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.

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.

Phosphorus effects on competitive interactions of smooth pigweed (Amaranthus hybridus) and common purslane (Portulaca oleracea) with lettuce (Lactuca sativa)

Weed Science ◽  
1998 ◽  
Vol 46 (3) ◽  
pp. 307-312 ◽  
Author(s):  
Bielinski M. Santos ◽  
Joan A. Dusky ◽  
William M. Stall ◽  
Donn G. Shilling ◽  
Thomas A. Bewick
Keyword(s):  
Competitive Ability ◽  
Organic Soils ◽  
Weed Species ◽  
Population Densities ◽  
Replacement Series ◽  
Amaranthus Hybridus ◽  
Extractable P ◽  
Common Purslane ◽  
Smooth Pigweed ◽  
Water Extractable

Replacement series studies were conducted under controlled conditions to determine the effect of phosphorus (P) rates and population densities on the competitiveness of smooth pigweed and common purslane with lettuce. Densities were 2, 4, and 8 plants per 113 cm2, whereas P rates were 0, 0.4, and 0.8 g PL−1soil. A P-deficient Histosol (0.3 mg water-extractable P L−1soil) was used. High P fertility enhanced the competitive ability of lettuce in smooth pigweed-lettuce mixtures. Smooth pigweed was not responsive to P rates. However, luxurious P consumption by smooth pigweed occurred, reducing the amount of the nutrient available for lettuce absorption. In common purslane-lettuce mixtures, the weed was responsive to P rates, increasing its competitive ability, whereas no increase in lettuce competitive ability was observed. Both weed species were more competitive than lettuce. Competition for P appears to be the main mechanism of common purslane interference on lettuce grown in low-P organic soils. Alternative fertilization strategies (i.e., banded applications) may reduce the effect of smooth pigweed on lettuce.

Interaction of Common Purslane (Portulaca oleracea) and Palmer amaranth (Amaranthus palmeri) with Sweetpotato (Ipomoea batatas) Genotypes

2020 ◽  
Author(s):  
Sushila Chaudhari ◽  
Katherine M. Jennings ◽  
David W. Monks ◽  
Lucky K. Mehra
Keyword(s):  
North Carolina ◽  
Ipomoea Batatas ◽  
Relative Yield ◽  
Palmer Amaranth ◽  
Amaranthus Palmeri ◽  
Replacement Series ◽  
Fresh Biomass ◽  
Drought Tolerant ◽  
Dry Biomass ◽  
Common Purslane

Greenhouse replacement series studies were conducted to determine the relative competitiveness of NC10-275 (unreleased, drought tolerant; upright, bushy, and vining growth with large leaves) and Covington (most commonly grown genotype in North Carolina; vining growth with smaller leaves) sweetpotato genotypes with weeds. Sweetpotato genotypes were grown with Palmer amaranth (tall growing) or common purslane (low growing) at five planting (sweetpotato:weed) proportions of 100:0, 75:25, 50:50, 25:75, and 0:100% at density of four plants pot-1. Reduction in common purslane shoot dry biomass was greater when growing with NC10-275 than when growing with Covington or alone. When growing with common purslane, shoot dry and root fresh biomass of Covington was 18 and 26% lower, respectively, than NC10-275. Relative yield (shoot dry biomass) and aggressivity index (AI) of common purslane was lower than both sweetpotato genotypes. Palmer amaranth shoot dry biomass was similar when growing alone or with Covington; whereas, it was reduced by 10% when growing with NC10-275 than alone. Palmer amaranth competition reduced shoot dry biomass and root fresh biomass of Covington by 23 and 42%, respectively, relative to NC10-275. Relative yield and AI of Palmer amaranth was greater than Covington but lower than NC10-275. This research indicates that sweetpotato genotypes differ in their ability to compete with weeds. Both sweetpotato genotypes were more competitive than common purslane, and the following species hierarchy exists: NC10-275 > Covington > common purslane. In contrast, NC10-275 was more competitive than Covington with Palmer amaranth, and the following species hierarchy exists: NC10-275 ≥ Palmer amaranth>Covington.

