scholarly journals Responses of Local Wheat Varieties to Greenbug Schizaphus graminum and Bird-Cherry Oat Aphid Rhopalosiphum padi Infestation

2021 ◽  
Vol 34 (1) ◽  
pp. 124-138
Author(s):  
Haider D. Al-Hussine ◽  
Aqeel A. Alyousuf
Keyword(s):  
Population Density ◽  
Rhopalosiphum Padi ◽  
Dry Weight ◽  
Growing Season ◽  
Abu Ghraib ◽  
Laboratory Studies ◽  
Population Densities ◽  
Wheat Varieties ◽  
Effective Role ◽  
Density Rate

Field and laboratory studies were conducted to assess the sensitivity of 12 varieties of local wheat varieties (IPA-95, IPA-99, Abu-Ghreib, Babel-113, Bhooth-10, Bhooth-22, and Bhooth-158, Baraka, Tammuz, Fatih, Latifia and Rasheed) against infestation by Greenbug Shizaphis graminum and Bird-Cherry Oat Aphid Rhopalosihum padi in the province of Basrah. The field trial was carried out in Al-Nashwa district, county of Shatt Al-Arab, during the growing season 2019/2020. The first infestation of R. padi appeared on 9/1/2020, and reached the peak of population density on 30/1/2020, while the first appearance of S. graminum was on 17/1/2020; it reached its peak on 13/2/2020. The results of responses of local wheat varieties to the infestation of Greenbug showed that the highest average population density of greenbug was on Bhooth-158, Abu-Ghraib, Bhooth-22, and Babel-113 reaching 51.59, 17.84, 16.41, and 16.63 aphids/plant, respectively. Whereas the lowest population densities were at Fatih, Tammuz, Bhooth-10, Rasheed, and IPA-99, with averages of 8.28, 8.09, 8.87, 7.19, and 7.62 aphids.plant-1, respectively. The highest density rate of R. padi was recorded on the cultivars IPA-95 and Abu-Ghraib, with an average of 139.83 and 169.31 aphids.plant-1 respectively, while the verities Bhooth-22, Bhooth-158, and IPA-99 recorded the lowest population density rate (89.03, 99.41, and 100.25 aphids.plant-1) compared to the other varieties. The results of the chemical analysis determined the proportions of some metabolites of the local wheat varieties and their relationship to the infestation of Greenbug and showed that phenols have an effective role by reducing the population density of aphids. The verities Rasheed and IPA-99 which recorded low population rates of the aphids have the highest rates of phenols at a rate of 7 and 6.78 mg.100g-1 dry weight Also, varieties Abu-Ghraib, IPA-99, and Rasheed cultivars recorded the highest productivity rates (weight of thousand grains), with an average of 33.47, 43, and 67.42 g, respectively.

Population dynamics and production of a brine shrimp, Parartemia zietziana Sayce (Crustacea : Anostraca), in two salt lakes in westren Victoria, Australia

1977 ◽  
Vol 28 (4) ◽  
pp. 417 ◽  
Author(s):  
R Marchant ◽  
WD Williams
Keyword(s):  
Population Dynamics ◽  
Population Density ◽  
Temperature Stress ◽  
Brine Shrimp ◽  
Dry Weight ◽  
Salt Lakes ◽  
Confidence Limits ◽  
Length Frequency ◽  
Population Densities ◽  
The Mean

Quantitative samples of P. zietziana were taken monthly for two years from Pink Lake and Lake Cundare. Shrimps were usually contagiously distributed. To reduce error, samples were stratified resulting in confidence limits of 40-50% for the mean population density. Despite this variability, stable trends emerged, and variation was not so great as to mask significant differences. Length-frequency analyses distinguished cohorts; a regression was established between length and dry weight, enabling growth to be estimated from samples. By combining growth with population densities in Allen curves, production was computed. In Pink Lake and Lake Cundare mean pro- duction was 11.3 and 1.0 g dry weight m-2 year-1 respectively. Generally there were two or three generations per year, but time and extent of recruitment were not predictable. Each generation suffered continuous mortality, the death of young shrimps accounting for most of the production. This mortality remains unexplained; there are no significant predators and salinity and temperature stress would occur only during summer.

