de 7,3 a 13,8 ºBrix con un comportamiento ascendente durante la maduración, contrario a la tendencia descendente que exhibió la firmeza y el pH con valores de 5,8 a 0,54 y 2,32 a 2,1 respectivamente; por su parte la ATT presentó una variación de 2,2 a 3. Se observó un incremento en la relación de madurez de 2,56 en el estado 0 a 6,17 en el estado 5. / Abstract. Colombian blueberry is a bush from the Vaccinium genus, known nowadays for the high antioxidants levels of its fruits known as berries, that is why they are very useful for inhibit the fat oxidation and also used as a nutraceutic for prevention of degenerative diseases in humans, facts which have enhanced the transformation and marketing possibilities. In the market there are fruits in different maturity grades, affecting the final quality obtained, partly because of the lack of a chemical characterization and a defined criterion for the fruit harvest. Because of that, maturitys grades have been established based on the epidermis color, being that a way for characterize the fruit and determine the harvest patterns. Fruits were taken at each stage of maturity and evaluated the average fruit weight, diameter, pH, total soluble solids (TSS), total titratable acidity (TTA), maturity ratio (TSS/TTA) and germination rate of seeds. According to the fruit color were established six maturitys states (0-5), diameter from 0.8 to 1 cm and average weight of 0.5 g. The SST showed values from 7.3 to 13.8 °Brix with an ascending behavior during the fruit ripening, contrary to the descending tendency showed by the firmness and the pH, with values from 5.8 to 0.54 and 2.32 to 2.1 respectively; meanwhile ATT showed a variation, from 2.2 to 3. It was observed an increase in the ripeness ratio from 2.56 in the state 0 to 6.17 in the state 5.

Parasitic witchweeds inflict most of their damage while still underground and attached to crop roots. Most selective translocated herbicides are detoxified by crops such as corn and thus cannot reach the attached parasites. Corn with target site resistance to acetolactate synthase (ALS)-inhibiting herbicides was tested to ascertain whether these herbicides could control witchweeds, assuming that witchweeds do not obtain amino acids from the crop. Postemergence directed sprays of 27 g ae ha−1 imazapyr 54 d after planting (DAP) delayed Striga asiatica emergence on corn in South Carolina from 3 wk (control) to 7 wk and to 11 wk when mixed with 45 g ae ha−1 AC 263 222. Treatments with up to 71 g ae ha−1 imazamox, and up to 71 g ae ha−1 AC 263 222 only delayed Striga emergence by 1 wk, and 71 g ae ha−1 imazethapyr was ineffective. ALS-inhibiting herbicides were far more effective when applied in 1-ml drenches above the seed at planting. Chlorsulfuron (10 g ai ha−1) and sulfometuron (50 g ai ha−1) were somewhat phytotoxic to Pioneer 3245IR. Rimsulfuron (30 g ai ha−1), metsulfuron (10 g ai ha−1), halosulfuron (120 g ai ha−1), and imazethapyr (140 g ae ha−1) were marginally active in Kenya, with some mature Striga hermonthica seed-bearing capsules appearing at harvest (12 wk). Imazapyr at 15 g ae ha−1 gave 70 to 95% suppression of capsule formation, whereas no capsules appeared at 30 g ae ha−1. The use of imazapyr in Kenya increased the harvest index by 17% when corn plants in Striga-infested soils were kept insect and disease free by using insecticides and fungicides. Thus, complete control can be achieved at affordable cost by farmers in subsistence conditions.

SummaryThe response of potato to different rates of nitrogen supply ranging from 0–40 g m−2 N was studied in five field experiments near Wageningen. NL (520 North). In total two late potato cultivars and two sites were used during successive seasons. The results are summarized in a set of regression equations separately for total crop and tubers. The relation between nitrogen taken up (g m−2) in the total crop and total dry matter production (g m−2) could be described with the exponential equation: 1942–1900 * 0.93X (r2=0.953, n=62). Nitrogen concentrations in the dry matter increased linearly with nitrogen uptake. Harvest indices for dry matter and nitrogen tended to decline with increase in N uptake. Cultivars differed only in the effect on N on tuber dry matter concentration. The relation between nitrogen uptake and nitrogen supply could be fitted with quadratic regression models. but coefficients were influenced by site and season.

Esta investigación evaluó la acumulación y distribución de materia seca en los diferentes órganos de la planta de cuatro variedades de papa (Solanum tuberosum L.) en el municipio de Zipaquirá (Cundinamarca) uno de los mayores productores de papa en Colombia. Se evaluaron las variedades Betina, Pastusa Suprema y Esmeralda (desarrolladas por el programa de mejoramiento genético de papa de la Facultad de Agronomía de la Universidad Nacional de Colombia) y la variedad Diacol Capiro, que es una de las más sembradas en el país. Se determinó la materia seca de cada uno de los órganos de la planta por medio de muestreos destructivos de tres sitios de siembra al azar por variedad, realizados cada dos semanas durante el ciclo de cultivo. Se observaron diferencias en cuanto al comportamiento de acumulación de materia seca en hojas y tallos, siendo mayor para Pastusa Suprema a las 16 semanas después de emergencia (sde). Betina y Esmeralda acumularon la mayor parte de la materia seca de los tubérculos en la etapa final del ciclo de cultivo, entre las 16 y 18 sde, mientras que Diacol Capiro y Pastusa Suprema acumularon materia seca en estos órganos en forma progresiva a lo largo del ciclo de cultivo. La variedad Pastusa Suprema presentó el menor Índice de Cosecha con 72% siendo inferior a las variedades Diacol Capiro, Esmeralda y Betina. Debido a esta alta partición de materia seca hacia los tubérculos en la etapa final del ciclo, no se recomienda la práctica de \"agobio\" o \"corte de rama\", ya que puede disminuir el rendimiento en estas variedades.This investigation evaluated the dry matter production and partitioning of four potato varieties (Solanum tuberosum L.) in the Zipaquirá town (Cundinamarca Department) one of the biggest production zones of potato in Colombia. Betina, Pastusa Suprema and Esmeralda (varieties developed by the program of genetic improvement of potato of the Faculty of Agronomy of the Universidad Nacional de Colombia) and Diacol Capiro variety (that is one of those more sowed in the country) were evaluated. The dry matter was determined at random of each one of the plant organs, samplings were taken of three sowing places. This procedure was carried out every two weeks during the crop cycle. Differences were observed regarding the behaviour of dry matter accumulation in leaves and stems, Pastusa Suprema presented the biggest accumulation in these organs in the 16 weeks after emergency (WAE). Betina and Esmeralda accumulated the main part of the tuber dry matter in the final stage of the crop cycle, between the 16 and 18 WAE, whereas Diacol Capiro and Pastusa Suprema accumulated dry matter in these organs in progressive form along the crop cycle. The Pastusa Suprema variety presented the smallest Harvest Index with 72% being inferior to the Diacol Capiro, Esmeralda and Betina varieties. Due to this high dry matter partition to the tubers en the final stage of crop cycle, does not recommended the agronomic practice of \"branch cut\", because it can reduce the yield in these varieties.