Competitive ability of cowpea genotypes with different growth habit

Weed Science ◽  
2006 ◽  
Vol 54 (4) ◽  
pp. 775-782 ◽  
Author(s):  
Guangyao Wang ◽  
Milton E. McGiffen ◽  
Jeff D. Ehlers ◽  
Edilene C. S. Marchi
Keyword(s):  
Growth Rate ◽  
Competitive Ability ◽  
Growth Habit ◽  
Biomass Accumulation ◽  
Growing Season ◽  
Similar Reduction ◽  
Relative Growth ◽  
Use Efficiency ◽  
Common Purslane ◽  
Prostrate Growth

Growth habit is an important determinant of competitive ability in legume crops. Erect ‘Iron-Clay’ (IC), semi-erect ‘IT89KD-288’ (288), and prostrate ‘UCR 779’ (779) cowpea genotypes were planted with four densities of common sunflower or common purslane to determine which cowpea growth habit is more competitive to these weeds having markedly different statures. Both sunflower and purslane reduced cowpea relative growth rate (RGR) but at different phases of the growing season. Low-growing purslane had an effect in the earlier part of the season, and sunflower decreased cowpea RGR in the middle of growing season. RGR of genotype IC was the least affected and genotype 779 the most reduced by sunflower. Cowpea apparently compensated for early season purslane competition by increasing RGR after purslane flowering, with RGR for the IC genotype increasing the most and 779 increasing the least. All cowpea genotypes caused a similar reduction in sunflower biomass accumulation; but purslane biomass was most reduced by genotype IC and least affected by genotype 288. Erect genotype IC is more competitive due to its taller stature, greater height growth rate, and higher position of maximal leaf area density, despite a lower photosynthetic rate and light use efficiency than the other cowpea genotypes. Our results suggest that erect cowpea growth habit may be generally more competitive with weeds compared to semi-erect or prostrate growth habit.

scholarly journals Influence of sulphur on morpho-physiological and yield parameters of rapeseed (Brassica campestris L.)

2013 ◽  
Vol 37 (4) ◽  
pp. 645-652 ◽  
Author(s):  
Ferdousi Begum ◽  
Feroza Hossain ◽  
Md Rafiqul Islam Mondal
Keyword(s):  
Growth Rate ◽  
Leaf Area ◽  
Seed Yield ◽  
Field Experiments ◽  
Growth Parameters ◽  
Research Station ◽  
Dry Matter Accumulation ◽  
Central Research ◽  
Area Index ◽  
Yield Attributes

Field experiments were conducted at the Central Research Station of Bangladesh Agricultural Research Institute (BARI), Joydebpur, Gazipur during the period from November to February in 2004-05 and 2005-06 to evaluate the effect of different levels of sulphur (0, 20, 40, 60, and 80 kg/ha) on rapeseed variety BARI Sarisha-15. Results showed that the most of the growth parameters and yield attributes were significantly influenced by different doses of sulphur. The growth parameters, yield and yield contributing characters were increased with the increasing levels of sulphur fertilizer up to 60 kg S/ha and with the doses beyond that were found to decrease. All growth parameters like plant height, leaf area, dry matter accumulation, leaf area index, crop growth rate, net assimilation rate, and relative growth rate and all yield components, such as number of siliquae per plant, seeds per siliqua, 1000-seed weight and seed yield per plant were found maximum from the treatment with 60 kg S/ha, which was at par with 80 kg S/ha. The highest seed yield (1990 and 1896 kg/ha) were found when S was used @ 60 kg/ha. The same treatment gave 24.71 % and 24.32 % higher seed yield than the control treatment, which were statistically identical with dose at 80 kg /ha of sulphur in both the years. DOI: http://dx.doi.org/10.3329/bjar.v37i4.14389 Bangladesh J. Agril. Res. 37(4): 645-652, December 2012

Critical Period for Weed Control in Grafted and Nongrafted Watermelon Grown in Plasticulture

Weed Science ◽  
2018 ◽  
Vol 67 (2) ◽  
pp. 221-228 ◽  
Author(s):  
Matthew B. Bertucci ◽  
Katherine M. Jennings ◽  
David W. Monks ◽  
Jonathan R. Schultheis ◽  
Frank J. Louws ◽  
...  
Keyword(s):  
Weed Control ◽  
Critical Period ◽  
Field Experiments ◽  
Citrullus Lanatus ◽  
Weed Species ◽  
Yellow Nutsedge ◽  
Study Results ◽  
Seedless Watermelon ◽  
Common Purslane ◽  
Weed Removal