SEASONAL DRY-WEIGHT DISTRIBUTION OF SINGLE-STALKED AND MULTI-TILLERED CORN HYBRIDS GROWN AT THREE POPULATION DENSITIES IN SOUTHERN ALBERTA

1977 ◽  
Vol 57 (4) ◽  
pp. 1041-1047 ◽  
Author(s):  
D. J. MAJOR
Keyword(s):  
Zea Mays ◽  
Population Density ◽  
Weight Distribution ◽  
Zea Mays L ◽  
Dry Weight ◽  
Population Densities ◽  
Corn Hybrids ◽  
Southern Alberta

Dry weights of component parts of the main stalk and tillers of corn (Zea mays L.) were determined for a multi-tillered hybrid, Stewart Multi G, and single-stalked hybrids, United UH 106 and Warwick SL 209, in 1974 and 1975. The hybrids were grown under irrigation at 35, 70, and 115 thousand plants/ha at Lethbridge, Alberta. Intrarow spacings equalled interrow spacings. At the end of the season, the multi-tillered hybrid had higher total yields at 35,000 plants/ha man single-stalked hybrids because of its large tillers but the single-stalked hybrids had a higher grain content than the multi-tillered hybrid. Tillers developed early in the season, but the number of tillers per plant decreased after reaching a maximum in late July, presumably due to population-density stresses. Decreases in tiller and stalk dry weight at the end of the season may have been due to translocation of carbohydrates to the main stalk and kernels.

Effect of wheat seeding rate on wild oat competition

1980 ◽  
Vol 20 (102) ◽  
pp. 77 ◽  
Author(s):  
BJ Radford ◽  
BJ Wilson ◽  
O Cartledge ◽  
FB Watkins
Keyword(s):  
Population Density ◽  
Grain Yield ◽  
Dry Weight ◽  
Field Trials ◽  
Wild Oat ◽  
Seeding Rate ◽  
Population Densities ◽  
Wild Oats ◽  
Wheat Population ◽  
A Site

A series of field trials was sown on black earth soils on the Darling Downs, Queensland, with five wheat seeding rates x five levels of wild oat infestation. The lowest seeding rate required to produce optimum grain yield at a site was higher in wild oat infested plots than in weed-free plots. Increase in seeding rate reduced the dry weight of wild oats at maturity and increased the dry weight of wheat at maturity until wheat population density exceeded 150 plants m-2. Increase in seeding rate also reduced wild oat seed production, especially at low wild oat population densities.

EFFECTS OF ROW SPACING AND POPULATION DENSITY ON GRAIN SORGHUM PRODUCTION IN SOUTHERN ALBERTA

1976 ◽  
Vol 56 (1) ◽  
pp. 31-37 ◽  
Author(s):  
B. R. HEGDE ◽  
D. J. MAJOR ◽  
D. B. WILSON ◽  
K. K. KROGMAN
Keyword(s):  
Population Density ◽  
Grain Yield ◽  
Yield Components ◽  
Growing Season ◽  
Grain Sorghum ◽  
Row Spacing ◽  
Population Densities ◽  
Southern Alberta ◽  
Sorghum Production ◽  
Narrow Row

Row spacings of 18–72 cm and population densities of 75,000 to 346,000 plants/ha had no consistent effect on grain yield of two sorghum hybrids (Pride X4004 and Pride X4053) because of compensating variations within yield components. Grain yield per panicle increased as row spacing increased but this was offset by a decrease in panicles per plant and panicles per square meter. Grain yield per panicle, panicles per plant, and panicles per square meter decreased as population density increased. The choice of row spacing and population density in field production will, therefore, depend on convenience factors related to crop management. Evapotranspiration for the growing season was 179 mm in 1973 and 204 mm in 1974. Highest water use efficiencies occurred at the low population densities and narrow row spacings. There were differences between the two hybrids. Grain yield of Pride X4004 was greater than that of Pride X4053 because the former produced a greater number of seed-bearing tillers. Grain yield differences in Pride X4004 among the three experiments were due to differences in grain yield per panicle.

