scholarly journals Response of tomato plants carrying Mi-1 gene to Meloidogyne incognita (Kofoid & White, 1919) Chitwood, 1949 under high soil temperatures

2018 ◽  
pp. 313-322 ◽  
Author(s):  
Zübeyir Devran ◽  
Tevfik Özalp
Keyword(s):  
Meloidogyne Incognita ◽  
Tomato Plants ◽  
High Soil ◽  
Soil Temperatures

scholarly journals White Root Rot of Raspberries

1951 ◽  
Vol 4 (3) ◽  
pp. 211
Author(s):  
GC Wade
Keyword(s):  
Soil Moisture ◽  
Root Rot ◽  
Soil Moisture Content ◽  
Soil Conditions ◽  
Causal Organism ◽  
White Root Rot ◽  
High Soil Moisture ◽  
High Soil ◽  
Soil Temperatures ◽  
Dry Soil

The disease known as white root rot affects raspberries, and to a less extent loganberries, in Victoria. The causal organism is a white, sterile fungus that has not been identified. The disease is favoured by dry soil conditions and high soil temperatures. It spreads externally to the host by means of undifferentiated rhizomorphs; and requires a food base for the establishment of infection. The spread of rhizomorphs through the soil is hindered by high soil moisture content and consequent poor aeration of the soil.

scholarly journals Systemically Induced Resistance and Microbial Competitive Exclusion: Implications on Biological Control

2012 ◽  
Vol 102 (3) ◽  
pp. 260-266 ◽  
Author(s):  
A. Martinuz ◽  
A. Schouten ◽  
R. A. Sikora
Keyword(s):  
Meloidogyne Incognita ◽  
Defense Mechanisms ◽  
Root Colonization ◽  
Competitive Exclusion ◽  
Spatial Separation ◽  
Agricultural Pests ◽  
Root Knot Nematode ◽  
Tomato Plants ◽  
Split Root ◽  
Induce Resistance

The root-knot nematode, Meloidogyne incognita, is among the most damaging agricultural pests, particularly to tomato. The mutualistic endophytes Fusarium oxysporum strain Fo162 (Fo162) and Rhizobium etli strain G12 (G12) have been shown to systemically induce resistance toward M. incognita. By using triple-split-root tomato plants, spatially separated but simultaneous inoculation of both endophytes did not lead to additive reductions in M. incognita infection. More importantly, spatially separated inoculation of Fo162 and G12 led to a reduction in Fo162 root colonization of 35 and 39% when G12 was inoculated on a separate root section of the same plant in two independent experiments. In an additional split-root experiment, spatial separation of Fo162 and G12 resulted in a reduction of Fo162 root colonization of approximately 50% over the water controls in two independent experiments. The results suggested that the suppressive activity of G12 on Fo162 and M. incognita is possibly related to the induction of specific plant defense mechanisms. Thus, although Fo162 and G12 have the ability to systemically repress M. incognita infection in tomato, they can be considered incompatible biocontrol agents when both organisms are present simultaneously on the same root system.

scholarly journals Multiyear Evaluation of the Durability of the Resistance Conferred by Ma and RMia Genes to Meloidogyne incognita in Prunus Under Controlled Conditions

2013 ◽  
Vol 103 (8) ◽  
pp. 833-840 ◽  
Author(s):  
Samira Khallouk ◽  
Roger Voisin ◽  
Ulysse Portier ◽  
Joël Polidori ◽  
Cyril Van Ghelder ◽  
...  
Keyword(s):  
Meloidogyne Incognita ◽  
Economic Losses ◽  
R Gene ◽  
R Genes ◽  
Tomato Plants ◽  
Controlled Conditions ◽  
Meloidogyne Spp ◽  
Resistance Breakdown ◽  
Susceptible Tomato ◽  
Prunus Spp

Root-knot nematodes (RKNs) (Meloidogyne spp.) are highly polyphagous pests that parasitize Prunus crops in Mediterranean climates. Breeding for RKN-resistant Prunus cultivars, as an alternative to the now-banned use of nematicides, is a real challenge, because the perennial nature of these trees increases the risk of resistance breakdown. The Ma plum resistance (R) gene, with a complete spectrum, and the RMia peach R gene, with a more restricted spectrum, both provide total control of Meloidogyne incognita, the model parthenogenetic species of the genus and the most important RKN in terms of economic losses. We investigated the durability of the resistance to this nematode conferred by these genes, comparing the results obtained with those for the tomato Mi-1 reference gene. In multiyear experiments, we applied a high and continuous nematode inoculum pressure by cultivating nematode-infested susceptible tomato plants with either Prunus accessions carrying Ma or RMia R genes, or with resistant tomato plants carrying the Mi-1 gene. Suitable conditions for Prunus development were achieved by carrying out the studies in a glasshouse, in controlled conditions allowing a short winter leaf fall and dormancy. We first assessed the plum accession ‘P.2175’, which is heterozygous for the Ma gene, in two successive 2-year evaluations, for resistance to two M. incognita isolates. Whatever the isolate used, no nematodes reproducing on P.2175 were detected, whereas galls and nematodes reproducing on tomato plants carrying Mi-1 were observed. In a second experiment with the most aggressive isolate, interspecific full-sib material (P.2175 × [‘Garfi’ almond × ‘Nemared’ peach]), carrying either Ma or RMia (from Nemared) or both (in the heterozygous state) or neither of these genes, was evaluated for 4 years. No virulent nematodes developed on Prunus spp. carrying R genes, whereas galling and virulent individuals were observed on Mi-1-resistant tomato plants. Thus, the resistance to M. incognita conferred by Ma in Prunus material in both a pure-plum and an interspecific genetic background, or by RMia in an interspecific background, appears to be durable, highlighting the value of these two genes for the creation of Prunus rootstock material.

