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.

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 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 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 Plant size, nutrient composition and biomass productivity of oats and faba bean in intercropping, and the effect of controlling Rhopalosiphum padi (Hom., Aphididae) on these properties

1990 ◽  
Vol 62 (1) ◽  
pp. 21-31 ◽  
Author(s):  
Juha Helenius
Keyword(s):  
Faba Bean ◽  
Field Experiments ◽  
Rhopalosiphum Padi ◽  
Relative Yield ◽  
Biomass Productivity ◽  
Plant Size ◽  
Damage Function ◽  
Point Of View ◽  
Daily Maximum ◽  
Replacement Series

Effects of mixed intercropping on plant size, content of mineral nutrients and biomass yields were examined in three field experiments in Southern Finland in 1983—1985. The stand types were monocrops and replacement series of mixtures with 2/3 and 1/3 or 1/3 and 2/3 of oats (Avena sativa) and faba bean (Vicia faba), respectively. In one of the experiments control of R. padi, by means of deltamethrin sprayings, was an additional experimental factor having two levels. The height of stems or the above ground biomass of oats either were not affected or were increased by crop diversification. Bean plants remained smaller in the mixtures than in the monocrop. In plant size, there was a significant interaction between stand type and the effect of aphicide spraying: Oat benefitted most from being grown in the mixture containing most bean, and there was an indication (not statistically significant) that in these mixtures bean had proportionately higher weight loss. This result was interpreted as giving some support to the hypothesis of interspecific compensation between oats and bean against aphid damage to oats. In oats, the content of N, P, K, Ca, and Mg all decreased from the stage of inflorescence emergence to the stage of the onset of milk development. Mixed cropping increased the content in oats of all these nutrients except Ca. At the same time, contents of P and K in bean were decreased. The changes in growth form and composition in oats induced by intercropping are discussed from the point of view of host plant relationship and damage function of the aphid pest. In terms of relative yield total (RYT), there was no overyielding in the dry matter, and in one case only was there overyielding in the nitrogen. During the period of population growth of R. padi, the daily maximum temperatures within the canopy were higher in the mixtures than in the monocrop of oats.

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 QUANTITATIVE COMPOSITION THE MICROORGANISMS OF RHIZOSPHERE AGRICULTURAL PLANTS

2021 ◽  
pp. 119-125
Author(s):  
Iryna Beznosko ◽  
Tetyana Gorgan ◽  
Iryna Mosiychuk
Keyword(s):  
Field Experiments ◽  
Rhizosphere Soil ◽  
Spring Barley ◽  
Growing Season ◽  
Organic Production ◽  
Quantitative Composition ◽  
Research Station ◽  
Trophic Groups ◽  
Hydrothermal Coefficient ◽  
Agricultural Plants

During 2020, on the basis of stationary and temporary field experiments, which are located in the Skvуra Research Station of Organic Production of NAAS, Nosiv SDS and the Institute of Vegetable and Melon NAAS were studied quantitative composition of the soil micromycetes under different agricultural crops: winter wheat, spring barley and onion. The vegetation period in the Kyiv region was characterized by – sufficiently moist (HTC 1,7), and in Chernihiv and Kharkiv regions drought prevailed (HTC 0,6). Adverse weather conditions such as drought or waterlogging are crucial factors in changing the number of mycobiomes in the studied soils.Stationary field experiments in the selection Nosivka during the ontogenesis winter wheat characterized the greatest number pedatrophic and less number of amylolytic, cellulosolytic ecological-trophic groups. The stationary experiments field researches were also conducted in Skvyra Research Station of Organic Production. Where the rhizosphere soil under spring barley crops is characterized by a larger number of micromycetes, as well as amylolytic and cellulolytic ecological-trophic groups. Was determined the number of soil micromycetes the main ecological and trophic groups. The rhizosphere soil on the stationary field of the Institute of Vegetable and Melon NAAS during the ontogenesis of different varieties of onions characterized by high number cellulosolytic group of micromycetes, which despite the decrease in the hydrothermal coefficient increased by the end of the growing season of the culture.Therefore, the interaction between plants and micromycetes is a dynamic process in which the hydrothermal coefficient during the growing season, soil type, and the root system of agricultural plants, this influences the formation of soil mycobiome.

Relationship between lodging, morphological characters and yield of varieties of maize (Zea mays L.)

1978 ◽  
Vol 91 (3) ◽  
pp. 633-638 ◽  
Author(s):  
S. U. Remison ◽  
Dele Akinleye
Keyword(s):  
Zea Mays ◽  
Field Experiments ◽  
Zea Mays L ◽  
Growing Season ◽  
Morphological Characters ◽  
Growing Seasons ◽  
Basal Internode ◽  
Ear Height ◽  
The Relationship ◽  
Rainforest Zone

SummaryField experiments were carried out in the early and late growing seasons in the rainforest zone of Nigeria to find out the relationship between lodging, morphological characters and yield of maize.Morphological characters associated with lodging were plant height, ear height and length of basal internode. There was a negative correlation between lodging and yield. Much of the lodging recorded, especially in the early growing season, was due to weak stems. Earliness, diameter of stem and leaf area had no relationship with lodging.

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.

Competition and growth of six cowpea (Vigna unguiculata) genotypes, sunflower (Helianthus annuus), and common purslane (Portulaca oleracea)

Weed Science ◽  
2006 ◽  
Vol 54 (5) ◽  
pp. 954-960 ◽  
Author(s):  
Guangyao Wang ◽  
Milton E. McGiffen ◽  
Jeff D. Ehlers
Keyword(s):  
Growth Rate ◽  
Field Experiments ◽  
Growth Habit ◽  
Growth Parameters ◽  
Weight Ratio ◽  
Relative Yield ◽  
Isotonic Regression ◽  
Weed Species ◽  
Replacement Series ◽  
Common Purslane

Varietal growth habit could play a key role in the competitiveness of crop plants with weeds. The relative competitiveness of two erect, two semierect, and two prostrate cowpea genotypes with a tall-growing (common sunflower) or a low-growing (common purslane) species was evaluated in 12 replacement-series experiments conducted in 2003 and 2004. Growth analysis of the six cowpea genotypes and two weed species were also conducted to investigate the relationship of competitiveness and growth. Cowpea genotype and competitor biomass were used to calculate relative yield total (RYT) and aggressivity indices (AI). RYT and AI means of six cowpea genotypes were compared using ANOVA, and an isotonic regression was used to confirm the relative competitive superiority of the cowpea growth types. All cowpea genotypes had similar RYTs when grown with sunflower or common purslane, indicating that cowpea used the same resources as sunflower or purslane. When grown with sunflower, erect and semierect genotypes had higher AI than prostrate genotypes. When grown with purslane, erect and prostrate genotypes had higher AI than semierect genotypes. The results were confirmed by isotonic regression tests on the respective AI order. Correlation and regression between AI and growth parameters showed that the relative growth rate (RGR), leaf area ratio (LAR), and height growth rate (HGR) explained 92% of the variation of AI when cowpeas were grown with sunflower and that leaf weight ratio (LWR) and biomass explained 82% of the variation of AI when cowpeas were grown with purslane. These experiments indicate that cowpea genotypes differ in their ability to compete with purslane or sunflower. Erect genotypes were the most competitive, suggesting that an erect growth habit may be more effective in suppressing weeds than a semierect or prostrate growth habit. These results are consistent with field experiments on the competitiveness of erect, semierect, and prostrate cowpea genotypes.

Sign in / Sign up

Export Citation Format

Share Document