scholarly journals Cowpea and beet intercropping agro-economic dynamics under spatial arrangement and cowpea population density

2020 ◽  
Vol 38 (2) ◽  
pp. 192-203 ◽  
Author(s):  
Aridênia P Chaves ◽  
Francisco Bezerra Neto ◽  
Jailma SS Lima ◽  
Josimar N Silva ◽  
Renato LC Nunes ◽  
...  
Keyword(s):  
Experimental Design ◽  
Population Density ◽  
Economic Efficiency ◽  
Maximum Yield ◽  
Growing Season ◽  
Spatial Arrangement ◽  
Productivity Index ◽  
Population Densities ◽  
System Productivity ◽  
Growing Seasons

ABSTRACT The objective of this work was to evaluate the effect of planting spatial arrangements between the cowpea and beet crops in intercropping and of cowpea population densities on the crop’s productivity and in the agro-economic efficiency of the association at two growing seasons. The experimental design was of randomised blocks with the treatments arranged in a 4 x 3 factorial scheme, in four replications. The first factor was constituted by three spatial arrangements between the component cultures (2:2, 3:3 and 4:4), formed by beet rows alternated with cowpea rows, while the second factor was constituted by the population densities of cowpea: 40, 60, 80 and 100% of the recommended population in single crop (RDSC). The production and its components were evaluated in the beet and cowpea. Apart from these characteristics, the following agro-economic indicators were also determined for each treatment: system productivity index (SPI), the land equivalent coefficient (LEC), and the monetary equivalent ratio (MER). The maximum production of commercial beet roots was obtained with 15.60 t ha-1 productivity at density of 61.82% of RDSC within the 4:4 arrangement, while the maximum yield of cowpea green grains of 2.23 t ha-1 was reached at density of 79.57% of RDSC within 2:2 spatial arrangement. The productivities of beet roots of extra A, extra AA and great types decreased with increasing cowpea population density, without any influence of the tested spatial arrangements. The maximum mean productivity of cowpea green pods of 1.74 t ha-1 was obtained at density of 87.47% of RDSC, reached within 2:2 spatial arrangement. The maximum economic efficiency of the cowpea-beet intercropping was obtained with MER of 1.11 at cowpea density of 100% of RDSC, irrespective of the spatial arrangement and growing season.

Population dynamics of Meloidogyne graminicola and Hirschmanniella oryzae in a double rice-cropping sequence in the lowlands of Myanmar

Nematology ◽  
2013 ◽  
Vol 15 (7) ◽  
pp. 795-807 ◽  
Author(s):  
Pa Pa Win ◽  
Pyone Pyone Kyi ◽  
Zin Thu Zar Maung ◽  
Dirk De Waele
Keyword(s):  
Population Density ◽  
Growing Season ◽  
Lowland Rice ◽  
Population Densities ◽  
Rice Varieties ◽  
Meloidogyne Graminicola ◽  
Rice Plants ◽  
Double Rice ◽  
Heading Stage ◽  
Rice Growing Season

