Effects of foliar applications of fungicides during plant growth on grain development and grain germinability in spring barley

In 1990 and 1991 grain samples of spring barley were obtained from plots in which fungal diseases were controlled until ear emergence using fungicide sprays, and from comparable plots which had received no fungicide applications. The grain was stored at 10^oC, and tested for germination at intervals during storage. Grain from plots treated with fungicide consistently exhibited more dormancy than grain from untreated plots. In 1992, grain development was monitored from anthesis to harvest-ripeness in treated and untreated plots of cvs Blenheim, Camargue and Tyne. In cvs Blenheim and Camargue, grains in fungicide-treated plots had a greater dry weight at harvest-ripeness, and dehydrated later in development than grains in untreated plots. Neither of these differences was observed in cv. Tyne. Possible interpretations of the effects of fungicide treatment of the parent plant on the physiology of the grain are discussed.     

不同播期冬小麦株型构建及其生育特征

针对黄淮平原中部冬小麦区秋季旱涝频发导致小麦播种推迟的现状,设计冬小麦10月15日(适期播种)、10月30日(中晚期播种)、11月15日(晚期播种)、11月30日(超晚期播种)、2月15日(早春播种)和3月1日(春播)6个播期,研究不同播期冬小麦株型构建及生长发育特征.结果表明： 随着冬小麦播期的推迟,其生长发育进程加快,早春播种和春播与适期播种相比生育期缩短115~130 d;10月30日(中晚期播种)之后的5个播期与适期播种相比株高降低,成穗数和有效小穗数减少;迟播小麦的叶位下移,冠层空间降低,叶面积减少;收获指数随播种期推迟由0.46(适期播种)提高到0.53(春播);冬小麦产量随播种期推迟显著下降,减产幅度最高达43.6%;冬小麦春季播种未经过冬季和早春阶段的自然低温处理,无春化过程依然可形成产量.     

Effects of defoliation at different growth stages and in different grain-filling environments on the growth and yield of spring barley

The yield of spring barley grown outside was little affected by the removal of all fully expanded leaves during late tillering or early stem extension but was decreased by defoliation either earlier or later. Removal of all except the top two leaves when 50% of the ears were fully emerged also had relatively little effect on yield but damage was increased if only the flag leaf was retained, especially if the leaves apart from the flag leaf were removed 10 days earlier when the first awns were visible. Defoliation treatments, including those which had little effect on barley grown outside, generally had proportionately greater effects if the plants were moved to a warm glasshouse at the start of grain filling.     

Effects of mildew on the growth and yield of spring barley: 1969-72

Mildew decreased grain yield by decreasing ear number and grain size (but not grain number/ear), the damage depending on the earliness and severity of mildew. In 1971 when mildew was early and severe, ethirimol seed dressings at 0.22 kg a.i./ha, which gave only early protection, increased yield more than did ethirimol sprays applied to protect the flag leaf and ear. In 1972 sprays were better than seed dressings at this rate because mildew was less severe during the seedling stages.     

Surveys of diseases of spring barley in England and Wales, 1976–1980

Samples from 200–300 randomly selected spring barley crops were taken annually at growth stage 73–77 (milky ripe) from 1976 to 1980. The number of samples from each region was proportional to the area of barley grown in each region. The percentage of the area of the top two leaves affected by diseases was recorded. Mildew (Erysiphe graminis) was the most widespread and severe disease recorded. Brown rust (Puccinia hordei) and rhynchosporium (Rhyn-chosporium secalis) occurred frequently but at relatively low levels. Yellow rust {Puccinia striiformis) and septoria (Septoria nodorum) were seen on less than 50% of the samples in most years, and halo spot (Selenophoma donacis) and net blotch (Pyrenophora teres) were rarely recorded. There was an association between the severity of rhynchosporium and the number of rain days in May and June. The highest levels of brown rust occurred in the south and east and rhynchosporium was more common in Wales and the south-west than in the east, but there were no differences in the regional distribution of other diseases. Cultivar resistance, sowing date, previous cropping and fungicide usage were all found to be associated with altered disease levels. The proportion of crops treated with a foliar fungicidal spray rose from 26% in 1976 to 47% in 1980. The use of tridemorph declined but that of triadimefon increased reaching 29% of crops treated by 1980. The use of ethirimol as a seed treatment declined from 16% of crops grown from treated seed in 1976 to 7% in 1980. Estimated yield losses between 1976 and 1980 varied between 4% and 9% due to mildew, between 0.3% and 0.8% due to brown rust and between 0.2% and 0.5% due to rhynchosporium.     

