scholarly journals Influence of different barley varieties on competition and yield performance in barley-oats mixtures at two levels of nitrogen fertilization

1991 ◽  
Vol 63 (4) ◽  
pp. 341-351
Author(s):  
Kari Jokinen
Keyword(s):  
Competitive Ability ◽  
Relative Yield ◽  
Grain Protein Content ◽  
Pure Stand ◽  
Replacement Series ◽  
Yield Performance ◽  
Relative Significance ◽  
Barley Cultivars ◽  
Relative Yield Total ◽  
Stand Yield

Competition between barley and oats, and yield performance of mixtures were evaluated in a two component replacement series field experiment at two levels of nitrogen applications (80 kgN/ha and 120 kgN/ha). Three barley cultivars (Aapo, Agneta ja Ida) and one oats cultivar (Veli) were used. The competitive relationship was independent of the pure stand yield of the cultivar. Ida and Agneta were more competitive than oats irrespective of nitrogen dose. Ida was the most dominant variety which was very likely due to the early development of the seedlings. Oats was slightly more competitive than the shortest cultivar Aapo at high nitrogen, although barley seedlings emerged before oats. Thus the competitive ability of a cultivar was not determined by one character of the plant only. The competition in mixtures had a greater effect on number of generative shoots and number of grains per head than on grain weight. The results revealed that the yield per plant in mixtures may be even the same as in monoculture, but the relative significance of different yield components may vary. The grain and protein yield of mixtures did not differ significantly from the yield of the highest yielding component grown alone. However, the ratio of actual and expected yield and the relative yield total were in most cases higher than one, indicating that some yield advantage may have been achieved. The genotypic composition of the stand had the greatest influence on the grain protein content of oats.

scholarly journals The effect of site on competition and yield advantages of mixtures of barley and oats

1991 ◽  
Vol 63 (4) ◽  
pp. 353-359
Author(s):  
Kari Jokinen
Keyword(s):  
Field Experiment ◽  
Grain Yield ◽  
Protein Content ◽  
Competitive Ability ◽  
Relative Yield ◽  
Early Growth ◽  
Average Yield ◽  
Replacement Series ◽  
Relative Yield Total ◽  
Genotypic Structure

Competition between six-row barley cv. Agneta and oats cv. Veli, and yield advantages of the mixtures were evaluated in a replacement series field experiment. The experiment was situated in a sloping area. Although barley was lower yielding (grain yield) than oats when the components were grown in monoculture, barley was dominant in all mixtures irrespective of the site. The competitive ability of barley decreased from the less productive site (top) to the more productive site (bottom). The improved competitive ability of oats was likely due to the faster early growth of oats. The grain yield of the mixture was about 4°70 (p >0.05) greater than the yield of the highest yielding component (oats) grown in monoculture on the more productive sites. The grain yield of the mixture was greater than the average yield of the pure stands and also the relative yield total exceeded one irrespective of the site. The grain weight of the species was independent of the genotypic structure of the stands. The protein content of oats was the highest, being greater in mixtures than in monocultures. The protein yield and the protein content of the mixture was between the values for pure stands.

scholarly journals Yield and competition in barley variety mixtures

1991 ◽  
Vol 63 (4) ◽  
pp. 287-305 ◽  
Author(s):  
Kari Jokinen
Keyword(s):  
Competitive Ability ◽  
Field Experiments ◽  
Spring Barley ◽  
Relative Yield ◽  
Growing Season ◽  
Morphological Characters ◽  
Replacement Series ◽  
Available Nitrogen ◽  
Relative Yield Total ◽  
Variety Mixtures

