Flag Leaf Emergence Research Articles

Genotype and fungicide effects on late-season root growth of winter wheat

The aim of this work was to investigate differences among genotypes in post-anthesis root growth and distribution of modern UK winter wheat cultivars, and the effects of fungicide applications. Post-anthesis root growth of up to six cultivars of winter wheat (Triticum aestivum L.), given either one or three applications of fungicide, was studied in field experiments during two seasons. Total root mass remained unchanged between GS63 (anthesis) and GS85, but root length increased significantly from 14.7 to 31.4 km m−2 in one season. Overall, there was no evidence for a decline in either root mass or length during grain filling. Root mass as a proportion of total plant mass was about 0.05 at GS85. There were significant differences among cultivars in root length and mass especially below 30 cm. Malacca had the smallest root length and Savannah the largest, and Shamrock had a significantly larger root system below 40 cm in both seasons. Fungicide applied at ear emergence had no significant effect on root mass in either season but increased root length (P<0.01) in the more disease-prone season. By maintaining a green canopy for longer, fungicide applied at flag leaf emergence may have resulted in delayed senescence of the root system and contributed to the post-anthesis maintenance of root mass and length.

Fungicide and cultivar affect post-anthesis patterns of nitrogen uptake, remobilization and utilization efficiency in wheat

Three successive field experiments (2000/01–2002/03) assessed the effect of wheat cultivar (Consort, Hereward and Shamrock) and fungicide (epoxiconazole and azoxystrobin) applied at and after flag leaf emergence on the nitrogen in the above-ground crop (Total N) and grain (Grain N), net nitrogen remobilization from non-grain tissues (Remobilized N), grain dry matter (Grain DM), and nitrogen utilization efficiency (NUtEg=Grain DM/Total N). Ordinary logistic curves were fitted to the accumulation of Grain N, Grain DM and Remobilized N against thermal time after anthesis and used to simultaneously derive fits for Total N and NUtEg.When disease was controlled, Consort achieved the greatest Grain DM, Total N, Grain N and NUtEg; in each case due mostly to longer durations, rather than quicker rates, of accumulation. Fungicide application increased final Grain DM, Grain N, Total N and Remobilized N, also mostly through effects on duration rather than rate of accumulation. Completely senesced leaf laminas retained less nitrogen when fungicide had been applied compared with leaf laminas previously infected severely with brown rust (Puccinia recondita) and Septoria tritici, or with just S. tritici. Late movement of nitrogen out of fungicide-treated laminas contributed to extended duration of both nitrogen remobilization and grain N filling, and meant that increases in NUtEg could occur without simultaneous reductions in grain N concentration.

Mechanical control of clover improves nitrogen supply and growth of wheat in winter wheat/white clover intercropping

The major objective for clover in a winter wheat/white clover intercropping system is to supply nitrogen (N) for the wheat. A field experiment was repeated in 2 years on a loamy sand in Denmark to investigate the possibilities for increasing N supply to the winter wheat by cutting and mulching the clover between the wheat rows. The clover was cut with a weed brusher on three different dates in each year. Intercropped wheat with unbrushed clover had a lower grain yield than wheat as a sole crop. Brushing increased wheat N uptake and wheat grain yields. Intercropping with two or three brushing dates gave higher wheat yields than wheat as the sole crop. The largest increases in grain N uptake, 21–25 kg N ha −1, were obtained for the brushings around wheat flag leaf emergence. The highest yield increases with a single brushing, 0.98–1.11 Mg DM ha −1, were obtained when brushing was performed during the stem elongation phase. The largest grain yields for treatments with two brushings were obtained with a first brushing at start of stem elongation and a second around flag leaf emergence. The first brushing probably provided N to increase the wheat leaf area index and thus the light interception, while the second brushing provided N to sustain the leaf area during grain filling and reduced clover biomass and therefore competition for water. Intercropping wheat and clover increased grain N concentrations by 0.11–0.39%-point compared with wheat as a sole crop. Intercropping may thus offer possibilities for improving the bread-making quality of organically grown wheat.