Fate of 15N-labelled fertilizer applied to spring barley grown on soils of contrasting nutrient status

An experiment with ¹⁵N-labelled fertilizer was superimposed on the Rothamsted Hoosfield Spring Barley Experiment, started in 1852. Labelled ¹⁵NH₄ ¹⁵NO₃ was applied in spring at (nominal) rates of 0, 48, 96 and 144 kg N ha^-1. The labelled fertilizer was applied to microplots located within four treatments of the original experiment: that receiving farmyard manure (FYM) annually, that receiving inorganic nutrients (PK) annually and to two that were deficient in nutrients: applications were made in two successive years, but to different areas within these original treatments. Maximum yields in 1986 (7.1 t grain ha^-1) were a little greater than in 1987. In 1987, microplots on the FYM and PK treatments gave similar yields, provided enough fertilizer N was applied, but in 1986 yields on the PK treatment were always less than those on the FYM treatment, no matter how much fertilizer N was applied. In plots with adequate crop nutrients, about 51% of the labelled N was present in above-ground crop and weed at harvest, about 30% remained in the top 70 cm of soil (mostly in the 0–23 cm layer) and about 19% was unaccounted for, all irrespective of the rate of N application and of the quantity of inorganic N in the soil at the time of application. Less than 4% of the added fertilizer N was present in inorganic form in the soil at harvest, confirming results from comparable experiments with autumn-sown cereals in south-east England. Thus, in this experiment there is no evidence that a spring-sown cereal is more likely to leave unused fertilizer in the soil than an autumn-sown one. With trace applications (ca. 2 kg N ha^-1) more labelled N was retained in the soil and less was in the above-ground crop. Where P and K were deficient, yields were depressed, a smaller proportion of the labelled fertilizer N was present in the above-ground crop at harvest and more remained in the soil.Although the percentage uptake of labelled N was similar across the range of fertilizer N applications, the uptake of total N fell off at the higher N rates, particularly on the FYM treatment. This was reflected in the appearance of a negative Added Nitrogen Interaction (ANI) at the highest rate of application. Fertilizer N blocked the uptake of soil N, particularly from below 23 cm, once the capacity of the crop to take up N was exceeded. Denitrification and leaching were almost certainly insufficient to account for the 19% loss of spring-added N across the whole range of N applications and other loss processes must also have contributed.     

The response of determinate and semi-determinate faba bean varieties to different sowing dates in the spring

Field trials conducted during 1986 and 1987 at the University of Nottingham compared the growth and development of two varieties of faba bean, Alfred and Ticol, in response to three different dates of sowing in the spring. Grain yields were greater the earlier the crop was sown. This difference was attributed to the larger canopy size, especially at the pod-filling stage of the earlier sown crops. This probably reflected the influence of temperature on the expansion and senescence of leaves during development. A semi-determinate variety of faba bean, Alfred, yielded 31% more than a determinate variety, Ticol. This difference was not attributable to any particular yield component. In 1986, it was correlated with pods per podding node and in 1987 with the number of seeds per pod. Three reasons can be advanced to explain this greater yield. Firstly, Ticol branched more than Alfred and so a greater proportion of its total reproductive nodes were borne on the branches rather than the mainstem. Branches were shown to be inferior in terms of yield production. Secondly, it was demonstrated that Ticol was probably less able to transfer stored assimilates from the stem to the developing pod than Alfred. Thirdly, Alfred had a larger canopy during pod development than Ticol.     

Evaluation of chlorophyll fluorescence in different densities of spring barley

Over the period 2008–2009, field experiments were carried out at the Lithuanian Institute of Agriculture on an Endocalcari-Epihypogleyic Cambisol (CMg-p-w-can). The study was aimed to establish the effects of spring barley crop stand density on the chlorophyll fluorescence and to estimate the relationship between grain yield and chlorophyll fluorescence value. The tests involved three spring barley varieties—Aura DS, Barke and Gustav. The three different stand densities were formed with seed rates of two, four and six million viable seeds per hectare. Our research findings indicated that increasing spring barley stand density did not exert any negative influence on major photosynthetic processes and did not result in any significant qualitative changes in light harvesting system. A significant varietal (factor B) influence was established on minimum fluorescence (F _o) and maximum fluorescence (F _m) values after short dark adaptation indicators (F _fact. = 19.66** and F _fact. = 9.33**, respectively). Growth stage (factor C) significantly influenced all fluorescence indicators—Fo, Fm and quantum efficiency of PSII after short dark adaptation (F _v/F _m)—in the five cases of the six tested. A significant effect of variety and growth stage interaction (B × C) was determined for 66.7% of the tested cases. The article presents a correlation between the grain yield of spring barley and fluorescence parameters. In most cases, the correlation was strong and significant. The interaction between the fluorescence parameters for individual varieties was responsible for 53.8–76.2% of grain yield data variation, which averaged over all varieties, amounted to 21.9–46.1%.     

