scholarly journals Effect of plant populations on the incidence of bean stem maggot (Ophiomyia spp.) in common bean intercropped with maize

2009 ◽  
Vol 45 (No. 4) ◽  
pp. 149-155
Author(s):  
K.H. Peter ◽  
G.B. Swella ◽  
D.M.K. Mushobozy
Keyword(s):  
Common Bean ◽  
Management Strategy ◽  
Plant Population ◽  
Optimum Combination ◽  
Plant Populations ◽  
Stem Damage ◽  
First Time ◽  
Ophiomyia Phaseoli ◽  
Bean Stem Maggot

Effects of three intercrop combinations and plant populations on bean stem maggot <i>Ophiomyia phaseoli</i>; <i>O. spencerella</i> and <i>O. centrosematis</i> was observed; with the latter being reported in Morogoro for the first time. The infestation was higher in the pure stands of beans than in the intercrops and decreased gradually down to two-thirds maize. The incidence of <i>Ophiomyia</i> spp. decreased with increasing plant populations. Low counts of larvae and pupae were recorded in intercrops. Stem damage was higher in pure bean plots, which also had higher larvae and pupae counts. The intercrop combinations gave a yield advantage at all plant populations except at population P<sub>3</sub> for one – third maize two thirds bean mixture. The highest yield advantage was obtained at P<sub>2</sub> for two thirds maize – one third beans treatment suggesting it to be the optimum combination for the two crops. It is concluded that a combination of BMM (one third bean-two thirds maize) at plant population P<sub>2</sub> may be considered as one of the <i>Ophiomyia</i> spp. management strategy in common bean.

A Systematic Design to Examine Effects of Plant Population and Spatial Arrangement in Intercropping, Illustrated by an Experiment on Chickpea/Safflower

1981 ◽  
Vol 17 (1) ◽  
pp. 63-73 ◽  
Author(s):  
R. W. Willey ◽  
M. R. Rao
Keyword(s):  
Total Population ◽  
Spatial Arrangement ◽  
Plant Population ◽  
Optimum Combination ◽  
Initial Increase ◽  
Systematic Design ◽  
Plant Populations

SUMMARYAn intercropping experiment is described, using a parallel-row systematic design, to examine four plant populations of chickpea in all combinations with 15 systematically arranged populations of safflower in 1:1 and 2:1 row arrangements; four populations of the sole crops were included. Safflower was usually dominant and increasing the total population (i.e. both crops combined) made it more so. Safflower yield was little affected by changes in its own population and was independent of changes in the chickpea population. Chickpea yield increased with increase in its own population and it was the dominant crop at high chickpea/low safflower populations. An initial increase in safflower population caused an increase in chickpea yield at the 1:1 row arrangement; otherwise increasing safflower population decreased chickpea yield. LERs at 2:1 indicated no real evidence of yield advantages for intercropping. At 1:1 advantages ranged up to 19%, with a maximum where the highest chickpea population was combined with a low safflower one. This optimum combination could not have been identified with earlier designs.

scholarly journals Genetic characterization at the species and symbiovar level of indigenous rhizobial isolates nodulating Phaseolus vulgaris in Greece

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Evdoxia Efstathiadou ◽  
Georgia Ntatsi ◽  
Dimitrios Savvas ◽  
Anastasia P. Tampakaki
Keyword(s):  
Phaseolus Vulgaris ◽  
Common Bean ◽  
Phylogenetic Affiliation ◽  
Rhizobial Inoculation ◽  
Rhizobial Species ◽  
The Common ◽  
First Time ◽  
Of Greece ◽  
Rhizobial Isolates

AbstractPhaseolus vulgaris (L.), commonly known as bean or common bean, is considered a promiscuous legume host since it forms nodules with diverse rhizobial species and symbiovars. Most of the common bean nodulating rhizobia are mainly affiliated to the genus Rhizobium, though strains belonging to Ensifer, Pararhizobium, Mesorhizobium, Bradyrhizobium, and Burkholderia have also been reported. This is the first report on the characterization of bean-nodulating rhizobia at the species and symbiovar level in Greece. The goals of this research were to isolate and characterize rhizobia nodulating local common bean genotypes grown in five different edaphoclimatic regions of Greece with no rhizobial inoculation history. The genetic diversity of the rhizobial isolates was assessed by BOX-PCR and the phylogenetic affiliation was assessed by multilocus sequence analysis (MLSA) of housekeeping and symbiosis-related genes. A total of fifty fast-growing rhizobial strains were isolated and representative isolates with distinct BOX-PCR fingerpriniting patterns were subjected to phylogenetic analysis. The strains were closely related to R. anhuiense, R. azibense, R. hidalgonense, R. sophoriradicis, and to a putative new genospecies which is provisionally named as Rhizobium sp. I. Most strains belonged to symbiovar phaseoli carrying the α-, γ-a and γ-b alleles of nodC gene, while some of them belonged to symbiovar gallicum. To the best of our knowledge, it is the first time that strains assigned to R. sophoriradicis and harbored the γ-b allele were found in European soils. All strains were able to re-nodulate their original host, indicating that they are true microsymbionts of common bean.