The Effects of Temperature and Humidity on a Field Population of Bradysia odoriphaga (Diptera: Sciaridae)

2020 ◽  
Vol 113 (4) ◽  
pp. 1927-1932
Author(s):  
Cai-hua Shi ◽  
Jing-rong Hu ◽  
You-jun Zhang
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Control Strategies ◽  
Beijing City ◽  
Drought Treatment ◽  
High Soil ◽  
Soil Temperatures ◽  
Water Contents ◽  
Soil Water Contents

Abstract The production of Chinese chives is reduced throughout China due to a root-feeding dipteran pest Bradysia odoriphaga Yang et Zhang (Diptera: Sciaridae), therefore deciphering the conditions influencing its growth and development are important in developing ecological control strategies. A study was conducted from 2014 to 2017 to determine the relationship between the abundance of B. odoriphaga and temperature (atmospheric and soil), soil water content, and atmospheric humidity in a Chinese chive field in Beijing City, China. Numbers of adults peaked in March and October to November and were lowest in July to August and December to next February; numbers of larvae were highest in December to next February and lowest in July to August. From 2014 to 2017, the numbers of adults and larvae were significantly correlated with monthly mean atmospheric temperatures and soil temperatures, but were not significantly correlated with monthly mean atmospheric relative humidity and soil water content. However, for both adults and larvae, numbers were significantly greater with high soil water contents compared with drought treatment. The results of this study suggest that the very low soil water contents, high atmospheric temperatures, and high soil temperatures were critical for regulating field populations of B. odoriphaga.

Comparison of host recognition, invasion, development and reproduction of Meloidogyne graminicola and M. incognita on rice and tomato

Nematology ◽  
2011 ◽  
Vol 13 (5) ◽  
pp. 509-520 ◽  
Author(s):  
Tushar K. Dutta ◽  
Stephen J. Powers ◽  
Brian R. Kerry ◽  
Hari S. Gaur ◽  
Rosane H.C. Curtis
Keyword(s):  
Meloidogyne Incognita ◽  
Host Recognition ◽  
Cortical Region ◽  
Root Knot Nematode ◽  
Root Tips ◽  
Root Knot Nematodes ◽  
Tomato Plants ◽  
Meloidogyne Graminicola ◽  
Second Stage ◽  
Tomato Roots

AbstractThe rice root-knot nematode Meloidogyne graminicola normally infects rice, wheat and several other graminaceous plants. Meloidogyne incognita is a serious pest of dicotyledonous crops, although it can infect and reproduce on some cereals. This paper demonstrates and compares host recognition, development and reproduction of these two species of root-knot nematodes on rice and tomato plants. Attraction bioassays in pluronic gel clearly showed that M. incognita preferred tomato roots to rice or mustard roots, whilst M. graminicola was more attracted towards rice compared with tomato or mustard roots. Based on the attraction data from this study, it can be hypothesised that either: i) the blend of attractants and repellents are different in good and poor hosts; or ii) relatively long-range attractants, together with shorter-range repellents, might affect nematode movement patterns. Some host specific attractants might also be involved. Meloidogyne incognita was able to invade and develop to adult female but did not produce eggs in rice roots. By contrast, M. graminicola developed and reproduced faster on both rice and tomato plants compared with M. incognita. Nevertheless, second-stage juveniles of both these root-knot nematodes showed a similar pattern of distribution inside the roots, preferring to accumulate at the root tips of rice or in the vascular cylinder and cortical region of tomato.

Seed germination and seedling establishment of Calamovilfa longifolia on Lake Huron sand dunes

1981 ◽  
Vol 59 (4) ◽  
pp. 460-469 ◽  
Author(s):  
M. A. Maun
Keyword(s):  
Sand Dunes ◽  
Linear Increase ◽  
Lake Huron ◽  
Fluorescent Light ◽  
Seedling Mortality ◽  
High Soil ◽  
Soil Temperatures ◽  
Number Of Leaves ◽  
Growth Chambers ◽  
Calamovilfa Longifolia

Caryopses ("seeds") of Calamovilfa longifolia (Hook.) Scribn. are dimorphic (brown and white) and are each enclosed in a lemma and palea. The most complete germination was obtained in lighted (fluorescent light of 1600 lx) growth chambers set at alternating temperatures of 25 °C day (14 h) and 10 °C night. Seed stratification did not increase total germination but the rate of germination was increased. The seeds imbibed about 50% by weight of water before germination was initiated.Under field conditions seeds accumulated in depressions. Seedlings failed to emerge from depths greater than 6 cm. The survival rate of seedlings was very low (0.5%) during 1978 because of a dry summer but was considerably higher in 1979 on south slopes (33%), under willow clumps (44%), and on north slopes (56%). Seedling mortality was due to high soil temperatures, desiccation, burial or exposure of seedlings, and biotic agents. Seedlings emerged from the soil mainly by elongation of the first internode. The coleoptile seemed to act as a protective sheath against high soil temperatures for the growing point enclosed within it. A significantly linear increase in height of seedlings, root length, and number of leaves occurred with an increase in the age of seedlings during both years.

Sign in / Sign up

Export Citation Format

Share Document