Significant Reduction In Grain Yield Research Articles

Effect of High Temperature During Heading and Early Filling on Grain Yield and Physiological Characteristics in Indica Rice

To disclose the physiological mechanism of heat tolerance in rice ( Oryza sativa L.), this article investigated the pollen development, yield components, and some physiological parameters of indica rice genotypes under high temperature (HT) treatment during heading and early filling stages. Two heat-sensitive genotypes, Shuanggui 1 and T219, and 2 heat-tolerant genotypes, Huanghuazhan and T226, were used in pot experiments with HT treatment (mean temperature during the day above 33ºC) and natural temperature (control) treatments from 0 to 10 d and 10 to 20 d after heading. Compared with the control, the HT treatment significantly reduced the rates of pollen and spikelet fertility in the heat-sensitive genotypes, but had no significant effects on the heat-tolerant genotypes. Seed-setting rate decreased significantly in the heat-sensitive genotypes under HT, leading to a significant reduction in grain yield. Moreover, the reductions of yield of heat-sensitive genotypes were greater in the HT treatment at heading stage (0–10 d after heading) than in the HT treatment at early grain-filling stage (11–20 d after heading). However, the heat-tolerant genotypes were in minor influence under the HT treatment. The activities of enzymes from rice leaves, which were involved in antioxidant system, significantly increased in the heat-tolerant genotypes when treated with HT, whereas they were maintained at relative high levels in the control. The ATPase activity in grains was significantly reduced in the heat-sensitive genotypes, but slightly influenced in the heat-tolerant genotypes. The high temperature increased leaf temperature and malondialdehyde content in leaves, and reduced root activity and photosynthetic rate of flag leaf in all genotypes. However, variation range was much less in heat-tolerant genotypes than in heat-sensitive genotypes. The results suggest that the relative high yield in heat-tolerant genotypes under high-temperature stress is associated with low leaf temperature, high root activity, and the high levels of ATPase activity in grains, photosynthetic rate, and activities of antioxidant enzymes in leaves.

Effect of heat-sterilization and EM (effective microorganisms) application on wheat (Triticum aestivumL.) grown in organic-amended sandy loam soil

Effective microorganisms (EM), a culture of coexisting beneficial microorganisms predominantly consisting of species of photosynthetic and lactic acid bacteria, yeast and actinomycetes, has been developed by Japanese Scientists. In the present study effect of soil sterilization on performance of a commercial EM biofertilizer (EM Bioab), in improving crop growth and yield in wheat ( Triticum aestivum L.) was studied in two types of organic amendments viz. farmyard manure (FYM) and Trifolium alexandrinum L. green manure (GM). Plant vegetative and reproductive growth and grain yield was better in heat-sterilized than in nonsterilized soil. EM application resulted an insignificant increase in root and shoot dry biomass and grain yield in heat sterilized FYM amended soil while in heat sterilized GM amendment it caused a significant reduction in grain yield. In nonsterilized soils EM application suppressed root and shoot growth at vegetative stage and had insignificant effect at maturity. Effect was more pronou...

Planting Date and Nitrogen Effects on Grain Yield and Protein Content of Spring Wheat

ABSTRACTHigh grain yield with adequate protein concentration is an important goal for spring wheat (Triticum aestivum L.) production. A field experiment conducted at two sites representing sandy loam and clay loam soils in Ottawa during 2003 and 2004 examined the effects of planting date and nitrogen (N) management on grain yield and grain protein concentration (GPC) in spring wheat. Cultivar AC Brio was planted at three dates at about 10 d intervals starting from the last week of April. Five N treatments were 0, 60, and 100 kg N ha−1 applied as preplant, 60+40 (preplant + topdress at boot stage), and 60 + 40 kg N ha−1 (preplant + foliar spray at boot stage). Both planting date and N had significant effects on grain yield and GPC. When planting was delayed beyond mid‐May, grain yield was reduced by 15 to 45% in three out of four site‐years. However, GPC increased by 6 to 17% in all late planting dates than the early plantings. Grain yields were increased with N application, but there was no benefit due to split N application as topdress or foliar spray than a single application at 100 kg N ha−1 Regardless of application method, GPC was greater with 100 kg N ha−1 than with 0 or 60 kg ha−1, and GPC was more responsive to applied N in a sandy loam soil than in the clay loam soil. Results of this study suggest that it is likely to achieve the target GPC in spring wheat without a significant reduction in grain yield if wheat is planted before the middle of May, especially in clay loam soil.

Effects of Alternate Furrow Irrigation with Supplemental Every-Furrow Irrigation at Different Growth Stages on the Yield of Maize (Zea mays L.)