Competition between spring barley varieties and yield performance of two-, three and four-variety mixtures were studied in two replacement series field experiments. In the first experiment, repeated in three successive years (1983 —85) the components were the six-row varieties Agneta, Arra, Hja-673 and Porno. In the second experiment (1984), including two nitrogen doses (50 and 100 kgN/ha), both six-row (Agneta, Pomo) and two-row (Ida, Kustaa) varieties were used. Arra in the first and Agneta in the second experiment were the most competitive varieties. The results suggested that the fast growth of Arra at the beginning promoted its competitive ability. Increase in available nitrogen usually strengthened the competitiveness of Agneta. The observed competitive differences between varieties were not related to the earliness of a variety, neither to the morphological characters (two- and six-row varieties) nor to the grain yield of a variety grown alone. The competitive ability was not always a stable character, the dominant suppression relationship varying from one environment to another (e.g. growing season, nitrogen dose). The observed overyielding was not statistically significant. The ratio of actual to expected yield and the relative yield total of several mixtures exceeded slightly one. As a conclusion, the yield advantage of mixtures was marginal. As a rule, the mixtures were not more stable than monocultures as determined by the coefficient of variation. However, the yield of some mixtures varied less than the yield of the most stable monoculture.

Inter-Specific Competition Between Seedlings of Pinus radiata, Eucalyptus regnans and Acacia melanoxylon

1994 ◽  
Vol 42 (1) ◽  
pp. 61 ◽  
Author(s):  
H Bi ◽  
ND Turvey
Keyword(s):  
Resource Use ◽  
Native Species ◽  
Relative Yield ◽  
Replacement Series ◽  
Eucalyptus Regnans ◽  
Acacia Melanoxylon ◽  
Relative Yield Total ◽  
Species Combination ◽  
Competitive Aggressiveness ◽  
Insight Into

A replacement series experiment was carried out to determine the competitive aggressiveness of three species, P. radiata, E. regnans and A. melanonylon towards each other at seedling stage. Seedlings of the three species were grown at an overall density of six plants per pot for each species combination, providing all combinations of two species from 0:6 to 6:O. In addition, seedlings were grown in pure stands from one plant to six plants per pot for the three species. The relative crowding coefficient, the relative yield total, the relative effects of intra- and inter-specific competition on the yield of each species were the four indices calculated. Acacia melanoxylon was the most aggressive species, followed by P. radiata then E. regnans. In comparison with their corresponding monoculture, A. melanonylon in mixtures showed the smallest decrease in shoot/root ratio, whilst P. radiata had a greater decrease and E. regnans showed the greatest reduction. The average relative yield total of E. regnans and A. melanoxylon was close to 1 for both shoots and roots, indicating an almost complete overlap in resource use between the two native species. The relative yield total of P. radiata and E. regnans was 1.27 for shoots and 1.48 for roots, suggesting a possible difference in resource use between them. The results of this experiment provide a valuable qualitative insight into the relative magnitudes of the effects of inter- and intra-specific competition between the seedlings of the three species.

scholarly journals COMPETITIVE RELATIVE ABILITY OF BARLEY CULTIVARS IN INTERACTION WITH TURNIP

2017 ◽  
Vol 35 (0) ◽  
Author(s):  
L. GALON ◽  
L.R. AGAZZI ◽  
F. NONEMACHER ◽  
F.J.M. BASSO ◽  
F.L. WINTER ◽  
...  
Keyword(s):  
Leaf Area ◽  
Competitive Analysis ◽  
Intraspecific Competition ◽  
Growth And Development ◽  
Aerial Part ◽  
Competitive Ability ◽  
Dry Mass ◽  
Replacement Series ◽  
Barley Cultivars ◽  
Relative Ability

ABSTRACT Among the weeds that cause interference with the growth and development of barley the turnip stands out, especially by the high competitive ability for the resources available in the environment. The research objective with the study was to evaluate the competitive ability of barley cultivars to live with a turnip biotype. Experiments were installed in a greenhouse, in the experimental outlining of randomized blocks designed with four repetitions. The treatments were arranged in replacement series, consisting of proportions of barley plants and turnip: 100: 0, 75:25, 50:50, 25:75 and 0: 100% which was equivalent to 20: 0, 15: 5, 10:10, 5:15 and 0:20 plants per pot. The barley was represented by BRS Cauê, BRS Elis and MN 610 and the competitor by turnip. The competitive analysis was made through diagrams applied in replacement experiments, among with use of relative competitiveness indices. The leaf area (AF) and the dry mass of the aerial part (MS) were evaluated at 50 days after the emergence of the species. The results show that there was competition between barley varieties with the turnip with mutual damage to the species involved in the community. Turnip negatively modified the AF and the MS of BRS Cauê, MN 610 and BRS Elis demonstrating higher competitive ability for the means of the resources. The interspecific competition causes greater damage to the AF and the MS species than the intraspecific competition. Thus, the turnip control is recommended the turnip control even when present at low densities of plants infesting the barley.

