Significant Reduction In Grain Yield Research Articles

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...

Melhoramento do trigo: VII. Herdabilidade e coeficientes de correlação entre caracteres agronômicos, em populações híbridas de trigo, em diferentes solos paulistas

Os cultivares C-3 e Siete Cerros foram cruzados e os cultivares pais, F1, F2 e retrocruzamentos para ambos os pais foram avaliados em um ensaio em delineamento de blocos ao acaso, com quatro repetições, em condição de vaso com solo de alta fertilidade. O experimento foi conduzido em telado localizado no Centro Experimental de Campinas. Correlações genéticas entre produção de grãos por planta e sete caracteres agronômicos, assim como valores do herdabilidade no sentido amplo e restrito para todos os caracteres, foram estimados, além de correlações fenotípicas e ambientes entre a produção de grãos e os sete caracteres. As correlações genéticas mostraram que produção de grãos foi associada positivamente com altura de planta (r = 0,377), número de espigas por planta (r = 0,919), número de espiguetas por espiga (r = 0,219) e peso de cem grãos (r = 0,814). Seleções para maior número de grãos por espiga e espigueta poderiam influir negativamente na produção de grãos. Os cultivares pais e as populações F1 e F2 foram também avaliados em vasos contendo solos de cinco diferentes locais das regiões tritícolas paulistas e referentes às profundidades de amostragem 0-30cm e 30-60cm. Como tratamento adicional, foi incluído um solo de várzea, da camada 0-30cm do Centro Experimental de Campinas. Nos solos ácidos com altos teores de alumínio, as plantas sensíveis a essas condições apresentaram acentuada redução na produção de grãos; altura das plantas; número de espigas por planta e de espiguetas por espiga; comprimento das espigas, e fertilidade das flores, evidenciada pela significativa diminuição do número de grãos por espiga e por espigueta. Quando foi utilizado o solo da camada 0-30cm de profundidade da Fazenda Canadá, em Assis, apresentando pH superior a 6,0, alta disponibilidade de bases, média de fósforo e ausência de Al3+, as correlações genéticas mostraram associações positivas entre produção de grãos com altura das plantas (r = 0,224), número de espigas per planta (r = 0,500) e de espiguetas por espiga (r = 0,856), e peso de cem grãos (r > 1,00), e negativas com número de grãos por espiga (r = 0,068) e por espigueta (r = -0,873) e com comprimento da espiga (r = 0,463). Para o solo da camada 0-30cm de profundidade de Itararé, apresentando pH = 4,6, baixa concentração de bases, reduzida disponibilidade de fósforo e altos teores de Al3+ as correlações genéticas mostraram que as plantas mais produtivas e, conseqüentemente, mais tolerantes ao Al3+, estavam associadas com plantas altas (r = 0,710), maior número de espigas por planta (r > 1,00); maior número de grãos por espiga e espigueta (r = 0,727 e r = 0,753 respectivamente), grãos mais pesados (r = 0,785) e provenientes de espigas mais longas (r = 0,733). Para o desenvolvimento de plantas baixas, tolerantes às condições de solo ácido e com alto potencial de produção, haveria necessidade de grandes populações F2 para assegurar o aparecimento de recombinantes desejáveis.

Barley growth in coal liquid and diesel liquid fuels from coal and oil: A comparison of potential toxic effects on Barley

The production of new liquid fuels from coal creates the potential for environmental releases of new products and waste materials via spills or leaching of material from waste storage areas. The chemical composition of these products and waste materials suggests possible toxic effects upon exposed plants and animals. In this study, barley was grown in field lysimeters containing three concentrations (0.07, 0.74, 7.421 m−2 equivalent to 80, 800, and 8000 gal/acre, respectively) of a sample product blend of Solvent Refined Coal (SRC) heavy and middle distillates. Three methods of soil amendment simulated possible spill clean-up alternatives: adding the coal liquid as a surface layer, as a subsurface layer covered by uncontaminated soil, or intermixed with the top 1 dm of soil. To permit comparison of the coal liquid with familiar commercial material, the study protocol was followed simultaneously in lysimeters amended with # 2 diesel fuel. Statistically significant reductions in grain yield were observed for both the SRC and diesel materials for all methods of soil amendment at concentrations equivalent to 0.74 and 7.421 m−2, and for the SRC material only when mixed with soil at a concentration equivalent to 0.071 m−2. Where differences between fuel types were observed, the coal liquid was consistently more toxic.

