Grain yield and ear development of spring barley as influenced by environmental conditions during early stages of plant development

Barley plants were grown until day 21 under conditions which were different in relation to photon flux density, carbon dioxide concentration and temperature. Dry weight and leaf area increase from day 7 until day 21, shoot apex development between day 15 and day 47, and yield of each treatment group were considered. Photon flux density was demonstrated to have a greater influence on net assimilation rate (NAR) of young plants than has carbon dioxide enrichment. High temperature treatment seems to influence NAR less than growth and developmental processes. Grain yield of high temperature treated plants was significantly lower than that of the other treatment groups. Significant correlations have been found between growth analysis values of young plants and some yield components of each treatment.     

Effects of fungicide treatments and variety on development, grain growth and yield of spring barley

The effects of four fungicide treatments for the control of mildew on spring barley were assessed in three field experiments, one in each of the years 1981, 1982, 1983. The fungicide treatments (+/ - triadimenol seed treatment and +/ - triadimefon foliar spray applied during early booting) were chosen to control mildew, and hence affect yield determining processes, at different times in the life of the crop. Two of the experiments also tested different nitrogen amounts and the third tested four varieties differing in their degree of mildew resistance. Mildew appeared too late to affect the production and survival of spikelets and shoots, but reduced average grain weight by reducing the rate of grain growth. Grains in the upper part of the ear had a considerably lower growth rate and final weight than grains in central and basal positions but there was no evidence that the effects of mildew on grain size depended upon grain position within the ear. Mildew incidence increased with increasing nitrogen and varietal susceptibility but there were few significant interactions between these factors and fungicide treatment for grain yield. The degree of mildew control achieved by the seed treatment varied with barley variety. Use of the two successive fungicide treatments did not yield more barley than use of either alone. Amongst varieties, grain positions within the ear and fungicide treatments there was a close correlation between rate of grain growth and final grain weight. Duration of grain growth was not related to rate of grain growth or final grain weight but was inversely correlated with mean temperature during the period of rapid grain growth. The temperature sums during the period of rapid grain growth were similar for the three years and it is suggested that a more precise knowledge of the relationships between mildew incidence, varietal susceptibility and rate of grain growth may enable more accurate predictions to be made about likely yield responses to fungicide treatments.     

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 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.     

The relationship between leaf canopy development and yield of barley

A study was carried out into the relationship between sowing date, canopy development and yield of four barley genotypes sown in autumn and spring. Yield was considered as the product of PAR absorbed by the crop canopy up till anthesis, the dry matter: radiation quotient, the ratio of grains m²at maturity to the weight of the crop at anthesis and the mean grain weight. Equations were derived to predict the time course of the proportion of PAR absorbed in relation to date of sowing using thermal time as predictor. In crops that were not short of water and were fully vernalised, genotypic differences were detected in plant population density, date of anthesis, and the four yield components identified above. All attributes except plant population density were affected by shortage of water but genotypes differed in their response.     

Effects of variation in ear temperature on growth and yield of spring wheat

Wheat plants were kept in a growth room at 15 ^oC from 7 days after an-thesis until maturity and their ears were warmed to 20 or 25 ^oC for various periods. Continuous warming initially increased the growth rate of the ear and decreased that of the stem, but hastened senescence of the ear and decreased final grain yield by decreasing dry weight per grain. Warming the ears increased the movement of ¹⁴C and nitrogen to them from the leaves and stem during the early stages of grain growth but decreased it later. Warming the ears for only the first 10 or 20 days also hastened ear senescence; grain yield decreased progressively with increase in duration of the warm period. All effects were greater at 25 than at 20 ^oC. The effects of changing ear temperature from 15 to 20 ^oC were independent of the temperature of the rest of the plant. Altering the humidity of the air around the ears by 4–7 mb at constant temperature had no effect on ear growth or senescence. Warming all of the plant except the ears from 15 to 20 ^oC increased ear growth slightly during early grain growth and decreased it later, irrespective of ear temperature: stem dry weight, leaf area and net photosynthetic rate of flag leaves and green stems were decreased and dark respiration rate of stems was increased.     

The development and yield of autumn- and spring-sown barley in south east Scotland

As part of a study of the relationship between plant development and grain yield, winter and spring barleys were sown in the autumn and spring. Apical development and leaf area development were monitored and the final yield was partitioned into grain weight and grain number. The photosynthetically active radiation (PAR) absorbed was calculated.
The main differences found were between sowings rather than between genotypes within sowings. The autumn sowing outyielded the spring sowing because the grains were heavier, although the autumn sowing tended to have fewer grains m^-2. In the autumn sowing the rate of initiation of spikelet primordia was slower, due to the lower temperatures encountered, but the initiation phase lasted longer and a larger proportion of primordia survived. However, the increased proportions of tillers to mainstem reduced the mean number of grains/ear.
The numbers of grains m^-2 and the yield were related to the PAR absorbed. In this analysis the earlier anthesis of the autumn-sown plants could be seen to be reducing the PAR absorbed and consequently the grains m^-2.     