The Influence of Increasing Carbon Dioxide and Temperature on Competitive Interactions Between a C3 Crop, Rice (Oryza sativa) and a C4 Weed (Echinochloa glabrescens)

1996 ◽  
Vol 23 (6) ◽  
pp. 795 ◽  
Author(s):  
AMP Alberto ◽  
LH Ziska ◽  
CR Cervancia ◽  
PA Manalo
Keyword(s):  
Elevated Co2 ◽  
Growth Temperature ◽  
Competitive Ability ◽  
Relative Yield ◽  
Co2 Concentration ◽  
The Philippines ◽  
Replacement Series ◽  
Lower Growth ◽  
C4 Species ◽  
Lower Growth Temperature

Many of the most troublesome weeds in agricultural systems are C4 plants. As atmospheric CO2 increases it is conceivable that competitive ability of these weeds could be reduced relative to C3 crops such as rice. At the International Rice Research Institute (IRRI) in the Philippines, rice (IR72) and one of its associated C4 weeds, Echinochloa glabrescens, were grown from seeding to maturity using replacement series mixtures (100:0, 75:25, 50:50, 25:75, and 0:100, % rice:%weed) at two different CO2 concentrations (393 and 594 μL L-1) in naturally sunlit glasshouses. Since increasing CO2 may also result in elevated growth temperatures, the response of rice to each CO2 concentration was also examined at daylnight temperatures of 27/21 and 37/29�C. At 27/21�C, increasing the CO2 concentration resulted in a significant increase in above ground biomass (+47%) and seed yield (+55%) of rice when averaged over all mixtures. For E. glabrescens, the C4 species, no significant effect of CO2 concentration on biomass or yield was observed. When grown in mixture, the proportion of rice biomass increased significantly relative to that of the C4 weed at all mixtures at elevated CO2. Evaluation of changes in competitiveness (by calculation of plant relative yield (PRY) and replacement series diagrams) of the two species demonstrated that, at elevated CO2, the competitiveness of rice was increased relative to that of E. glabrescens. However, at the higher growth temperature (37/29�C), growth and reproductive stimulation of rice by elevated CO2 was reduced compared to the lower growth temperature. This resulted in a reduction in the proportion of rice:weed biomass present in all mixtures relative to 27/21�C and a greater reduction in PRY in rice relative to E. glabrescens. Data from this experiment suggest that competitiveness could be enhanced in a C3 crop (rice) relative to a C4 weed (E. glabrescens) with elevated CO2 alone, but that simultaneous increases in CO2 and temperature could still favour a C4 species.

scholarly journals Competition and yield advantage in barley-barley and barley-oats mixtures

1991 ◽  
Vol 63 (4) ◽  
pp. 255-285 ◽  
Author(s):  
Kari Jokinen
Keyword(s):  
Grain Yield ◽  
Nitrogen Fertilization ◽  
Competitive Ability ◽  
Relative Yield ◽  
Growing Season ◽  
Protein Yield ◽  
Total Density ◽  
Initial Development ◽  
Relative Yield Total ◽  
Competitive Relations

