scholarly journals A Population of Meloidogyne javanica in Spain Virulent to the Mi Resistance Gene in Tomato

Plant Disease ◽  
2001 ◽  
Vol 85 (3) ◽  
pp. 271-276 ◽  
Author(s):  
C. Ornat ◽  
S. Verdejo-Lucas ◽  
F. J. Sorribas
Keyword(s):  
Population Density ◽  
Negative Correlation ◽  
Meloidogyne Javanica ◽  
Initial Population ◽  
Initial Population Density ◽  
Tomato Yield ◽  
Final Population ◽  
Tomato Cultivars ◽  
Mi Gene ◽  
Susceptible Tomato

A population of Meloidogyne javanica virulent to Mi-gene in tomato was identified in Spain. It reproduced similarly on resistant and susceptible tomato cultivars in the greenhouse, microplots, and in the field. In monoxenic cultures, reproduction of the virulent M. javanica was higher than that of an avirulent population on resistant but not on susceptible tomatoes. The virulent population suppressed tomato yield of both resistant and susceptible tomatoes by 29% in microplots. Initial population density (Pi) was inversely correlated with Pf (final population density)/Pi on both resistant and susceptible tomatoes in the field. A negative correlation was found between Pi and tomato yield for the susceptible but not for the resistant cultivar.

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.

scholarly journals Reaction of wild Solanaceae rootstocks to the parasitism of (Meloidogyne javanica)

2019 ◽  
Vol 37 (1) ◽  
pp. 17-21 ◽  
Author(s):  
Jéssica Cardoso ◽  
Luiza Tonelli ◽  
Talita S Kutz ◽  
Fernanda D Brandelero ◽  
Thiago de O Vargas ◽  
...  
Keyword(s):  
Wild Species ◽  
Meloidogyne Javanica ◽  
Control Treatment ◽  
Egg Mass ◽  
Santa Cruz ◽  
Root Knot Nematode ◽  
Final Population ◽  
Solanum Viarum ◽  
Susceptible Tomato ◽  
Reproduction Factor

ABSTRACT Intensive production of vegetables in greenhouses can increase the amount of inoculum of soil-borne pathogens, such as the root-knot nematode. Thus, in this study we aimed to evaluate the potential of Solanaceae as rootstocks resistant to Meloidogyne javanica nematodes as an alternative to tomato grafting. The experiment consisted of seven treatments: wild species joá-vermelho (Solanum capsicoides), joá-bagudo (Solanum palinacanthum), joá-bravo (Solanum viarum), jurubeba (Solanum spp.) and the commercial tomato cultivars Santa Cruz Kada, Batalha and Guardião. The analyzed variables were gall index; egg mass index; final nematode population; reproduction factor (FR) and reaction: susceptibility, resistance and immunity; fresh shoot and root mass and number of eggs per gram of roots. The wild species joá-vermelho, joá-bagudo and jurubeba showed resistance, with the lowest indexes of galls, egg mass, final population of nematodes and number of eggs per gram of root, not differing from the resistant control treatment (hybrid rootstock Guardião), with a reproduction factor less than 1, showing potential to be used as a resistant rootstock to M. javanica. Joá-bravo species showed susceptibility to the root-knot nematode, with a FR>1, not differing from the susceptible tomato Santa Cruz Kada. These results confirm the resistance of wild species to nematode parasitism, which can prove the viability of use as possible alternative rootstocks, and reinforce the idea that more studies should be carried out aiming to provide more viable options for farmers and plantlet producers.

scholarly journals RESISTANCE OF POTATO GENOTYPES TO Meloidogyne javanica

2017 ◽  
Vol 30 (2) ◽  
pp. 536-540 ◽  
Author(s):  
JAQUELINE TAVARES SCHAFER ◽  
CESAR BAUER GOMES ◽  
ARIONE DA SILVA PEREIRA ◽  
FERNANDA FERREIRA CRUZ ◽  
DANIELLE RIBEIRO DE BARROS
Keyword(s):  
Potato Cultivar ◽  
Meloidogyne Javanica ◽  
Temperate Climate ◽  
Initial Population ◽  
Nematode Reproduction ◽  
Potato Plants ◽  
Final Population ◽  
Susceptible Control ◽  
Different Levels ◽  
Reproduction Factor

ABSTRACT The objective of this study was to evaluate the resistance of a group of clones and cultivars from the potato breeding program of Embrapa to Meloidogyne javanica. The experiment was conducted at Embrapa Temperate Climate, Pelotas / RS, under greenhouse conditions at temperatures of 25 ± 5°C. Individual potato plants of different genotypes [BRSIPR Bel, BRS F63 (Camila), CL02-05, F23-11-06, F32-02-06, F38-03-07, F189-09-06, F23-24-06 and F22-01-08], kept in pots with sterilized soil were inoculated with 5,000 eggs and J2 of M. javanica, using six replicates per treatment. The susceptible control, potato cultivar BRS Ana was inoculated with the same level of inoculum. Fifty-five days after inoculation, the number of galls on the roots of each plant was determined as well as the number of protuberances caused by nematodes in the different treatments. Then, the roots of each plant were processed for counting the number of eggs and J2, as well as determining the nematode reproduction factor (FR: final population / initial population). All genotypes were susceptible (FR> 1.00) to M. javanica. However, there were different levels of susceptibility among the cultivars tested.

Experiment on obtaining an algologically pure culture of Tetraselmis viridis in non-sterile conditions

2020 ◽  
pp. 94-100
Author(s):  
Svetlana Yu. Gorbunova ◽  
Rudolf P. Trenkenshu
Keyword(s):  
Population Density ◽  
Pure Culture ◽  
Sea Water ◽  
The Black Sea ◽  
Initial Population ◽  
Green Microalgae ◽  
Infected Culture ◽  
Initial Population Density ◽  
Mechanical Removal ◽  
Tetraselmis Viridis

The possibility of obtaining an algologically pure culture of Tetraselmis viridis, grown on the Black Sea water in non-sterile conditions, was shown experimentally. Our experiments showed that at low initial population density of the culture after 1–3 days, there was an infection of the culture with blue-green species of microalgae (Oscillatoria sp.). Thrice repeated mechanical removal of blue-green microalgae cells by filtering the infected culture allowed obtaining an algologically pure culture of T. viridis. Under similar conditions of T. viridis cultivation, but with the initial addition of NaCl (15 g/l) to the nutrient medium aimed at increasing salinity to the Mediterranean level, there was no contamination of the culture.

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