Effects of Plant Population on Sole-crop Cassava in Sierra Leone

1978 ◽  
Vol 14 (3) ◽  
pp. 239-244 ◽  
Author(s):  
W. Godfrey-Sam-Aggrey
Keyword(s):  
Sierra Leone ◽  
Yield Components ◽  
Dry Matter ◽  
Weight Ratio ◽  
Land Plant ◽  
Plant Population ◽  
Root Weight ◽  
Plant Populations ◽  
Sole Crop ◽  
Yield And Yield Components

SUMMARYEffects of plant population on mean yield and yield components of 2-year sole cassava crops were studied on Njala upland soils of Sierra Leone in two experiments. Increasing plant population of multi-shoot Cocoa cassava over 7000/ha decreased all the parameters studied except top/root weight ratio, which increased. The observed effects were attributed to competition for environmental resources, since area of land/plant unit decreased as plant population increased. The relations between plant populations and yields of fresh root and cortex dry matter were asymptotic, indicating that the respective yields were products of the vegetative phase of cropping.

scholarly journals Plant population and soil origin effects on rhizosphere nematode community composition of a range-expanding plant species and a native congener

Oecologia ◽  
2020 ◽  
Vol 194 (1-2) ◽  
pp. 237-250
Author(s):  
Rutger A. Wilschut ◽  
Kim J. H. Magnée ◽  
S. Geisen ◽  
W. H. van der Putten ◽  
O. Kostenko
Keyword(s):  
Plant Species ◽  
Plant Population ◽  
Enemy Release ◽  
Native Range ◽  
Centaurea Stoebe ◽  
Plant Populations ◽  
Range Theory ◽  
Dispersal Abilities ◽  
Population Effects ◽  
Root Feeding

Abstract Climate change causes species range expansions to higher latitudes and altitudes. It is expected that, due to differences in dispersal abilities between plants and soil biota, range-expanding plant species will become associated with a partly new belowground community in their expanded range. Theory on biological invasions predicts that outside their native range, range-expanding plant species may be released from specialist natural enemies, leading to the evolution of enhanced defence against generalist enemies. Here we tested the hypothesis that expanded range populations of the range-expanding plant species Centaurea stoebe accumulate fewer root-feeding nematodes than populations from the original range. Moreover, we examined whether Centaurea stoebe accumulates fewer root-feeding nematodes in expanded range soil than in original range soil. We grew plants from three expanded range and three original range populations of C. stoebe in soil from the original and from the new range. We compared nematode communities of C. stoebe with those of C. jacea, a congeneric species native to both ranges. Our results show that expanded range populations of C. stoebe did not accumulate fewer root-feeding nematodes than populations from the original range, but that C. stoebe, unlike C. jacea, accumulated fewest root-feeding nematodes in expanded range soil. Moreover, when we examined other nematode feeding groups, we found intra-specific plant population effects on all these groups. We conclude that range-expanding plant populations from the expanded range were not better defended against root-feeding nematodes than populations from the original range, but that C. stoebe might experience partial belowground enemy release.

Genotypic response of common bean to natural field populations of bean fly (Ophiomyia phaseoli) under diverse environmental conditions

2010 ◽  
Vol 117 (1) ◽  
pp. 139-145 ◽  
Author(s):  
Pascal P. Okwiri Ojwang ◽  
Rob Melis ◽  
Josephine M. Songa ◽  
Mwangi Githiri
Keyword(s):  
Common Bean ◽  
Environmental Conditions ◽  
Natural Field ◽  
Ophiomyia Phaseoli ◽  
Bean Fly

The influence of inter-row spacing and plant population on the yield of peanuts at Katherine, N.T

1962 ◽  
Vol 2 (4) ◽  
pp. 54 ◽  
Author(s):  
LJ Phillips ◽  
MJT Norman
Keyword(s):  
Plant Population ◽  
Row Spacing ◽  
Clay Loam ◽  
Plant Populations ◽  
Kernel Yield ◽  
Multifactorial Experiment