Effects of net blotch on growth and yield of spring barley

The effect of net blotch on the growth and yield of cv. Beatrice spring barley was examined in a greenhouse experiment. Separate inoculations at growth stages 21 and 34 reduced green leaf area, root weight, leaf sheath and stem weight and tiller number. The early inoculated plants, which responded and recovered more rapidly than later treated ones, suffered a loss in grain yield and this was related to the amount of disease, the loss in green leaf area and the reduction in unit leaf rate.     

Effects of chemical treatments for mildew control at different times on the growth and yield of spring barley

Experiments in 1973 and 1974 tested the effects of ethirimol seed treatment and the timing of single sprays of ethirimol or tridemorph, on mildew control and the growth and yield of spring barley. These treatments were compared with selected combinations of two treatments designed to give longer protection. In 1973, combinations of seed treatment and spray, or two sprays, did not yield better than the best component treatment applied alone or the most effective single spray of tridemorph applied on 1 June. In 1974, mildew developed usually early and yields were increased by applying ethirimol to the seed plus a tridemorph spray or two tridemorph sprays. However, barley sprayed once with tridemorph on 20 May, the expected best date, yielded more than barley receiving a seed treatment of ethirimol plus a tridemorph spray applied on either 3 or 12 June. Sprays of captafol and tridemorph, applied as separate treatments, successively to the same plots on three occasions, gave the best yields in both years. Treatments most affected ear number but they did have some effect on all components of yield. In 1974 there was a significant relationship between ear number and the variance of the number of grains per ear.     

Role of oxidative stress on growth responses of spring barley exposed to different environmental stressors

Aims Oxidative stress is one of the most important mechanisms in a plant's reaction to the effects of different stressors; however, its role in plants' resistance is still poorly understood. The objective of this study is to evaluate an influence of oxidative stress induced by stress factors of different origin—ozone, ultraviolet (UV)-B radiation, drought, cadmium (Cd) and copper (Cu), to growth of spring barley and to check the hypothesis, that intensification of oxidative stress is the main factor of growth depression induced by strong treatments of different stressors; meanwhile, mitigation of oxidative stress determines eustress-induced growth stimulation.Methods A pot experiment was carried out in phytotron chambers with a controlled environment. Spring barley (Hordeum vulgare L.) plants were exposed to different doses of investigated environmental stress factors (O 3, UV-B radiation, drought, Cd and Cu), and their effects on shoots growth, accumulation of superoxide (O 2 .?), intensification of lipid peroxidation and antioxidative protection (superoxide dismutase, glutathione reductase and catalase activities and concentration of carotenoids) were measured. Analysis of variance (ANOVA) with classical eta-squared (η 2) values was used to evaluate and to compare the contribution of non-specific oxidative stress and stressor-specific mechanisms on plants growth.Important findings Low doses of most stressors stimulated antioxidative protection and growth of barley shoots, reduced the concentration of O 2 .? and/or intensity of lipid peroxidation. Whereas an impairment of growth and intensification of oxidative stress as well as a reduction in concentration of carotenoids and further increase in activity of antioxidative enzymes were noticed when the intensity of the stressors was increased. In the cases of ozone and UV-B stress, the effects of oxidative stress on plant growth was mitigated by strong antioxidative protection—highly increased catalase (CAT) and superoxide dismutase (SOD) activities, respectively. In the cases of drought and Cu, relatively strong oxidative stress was the major cause of plant growth depression. Additionally, mitigation of oxidative stress due to increased SOD activity was likely to be one of the main causes of growth stimulation induced by low doses of UV-B, Cd and Cu stress. Possible reasons for O 3 -induced growth stimulation were increased CAT activity and concentration of carotenoids. Generalizing the effects of different stressors, the contribution of non-specific oxidative stress on plant growth was stronger compared with stressor-specific action mechanisms: oxidative stress determined 42% of the changes in plants' dry biomass, whereas the contribution of stressor-specific mechanisms accounted for 35% of variability in barley growth.     

