Showing papers on "Globodera rostochiensis published in 1985"
TL;DR: Histological changes in roots of potato plants with the gene H 1, which confers resistance to the potato cyst-nematode Globedera rostochiensis pathotype Ro 1, are described for periods of 24 h to 10 days after invasion by second-stage juveniles of G. rost Cochiensis.
Abstract: Histological changes in roots of potato plants with the gene H 1 , which confers resistance to the potato cyst-nematode Globedera rostochiensis pathotype Ro 1, are described for periods of 24 h to 10 days after invasion by second-stage juveniles of G. rostochiensis . The changes are compared with those which occur in roots of a susceptible cultivar. Experiments were carried out on potato roots growing from sprouting tuber pieces on water agar. Root cells surrounding the invading nematode undergo a hypersensitive-like response and become necrotic. Cell walls of inner cortical and stelar cells adjacent to the stylet of the invading nematode break down to form a syncytial complex but cells surrounding the syncytium become necrotic, presumably limiting movement of nutrients from plant to nematode. Ultrastructural changes of cells in the cortex and the stele are illustrated and discussed.
85 citations
TL;DR: Diapause was therefore demonstrated unequivocally in this population of G. rostochiensis, and must have been caused by environmental conditions during development of the females on potato roots.
Abstract: Hatching of G. rostochiensis Ro1 in picrolonic acid, distilled water and potato root diffusate was studied simultaneously at two laboratories. Although conditions of culture and storage of the nematodes, production of the diffusate and methods of hatching were standardised, there were differences in the proportion of viable eggs that hatched. These were probably due to discrepancies in the assessment of viability of unhatched eggs, compounded by differences in efficacy of the diffusates produced in the two laboratories. Hatch tended to be slow and prolonged in tests in autumn and early winter and rapid in spring and summer. Hatching curves differed for cysts from the same population reared at the two locations. Diapause was therefore demonstrated unequivocally in this population of G. rostochiensis. It must have been caused by environmental conditions during development of the females on potato roots.
38 citations
TL;DR: Scanning microdensitometry showed that stimulation of hatch by potato root diffusate increased lipid utilization by the unhatched juvenile and late hatching individuals had a significantly reduced lipid content at eclosion.
Abstract: The potential infectivity of second stage juveniles of Globodera rostochiensis was influenced by the amount of their lipid reserves at the time of hatching. Scanning microdensitometry showed that stimulation of hatch by potato root diffusate increased lipid utilization by the unhatched juvenile and late hatching individuals had a significantly reduced lipid content at eclosion. Late hatching juveniles had impaired infectivity and delayed development compared with juveniles emerging from the same cysts soon after stimulation. This effect was not caused by initial differences in lipid content. The results are discussed in the context of the significance of delayed hatching in G. rostochiensis.
26 citations
TL;DR: Hatch and unhatched second stage juveniles of the potato cyst-nematode, Globodera rostochiensis can survive sub-zero temperatures by supercooling when not in contact with water, but when frozen in water free juveniles cannot survive ice seeding across the cuticle and concomitant freezing of their body contents.
22 citations
TL;DR: The results were analysed in several ways and the untreated yield as a proportion of the treated provided the best means of expressing and comparing tolerance; but whichever method was used the tolerance rankings of the cultivars and clones were similar.
Abstract: SUMMARY
Three field experiments were made to determine the effectiveness of small-plot trials in detecting differences between potato cultivars/clones in their tolerance of damage by potato cyst-nematodes. A nematicide (aldicarb) was applied at three rates to decrease nematode damage. The largest rate of aldicarb increased tuber yields most but the relationship between yield response and nematicide rate was not linear. The yield increases of the cultivars and clones differed, indicating that they have different degrees of tolerance of potato cyst nematodes. The results were analysed in several ways and the untreated yield as a proportion of the treated provided the best means of expressing and comparing tolerance; but whichever method was used the tolerance rankings of the cultivars and clones were similar.
At two sites infested with Globodera rostochiensis, the rankings of the 10 cultivars and clones were similar but at a third site, heavily infested with G. pallida, they were different. Aldicarb decreased the nematode population density after harvest at the G. pallida site but was less effective at the G. rostochiensis sites, which were less heavily infested. Growing resistant or partially resistant potatoes usually prevented nematode increase, and the more resistant cultivars and clones decreased population densities markedly.