Leaf Removal to Simulate Grazing of Corn by Lambs1

AbstractMost of the corn grown in the United States is harvested for grain or silage. Only a small percent is grazed. In corn growing areas where lambs are available, corn might provide some limited grazing without affecting yield. Field experiments (Aridic calciustoll soils) were conducted during 1978–1980 to simulate the grazing of corn by lambs. The lower 2, 4, 6, 8, and 10 leaves were removed at 90 to 100% silking and at 2‐week intervals for 6 weeks thereafter. Removing the bottom 10 leaves either at 90 to 100% silking or 2 weeks afterward caused a significant reduction in grain yield, 1,000‐kernel weight and number of kernels per ha. No significant yield losses were measured with less severe defoliation or defoliation at later stages of maturity.The data showed that 890 kgha of oven‐dried forage could be removed during the first 4 weeks after 90 to 100% silking or 1,284 kg/ha after 4 weeks from silking without significant yield reductions. At the later stages, protein and P content are below the level required for proper lamb growth.These studies indicate that yield losses can be minimized by restricting leaf removal during and after pollination. However, before this can become an acceptable practice, additional investigations are needed to study the effects that lambs might have on ears, stalks, and soil compaction.

EFFECT OF CEREAL APHID INFESTATION ON GRAIN YIELD AND PERCENTAGE PROTEIN OF BARLEY, WHEAT, AND OATS IN SOUTHWESTERN QUEBEC

AbstractNatural infestations of cereal aphids caused significant reductions in grain yield in field plots of early and late cultivars of barley, wheat, and oats in southwestern Quebec. Severely reduced grain yields resulted when caged plants of wheat and late cultivars of barley and oats were artificially infested, but early cultivars of barley and oats were less affected. The percentage protein of grain was significantly reduced in all crops, but wheat and late oats were most affected.

Über die Wirkung von Pydanon auf Halmlänge und Ertrag von Winterweizen und Winterroggen

Influence of Pydanon upon Stalk Length and Grain Yield of Winter Rye and Winter Wheat..In pot experiments with three varieties of winter rye a considerable reduction of stalk length was obtained by the growth regulator Pydanon without a significant reduction of grain yield. The necessary amount of active substance however was rather high and the period of time for optimal application was limited. Winter wheat did not respond to Pydanon.

Effect of Fertility Treatments on the Growth, Chemical Composition and Yield of No‐Tillage Corn on Orchardgrass Sod1

AbstractMany data are available on the relative efficiencies of various fertility treatments for corn (Zea mays L.) when grown by the conventional methods of clean tillage. Few data are available, however, on the relative efficiencies of sources and rates of N, P, and K on the growth, chemical composition, and yield of corn grown with the notillage system.An experiment was conducted at Blacksburg, Virginia, on Groseclose silt loam (Typic, Hapludults; clayey, mixed, mesic) to determine the effects of 168 and 280 kg N/ha, 0 and 100 kg P/ha from partially and fully acidulated rock phosphate, 25 kg P/ha from fully acidulated rock phosphate, and 140 kg K/ha from KCI and K2~SO4 on the growth, chemical composition of leaves and yield of notillage corn on a chemically killed orchardgrass sod.Growth was significantly slower with the higher rate of N, but significantly increased with increased rates of applied P. Plant growth rate was unaffected by sources of K. Leaf concentrations of N and K were unaffected by rates of N and sources of K, respectively, but the P and K concentrations were significantly increased with the higher P rates. Leaf Mn concentration was higher with the higher rate of N than with the lower rate. The Ca, Mg and Mo concentrations in the leaf increased with P fertilization, but the Zn concentration decreased with P fertilization.Corn yields were significantly higher with concentrated superphosphate than with partially acidulated rock phosphate applied at the same rate of P. The higher rate of N resulted in a significant reduction in grain yield of 552 kg/ha. There was no response to S in the K2SO4.