The effect of water stress caused by alternate furrow irrigation (AFI) on the yield of maize may be alleviated by applying every-furrow irrigation (EFI) at stress sensitive growth stages. This research was conducted in two different areas with deep and shallow water tables to examine the amount of water used, yield, yield components and water use-efficiency of maize under AFI at 7-day intervals supplemented with EFI at different stages. AFI resulted in significant reduction in grain yield and in both Bajgah and the Kooshkak areas with deep and shallow water tables, respectively. This occurred due to probable water stress and reduction in 1000-grain weight. However, under AFI supplemented with EFI once or twice at the tasseling or silking stage grain yields were statistically equal to those obtained in EFI although the amount of water used was about 30% smaller in both Bajgah (deep water table) and Kooshkak areas (shallow water table). In both areas the water-use efficiency for grain yield under these irrigation treatments was 1.04 and 0.97 kg grain per m3 of water, respectively.

Azoxystrobin Rate and Timing Effects on Rice Sheath Blight Incidence and Severity and Rice Grain and Milling Yields.

Lack of sheath blight resistant varieties requires rice (Oryza sativa) farmers to use fungicides to avoid significant reductions in grain yield and milling yield. Studies were conducted to determine the best rate and rice growth stage for a single application of azoxystrobin, a fungicide recently labeled for this use, to effectively control sheath blight. Azoxystrobin was applied foliarly to inoculated field plots in 2000 to 2002 using rates of 0.22, 0.17, and 0.11 kg a.i. ha -1 at 7 days after panicle differentiation (PD+7), boot (B), and heading (H) growth stages and at 0.17 kg a.i. ha-1 at 5, 10, and 15 days after heading. Sheath blight severity (measured on a 0 to 9 scale) and incidence (percent tillers infected) were assessed 1 to 2 weeks before harvest. A fungicide application made between PD+7 and H significantly reduced sheath blight severity, which resulted in significantly higher yield and head rice milling yield compared with inoculated unsprayed plots. There were no significant effects of fungicide rate at the PD+7, B, and H growth stages. Fungicide-treated plots had yield and milling yield similar to the very lightly diseased, uninoculated check plots included for comparison. With fungicide application made postheading, rice had higher disease severity, resulting in lower yields and milling yield compared with rice receiving earlier applications.

Yield Loss Potential of Phaeosphaeria Leaf Spot of Maize Caused by Phaeosphaeria maydis in the United States.

The ability of Phaeosphaeria leaf spot (PLS) to reduce yields of maize was evaluated over two winter growing seasons in southern Florida. Nine commercial maize hybrids, varying in reaction to PLS, were planted in a split-plot design with hybrids as whole plots and inoculated versus uninoculated treatments as subplots. The most susceptible hybrid, Pioneer brand 3489, sustained a significant reduction in grain yield (11 to 13%) and 400-kernel weight (5 to 10%) in the trials. Regression analyses indicated that grain yields and 400-kernel weights were reduced 0.23 and 0.16%, respectively, for each percent increase in PLS severity at the mid-dent stage. Because most U.S. maize hybrids are resistant, and PLS develops late in the grain-filling period, its potential to cause substantial losses in the United States appears limited at this time.

Developing stand establishment of rice ( O m in sativa) flood-prone lowland situations-an exploratory study under on-station and on-farm location

A field study was conducted both under on-station location at the Central Rice Research Institute, Cuttack, in 1996 and successively under on-farm location at farmers field in 1997. The locations were identified under rainfed lowland ecologies, characterized with aberrant micro-environment constraining the normal yield potential of rice (Oryza sativa L.). Generally, the ecology experiences a waterlogged situation during entire crop-growing period. Water depth fluctuated between 0 and 50 cm; thereby the situation could be ldentified - a2 intermediate deep water situation. The cropping geometry constitutlng 4 rows *- continuous seeding alternated with 1 row skip (no seeding) at 15 cm x 20 cm spacing arrangement under 4 : 1 stand situation achieved the maximum grain yield, 2.46 and 2.33 tonnesfha in 1996 and 1997, respectively, comparable with that devoid of any skip within the entire stand. Nonetheless it also ldentified a semi-dwarf plant type CR 260-77, superior to other plant types assessed under the identical situation. Therefore, the study has a great applied slgnificance ensuring considerable relief in operational expenditure over that incurred traditionally following conventional method of stand establishment; importantly, no significant reduction in grain yield was realized herein compared with conventional method.

