scholarly journals Population changes of the potato cyst nematode (Giobodera rostochiensis) during irregular crop rota­tion

1999 ◽  
Vol 35 (No. 4) ◽  
pp. 125-130
Author(s):  
J. Šedivý

For a period of 17 years, changes in the n umber of potato cyst nematode (PCN) cysts in the soil and in their contents were studied in two fields with an irregular crop rotation and growing resistant and susceptible potato cultivars. In all years, numbers of cysts per I 00 g of soil were higher at Skorkov (S) than at Ot radovice (0). At the beginning of the experiment, the percentages of empty PCN cysts were 30 and 28%, respectively, but they increased to 92.5 and 94.6%, respectively, by the end of it. The remaining cysts contained dead eggs/larvae and empty egg cases. Thus, the number of cysts per I 00 g of soil cannot be used to estimate the degree of soil infestation with the PCN without also knowing the number of viable stages in the cysts. When the experiment started the mean number of viable eggs/larvae per cyst was 62.7 in fields and 51.3 in field 0; no viable stages of the pest were found at the end of the experiment. Parallel to the decline in the number of viable eggs/larvae per cyst, the numbers of cysts with viable contents also declined in both fields. The mean number of dead eggs/larvae per cyst showed considerable variation in the course of the experiment.  In fields it varied within a range of 1 5.9-69.4 individuals per cyst. Over the years the number of empty egg cases per cyst showed an irregular increasing trend. In field S their number varied from 34.9 to 1 97.5 per cyst. In field 0 from 46.3 to 218. No unequivocal negative effect of cropping resistant potato cultivars on the number of PCN cysts in the soil has been ascertained. In most years. The cropping of resistant cultivars was followed by an increased number of empty cysts in soil samples in both experimental fields.  The effect of growing resistant cultivars on the number of viable eggs/ larvae was negative in both fields, resulting in decreased mean numbers of viable individuals per cyst. The mean number of dead eggs/larvae per cyst was variable.  The number of empty egg cases was usually higher after the harvest of a resistant potato cultivar. The numbers of empty cysts and those with dead contents increased distinctly after an application of pig manure prior to growing the resistant cultivar and in subsequent years. The mean number of cysts in the soil, and of viable stages in the cysts also declined after a crop of rye. Regula r cropping of resistant potato cultivars at 3-year intervals, once interrupted by growing a susceptible plant cultivar, decreased the occurrence of viable stages of the PCN below the detectable level.

2002 ◽  
Vol 38 (SI 1 - 6th Conf EFPP 2002) ◽  
pp. 189-194
Author(s):  
L.A. Pylypenko

Potato is the fourth important cultivated crop in Ukraine; the potato cyst nematode Globodera rostochiensis, Ro1 consists<br />one of the most serious threats to its industry. A total of 3769 cultivars and hybrids were assessed for resistance<br />to G. rostochiensis from 1992 to 2002. On the base of the two-stages assay, resistance was identified at 419 and partial<br />resistance at 90 genotypes, which had inherited resistance from 39 resistant cultivars and 23 hybrids. Resistance of the<br />74 genotypes was confirmed in both greenhouse and field plots; their effectiveness in reduction of population densities<br />of G. rostochiensis varied from 51 to 96% in one season. The tolerance of 5 Ukrainian potato resistant cultivars was<br />investigated in the field plots and all of them were classified as intolerant.


2014 ◽  
Vol 91 (5) ◽  
pp. 447-458 ◽  
Author(s):  
Jonathan L. Whitworth ◽  
Richard G. Novy ◽  
Jeffrey C. Stark ◽  
Stephen L. Love ◽  
Michael K. Thornton ◽  
...  