19 citations
TL;DR: Tubers from resistant plants were lower in phenols and discolored less than tubers from susceptible plants and tuberculos from 7 potato cultivars and 1 clone known to be susceptible to the golden nematode were compared.
Abstract: Phenolic content and discoloration were determined for 13 commercial potato cultivars and 6 potato clones grown at 2 locations over a period of 5 successive years. Tubers from 6 potato cultivars and 5 potato clones resistant to the golden nematode were compared with tubers from 7 potato cultivars and 1 clone known to be susceptible to the golden nematode. Tubers from resistant plants were lower in phenols and discolored less than tubers from susceptible plants.
12 citations
TL;DR: In this article, the potential of antigenic differences for discriminating pathotypes of the potato cyst nematodes Globodera pallida and G. rostochiensis has been examined by the use of an antiserum raised to a homogenate of potato cysts nematode larvae.
Abstract: The potential of antigenic differences for discriminating pathotypes of the potato cyst nematodes Globodera pallida and G. rostochiensis has been examined by the use of an antiserum raised to a homogenate of potato cyst nematode larvae. Species-specific antigens were detected among reference pathotypes but more variability was detected among field populations, and cluster analysis was used to interpret the precipitation are pattern produced by Laurell crossed-immunoelectrophoresis. A division into species was seen with this analysis but no definite pathotype groupings were detected. Cross-reaction with other cyst-nematode species was limited to general non-specific precipitation. The antigens were all proteinaceous, did not arise from micro-organisms within the cyst and were mainly hydrophilic with an acidic isoelectric point. Peptidase and acid phosphatase activity was detected in some precipitation arcs but this was not species specific.
10 citations
TL;DR: Calculations of coefficients of similarity based on six enzymes, phosphoglucose isomerase, phosphoglucomutase, glycerol-3-phosphate dehydrogenase, enolase, hexokinase and malate dehydrationrogenase and the construction of a dendrogram for several Northern Ireland populations indicated clear separations between G. pallida and G. rostochiensis.
Abstract: Isoelectric focusing on thin layers of polyacrylamide or agarose gels may be used to separate proteins from the potato cyst nematodes Globodera rostochiensis and G. pallida. General protein patterns may be used to identify the two species, even from single cysts. Densitometry of species-specific protein bands may be used to assess the proportions of G. rostochiensis and G. pallida in potato cyst nematode samples. Staining for the enzymes phosphoglucomutase and phosphoglucose isomerase also revealed species-specific patterns, and variation among G. pallida populations was observed. Thus calculations of coefficients of similarity based on six enzymes, phosphoglucose isomerase, phosphoglucomutase, glycerol-3-phosphate dehydrogenase, enolase, hexokinase and malate dehydrogenase and the construction of a dendrogram for several Northern Ireland populations indicated clear separations between G. pallida (Pa1), G. pallida (Pa3) and G. rostochiensis (Ro1). The use of the technique of isoelectric focusing as a routine research and advisory tool in nematology, and as a means of further understanding the genetic basis of pathotype schemes, is discussed.
8 citations
TL;DR: Two forms of Solanum nigrum subsp.
Abstract: Two forms of Solanum nigrum subsp. nigrum, two forms of S. nigrum subsp. schultesii, S. americanum, S. chenopodioides, S. sarrachoides, S. scabrum, S. villosum subsp. villosum and S. villosum subsp. puniceum were grown in pots for over 4 months to measure their effect on numbers of potato cyst–nematodes, Globodera rostochiensis and G. pallida, in the soil. No Solanum tested significantly reduced numbers of G. rostochiensis or G. pallida. Solanum americanum, S. sarrachoides and S. villosum puniceum increased numbers of G. pallida slightly.
6 citations
TL;DR: The most effective nematicides were organophosphorus compounds, generally of the type O, O-diethyl O-phosphoro-thioates or O,Odithyl phosphorodithioates, carbamates and benzimidazoles.