Relative effectiveness of various sources, methods, times and rates of copper fertilizers in improving grain yield of wheat on a Cu-deficient soil

A field experiment was conducted to determine the relative effectiveness of various sources, methods, times and rates of Cu fertilizers on grain yield, protein concentration in grain, concentration of Cu in grain and uptake of Cu in grain of wheat (Triticum aestivum L.), and residual concentration of DTPA-extractable Cu in soil on a Cu-deficient soil near Porcupine Plain in northeastern Saskatchewan. The experiment was conducted from 1999 to 2002 on the same site, but the results for 2002 were not presented because of very low grain yield due to drought in the growing season. The 25 treatments included soil application of four granular Cu fertilizers (Cu lignosulphonate, Cu sulphate, Cu oxysulphate I and Cu oxysulphate II) as soil-incorporated (at 0.5 and 2.0 kg Cu ha-1), seedrow-placed (at 0.25 and 1.0 kg Cu ha-1) and foliar application of four solution Cu fertilizers (Cu chelate-EDTA, Cu sequestered I, Cu sulphate/chelate and Cu sequestered II at 0.25 kg Cu ha-1) at the four-leaf and flag-leaf growth stages, plus a zero-Cu check. Soil was tilled only once to incorporate all designated Cu and blanket fertilizers into the soil a few days prior to seeding. Wheat plants in the zero-Cu treatment exhibited Cu deficiency in all years. For foliar application at the flag-leaf stage, grain yield increased with all four of the Cu fertilizers in 2000 and 2001, and in all but Cu sequestered II in 1999. Foliar application at the four-leaf growth stage of three Cu fertilizers (Cu chelate-EDTA, Cu sequestered I and Cu sulphate/chelate), soil incorporation of all Cu fertilizers at 2 kg Cu ha-1 and two Cu fertilizers (Cu lignosulphonate and Cu sulphate) at 0.5 kg Cu ha-1 rate, and seedrow placement of two Cu fertilizers (Cu lignosulphonate and Cu sulphate) at 1 kg Cu ha-1 increased grain yield of wheat only in 2001. There was no effect of Cu fertilization on protein concentration in grain. The increase in concentration and uptake of Cu in grain from Cu fertilization usually showed a trend similar to grain yield. There was some increase in residual DTPA-extractable Cu in the 0–60 cm soil in Cu lignosulphonate, Cu sulphate and Cu oxysulphate II soil incorporation treatments, particularly at the 2 kg Cu ha-1 rate. In summary, the results indicate that foliar application of Cu fertilizers at the flag-leaf growth stage can be used for immediate correction of Cu deficiency in wheat. Because Cu deficiency in crops often occurs in irregular patches within fields, foliar application may be the most practical and economical way to correct Cu deficiency during the growing season, as lower Cu rates can correct Cu deficiency. Key words: Application time, Cu source, foliar application, granular Cu, growth stage, placement method, rate of Cu, seedrow-placed Cu, soil incorporation

Mapping of QTLs for leaf developmental behavior in rice (Oryza sativa L.)

Leaf developmental behavior in rice (Oryza sativa L.) is one of the important agronomic characteristics, which not only determines vegetative growth but also influences grain yield. This study was conducted to identify quantitative trait loci (QTLs) for total number of leaves (TNL), days to the emergence of flag-leaf (DEF) and the leaf emergence rates (LER) on main stem, which mainly represent leaf developmental behavior, using recombinant inbred lines (RILs) derived from a cross between a japonica variety, Asominori and an indica variety, IR24, cultivated in 2001 and 2002. The transgressive segregations in both parental directions and continuous variations of all three tested traits were observed. Significant correlations among these traits were detected. A total of fourteen QTLs for leaf development behavior were detected with 289 RFLP markers. Six QTLs controlling TNL were mapped to chromosomes 3, 5, 6, 8, 9, 12, and accounted for 5.6∼15.7% of the total phenotypic variations, and three QTLs for DEF were mapped to chromosome 3, 6, 8 and accounted for 10.7∼35.4% of total phenotype variation and five QTLs for LER were mapped to chromosome 1(two QTLs), 2, 4, 9 and explained 6.2∼17.5% of phenotype variation. The identification of QTLs for leaf developmental behavior in rice may be useful for selection of ‘fast growing genotype’ before heading using maker-assisted selection.