A pot evaluation of the sensitivity of spring barley (Hordeum vulgare L.) to water stress applied at different growth stages

Two-year pot experiments with three varieties of spring barley were carried out. Water stress (water deficit of soil up to 40% of field water-holding capacity) was employed in four basic growth stages of plants: tillering, shooting (stem extension stage), ear formation and milk maturity. Reactions of the plants to water stress were expressed by a decline in the grain yield of the studied varieties throughout the growing season. The greatest losses in production of spring barley grain due to the experienced water stress of the plants were found at the beginning of ear formation and milk maturity stages of the grain. The sensitivity of the plants to the stress caused by water deficit in the soil during the initial period of their vegetative growth was smaller. Varieties showed significantly different sensitivities to the experienced water stress, depending on the growth stage during which the plants suffered from the stress.     

Effects of aerial pollutants on the growth and yield of spring barley

Open-topped chambers were used to determine the effect of field concentrations of aerial pollutants on the growth and yield of spring barley. Experiments were conducted in the Marston Valley, Bedfordshire, where sulphur dioxide and fluoride are the major pollutants. The charcoal filtered chambers enabled pollutant concentrations to be reduced by 60–70%. Cleaning the air increased straw and grain yields. The filtration was non-selective and did not identify the injurious agent. The chambers were found to accelerate the crop's development by 7–8 days and reduce yield by suppressing tillering.     

Effects of a short-term p-hydroxybenzoic acid application on grain yield and yield components in different tiller categories of spring barley

The aim of these experiments was to evaluate how thresholds for phytotoxic substances obtained in seedling bioassays relate to yield losses or changes in yield components of mature barley crops after a short-term exposure to p-hydroxybenzoic acid. Under laboratory conditions a treatment with 1.81 mM p-hydroxybenzoic acid significantly reduced the radicle length of barley, whereas coleoptile elongation was less sensitive. The inhibition of the radicle length and coleoptile elongation was greater if the pH of the test solution was not buffered at pH 5.5. In a glasshouse trial the effect of p-hydroxybenzoic acid on the radicle and coleoptile elongation of spring barley was compared with the yield response after a three day exposure either during germination or at the double ridge stage of apex development. Applications of 0.72 mM, 1.44 mM and 3.62 mM p-hydroxybenzoic acid averaged over the treatments during germination or at the double ridge stage of development caused a yield reduction in the single ear weight of 5%, 13% and 19% in comparison with the control, respectively. The higher tiller categories in general showed a greater sensitivity towards an application of p-hydroxybenzoic acid and, therefore, could not compensate for the yield decrease of the main stem tiller. A single application of p-hydroxybenzoic acid either at germination or at the double ridge stage may cause yield losses, as reported from no-till systems or cereal monocultures. The data have implications for the interpretation of seedlings bioassays in allelopathic research and their applicability in estimating yield losses caused by phytotoxic substances. ei]Section editor: R Merckx     

Uptake and leaching of nitrogen from artificial urine applied to grassland on different dates during the growing season

Artificial urine, equivalent to 30 g N m^-2, was applied to replicated plots in a perennial ryegrass (Lolium perenne L.) sward, each plot receiving a single application on one of six dates between July and November 1990. Recoveries of urine-N in herbage up to the end of the growing season in November decreased linearly for consecutive application dates, ranging from 40% of the urine-N applied in July to a negligible proportion of the final application. In contrast, contents of urine-derived N remaining in the soil (to 1-m depth) in November increased from 3% of the N applied in July to 66% for the final application. Almost all of this was present as nitrate + nitrite-N. Only soils that had received urine in September or later contained significantly greater quatities of mineral-N than the control plots. The mineral-N content of soils collected the following April indicated that most of this urine-derived N had been lost from the soil over the winter. Estimates of the quantities of N leached ranged from 0.7 g N m^-2 from untreated plots to 18.6 g N m^-2 from plots treated with urine in November. Although grass yields and N uptakes in March and April provided evidence of a residual effect from the previous year's urine applications, contents of mineral-N and of potentially mineralisable N in urine-treated soils in April were not significantly different from those in untreated soils.     