Barnyardgrass (Echinochloa crus-galli) Control in Water-Seeded Rice (Oryza sativa) with Cyhalofop-butyl1

Abstract: Field experiments were conducted in 1996 and 1997 to evaluate barnyardgrass (Echinochloa crus-galli) control, rice (Oryza sativa) yield, and grain quality with cyhalofop-butyl applied early postemergence (EPOST) or late postemergence (LPOST) in drained or flooded plots at rates of 0.15 to 0.4 kg ai/ha and standard treatments of molinate or propanil. Control with cyhalofop-butyl at 0.15 and 0.2 kg/ha applied in drained plots was greater compared to propanil and generally increased when treatments were applied EPOST to plots reflooded 2 d after treatment. Barnyardgrass control with cyhalofop-butyl at 0.15 and 0.2 kg/ha applied in flooded plots was similar to or better than the control obtained with molinate. Rice yields generally reflected differences in barnyardgrass control and were greatest with cyhalofop-butyl applied EPOST in drained plots. The 0.4 kg/ha rate of cyhalofop-butyl resulted in rice foliar injury and significant reductions in grain yield. Grain qualitative characteristics (total m...

Feeding by redlegged earth mite (Halotydeus destructor) on seedlings influences subsequent plant performance of different pulse crops

Damage caused by redlegged earth mite to seedlings of 6 pulse species and its effect on subsequent plant growth and grain yield were examined under controlled and field conditions. Seedling damage caused by redlegged earth mite affected subsequent plant growth and reduced seed yield, but the responses varied among different pulse species. Field pea and yellow lupin were the most susceptible at seedling stage and flowering, but only yellow lupin suffered significant reduction in grain yield (30%) in the field. Narrow-leafed lupin suffered moderate damage, faba bean slight damage, while chickpea and lentil suffered little or no damage. The practical implications of these results are discussed.

Adverse Effects of Soybeans on Subsequent Wheat and Triticale Crops

ABSTRACT Except where a good legume sod is plowed under or a heavy application of manure is used, N fertilizer applications are generally necessary for producing high yields from grain crops. A soybean (Glycine max (L.) Merr)-wheat (Triticum aestivum L.) rotation appears to be a logical opportunity to use legume N as a sustainable grain production resource. An experiment conducted to compare N from soybeans with fertilizer N resulted in a 46% reduction in wheat yield following soybeans where wheat was not fertilized with N. Subsequent research showed that when soybeans were allowed to grow to bloom stage or later preceding a wheat or triticale (× Triticosecale Wittmack) crop a significant reduction in grain yield resulted from the previous soybean crop. When the grain crop was fertilized with 80 lbs/acre of N this response did not occur. The experimental results suggest that soybean root exudates are responsible for the decrease in wheat and triticale growth and yield.

Methane emissions from rice fields amended with biogas slurry and farm yard manure

In an experiment on methane-emission measurements from rice fields amended with urea, biogas spent slurry (BSS) + urea, and farm yard manure (FYM) + urea, three distinctive peaks in the methane emissions were observed at 15, 46, and 69 days after transplanting (DAT) due to the availability of readily degradable C-sources. In all cases, the highest peak was at 69 DAT. The steepest Eh drop to a minimum of -320 mV was reached within two weeks of submergence. pH ranged between 7.5 and 8.5. The combined fertilization (FYM + urea) plot showed the maximum emission rate of 4.86 mg m−2 h−1 with a total load of 49.44 kg ha−1 and was 2.3 times higher than (BSS + urea)-treated plot (22.08 kg ha−1). Grain yields in urea, (BSS + urea) and (FYM + urea) plots were 3.34, 2.94, and 2.85 t ha−1 respectively, suggesting that biogas slurry is a preferred source over FYM causing lesser environmental pollution without any significant reduction in grain yield.

Effect of powdery mildew (Erysiphe graminis f.sp. hordei) on photosynthesis and grain yield of partially resistant genotypes of spring barley (Hordeum vulgare L.)

AbstractThe effect of powdery mildew on the photosynthesis and grain yield of partially resistant spring barley was investigated. The effect of powdery mildew on the CO2 exchange rate (CER) of inoculated and non‐inoculated leaves was measured in several glasshouse experiments. Grain yield reduction by powdery mildew was determined in three field experiments. The CER of the inoculated leaves was reduced by infection but that of the non‐inoculated leaves was not significantly different from that of the corresponding leaves of the control plants. The reduction in CER of the different genotypes was closely related to the percentage leaf area infected with powdery mildew.The correlation between degree of mildew infection and grain yield reduction varied between r = 0.84 (significant at P = 0.01) and r = 0.41 (not significant). Differences in greenness of the crop were correlated better with grain yield reduction (r = 0.66, P = 0.01) than powdery‐mildew infection itself. Low percentages of powdery‐mildew infection did not lead to significant reduction in grain yield. Partial resistance to powdery mildew could thus be a valuable attribute of future barley varieties.