Effects of triazole and strobilurin fungicide programmes, with and without late-season nitrogen fertiliser, on the baking quality of Malacca winter wheat

Field experiments were conducted over 3 years to study the effect of applying triazole and strobilurin fungicides on the bread-making quality of Malacca winter wheat. Averaged over all years the application of a fungicide programme increased yields, particularly when strobilurin fungicides were applied. Reductions in protein concentration, sulphur concentration, Hageberg falling number and loaf volumes also occurred as the amount of fungicide applied increased. However, there were no deleterious effects of fungicide application on sodium dodecyl sulphate (SDS) sedimentation volumes, N:S ratios or dough rheology. Effects of fungicide application on bread-making quality were not product specific. Therefore, it appears that new mechanisms to explain strobilurin effects on bread-making quality do not need to be invoked. Where reductions in protein concentration did occur they could be compensated for by a late-season application of nitrogen either as granular ammonium nitrate at flag leaf emergence or foliar urea at anthesis. These applications, however, sometimes increased the N:S ratio of the extracted flour and failed to improve loaf volume. Multiple regression analysis revealed that main effects of year, flour protein concentration and N:S ratio could explain 93% of the variance in loaf volume caused by season, fungicide and nitrogen treatments. However, an equally good fit was achieved by just including sulphur concentration with year.

Effects of the fungicides azoxystrobin and tebuconazole on Didymella exitialis, leaf senescence and grain yield in wheat

The effects of the fungicides azoxystrobin and tebuconazole on Didymella exitialis, and on senescence and yield of wheat, were studied in 10 field trials with low (eight trials), medium–low (one trial) or high (one trial) levels of visible disease over three growing seasons. Fungicides were applied at three alternative growth stages between flag leaf emergence and anthesis. Didymella exitialis was commonly isolated from symptomless seedling and adult leaves, with the frequency of isolation in each leaf position increasing until leaf senescence. Pycnidia of the Ascochtya anamorph of D. exitialis commonly formed on dead areas of seedling leaves, and perithecia on adult leaves, especially on senesced flag leaves. Azoxystrobin reduced the rate of isolation of D. exitialis from symptomless flag leaves and the area of senesced flag leaves with perithecia, while tebuconazole either had no effect or increased levels in symptomless and senesced flag leaves, depending on the trial. There were no consistent effects of crop growth stage of fungicide application on D. exitialis levels. Both fungicides maintained green leaf area for longer than in untreated plots—azoxystrobin on average for 4 days and tebuconazole for 2.3 days across all of the trials. There were also no consistent effects of application growth stage on green leaf area retention. Tebuconazole increased yield in nine of the trials by an average of 5.3% and azoxystrobin in all of the trials (average 6.1%). The best fungicide × timing combination in each trial resulted on average in a 9% yield increase (range 2–27%). This study suggests that D. exitialis is only a weak pathogen of wheat and has a minimal effect on flag leaf senescence.

Effects of triazole and strobilurin fungicide programmes, with and without late-season nitrogen fertiliser, on the baking quality of Malacca winter wheat

Field experiments were conducted over 3 years to study the effect of applying triazole and strobilurin fungicides on the bread-making quality of Malacca winter wheat. Averaged over all years the application of a fungicide programme increased yields, particularly when strobilurin fungicides were applied. Reductions in protein concentration, sulphur concentration, Hageberg falling number and loaf volumes also occurred as the amount of fungicide applied increased. However, there were no deleterious effects of fungicide application on sodium dodecyl sulphate (SDS) sedimentation volumes, N:S ratios or dough rheology. Effects of fungicide application on bread-making quality were not product specific. Therefore, it appears that new mechanisms to explain strobilurin effects on bread-making quality do not need to be invoked. Where reductions in protein concentration did occur they could be compensated for by a late-season application of nitrogen either as granular ammonium nitrate at flag leaf emergence or foliar urea at anthesis . These applications, however, sometimes increased the N:S ratio of the extracted flour and failed to improve loaf volume. Multiple regression analysis revealed that main effects of year, flour protein concentration and N:S ratio could explain 93% of the variance in loaf volume caused by season, fungicide and nitrogen treatments. However, an equally good fit was achieved by just including sulphur concentration with year.