In 1957-58 and 1958-59, Virginia Bunch and Natal Common peanuts were sown on Tippers clay loam at Katherine, N.T., in a multifactorial experiment at two inter-row spacings (2 ft and 3 ft), four plant populations (10, 20, 40 and 80 thousand per acre) and two dates. In 1960-61, Natal Common only was sown at the same inter-row spacings, at two dates, and at populations of 10, 20, 30 and 40 thousand per acre. Over two seasons, the yield of Virginia Bunch kernels was not significantly influenced by variation in population, though the yield of hay was 42 per cent higher at 80,000 plants per acre than at 10,000 plants per acre. Kernel yields from 2 f t rows were 14 per cent higher than from 3 f t rows. In the first two seasons, the yield of Natal Common kernels was lower at 80,000 plants per acre than at 40,000 plants per acre. Over three seasons, maximum kernel and h g yields were achieved at 40,000 plants per acre ; the kernel yield at this population was 35 per cent greater than at 10,000 plants per acre. With early-planted Natal Common, 2.ft rows gave an 11 per cent higher yield of kernels than 3 f t rows, but with later planting there was no significant effect of inter-row spacing. The optimum economic seeding rates were estimated approximately as 30 lb an acre for Virginia Bunch and 45 lb an acre for Natal Common.

Effects of Sheep Grazing Astrebla Grasslands in Central Western Queensland. Iii. Dynamics of Astrebla Spp. Under Grazing and Exclosure Between 1975 and 1986.

1991 ◽  
Vol 13 (1) ◽  
pp. 36 ◽  
Author(s):  
DM Orr ◽  
CJ Evenson
Keyword(s):  
Population Dynamics ◽  
Seed Production ◽  
Basal Area ◽  
Summer Rainfall ◽  
High Variability ◽  
Plant Population ◽  
Sheep Grazing ◽  
Plant Population Dynamics ◽  
Winter Rainfall ◽  
Plant Populations

The basal area, yield and plant populations of Astrebla spp. were monitored under grazing and exclosure in Astrebla grasslands between 1975 and 1986. This study was undertaken to develop an understanding of how Astrebla spp. respond to grazing, particularly in relation to the high variability of rainfall. Basal area and yield of Astrebla spp. varied widely between years in response to summer rainfall, with few differences between exclosure and grazing. The failure of summer rainfall resulted in increased utilization of Astrebla spp. but this effect was partially offset in some years by the growth of forb species following winter rainfall. Grazing stimulated the recruitment of Astrebla spp. seedlings by increasing the density of inflorescences which, in turn, increased seed production. Survival of seedling cohorts depended on adequate summer rainfall and grazing tended to enhance cohort survival. There was a greater plant flux under grazing than under exclosure. It was concluded that rainfall is the major factor influencing the biomass and plant population dynamics of Astrebla spp. and that grazing up to about 30% utilization is not detrimental to Astrebla spp.

scholarly journals Plant Population Affects Yield and Fruit Size of Pumpkin

HortScience ◽  
1999 ◽  
Vol 34 (6) ◽  
pp. 1076-1078 ◽  
Author(s):  
Stephen Reiners ◽  
Dale I.M. Riggs
Keyword(s):  
Growth Habit ◽  
Plant Competition ◽  
Fruit Size ◽  
Field Studies ◽  
Plant Population ◽  
Lower Yield ◽  
Marketable Yield ◽  
Plant Populations ◽  
Fruit Number ◽  
Row Width

Field studies were conducted in 1996 on two pumpkin (Cucurbita pepo L.) cultivars, `Howden' (vining-type growth habit) and `Wizard' (semi-bush growth habit), at two locations to determine the effect of plant population and row width on marketable yield. Increasing plant populations from 2990 to 8960 plants per hectare resulted in significantly greater fruit number and yield at both locations and for both varieties. Average fruit size declined at the highest populations. Increasing row width from 1.8 to 3.6 m resulted in a slight but significant decrease in number of fruit per hectare with no effect on other yield parameters. At one location, the effect of row width on yield and number of fruit per hectare depended on the population. At low populations, row width did not influence yield or fruit number; at high populations, wide rows produced lower yield and fewer fruit than narrow rows. The results demonstrate that growers may increase pumpkin yield by increasing plant populations but should use narrower row widths and wider in-row spacing. Growers who choose higher populations should ensure that all inputs are optimized to reduce potential plant-to-plant competition and use regionally adapted cultivars.

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