Effects of CCC and GA on internodal development of barley

Summary The effect of applying (2-chloroethyl)trimethylammonium chloride (CCC) or gibberellic acid (GA) as foliar sprays on internodal development of barley was studied. CCC applied to the whole plant at main tiller leaf stages 1, 2 or 3 decreased shoot elongation, and prevented elongation of internode 6 (internode 5 subtended the head). CCC at all stages delayed senescence of the lower leaves. CCC sprayed at all 6 leaf stages and GA sprayed at main tiller leaf stages 1, 2, 3 or 4 reduced plant height at maturity. GA treatment at leaf stages 2, 3 or 4 initially stimulated internodal elongation; elongation of later developed internodes was inhibited resulting in shorter plants at maturity. Only the treatment with GA at leaf stages 5 and 6 resulted in increased plant height.     

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.     

Effects of seed deterioration and seed-bed environment on emergence and yield of spring-sown barley

Seedling emergence from barley seeds, deteriorated by storage at supra-optimal moisture contents and temperatures, was adversely affected by sowing early in spring when soil temperatures were low, and by sowing into wet seed beds. There were significant interactions between seed lots of varying levels of deterioration and seed bed condition, because the more severely deteriorated lots emerged proportionately less well than the control, non-deteriorated lots. The yield results also showed significant interactions between seed lots and seed-bed condition because plants from deteriorated seeds in low populations resulting from partial emergence failure were unable to compensate and produce plot yields similar to those of higher populations.     

Effects of timing of sulphur application on yield,S-uptake and quality of barley

The effect of N application (four levels) and time of S application (from sowing to the middle of heading) on yield and quality of spring barley (Hordeum vulgare L.) was investigated in pot experiments. Also, a no S treatment was included. At the two lowest N levels grain yield was unaffected by S application, but with increasing N level there was an increasing yield response to S application. Deficiency symptoms were observed from the beginning of tillering onwards at the highest levels of N application. Sulphur applied when the flag leaf was first visible eliminated the symptoms and prevented yield reductions. Mineralised soil organic S fulfilled the S requirements of plants grown at the lowest N rate and sustained plants at the higher N levels until the late S application. The effectiveness of a late S application may be lower under field conditions because of poor mobility of S in the soil under dry conditions. Late S application caused the percentage of fertiliser-derived S in grain to decrease at all N levels. Without S application the concentrations of the S-containing amino acids cysteine and methionine decreased on both dry weight and protein basis, especially at the highest N levels. Late S application even at the middle of heading prevented this reduction of S-containing amino acids. This indicates that adequate protein quality may be achieved by delayed S application despite yield reductions.     

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     

干旱胁迫对玉米叶片光合特性和穗发育特征的影响

玉米是需水量较大的粮食作物之一,拔节至开花的穗期是其一生中的需水临界期,研究玉米穗期对干旱胁迫的响应机制对提高玉米干旱适应性具有重要意义。以筛选后的干旱敏感自交系PH6WC(6WC)和抗旱自交系郑58(Z58)为试验材料,采用测坑控水试验,于穗期设置3个水分处理(正常灌水CK、轻度干旱LD、中度干旱MD),研究了穗期不同水分处理对雌雄穗发育特性、开花吐丝间隔以及穗位叶光合特性的影响。结果表明:LD对Z58的株高、雄穗生长特性、叶绿素相对含量和光系统II最大光化学效率没有显著影响,但雌穗长显著降低;MD显著降低了Z58的穗位叶光合特性、雌雄穗的穗长和干物质积累。对于6WC,LD抑制了其植株生长和穗的发育,使雌穗长、雌穗直径、雄穗长、干物质向穗的分配比率、穗位叶的叶绿素a、叶绿素b和光合性能综合指数(PI_ABS)分别降低了35.3%、11.8%、20.6%、25%、21.1%、20%、23.8%;干旱胁迫程度越重对6WC雌雄穗的发育影响越大。此外,LD与MD分别延长6WC的开花吐丝间隔期(ASI)至5天、9天,LD和MD分别延长Z58的ASI 0、3天。综上所述:穗期...     

Effects of powdery mildew at different growth stages on grain yield of barley

Pot-grown barley plants (cv. Proctor) were exposed to infection by powdery mildew during four stages of development, G.S. 2–6, G.S. 7–9, G.S. 10-10-5 and G.S. 11 (Feekes scale, Large, 1954). All combinations were examined (i.e. 2⁴ factorial). The numbers of fertile tillers at harvest were significantly reduced by mildew during periods G.S. 2–6 and G.S. 7–9. Numbers of grains per head and grain size (1000 grain weight) were significantly reduced by mildew only during G.S. 2–6. Effects, on components of yield, of the four mildew treatments were found to be almost entirely additive. The only significant interactions found were for grain size: in this instance there was some interaction between treatments at G.S. 2–6 and G.S. 10-10-5 and between treatments at G.S. 2–6, G.S. 7–9 and G.S. 10-10-5.     