Crop uptake of 15N labelled fertilizer in spring wheat affected by application time

Time of nitrogen fertilizer application on crop recovery was studied in a field experiment at Foulumgaard, Denmark, in 2001. A solution of 15N-ammonium-15N-nitrate was applied in bands parallel to a single row of spring wheat grown in frames of 30 cm×40 cm. The labelled fertilizer was applied on 16 dates with intervals of 4–5 days from tillering to the start of grain-filling. Crop 15N recovery increased by 0.47%-point day−1 when the time of fertilizer application was postponed from tillering until the second node stage (GS32). On the other hand, a decrease in crop 15N recovery of –0.19%-point day−1 was recorded from GS47 to maturity (GS85–87). The effect of the 16 application times on 15N recovery was described by two straight lines having intersection at the time of full expanded flag leaf and ear emergence halfway (GS55). It was concluded that leaf area expansion is important for crop N demand and 15N recovery.

A wheat canopy model for use in disease management decision support systems

SummaryA model is described which predicts those aspects of wheat canopy development and growth which are influential in determining the development of epidemics of foliar pathogens, the efficacy of foliar applied fungicides and the impact of disease on yield; specifically the emergence, expansion and senescence of upper culm leaves in relation to anthesis date. This focus on upper leaves allowed prediction of leaf emergence dates by reference to anthesis, rather than sowing. This avoided the step changes in flag leaf emergence date with temperature, reported with earlier models, without the additional complexity of a stochastic approach. The model is designed to be coupled to models of foliar disease, where the primary effect on yield is via reduction in green canopy area and hence interception of photosynthetically active radiation. Mechanisms were incorporated to allow observations of crop development during the growing season to update state variables and adjust parameters affecting future predictions. The model was calibrated using experimental data, and validated against independent observations of crop development on four wheat cultivars across seven contrasting sites in the UK. Anthesis date and upper culm leaf emergence were always predicted within one week of their observed dates.

The effects of adding picoxystrobin, azoxystrobin and nitrogen to a triazole programme on disease control, flag leaf senescence, yield and grain quality of winter wheat

The effect of adding strobilurins to a triazole (epoxiconazole) fungicide programme on the quality of a range of wheat cultivars was assessed in field experiments in three successive years. Strobilurin was applied at just flag leaf emergence (azoxystrobin) or at the start of stem extension (azoxystrobin or picoxystrobin) and again at flag leaf emergence or at flag leaf emergence and again at ear emergence (azoxystrobin). All strobilurin treatments reduced disease levels, delayed senescence of the flag leaf and consistently increased yields, thousand grain weight and specific weight. Reductions in Hagberg falling number were observed, even by fungicide applications at the start of stem extension, but effects were small compared to the variation among cultivars. Application of fungicide (triazole or strobilurin) before ear emergence increased the amount of blackpoint, but this was partly countered by applying azoxystrobin at ear emergence. The effect of fungicide on protein concentration differed over seasons and cultivar. Where they occurred, small reductions in protein concentration could be compensated for by extra application of nitrogen as foliar urea at anthesis. Foliar urea (40 kg N ha −1) applied at anthesis also improved Hagberg falling number and reduced blackpoint in one of the growing seasons. In one season, the effect of foliar urea at anthesis was compared with applications of granular fertiliser at flag leaf emergence. The granular treatment produced grain with more concentrated protein, while the later, foliar application produced higher specific weights.