The rice root-knot nematode, Meloidogyne graminicola, and the rice root nematode, Hirschmanniella oryzae, are considered potentially important nematode pathogens in lowland rice. A study was undertaken from December 2009 until December 2010 in the Ayeyarwady River Delta, the major lowland rice-producing area of Myanmar, to monitor the population dynamics of M. graminicola and H. oryzae in a naturally infested field. Root samples of the two rice varieties Yatanartoe and Taungpyan that are commonly cultivated in double rice-cropping sequences in Myanmar and represent irrigated and rainfed lowland rice varieties, respectively, were obtained for nematode analysis. During the summer-irrigated rice-growing season the root population density of second-stage juveniles (J2) of M. graminicola showed two distinct peaks – at the maximum tillering stage of the rice plants in January and at the heading stage of the rice plants in March 2010. With the onset of the monsoon rains, the J2 population densities in the roots of ratoon rice plants gradually decreased in May. During the rainfed monsoon rice-growing season, very low population densities of M. graminicola J2 were detected in the roots of rice plants, while the root population density of H. oryzae juveniles and adults showed two distinct peaks – at the maximum tillering stage of the rice plants in August and at the heading stage of the rice plants in October 2010. With the onset of the dry season, population density of H. oryzae in the roots reached the lowest density at harvest in November. Root galling caused by M. graminicola followed the same trend as the J2 population densities throughout the irrigated season. No root galls were observed during the monsoon season. Our results can be used for practical purposes aimed at a better management of both M. graminicola and H. oryzae.

The effect of varying plant population density on the seed yield of Navy beans (Phaseolus vulgaris)in south-east Enland

1977 ◽  
Vol 88 (3) ◽  
pp. 567-576 ◽  
Author(s):  
D. H. Scarisbrick ◽  
J. M. Wilkes ◽  
R. Kempson
Keyword(s):  
Phaseolus Vulgaris ◽  
Population Density ◽  
Seed Yield ◽  
Plant Density ◽  
Growing Season ◽  
Plant Population ◽  
Population Densities ◽  
Growing Seasons ◽  
Navy Beans ◽  
Plant Population Density

SUMMARYNavy beans were precision drilled in 1973–5 at a range of plant population densities. Within each growing season the density treatments did not influence seed yield, but mean yields differed significantly between years. The results suggest that cultivars similar to Purley King can only be regarded as a reliable break crop in a season such as 1973 which was slightly warmer and drier in mid-summer than average. Although the rate of drying increased with increasing plant density in two of the growing seasons, no practical advantages are proposed.

scholarly journals Competition of pigweed (Amaranthus dubius) with sweetpotato (Ipomoea batatas)

1969 ◽  
Vol 71 (1) ◽  
pp. 7-11 ◽  
Author(s):  
Nelson Semidey ◽  
Lii C. Liu ◽  
Francisco H. Ortiz
Keyword(s):  
Population Density ◽  
Linear Relationship ◽  
Ipomoea Batatas ◽  
Field Experiments ◽  
Dry Weight ◽  
Yield Reduction ◽  
Research Centers ◽  
Population Densities ◽  
Natural Infestation ◽  
Effect On Yield

Two field experiments were conducted at the Isabela and Juana Díaz Research Centers in 1982-83 to determine the effect of pigweed (Amaranthus dubius Mart.) density on yield of sweetpotato [Ipomoea batatas (L.) Lam]. Pigweed densities of 0, 4, 7, 13 and 27 plants/m2 were adjusted by hand at Isabela and those of 0, 11, 23, 45 and 91 plants/m2 were maintained at Juana Díaz. Pigweed population averaged 27 plants/m2 at Isabela and 91 plants/m2 at Juana Díaz under natural infestation. Sweetpotato yield was reduced significantly from 4 plants/m2 at Isabela and from 11 plants/m2 at Juana Díaz. The highest sweetpotato yield was obtained on weed-free plots with 11,823 kg/ha at Isabela and 27,724 kg/ha at Juana Díaz. The greatest yield reduction (91%) resulting from pigweed competition (at Juana Díaz) was at a density of 91 plants/m2. At Isabela, a density of 13 plants/m2 caused the greatest yield reduction (78%). The effect of pigweed on number of root-tubers followed a similar trend as the effect on yield. Dry weight of pigweed per plant was significantly greater at population densities of 4 and 7 plants/m2 at Isabela. At Juana Díaz, dry weight of pigweed was significantly higher at a population density of 11 plants/m2. The regression between sweetpotato yield and the different population densities of pigweed showed an inverse linear relationship at both localities.