Effect of cultivar on response of wheat and barley to chloride fertilization

Crop cultivar has been shown to affect the frequency and magnitude of yield responses to chloride (Cl−) fertilizer applications. Information regarding the Cl− responsiveness of cereal cultivars commonly grown in western Canada is limited, however. Field experiments were conducted in Manitoba in 1990 and 1991 to determine the effect of Cl− fertilization on plant nutrient status, grain yield and grain quality of Katepwa, Roblin, Biggar and Marshall wheat (Triticum aestivum L.) and of Bedford, Brier, Argyle and Heartland barley (Hordeum vulgare L.). Chloride fertilization increased the concentration of Cl− in plant tissue of all cultivars. Increased grain yield and improved grain quality due to Cl− fertilization occurred more frequently in wheat than in barley; however, cultivars within a species differed in Cl− responsiveness. The application of 50 kg Cl− ha−1 significantly increased grain yield for Heartland barley by 905 kg ha−1 in one of four experiments, for Roblin wheat by 492 kg ha−1 in one of four experiments, for Biggar wheat by an average 333 kg ha−1 in two of four experiments and for Marshall wheat by an average 363 kg ha−1 in two of four experiments. However, the application of 50 kg Cl− ha−1 resulted in significant reduction in grain yield for Bedford in one of four experiments and for Marshall in one of four experiments. Yield responses to Cl− were not related to soil Cl− content or Cl− concentration in plant tissue. Key words: Chloride, fertilizers, wheat, barley, cultivars, yield

Management Effects on Yield and Yield Components of Late‐Planted Wheat

Intensive cereal management can increase the yield and performance of winter wheat (Triticum aestivum L. emend. Thell.), but wet soils often delay planting along the Gulf Coast. Field experiments were conducted at four locations in 1991 and two locations in 1992 to evaluate the effects of two seeding rates (84 or 168 kg ha−1) and two. topdress N rates (90 or 90 + 45 kg ha−1) for an early and late‐maturing cultivar planted at a recommended date or 35 d later. Main effects were generally more significant than interactions except for those involving environment (year‐location). Late planting resulted in significant reduction in grain yield even though more spikes per square meter were produced. Wheat kernels from the recommended planting date were heavier and each spike contained more kernels, which resulted in higher grain yield. Additional N significantly increased yield when the crop was planted at the recommended date by increasing kernels per spike and spikes per square meter, but did not increase yield of the late‐planted crop. Grain yield was not affected by seeding rate for the early planted wheat. Seeding rate effects were influenced by the environment for late planting; however, there was evidence that the higher seeding rate increased yield of the late‐planted crop. Delayed planting reduced yields due to a decrease in kernel weight and kernel number per spike, but the magnitude of yield loss was reduced by using an early‐maturing cultivar and a higher seeding rate.

Selection for Early Flowering Results in Simultaneous Selection for Reduced Nuclear DNA Content in Maize

AbstractSeveral studies have indicated a possible link between genome size and earliness in maize. In this study, an original maize population, South African photo‐period insensitive maize composite II (C0) and several selected generations were analyzed for days to flowering, plant height, ear height, and yield. The selection criterion was earliness. Over six cycles of selection a 14‐day decrease in days to flowering was obtained with no significant reduction in grain yield. In the initial population (C0) and the most advanced selection (C6) 101 plants were analyzed for nuclear DNA content. A significant decrease in the mean nuclear DNA content of the C0 population (102 AU) was observed with respect to the C0 population (105 AU). This reduction was the result of a decrease in frequency of plants in the C6 population with large genome sizes. Therefore it was concluded that selection for earliness resulted in selection against plants with large genome sizes. Hence, the nucleotype of a maize plant can be modified by selection such as early flowering time.

Influence of head blast infection on seed germination and yield components of finger millet(Eleusine coracanaL. Gaertn)

Abstract Head blast caused a significant reduction in grain yield, a result of reduction in spikelet length, grain weight and number of grains per head. The correlations between field infection and yield, and between field infection and percentage seed germination, were both statistically non‐significant.