AbstractField experiments determined the critical period for weed control (CPWC) in grafted and nongrafted watermelon [Citrullus lanatus(Thumb.) Matsum. & Nakai] grown in plasticulture. Transplant types included ‘Exclamation’ seedless watermelon as the nongrafted control as well as Exclamation grafted onto two interspecific hybrid squash (ISH) rootstocks, ‘Carnivor’ and ‘Kazako’. To simulate weed emergence throughout the season, establishment treatments (EST) consisted of two seedlings each of common purslane (Portulaca oleraceaL.), large crabgrass [Digitaria sanguinalis(L.) Scop.], and yellow nutsedge (Cyperus esculentusL.) transplanted in a 15 by 15 cm square centered on watermelon plants at 0, 2, 3, 4, and 6 wk after watermelon transplanting (WATr) and remained until the final watermelon harvest at 11 WATr. To simulate weed control at different times in the season, removal treatments (REM) consisted of two seedlings of the same weed species transplanted in a 15 by 15 cm square centered on watermelon plants on the same day of watermelon transplanting and allowed to remain until 2, 3, 4, 6, and 11 WATr, at which time they were removed. Season-long weedy and weed-free controls were included for both EST and REM studies in both years. For all transplant types, aboveground biomass of weeds decreased as weed establishment was delayed and increased as weed removal was delayed. The predicted CPWC for nongrafted Exclamation and Carnivor required only a single weed removal between 2.3 and 2.5 WATr and 1.9 and 2.6 WATr, respectively, while predicted CPWC for Kazako rootstock occurred from 0.3 to 2.6 WATr. Our study results suggest that weed control for this mixed population of weeds would be similar between nongrafted Exclamation and Exclamation grafted onto Carnivor. But the observed CPWC of Exclamation grafted onto Kazako suggests that CPWC may vary with specific rootstock–scion combinations.

Influence of Nitrogen Status on the Sensitivity of Glyphosate-Resistant and -Susceptible Tall Waterhemp (Amaranthus tuberculatus) and Palmer Amaranth (Amaranthus palmeri)

Weed Science ◽  
2016 ◽  
Vol 64 (4) ◽  
pp. 735-742 ◽  
Author(s):  
Jonathon R. Kohrt ◽  
Julie M. Young ◽  
Joseph L. Matthews ◽  
Bryan G. Young
Keyword(s):  
Growth Rate ◽  
Crop Production ◽  
Field Experiments ◽  
Nutrient Status ◽  
Palmer Amaranth ◽  
Fertilizer Treatment ◽  
Weed Species ◽  
Corn Production ◽  
Volume Number ◽  
Amaranthus Tuberculatus

Anecdotal observations of improved glyphosate efficacy on glyphosate-resistant (GR) tall waterhemp populations in corn production compared with soybean suggested the presence of nitrogen (N) fertilizer may influence the expression of glyphosate resistance. Greenhouse and field experiments were conducted to determine the influence of soil-applied nitrogen fertilizer on the growth rate and sensitivity of glyphosate-susceptible (GS) and GR tall waterhemp and Palmer amaranth. The addition of supplemental fertilizer increased the relative growth rate (plant height and shoot volume), number of nodes, and percentage of shoot nodes with axillary branches on GS and GR biotypes of both weed species. The axillary bud activity was increased 52 and 8% with increasing N for the GR and GS biotypes of tall waterhemp and Palmer amaranth, respectively. The GS populations of tall waterhemp and Palmer amaranth were more sensitive to glyphosate in the greenhouse under increased fertilizer levels compared with no fertilizer. Additionally, GR tall waterhemp was more sensitive to glyphosate under the higher fertilizer treatments, which resulted in a reduction in the calculated resistance factor (RF) from 27.8 under no fertilizer to 4.7 for the high fertilizer treatment. The RF for GR Palmer amaranth was not influenced by the fertilizer treatments in the greenhouse. Field experiments demonstrated that glyphosate efficacy may be greater on GR populations of tall waterhemp and Palmer amaranth under high N conditions, but these results were not consistent and most likely were influenced by soil moisture in 2012, which was more limiting than N supply. This research implies that soil fertility can influence the sensitivity of some GR weed species to glyphosate and the RF. Therefore, the evolution and management of GR weed species in commercial crop production may be influenced by the nutrient status of the soil and the use of supplemental fertilizers.

scholarly journals Drought and Ozone Stress Effects on Competition among Selected Prairie Grass Species and Giant Foxtail

1999 ◽  
Vol 9 (2) ◽  
pp. 227-234 ◽  
Author(s):  
Gregory A. Endress ◽  
Anton G. Endress ◽  
Louis R. Iverson
Keyword(s):  
Leaf Area ◽  
Water Availability ◽  
Relative Yield ◽  
Leaf Number ◽  
Grass Species ◽  
Big Bluestem ◽  
Weed Species ◽  
Replacement Series ◽  
Giant Foxtail ◽  
The Impact