scholarly journals Foliar applications of bio-fabricated selenium nanoparticles to improve the growth of wheat plants under drought stress

2020 ◽  
Vol 9 (1) ◽  
pp. 706-714
Author(s):  
Muhammad Ikram ◽  
Naveed Iqbal Raja ◽  
Bilal Javed ◽  
Zia-ur-Rehman Mashwani ◽  
Mubashir Hussain ◽  
...  
Keyword(s):  
Drought Stress ◽  
Field Capacity ◽  
Dry Weight ◽  
Positive Control ◽  
Morphological Characterization ◽  
Leaf Length ◽  
Selenium Nanoparticles ◽  
Fresh Weight ◽  
Wheat Varieties ◽  
Shoot Dry Weight

AbstractThe present study was aimed to biosynthesize selenium nanoparticles (SeNPs) and assess their foliar applications to improve the growth of wheat plants under controlled irrigation and drought stress. Bud aqueous extract of Allium sativum L. was used as a reducing and stabilizing agent of SeNPs followed by their optical and morphological characterization by using ultraviolet-visible spectroscopy, scanning electron microscopy, Fourier-transform infrared, and energy dispersive X-ray analysis. Various concentrations of SeNPs (10, 20, 30, and 40 mg/L) were applied exogenously to drought-tolerant (V1) and drought-susceptible (V2) wheat varieties at the trifoliate stage. Under the positive control conditions, plants were irrigated with 450 mL of water/pot (100% field capacity); and under water-deficit environment, plants were irrigated with 160 mL of water/pot (35% field capacity). Remarkable increase in plant height, shoot length, shoot fresh weight, shoot dry weight, root length, root fresh weight, root dry weight, leaf area, leaf number, and leaf length has been observed when 30 mg/L concentration of SeNPs was used. However, the plant morphological parameters decreased gradually at higher concentrations (40 mg/L) in both selected wheat varieties. Therefore, 30 mg/L concentration of SeNPs was found most preferable to enhance the growth of selected wheat varieties under normal and water-deficient conditions.

Effects of crop sequence and rainfall on population dynamics of Fusarium solani f.sp. phaseoli in soil

1992 ◽  
Vol 70 (10) ◽  
pp. 2005-2008 ◽  
Author(s):  
Robert Hall ◽  
Lana Gay Phillips
Keyword(s):  
Population Dynamics ◽  
Phaseolus Vulgaris ◽  
Population Density ◽  
Fusarium Solani ◽  
Population Densities ◽  
Total Rainfall ◽  
Colony Forming Units ◽  
Bean Crop ◽  
Previous Summer ◽  
Crop Sequence

Evidence is presented that population dynamics of Fusarium solani f.sp. phaseoli in soil depend on the effects of crop sequence and rainfall on parasitic activities of the pathogen. In a rotation trial started in 1978 and conducted over 14 years, population densities (colony-forming units/g) of the fungus in soil remained below 50 in treatments (fallow, repeated corn, repeated soybean) where the preferred host plant (common bean, Phaseolus vulgaris) was not grown. Where bean was grown every 3rd year or every year, population densities reached 475 and 660, respectively, by 1984. Thereafter, population densities of the fungus fluctuated widely from year to year in both rotation and repeated bean treatments. In the rotation treatment, peaks in population density of the pathogen coincided with the years of bean production. In repeated bean plots between 1985 and 1991, population density of the fungus in June was significantly correlated (r = 0.77, p = 0.04) with total rainfall received during the previous summer (June–August). It is postulated that higher rainfall during the growing season of the bean crop stimulated root growth and root infection, leading to the accumulation of higher levels of potential inoculum in infected tissue and the release of higher levels of inoculum into the soil by the following June. Key words: Fusarium solani f.sp. phaseoli, bean, Phaseolus vulgaris, rainfall, crop rotation.

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