Effects of barley mildew on green leaf area and grain yield in field and greenhouse experiments

In 1980 the relationships between mildew severity, green leaf area (GLA) and grain yield of spring barley were examined using greenhouse-grown plants and plants grown in micro-plots in the field. Mildew, by causing premature senescence, reduced GLA and grain yield was strongly correlated with GLA integrated from growth stages 2–10.5 on the Feekes scale. Early mildew attack reduced all yield components (including grain size) even when fungicidal control had eliminated mildew by anthesis. Analyses of culms at anthesis and harvest supported the view that the smaller grain size associated with early mildew attack resulted from a deficiency in carbohydrate stored in culms before anthesis and available for retranslocation to the developing grain. Amounts of total soluble carbohydrate at anthesis and the amounts lost beween anthesis and harvest were both strongly correlated with GLA up to anthesis.     

Exploitation of yield stability in barley

Key message

Analyses of registration trials of winter barley suggested that yield and yield stability can be enhanced by developing hybrid instead of line varieties.

Abstract

Yield stability is central to cope with the expected increased frequency of extreme weather conditions. The objectives of our study were to (1) examine the dimensioning of field trials needed to precisely portray yield stability of individual winter barley (Hordeum vulgare L.) genotypes, (2) compare grain yield performance and yield stability of two-rowed lines with those of six-rowed lines and hybrids, and (3) investigate the association of various agronomic traits with yield stability. Static and dynamic yield stability as well as grain yield performance was determined in five series of 3-year registration trials of winter barley in Germany. Each series included 4 or 5 six-rowed hybrids, 40–46 six-rowed inbred lines, as well as 42–49 two-rowed inbred lines. The genotypes were evaluated in 10–45 environments, i.e. year-by-location combinations. We found that precise assessment of yield stability of individual genotypes requires phenotyping in at least 40 test environments. Therefore, selection for yield stability is not usually feasible since the required number of test environments exceeds the common capacity of barley breeding programs. Also, indirect improvement of yield stability by means of agronomic traits seemed not possible since there was no constant association of any agronomic trait with yield stability. We found that compared with line varieties, hybrids showed on average higher grain yield performance combined with high dynamic yield stability. In conclusion, breeding hybrid instead of line varieties may be a promising way to develop high yielding and yield stable varieties.     

Effects of Fusarium culmorum head blight on mycotoxin accumulation and yield traits in barley doubled haploids

The susceptibility of barley doubled haploids (DH) to Fusarium head blight (FHB) was investigated. Heads of 24 DH lines (11 two-rowed and 13 six-rowed) derived from F₁ Maresi (two-rowed) × Pomo (six-rowed) hybrids were inoculated with a conidial suspension of the single isolate IPO348-01 of Fusarium culmorum. The experiment was carried out in three consecutive years (1996–98) in one location. The number of kernels per ear, 1000-kernel weight and kernel weight per ear were recorded in inoculated and control plots. In the infected kernels nivalenol (NIV) content and deoxynivalenol (DON) content were determined. The effects of genotype, year and genotype-year interaction on reduction of yield traits were significant. For mycotoxin content only genotype and year effects were found to be important. The average NIV concentration in kernels of inoculated lines ranged from 0.15 mg/kg in the two-rowed line MP7 to 6.36 mg/kg in the six-rowed line MP113. A low accumulation of DON was observed in the studied population (from 0.01 to 0.20 mg/kg). Generally, no significant differences in mycotoxin content were found between two-rowed and six-rowed genotypes. The line MP7 was found to be superior — with the lowest mycotoxin accumulation, and reduction in yield traits. Environmental conditions (years) affected DON and NIV level in kernels; however, the tendency to a lower or higher accumulation of mycotoxin in individual lines was stable over the years.     

大麦产量构成模型

通过产量构成法构建了适用于不同地区不同品种的大麦产量模拟模型.以南京、昆明、武汉3个地区各试验处理中不同大麦品种最适条件下的产量因素为基础,建立了最适条件下每株穗数相对值、每穗粒数相对值、千粒重相对值与累积光合有效辐射的回归方程,构建了实际条件下的不同大麦品种每株穗数、每穗粒数和千粒重与这三者在最适条件下的潜在值和实际条件下的水肥丰缺因子等变量的函数关系.模型较为全面地考虑了大麦品种生长发育的内外因素,内因主要体现为品种遗传特性（潜在的每株穗数、潜在的每穗粒数、潜在的千粒重和灌浆期因子）,外因包括光合有效辐射和水肥丰缺因子.运用武汉、昆明、扬州3个地区不同品种、不同播期的田间试验资料对模型进行了测试和检验.结果表明,模型对大麦产量构成因子及理论产量的模拟效果较好,模拟值与观测值吻合度高,每株穗数、每穗粒数和千粒重相对误差（RE）绝对值的平均值分别为1.96%、1.88%和1.67%,对这三者及理论产量的模拟值和观测值进行y=x回归分析,相关系数（r）在0.9464～0.9987,相关性显著,说明模型具有较高的预测性和适用性.