Competition and yield advantage in barley varietal mixtures and in barley-oats mixtures were investigated. The trials were based on replacement series, but in a few cases the overall density of the stand was varied on the basis of an addition series. Both models of competition, one based on the de Wit model and the other upon a linear regression model, agreed as to which component was the dominant and which was the subordinate in the mixture. The competition coefficients from regression analyses depicted competition between components better in a dense than in a sparse stand. The competitive ability of a genotype did not depend directly upon individual characters of the genotype, such as rate of initial development, earliness, culm height, tillering capacity or grain yield in monoculture (adaptation), A good combination of characters from the viewpoint of competition was provided by the barley cv. Arra with its rapid initial development and rapid culm growth (earliness), the variety being dominant irrespective of number of components in the mixture, stand density, level of nitrogen fertilization or growing season. This suggests that competitive relations and distribution of resources within a mixture are determined at an early stage in the growing period. In other cases the competitive ability of a genotype varied from one environment to another with the competitive relations between components being inconsistent. The dominance of an aggressor usually increased with increasing nitrogen fertilization especially when the total density of the stand was high. As a rule, competition affected all the components of yield with the kernel weight being least affected. The grain yield of varietal mixtures did not differ from the yield of the highest yielding component grown alone, i.e., mixtures did not over yield. The relative yield total of varietal mixtures was higher at low (RYT > 1) than at optimal densities (RYT =1). Also the relative yield total was higher under conditions where the nitrogen fertilization was not optimal. The results of a varietal trial repeated during three successive years indicated that the relative yield total of a given mixture varied from one growing season to another, fluctuating around unity. Thus highly adapted barley varieties appear to compete for the same resources, and the grain yield advantage of such mixtures is marginal. The results of the barley-oats mixture trials revealed that the mixture may over yield. The relative yield totals of barley-oats mixtures were usually equal to or greater than unity the latter suggesting that the mixtures of barley and oats may use resources more efficiently than monocultures, and some grain yield advantage could be achieved with such mixtures. The protein yield of the barley-oats mixtures did not differ from the yield of the highest yielding component grown alone. The ratio of actual and expected protein yield and the relative protein yield total were usually slightly greater than one. The grain yields of mixtures were not consistently more stable than monocultures as determined by the coefficient of variation.

scholarly journals Assessment of competition and yield advantage in addition series of barley variety mixtures

1991 ◽  
Vol 63 (4) ◽  
pp. 307-320 ◽  
Author(s):  
Kari Jokinen
Keyword(s):  
Nitrogen Fertilization ◽  
Maximum Yield ◽  
Relative Yield ◽  
Dominance Order ◽  
Replacement Series ◽  
Available Nitrogen ◽  
Relative Yield Total ◽  
Variety Mixtures ◽  
Growing Conditions ◽  
The Relationship

In an addition series experiment the competition between three barley varieties (Agneta, Arra and Porno) and the yield performance of mixtures were evaluated. Also two levels of nitrogen fertilization (50 and 100 kgN/ha) were applied. Two approaches (the replacement series and the linear regression equation) were used to analyse the competitive relationship based on grain yields in two-component mixtures. In three component mixtures the replacement series approach was applied. Both methods showed a similar dominance order of the varieties with Arra always being dominant and Agneta subordinate. The relationship between varieties was independent of the number of varieties in the mixture. Increase in available nitrogen strengthened the competitiveness of Arra especially in the dense, two-variety mixtures. Some mixtures over yielded but the differences were not statistically significant. The yield advantage based on relative yield total or on the ratio of actual and expected yield was greatest when the density and nitrogen fertilization were low and especially when one component in the mixture was a rather low yielding variety (Agneta). The land equivalent ratios (LER) (the reference pure culture yield was the maximum yield of each variety) were close to one, suggesting that under optimal growing conditions the yield advantage of barley varietal mixtures is marginal.

scholarly journals Lowbush Blueberry-Bunchberry Competition

1993 ◽  
Vol 118 (1) ◽  
pp. 54-62 ◽  
Author(s):  
David E. Yarborough ◽  
Prasanta C. Bhowmik
Keyword(s):  
Relative Yield ◽  
Dry Weight ◽  
Replacement Series ◽  
Area Index ◽  
Competitive Effects ◽  
Greenhouse Study ◽  
Cornus Canadensis ◽  
Lowbush Blueberry ◽  
Relative Yield Total ◽  
Aboveground Growth