Characterization of development and stem elongation of reed canary grass under northern conditions

Reed canary grass ( Phalaris arundinacea L.) is a potential crop for energy and paper production and might also be a useful forage crop under northern growing conditions. Knowledge of phenological traits is needed to adjust the production system according to various end-use requirements. This study aimed at describing variation in plant development, plant height and stem elongation among local and elite populations of reed canary grass. Field experiments were carried out between 1994 and 1997 in Finland. Six developmental stages were determined and plant height was measured at weekly intervals. Differences among groups of reed canary grass were statistically significant. Cultivars developed earlier than local groups, although they needed 3 days more for seed ripening. They were also taller than local populations at time of seed ripening. However, local groups were slightly taller than cultivars during early stages of development. At time of seed ripening some local populations were taller than elite material. Their places of origin could represent potential collection areas for populations showing increased plant height. Seed ripened approximately 95 days from the beginning of the growing season, when the temperature sum was 737 °C days of degree. At time of seed ripening 98% of maximum plant height was reached. A long latent period from reaching maximum plant height to harvest in the following spring is justified for non-food production because biomass continues to increase markedly after seed ripening. Stem elongation was fastest around flag leaf emergence and appearance of inflorescences. Knowledge of the fixed stage of plant development and plant height at each stage provides possibilities to adjust the production system and harvest time according to different end-uses: forage, non-food, and seed production. Information from this study will serve as a basis for further investigations and could be used in breeding reed canary grass.

Spring wheat leaf appearance and temperature: extending the paradigm?

Extensive research shows temperature to be the primary environmental factor controlling the phyllochron, or rate of leaf appearance, of wheat (Triticum aestivum L.). Experimental results suggest that soil temperature at crown depth, rather than air temperature above the canopy, would better predict wheat leaf appearance rates. To test this hypothesis, leaf appearance in spring wheat ('Nordic') was measured in a 2-year field experiment (Nunn clay loam soil; fine, smectitic, mesic Aridic, Argiustoll) with three planting dates and two soil temperature treatments. One temperature treatment (denoted +3C) consisted of heating the soil at crown depth to 3 degrees C above the ambient soil temperature (denoted +0C). Main stem cumulative leaf number was measured at least weekly until flag leaf emergence. Leaf appearance was essentially linear with both air and soil growing degree-days (GDD), although there was a stronger linear relationship with soil GDD in the +0C plants than in +3C plants. A weak positive relationship between planting date and the phyllochron was observed. Unexpectedly, we found that heating the soil did not increase the rate of leaf appearance, as the paradigm would predict. To explain these results, we propose extending the paradigm in two ways. First, three processes are involved in leaf appearance: (1) cell division at the shoot apex forms the primordium; (2) cell division in the intercalary meristem forms the cells that then (3) expand to produce the leaf. Cell division is predominantly controlled by temperature, but cell expansion is considerably more affected by factors other than temperature, explaining the influence of other factors on the phyllochron. Secondly, the vertical distribution of the two meristems and region of cell expansion occur over a significant distance, where temperature varies considerably, and temperature at a specific point (e.g. crown depth) does not account for the entire temperature regime under which leaves are developing.

Fungicidal control of Pyrenophora tritici-repentis in wheat

The use of fungicides to control yellow spot in wheat, caused by Pyrenophora tritici-repentis, in the northern wheat region of Australia, was examined in three field experiments. Field conditions were conducive to disease development. This was aided by spreading stubble infested with P. tritici-repentis and by regular spray irrigations, and moderate yellow spot epidemics resulted in all 3 years. Within the three experiments, 12 fungicides were evaluated for their ability to reduce the impact of yellow spot on grain yield. Single spray applications of the fungicides, some at varying rates, were made at 90% flag leaf emergence. Treated controls had 3–4 applications of propiconazole at 62 mL a.i./ha or tebuconazole at 72.5 mL a.i./ha throughout the season. Grain yield losses of up to 59% were recorded in the untreated plots. A reduction in grain size rather than a decrease in the number of grains was responsible for the yield losses. Yield losses were significantly lower following application of flusilazol, prochloraz, propiconazole and tebuconazole in cw. Hartog and Banks, in the first experiment. Application of azoxystrobin at 125 and 250 g a.i./ha, difenoconazole at 125 mL a.i./ha, epoxyconizole at 72 mL a.i./ha, propiconazole at 125 mL a.i./ha, tebuconazole at 125 mL a.i./ha or trifloxystrolin at 150g a.i./ha significantly reduced losses in the third experiment, sown with cv. Sunstate. This work has demonstrated that fungicidal control of yellow spot in wheat in the northern region can be a viable control option in years of high yield potential and high disease pressure.

