ISSN:
1871-4528
Keywords:
Larvenschlupf
;
Sterilisationsverfahren
;
Entwicklungszyklus der Nematoden im Nährager
;
in vitro-Nematodenpopulation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Description / Table of Contents:
Summary A monoxenicin vitro culture technique can distinguish small differences in the presumed polygenically determined resistance reactions of potato genotypes toGlobodera pallida (Stone) Behrens (Pa3) and can be used in selection. The basis for such a resistance test is the simple and reproducible cultivation ofG. pallida with the aim of achieving the complete life cycle of the nematode under monoxenic conditions. A routine practical technique was developed for hatching the juveniles in a closed system (Figure 1). This was achieved by the introduction of a hatching solution which was a mixture of root washings and 0.6 mmol l−1 picrolonic acid with a pH of 5.9 (=pH value of the nutrient agar). Using special hatching tubes the juveniles from 1000 cysts per tube could be hatched and counted within 2 or 3 days, as shown by experiment (Figure 3). Finally, the juveniles were surface sterilised in a special apparatus and distributed serially to the test genotypes (Figure 2). A density of 1000 juveniles per genotype gave the highest nematode infection (Figure 4) but allowance must be made for the surface sterilisation which in giving a high standard of asepsis killed up to 80% of the juveniles. At the same time especially vital juveniles were selected, thereby guaranteeing that the test was stringent and unequivocal. A variant of the technique used germ-free cysts which had been formed under monoxenic conditions. These were removed and crushed. The hatching effect of the genotypes' roots meant that 500 nematode eggs were sufficient for high infection. The test scores were based on the development within the roots of invading juveniles which could be observed continuously with a stereomicroscope. Males (Figure 5) and females (Figure 6) could be easily distinguished at low magnification (x10) 3–4 weeks and 4–6 weeks after the introduction of surface sterilised juveniles and monoxenically cultivated cysts respectively.
Notes:
Zusammenfassung Durch die monoxenischein vitro-Kultivierung können geringe quantitative Unterschiede in der vermutlich polygen-vererbten Resistenzreaktion von Kartoffelgenotypen gegenüberGlobodera pallida (Stone) Behrens (Pa3) festgestellt und für die Selektion verwendet werden. Grundvoraussetzung hierfür ist die einfache und reproduzierbarein vitro-Kultivierung vonG. pallida. Für die Schlupfaktivierung, die Oberflächensterilisation und die Zugabe definierter Larvendichten wurden routinemässig durchführbare Verfahren entwickelt, die einen vollständigen Lebenszyklus der Nematoden unter monoxenischen Bedingungen ermöglichen. Die aus dieserin vitro-Population gewonnenen keimfreien Zysten können für eine vereinfachte Resistenzprüfung eingesetzt werden. Die Testauswertung orientiert sich an der Entwicklung der in die Wurzeln eingedrungenen Larven. Sie kann mit einem Stereomikroskop kontinuierlich beobachtet werden.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02358130
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