The competitive effects of bunchberry Cornus canadensis L. on native stands of blueberries Vaccinium angustifolium Ait. was assessed in 1986 and 1987, and in the greenhouse in 1987 with replacement series experiments. In the field, blueberry and bunchberry fruit were harvested in August and all aboveground growth was cut, the species were separated, and dry weight was determined. The relative yield total (RYT), defined as the dry weight (DW) of the combined aboveground portions of the blueberry and bunchberry divided by their respective DW at 100% cover, was >1 and showed an increase with increasing proportion of bunchberry. Blueberry relative yield, defined as the DW of the aboveground portion divided by the DW at 100% cover, was >1, but bunchberry relative yield DW was ≤1. Regression of individual on associate DW yield indicates blueberry is as aggressive as bunchberry. Blueberry fruit count and yield decreased with increasing bunchberry density. In the greenhouse study, plant count and cover were assessed weekly, and leaf area index (LAD and DW were obtained at the end of the study. RTY > 1, and combined DW increased with increasing proportion of bunchberry. The LAI of blueberry or bunchberry was higher in mixtures than in pure stands. Blueberries are competitive with bunchberry, but in native fields, open areas among clones allow faster growing bunchberry to spread without competition.

Aggressivity: Cucumber vs. Amaranth

2006 ◽  
Vol 20 (4) ◽  
pp. 986-991 ◽  
Author(s):  
Adrian D. Berry ◽  
William M. Stall ◽  
B. Rathinasabapathi ◽  
Gregory E. Macdonald ◽  
R. Charudattan
Keyword(s):  
Field Study ◽  
Relative Yield ◽  
Dry Weight ◽  
Replacement Series ◽  
Live Oak ◽  
Relative Yield Total ◽  
Smooth Pigweed ◽  
Series Study ◽  
Weight Data

A replacement series study was conducted to describe the aggressivity between cucumber, smooth pigweed, and livid amaranth. Cucumber was three times more competitive than smooth pigweed or livid amaranth, under the conditions of this study. However, there was equal competition and no antagonism between smooth pigweed and livid amaranth. Where cucumbers were planted in mixture with either of the two weeds, the relative yield total values were approximately 10 to 20% higher than the monocultures. Cucumber was a superior competitor when grown in mixture with smooth pigweed or livid amaranth, and the following aggressivity hierarchy exists: cucumber > livid amaranth = smooth pigweed. Results from the additive field study indicated that amaranth dry weights were significantly affected by smooth pigweed and livid amaranth density. Dry weight of amaranth was decreased by 48% at Gainesville and 25% at Live Oak, at 18 plants/m2. Despite differences between the Gainesville and Live Oak results, the dry weight data were similar for both smooth pigweed and livid amaranth at each location.

Impact of Soil pH on Cogongrass (Imperata cylindrica) and Bahiagrass (Paspalum notatum) Competition

2018 ◽  
Vol 32 (3) ◽  
pp. 336-341 ◽  
Author(s):  
Candice M. Prince ◽  
Gregory E. MacDonald ◽  
Jason A. Ferrell ◽  
Brent A. Sellers ◽  
Jingjing Wang
Keyword(s):  
Soil Ph ◽  
Competitive Ability ◽  
Relative Yield ◽  
Imperata Cylindrica ◽  
Management Tool ◽  
Paspalum Notatum ◽  
Replacement Series ◽  
Cultural Management ◽  
Disturbed Areas ◽  
Poor Soil

AbstractCogongrass is commonly found in disturbed areas in Florida, where it is increasingly becoming a problem in bahiagrass pastures. Soil pH has been suggested as a possible mechanism for this invasion; to evaluate this, replacement series competition studies were conducted under greenhouse conditions at two soil pH levels: pH 4.5, or pH 6.8. Cogongrass ramets and bahiagrass seedlings were planted at proportions of 0:40, 1:20, 2:10, 4:1, and 8:0, respectively. Aboveground biomass was measured after 8 weeks and used to calculate relative yield, relative crowding coefficients, and aggressivity values. At soil pH 4.5, the relative competitiveness of cogongrass and bahiagrass was similar, with both species contributing equally to relative yield. At soil pH 6.8, bahiagrass seedlings showed greater competitive ability than cogongrass ramets. Relative crowding coefficient and aggressivity values supported this, with bahiagrass showing increased competitiveness under higher soil pH. This indicates that decreases in soil pH, often associated with poor soil fertility, is likely a contributing factor for cogongrass invasion into bahiagrass pastures. Soil amendments to raise pH may provide a cultural management tool for cogongrass infestations in pastures.

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