Field Corn Response to Acid Rain‐Drought Stress Interaction

AbstractTwo studies were conducted in 1988 to examine the effects of simulated acid rain in combination with various levels of drought stress on the grain yield of field grown corn (Zea mays L., ‘B73 × Mo17’ and ‘FS854’). In both studies corn was treated with twice weekly applications of simulated rainfall of pH 5.6 or 3.0 at amounts that totaled 100% (30 cm), 50% (15 cm), and 25% (7.5 cm) of the seasonal average for Champaign‐Urbana, IL. In addition to those treatments, in one of the studies the plants were subjected to daily wetting with the appropriate simulated rain from tassel emergence through pollination and fertilization. In both studies, reduced moisture levels resulted in significant reduction in grain yield but simulated rain of pH 3.0 had no effect on yield at any of the moisture levels studied. For both cultivars in both studies, reducing rainfall application from seasonal average to one‐half of the normal decreased yields by approximately 30%. When only one‐fourth of the seasonal rainfall amount was applied, yields were decreased between 40 and 55% compared to the yield for plants receiving the seasonal average rainfall. Results from these studies suggest that application of simulated acid rain of pH 3.0 has little or no negative effect on grain yield of the corn cultivars evaluated, even when relatively severe moisture stress was present, and when plants were subjected to daily wetting from tassel emergence through fertilization.

STUDIES OF RECOVERY FROM ARTIFICIALLY INDUCED LODGING IN SEVERAL SIX-ROW BARLEY CULTIVARS

Artificial lodging treatments were applied to several six-row barley cultivars (Hordeum vulgare L.) in 1985 and 1986 in field plots at the University of Alberta Research Station, Edmonton, to determine the effects of lodging from the milk stage to maturity. For all cultivars the largest significant reduction in grain yield was obtained from lodging induced at the milk stage (average 21% yield reduction), with later lodging resulting in relatively less yield reduction (4% at preharvest). Significant effects of lodging treatments on thousand-kernel weight and hectoliter weight followed the same pattern. Incidence of disease (mainly scald) was significantly increased by the induction of lodging in one of the two years. Final lodging scores at maturity were significantly higher the later that lodging was induced, associated with generally reduced ability to recover from lodging. In 1 year of testing, the semidwarf cultivar Duke was found to be superior to the semidwarf cultivar Samson for lodging resistance, for ability to recover from lodging applied at all stages, for grain yield, thousand-kernel weight, and for disease resistance. In both years the cultivar Johnston had very poor lodging resistance and almost no ability to recover from lodging, whereas Leduc and Klondike were intermediate for these traits. A simple artificial lodging test is proposed for obtaining improved data on the lodging resistance and lodging recoverability of new cultivars.Key words: Lodging recovery, cultivar evaluation, disease level, grade reduction, growth stages, yield

Effects of air filtration at small SO 2 and NO 2 concentrations on the yield of barley

Two cultivars of Igri and Gerbel winter barley Horteum vulgare L. were grown in open-top chambers in filtered and unfiltered air at a site with approximately 10 nl litree −1 SO 2 and 12 nl litre −1 NO 2 (seasonal mean). The experiment ran for three consecutive seasons 1982–1983, 1983–1984, 1984–1985, and significant effects of filtration were observed for each crop. In years 1982–1983 and 1984–1985, the crops in unfiltered air yielded larger grain dry matter, 9% in 1982–1983, and 8% in 1984–1985. For both crops, the differences were statistically significant at the 5% level. Differences were also observed for the remaining above-ground dry matter, and these were consistent in direction in each year but statistically significant only in 1984–1985. In both growing seasons (1982–1983 and 1984–1985), there were no major pest infestations and no long-term water stress or photochemical ozone episodes. In the remaining experiment (1983–1984) similar air concentrations of SO 2 and NO 2 produced effects of the opposite sign to those observed in 1982–1983 and 1984–1985. Significant reductions in grain yield (13%) were obtained in unfiltered air. The only major environmental difference for the 1983–1984 crop was a notable dry period in May and June 1984 with marked water stress in the crop, requiring irrigation. These results suggest that the relationship between yield and pollutant concentration may be confounded by additional stresses, many of which are a common component of the growing season for major crops.

Yield losses in resistant and susceptible varieties of rice in Nigeria due toChilo zacconiusand other stem borers

Abstract In a screenhouse experiment, rice plants of eight varieties were artificially infested at the early tillering and booting stages with African striped borer, Chilo zacconius Bleszynski, one Iarva per tiller. In the mature plants there was found to be a reduction in height and an increase in tiller number among susceptible varieties and, to a lesser extent, among the resistant varieties. Additional tillers gave rise to panicles which had not matured by the time the uninfested tillers were harvested; as a result there was a significant reduction in grain yield and grain weight among the susceptible varieties. In a separate field trial some plots were protected with 3% carbofuran at 13 kg/ha. Infestation by the stem borers Maliarpha separatella Ragonot, C. zacconius and Sesamia spp. was consistently higher in protected susceptible varieties than in unprotected and protected resistant varieties. Yields were about twice as high in protected as in unprotected plots of susceptible varieties, but there wa...