Yield Reduction in Wheat in Relation to Leaf Disease From Yellow (tan) Spot and Septoria Nodorum Blotch

Yellow or tan spot (caused by Pyrenophora tritici-repentis) and septoria nodorum blotch (caused by Phaeosphaeria nodorum) occur together and are a constraint to wheat yields in Australia. Recently, higher crop yields and lower fungicide costs have made fungicides an attractive management tool against these diseases. Yield-loss under different rates of progress of yellow spot and septoria nodorum blotch was examined in four experiments over three years to define the relationship between disease severity and yield. In these experiments, differences in disease were first promoted by inoculations either with P. tritici-repentis-infected stubble or aqueous spore suspensions of P. nodorum. Disease progress was further manipulated with foliar application of fungicide. The pattern of disease development varied in each year under the influence of different rainfall patterns. The inoculation and fungicide treatments produced differences in disease levels after flag leaf emergence. The infection of yellow spot or septoria nodorum blotch caused similar losses in grain yield, ranging from 18% to 31%. The infection by either disease on the flag or penultimate leaf provided a good indication of yield-loss. Disease severity on flag leaves during the milk stage of the crop or an integration of disease as area under the disease progress curve on the flag leaves based on thermal time explained more than 80% variance in yield in a simple regression model. The data provided information towards the development of disease management strategies for the control of septoria nodorum blotch and yellow spot.

Inheritance of a Thermo-sensitivity Gene Controlling Flower Initiation in Sorghum

The existence of a sorghum (Sorghum bicolor Moench) thermo-sensitivity gene has been proposed to account for the acceleration of flower initiation when plants are exposed to a temperature lower than 20°C. Four varieties and their F1, F2, F3 and BC1F1 populations were evaluated for days to emergence of flag leaf (DEFL) under the field condition of a long daylength (> 13 h) and temperatures over 20°C for at least 40 days after sowing. The F1 hybrids, Hiromidori (Norin Ko-2) : 390 (early) × Regs.Hegari (late) and Natsuibuki (Norin Ko-9) : MS175 (late) × Daikoukaku (early), showed the same flowering response as Regs.Hegari and MS175 which show a delay in DEFL under temperatures over 20°C, suggesting the presence of a dominant thermo-sensitivity gene. In two different F2 populations, the segregation of early and late plants for DEFL fitted in with the expected ratio of 1 : 3, indicating that a single dominant gene was controlling the phenotype. The inheritance mode was confirmed in two different BC1F1 populations, where the expected ratio of 1 : 1 (early : late) was observed in the segregation of BC1F 1 of 390 × F1 and F1 × Daikoukaku. As expected, no segregation was observed in BC1F1 populations of F1 × Regs.Hegari and MS175 × F1. These results suggest that the sorghum thermo-sensitivity for flower initiation is controlled by a monogenic dominant gene of late over early, and the symbol TT is assigned to the genotype in which flower initiation is accelerated by the exposure to a temperature lower than 20°C.

Effect of leaf spotting diseases on grain yield and seed traits of wheat in southern Saskatchewan

Although leaf spotting diseases have been reported to have a negative effect on grain yield and seed characteristics of wheat (Triticum spp.), the magnitude of such effects on wheat grown on dryland in southern Saskatchewan is not known. A fungicide experiment was conducted at Swift Current (Brown soil) and Indian Head (Black soil) from 1997 to 1999 to determine the effect of leaf spotting diseases on yield and seed traits of wheat. Two fungicides, Folicur 3.6F and Bravo 500, were applied at different growth stages on three common wheat (Triticum aestivum L.) and three durum wheat (T. turgidum L. var durum) genotypes. Fungicide treatments generally did not affect yield, kernel weight, test weight or grain protein concentration, and these effects were relatively consistent among genotypes. Folicur applied at head emergence in 1997 and at flag leaf emergence and/or head emergence in 1998 increased yield at Indian Head (P &lt; 0.05). Fungicides applied at and before flag leaf emergence tended to increase kernel weight. Grain protein concentration increased only in treatments of Bravo applications at Indian Head in 1998. These results suggested that under the dryland environment and management in southern Saskatchewan leaf spotting diseases generally have a small effect on yield, kernel weight, test weight and protein concentration. Key words: Wheat, leaf spotting diseases, fungicide, yield