Effects of powdery mildew on grain filling in spring barley in contrasting environments

Circumstantial evidence from field experiments at Rothamsted suggested that effects of powdery mildew on grain filling in spring barley may be determined partly by temperature during the grain-filling period. An experiment was, therefore, done which compared the effects of fungicides applied to control powdery mildew on grain filling in early- and late-sown spring barley plants kept either out-of-doors throughout their growth (‘cool’ environment) or under the same conditions until the start of grain filling and then transferred to a heated glasshouse (‘warm’ environment) until harvested. Fungicides that controlled mildew increased the total grain yield of the late-sown barley more than that of the early-sown and much more in the warm environment than in the cool. On average, the effect of the fungicides in the cool environment was to increase grain yield by 17·7%. Small increases in numbers of grains/ear (+ 3·4%) and thousand-grain weight (TGW) (+ 2·3%) contributed to this increase but it could be attributed principally to an average increase in numbers of ears/plant of 12·4%. Contrastingly, fungicides increased average grain yield in the warm environment by 58·2%. Effects of the fungicides on numbers of ears/plant (+ 27·8%) and on numbers of grains/ear (+ 4·5%) were not significantly different to those in the cool environment, and the much greater responses in the warm than in the cool environment could be attributed mostly to much larger effects on grain size (+ 19·2%) The greater benefits of the fungicides and, by implication, the greater damage done by powdery mildew in the warm than in the cool environment cannot, unequivocally, be attributed to differences in temperature during grain-filling because the two environments clearly differed in other ways and especially in light intensity. Nevertheless, the results obtained do illustrate the potential risks involved in using data obtained under one set of circumstances to predict what will happen in another, especially when environments differ as greatly as glasshouses and fields.     

Plasticity in laying dates of Canada Geese in response to spring phenology

Observed phenological changes can be explained either by individual phenotypic plasticity or by evolutionary changes, but there is more evidence pointing towards phenotypic plasticity to explain the mechanism behind changes in bird phenology. However, most studies on phenology have been conducted on insectivorous bird species for which breeding is closely tied to temperature and insect emergence. In this study, we examined the consequences of climatic conditions on the nesting phenology of temperate breeding Canada Geese Branta canadensis maxima, which rely on a continuous food supply, during a 14‐year period (2003–16). We determined whether laying dates were plastically adjusted to spring environmental conditions, and whether this adjustment resulted in a laying date advancement. We further estimated the strength and shape of selection acting on breeding timing, by looking at the effect of laying date on the relative number of young successfully hatched in a nest. We found that Geese plastically adjusted their laying date to spring maximum temperature (and not to precipitation or ice break‐up), resulting in a 9‐day advancement of laying date in the population for that period. Laying date was also moderately repeatable (r = 0.23) and subject to directional selection, but stabilizing selection was negligible. We thus demonstrate how Canada Geese plastically adjust laying dates to temperature, which may further be beneficial to nesting success. Evolutionary change of laying date to selection related to climate change, however, is still possible.     

Effect of seed nitrogen on response to applied nitrogen in six spring barley (Hordeum vulgare L.) cultivars in a glasshouse

Summary Variation in the nitrogen content of seed of six barley cultivars was brought about by growing parent plants at four nitrogen levels. Shoot dry weight of plants grown for 23 days from these seeds was generally enhanced by an increase in seed nitrogen content. The most responsive cultivar was a primitive type of barley from Ethiopia. Cultivars with a longer breeding history were less responsive. Risø 1508 apparently had physiological and biochemical limitations in responding to extra seed nitrogen. In the barley cultivars studied extra seed nitrogen seems to supplement, rather than substitute for, nitrogen fertilizer in the seed bed.     

Distribution of spring barley roots in Danish soils,of different texture and under different climatic conditions

Summary Spring barley root profiles have been investigated in three years with different climatological conditions during the growing season. In total, 50 root profiles were determined by measuring cm root/ml soil in different 10 cm sections of the profile. The investigations, show that the root density was nearly identical for all soil types within the upper part of the plough layer. The decrease in root density with depth is most pronounced for the sandy soils and less for the loamy soils. The mean max. root depth in the sandy soils was roughly 70 cm, while it was roughly 140 cm for the loamy soils. A comparison between the clay and silt content in the subsoil and the thickness of soil layers with more than given root densities shows that there is no correlation between texture and thickness of soil layers with more than 1.0 cm root/ml soil, while there was a clear, positive correlation between thickness of soil layers with lower root densities and the clay and silt content in the subsoil. The different climatological conditions during the growing season give rise to differences in the root development. Very wet springs seem to impede root development in loamy soils with slowly permeable subsoils, while this is not the case in the sandy soils.