Differential responses of species to environmental stress may interfere with restoration of prairie ecosystems or change community structure. The impact of increasing atmospheric ozone (O3) concentrations and/or low water on the growth of Andropogon gerardii Vitm. (big bluestem) and Sorghastrum nutans (L.) Nash (indian grass), two common warm-season native grasses, and Setaria faberi Herrm. (giant foxtail), a vigorous annual weed species, were studied in replacement series. Giant foxtail grew better than either big bluestem or indian grass under all tested conditions. The leaf areas of all three species were primarily controlled by water availability. Big bluestem and indian grass accumulated biomass equally well under high water availability, but with low water, indian grass accumulated more biomass than did bluestem. Three-way analysis of variance showed biomass, leaf area, and leaf number differed among species; low water was significant in all cases except for indian grass leaf area; and the O3 effect was significant only in the case of foxtail biomass. The interaction of O3 concentration and low water was significant only for indian grass biomass and leaf number; the interaction of species combination and low water was significant only for big bluestem leaf area and biomass. Relative yield calculations indicated that under conditions of elevated O3 and low water, big bluestem was the least competitive, while indian grass was most competitive. Intraspecific competition was common, each species apparently utilizing the environment in different ways. The results also suggest that giant foxtail at a low relative density may be used as a nurse species in prairie restorations as growth of big bluestem and indian grass were improved when in mixtures with foxtail.

Competition between wheat and canarygrass biotypes and their response to herbicides

Weed Science ◽  
1999 ◽  
Vol 47 (1) ◽  
pp. 55-61 ◽  
Author(s):  
Catherine G. Afentouli ◽  
Ilias G. Eleftherohorinos
Keyword(s):  
Growth Rate ◽  
Grain Yield ◽  
Competitive Ability ◽  
Field Experiments ◽  
Wheat Yield ◽  
Wheat Grain ◽  
Weed Species ◽  
Stages Of Growth ◽  
Early Stages ◽  
Herbicide Control

Field experiments were conducted in Thessaloniki, Greece, from 1991 to 1994 to study the competition of littleseed canarygrass and short-spiked canarygrass biotypes in wheat and to evaluate their response to diclofop, fenoxaprop, tralkoxydim, and CGA-184927. Competitive ability of all canarygrass biotypes was similar, though species differed in panicle numbers. All littleseed canarygrass biotypes showed faster growth rate than the short-spiked canarygrass biotypes. Wheat grain yield decreased as canarygrass density increased. For example, 152 and 304 canarygrass plants m–2reduced wheat yield 32 and 42%, respectively. None of the canarygrass biotypes at any density had any effect on grain yield of wheat when cold and dry weather prevailed during the early stages of growth. CGA-184927 and tralkoxydim were more effective herbicides against all short-spiked canarygrass biotypes than fenoxaprop and diclofop. CGA-184927 and fenoxaprop provided > 98% control of all littleseed canarygrass biotypes; control with tralkoxydim was < 80%; and diclofop gave 82 to 96% control of this weed species. Herbicide control of canarygrass increased wheat yield relative to the weedy control, and only diclofop was phytotoxic to wheat.

Influence of interference from a mixed weed species stand on soybean (Glycine max (L.) Merr.) growth

1993 ◽  
Vol 73 (4) ◽  
pp. 1293-1304 ◽  
Author(s):  
Rene C. Van Acker ◽  
Stephan F. Weise ◽  
Clarence J. Swanton
Keyword(s):  
Glycine Max ◽  
Growth Analysis ◽  
Field Experiments ◽  
Weight Ratio ◽  
Dry Weight ◽  
Development Stage ◽  
Yield Component ◽  
Weed Species ◽  
Weed Interference ◽  
Net Assimilation

Field experiments were conducted to examine soybean-weed interactions under Ontario conditions. Trials were conducted at Elora, Ontario in 1990 and 1991 using comparative growth analysis to investigate the aboveground response of soybean to weed interference from a mixed weed species stand. Although season-long weed interference caused a significant decrease in soybean grain yield, weeds could remain in the crop up to 40 d after emergence, between R1 and beginning pod development stage (R3), in 1990 and up to 16 d after emergence, 3rd node development stage (V3), in 1991 without causing more than a 5% yield loss. These critical times of weed removal coincided with the timing of significant effects of weed interference on soybean LAI. Weed interference also significantly reduced total aboveground soybean dry weight and crop growth rate. Pods m−2 was the yield component most affected by season-long weed interference. Although there was no consistent effect of weed interference upon net assimilation rate and leaf weight ratio, weed interference resulted in a decrease in dry weight distribution to branch stems, causing as much as a fivefold reduction in allocation to branch stems. It may be useful to develop early branching soybean varieties, or use narrower row spacing, to enhance soybean competitiveness against weeds. Key words: Soybean (Glycine max), weed interference, growth analysis, leaf area, yield components

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