The effects of fungicides on rate and duration of grain filling in winter wheat in relation to maintenance of flag leaf green area

Three field experiments were conducted on sandy-loam soils comparing the effects of triazole, strobilurin and oxazolidinedione fungicides applied at flag leaf emergence and again at ear emergence to wheat between 1998 and 2000. Cultivars Hereward and Consort were included in all 3 years, Cockpit in 1999 and 2000 and Charger in 1999. Foliar disease, green area of the flag leaf, grain weight and moisture content were assessed weekly during grain filling and senescence. Grain yield, 1000 grain weight (TGW) and specific weights were measured at harvest maturity. Septoria tritici was the dominant disease in all cultivars except Cockpit, where Puccinia striiformis caused most damage. Consort was more affected than Hereward by S. tritici in all years. Effects of fungicides on disease control were usually reflected in green flag leaf area duration (GFLAD), with large gains in Consort and Cockpit. In 2000, however, fungicides increased GFLAD of Hereward and Consort by similar amounts. Apical grains had smaller water content than medially placed grains. Maximum water content was positively influenced by fungicides where significant disease was controlled before maximum grain weight had been attained. Grain weight in Hereward was less affected than other cultivars by fungicides in both positions. Grain filling rates varied between cultivar and ear position by inconsistent and small amounts, but large and significant gains from fungicide treatment were made in grain filling periods. These varied from 0·16 days per day GFLAD in Hereward to 0·69 days per day GFLAD in Consort in apical grains in 2000. Gains in GFLAD were associated with increased yield, TGW and specific weight, but these relationships varied with cultivar. Increases in GFLAD by fungicide in Hereward in 2000 occurred much later relative to grain filling and thus after the time of maximum grain water content, resulting in smaller gains in filling duration, yield, TGW and specific weight than that seen in Consort. There was no evidence of differing relationships between GFLAD and yield for the different fungicide groups used in these experiments.

Effect of barley-legume intercrop on disease frequency in an organic farming system

The effect of barley-legume intercrop in an organic farming system on disease incidence was investigated. The legumes&lt;br /&gt;were lupin, faba bean and pea. Diseases were detected on pea and barley. On pea, only ascochyta blight (Ascochyta pisi)&lt;br /&gt;was observed. When either pea variety was intercropped with barley, the level of ascochyta blight was reduced. Net&lt;br /&gt;blotch (Pyrenophora teres), brown rust (Puccinia recondita) and powdery mildew (Blumeria graminis f.sp. hordei) (in&lt;br /&gt;order of incidence) were monitored on barley between flag leaf emergence and heading. The levels of all three diseases&lt;br /&gt;were reduced in every intercrop treatment compared to the barley monocrop. However, this reduction was only statistically&lt;br /&gt;significant in the pea treatments for net blotch.

Studies on the Cultivation of Spring Wheat Seeded in Early Winter in Central Hokkaido.

Spring wheat was sown in early winter, and the suitable amount and application timing of nitrogen (N) fertilizer to obtain both high yield and high protein content in the grains were examined. N fertilizer of 0-16 g N m-2 in total was applied in a lump just after snow melting, or in divided doses once just after snow melting (4-13 g N m-2) and once at flag-leaf emergence stage (3-6 g N m-2). In the plants supplied with 10g N m-2 in total, which is optimum for spring seeding, the plants seeded in early winter showed nearly the same N absorption as those seeded in spring, but higher biomass and higher harvest index resulting in higher yield than those seeded in spring. The increase of N supply for the plants seeded in early winter increased N absorption, biomass, harvest index, yield and protein content. In the plants supplied with N fertilizer in divided doses, the yield was lower but the protein content was higher than in those supplied with the same amount of N in a lump. However, we considered that the application of 7-10 g N m-2 just after snow melting and 3-6 g N m-2 at the flag-leaf emergence stage is better to increase the yield protecting the lodging and increasing the protein content that are desirable for bread and soy-sauce making.