Optimising initial population density, growth time and nitrogen nutrition for assessing resistance of wheat cultivars to root-lesion nematode (Pratylenchus thornei)

2015 ◽  
Vol 44 (2) ◽  
pp. 133-147 ◽  
Author(s):  
J. P. Thompson ◽  
T. G. Clewett ◽  
M. M. O’Reilly
Keyword(s):  
Population Density ◽  
Nitrogen Nutrition ◽  
Growth Time ◽  
Initial Population ◽  
Wheat Cultivars ◽  
Root Lesion Nematode ◽  
Initial Population Density ◽  
Pratylenchus Thornei ◽  
Density Growth ◽  
Lesion Nematode

scholarly journals Impacts of Root-Lesion Nematode (Pratylenchus thornei) on Plant Nutrition, Biomass, Grain Yield and Yield Components of Susceptible/Intolerant Wheat Cultivars Determined by Nematicide Applications

Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 296
Author(s):  
John P. Thompson ◽  
Timothy G. Clewett
Keyword(s):  
Grain Yield ◽  
Yield Components ◽  
Root Zone ◽  
Wheat Cultivars ◽  
Root Lesion Nematode ◽  
Population Densities ◽  
Poor Growth ◽  
Pratylenchus Thornei ◽  
Lesion Nematode ◽  
The Impact

Field experiments testing rates of various nematicides, with and without NPZn fertiliser, were analysed to investigate how root-lesion nematode (Pratylenchus thornei) affects growth and yield components of susceptible/intolerant wheat cultivars in a subtropical environment. Plant response to nematode attack was assessed by regression and principal components analyses of various plant parameters at different crop development stages, in relation to different nematode population densities in the roots and root-zone soil. Reduction in P. thornei population densities by nematicides resulted in increased numbers of tillers, plant biomass, N and P concentrations and uptakes, numbers of spikes and kernels, and grain yield. Grain yield was strongly correlated with number of kernels, biomass and number of spikes, and negatively correlated with number of P. thornei in the root-zone soil at stem elongation. This study showed that P. thornei damage to roots decreased wheat yield through limiting N and P concentrations and uptakes in plant tops causing poor growth that commenced early and continued through the life of the crop. Genetic, environmental and management factors that reduce population densities of P. thornei, and decrease the impact of the nematodes starting in early crop growth, will greatly increase spike and kernel numbers and grain yield.

Effect of initial population density ofPratylenchus brachyuruson maize

2006 ◽  
Vol 39 (3) ◽  
pp. 205-208 ◽  
Author(s):  
P. S. Chindo ◽  
A. M. Emechebe ◽  
P. S. Marley
Keyword(s):  
Population Density ◽  
Initial Population ◽  
Initial Population Density

Metabolomic profiling of wheat genotypes resistant and susceptible to root-lesion nematode Pratylenchus thornei

2021 ◽  
Author(s):  
Md Motiur Rahaman ◽  
Rebecca S. Zwart ◽  
Thusitha W. T. Rupasinghe ◽  
Helen L. Hayden ◽  
John P. Thompson
Keyword(s):  
Root Lesion Nematode ◽  
Wheat Genotypes ◽  
Metabolomic Profiling ◽  
Pratylenchus Thornei ◽  
Lesion Nematode

scholarly journals A theoretical framework for multi-species range expansion in spatially heterogeneous landscapes

2021 ◽  
Author(s):  
Lukas Eigentler ◽  
Nicola R Stanley-Wall ◽  
Fordyce A Davidson
Keyword(s):  
Population Density ◽  
Range Expansion ◽  
Theoretical Framework ◽  
Dominant Mode ◽  
Bacterial Biofilm ◽  
Time Interval ◽  
Initial Population ◽  
Initial Population Density ◽  
Competitive Outcome ◽  
The Impact

Range expansion is the spatial spread of a population into previously unoccupied regions. Understanding range expansion is important for the study and successful manipulation and management of ecosystems, with applications ranging from controlling bacterial biofilm formation in industrial and medical environments to large scale conservation programmes for species undergoing climate-change induced habitat disruption. During range expansion, species typically encounter competitors. Moreover, the environment into which expansion takes place is almost always heterogeneous when considered at the scale of the individual. Despite the ubiquitous nature of these features, the impact of competition and spatial landscape heterogeneities on range expansion remains understudied. In this paper we present a theoretical framework comprising two competing generic species undergoing range expansion and use it to investigate the impact of spatial landscape heterogeneities on range expansion with a particular focus on its effect on competition dynamics. We reveal that the area covered by range expansion during a fixed time interval is highly variable due to the fixed landscape heterogeneities. Moreover, we report significant variability in competitive outcome (relative abundance of a focal species) but determine that this is induced by low initial population densities, independent of landscape heterogeneities. We further show that both area covered by range expansion and competitive outcome can be accurately predicted by a Voronoi tessellation with respect to an appropriate metric, which only requires information on the spatial landscape and the response of each species to that landscape. Finally, we reveal that if species interact antagonistically during range expansion, the dominant mode of competition depends on the initial population density. Antagonistic actions determine competitive outcome if the initial population density is high, but competition for space is the dominant mode of competition if the initial population density is low.

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