Abstract: SUMMARY
Control of potato cyst-nematode, Globodera rostochiensis, was examined on potato or tomato in pots and on potato in field plots by various chemicals incorporated into the soil at planting. The most effective nematicides were organophosphorus compounds, generally of the type O,O-diethyl O-phosphoro-thioates or O,O-diethyl phosphorodithioates, carbamates and benzimidazoles. In organic soils, the more lipophilic compounds were less effective, presumably because of sorption onto soil organic matter.
Foliar sprays of chemicals, including oxamyl which is known to be translocated to roots, gave poor control of G. rostochiensis.
The root-knot nematode, Meloidogyne incognita, on tomato, widely used in screening for nematicidal activity, was controlled by aldicarb or phoxim incorporated into the soil at planting, but not by benomyl or thiabendazole, in contrast to the moderate effectiveness of these latter two chemicals against G. rostochiensis.
6 citations
TL;DR: It is concluded that testing new clones early in a breeding programme by root-ball counting of cysts with four to five replicates is a sufficient method to separate the susceptible clones from resistant and moderately resistant ones.
Abstract: Clones from the international test assortment were tested for resistance to Globodera pallida (Pa2 and Pa3) and estimated by root-ball counting and by extraction of the total number of cysts to show the practicability of the root-ball test. New clones in a breeding programme were tested by root-ball counting for resistance to Globodera rostochiensis (Ro1) and G. pallida (Pa2 and Pa3), and the statistical aspects are discussed. The conclusion is that testing new clones early in a breeding programme by root-ball counting of cysts with four to five replicates is a sufficient method to separate the susceptible clones from resistant and moderately resistant ones.
TL;DR: The Sunrise potato variety is an early maturing variety with round to oblong, moderately smooth, white skinned tubers with medium-shallow eyes, which is primarily a table potato; however, in southern areas it can be used for chips when processed without prolonged storage at low temperatures.
Abstract: The Sunrise potato variety is an early maturing variety with round to oblong, moderately smooth, white skinned tubers with medium-shallow eyes. Its characteristics are closely parallel to those of Superior, except Sunrise is resistant to race A of the golden nematode (Globodera rostochiensis). Sunrise is primarily a table potato; however, in southern areas it can be used for chips when processed without prolonged storage at low temperatures. Sunrise is resistant to virus X and does not show the net necrosis symptoms caused by leafroll virus. Its parents are Wauseon and B 6563-2, a selection from the USDA breeding program.
TL;DR: The multiplication of G. rostochiensis, pathotype 1, on potato variety grafts (resistant, susceptible, different vegetation periods) gave the following results: the vegetative period of the grafts, essentially determined by the scion, and the multiplication rate of G., rost Cochiensis develop in the same direction.
Abstract: The multiplication of G. rostochiensis, pathotype 1, on potato variety grafts (resistant, susceptible, different vegetation periods) gave the following results: 1) the vegetative period of the grafts, essentially determined by the scion, and the multiplication rate of G. rostochiensis develop in the same direction; 2) the effects of the resistance factor (H1) of Solanum tuberosum ssp. andigenum are obviously restricted to the roots; they are not affected by the scion of a susceptible variety.
Journal Article•
TL;DR: The root-knot nematode, Meloidogyne incognita on tomato, widely used in screening for nematicidal activity, was controlled by aldicarb or phoxim incorporated into the soil at planting, but not by benomyl or thiabendazole, in contrast to the moderate effectiveness of these latter two chemicals against G. rostochiensis.
Abstract: SUMMARY
Control of potato cyst-nematode, Globodera rostochiensis, was examined on potato or tomato in pots and on potato in field plots by various chemicals incorporated into the soil at planting. The most effective nematicides were organophosphorus compounds, generally of the type O,O-diethyl O-phosphoro-thioates or O,O-diethyl phosphorodithioates, carbamates and benzimidazoles. In organic soils, the more lipophilic compounds were less effective, presumably because of sorption onto soil organic matter.
Foliar sprays of chemicals, including oxamyl which is known to be translocated to roots, gave poor control of G. rostochiensis.
The root-knot nematode, Meloidogyne incognita, on tomato, widely used in screening for nematicidal activity, was controlled by aldicarb or phoxim incorporated into the soil at planting, but not by benomyl or thiabendazole, in contrast to the moderate effectiveness of these latter two chemicals against G. rostochiensis.