1982 ◽  
Vol 99 (1) ◽  
pp. 79-83 ◽  
Author(s):  
M. J. De Maine

SUMMARYIn a breeding programme to combine quantitative resistance to two important potato pathogens, Phytophthora infestans causing late blight in foliage and Qlobodera pallida (the cream potato cyst-nematode), tetraploid (4 ×) off spring were obtained by crossing dihaploids, mainly as females, with tetraploids. Glasshouse and field tests in the first and second tuber-years showed that most of the off spring of highly blight-resistant dihaploids had high resistance to P. infestans. Two such dihaploids, PDH 182 and PDH 247, crossed with a tetraploid selected for high general combining ability for potato cyst-nematode (PCN) resistance, gave off spring all of which were highly blight resistant. About one third also had high PCN resistance.Detached leaflet tests were used for rapid blight resistance screening of other progenies from dihaploid × 4 × crosses in their seedling year. Differences were found in the effects of 4 × parents on the mean resistances of progenies from blight-resistant dihaploids.The results also showed differences between dihaploids in their effectiveness in transmitting blight resistance to 4 × offspring. This could be due to differences in the mode of unreduced female gamete formation, i.e. first division restitution or second division restitution (SDR). If all the unreduced gametes were produced by SDR, the differences could be due to differences in homozygosity between dihaploids with respect to blight resistance genes.The dihaploid × 4 × crosses gave few offspring per pollination. The few seedlings obtained may be offset by a higher frequency with the required characters. Since fewer seedlings would have to be grown in order to find the required combination of characters, savings could be made in planting and resistance-testing facilities over those required in conventional breeding.The tetraploid hybrids obtained can be used in a second cycle of breeding in three ways simultaneously: by crossing with other tetraploids, by crossing with dihaploids selected for complementary characters and to produce dihaploids with combined resistances.


Plant Disease ◽  
2010 ◽  
Vol 94 (12) ◽  
pp. 1510-1510 ◽  
Author(s):  
A. Mahran ◽  
S. Turner ◽  
T. Martin ◽  
Q. Yu ◽  
S. Miller ◽  
...  

The golden potato cyst nematode, Globodera rostochiensis (Wollenweber, 1923) Behren, is an economically important parasite of potato (Solanum tuberosum L. subsp. tuberosum) and is recognized as a quarantine pest internationally (2). This pest attacks potato plants and causes stunting of the haulm and the root system, leaf yellowing, and tuber yield losses (2). The pathotype scheme proposed by Kort et al. distinguishes five pathotypes (Ro1, Ro2, Ro3, Ro4, and Ro5) of G. rostochiensis using differential Solanum clones (1). Several resistance genes and quantitative trait loci (QTL) that have been identified in wild Solanum species confer resistance to different G. rostochiensis pathotypes and have been introgressed into commercial potato cultivars (2). Determining G. rostochiensis pathotype(s) is essential to implement efficient management strategies, which include using resistant potato varieties. G. rostochiensis was discovered in the municipality of Saint-Amable, Quebec (QC), Canada in 2006 (3) and was subsequently characterized (4). In this study, cysts were collected from 11 representative infested fields and confirmed to be G. rostochiensis (3). The pathotypes of these nematodes were assessed on seven differential clones (S. tuberosum subsp. tuberosum cv. Desiree, S. tuberosum × S. andigena cv. Maris Piper, S. kurtzianum hybrid 60.21.19, S. vernei hybrid 62.33.3, S. vernei hybrid 58.1642/4, S. vernei hybrid 65.346/19, and S. multidissectum hybrid P55/7) in 2007 and 2009. Briefly, in each 1-liter plastic pot containing 907 g (2 lbs) of soil (3:1 loam/grit v v-1), a single differential Solanum clone was planted and 15 cysts from 1 of 11 fields were inoculated. Five replicates were set up for each Solanum-nematode combination and the pots were arranged in a completely randomized design in a greenhouse at 22°C with a 16-h light period per day. Nine weeks after inoculation, cysts were extracted from each pot and counted. Reproduction factor (Rf) for each replicate was calculated (Rf = Pf/Pi; Pf is the final cyst number and Pi is the initial cyst number added to each pot). Rf values were used to categorize the differential clones into two groups, “susceptible” leading to increase in nematode numbers (Rf > 1) and “resistant” resulting in decrease in nematode numbers (Rf ≤ 1) (1). Our results in 2007 and 2009 were consistent and the pathotype of the nematodes collected from all the fields were identified as Ro1. To our knowledge, this is the first time that the pathotype of G. rostochiensis in the Saint-Amable regulated area was identified. Accordingly, potato cultivars carrying genes or QTL resistant to G. rostochiensis pathotype Ro1 can be used to reduce the nematode numbers in infested fields in the Saint-Amable area, QC. References: (1) J. Kort et al. Nematologica 23:333, 1977. (2) R. J. Marks and B. B. Brodie. Potato Cyst Nematodes: Biology, Distribution, and Control. 1st ed. CAB International, Wallingford, 1998. (3) F. Sun et al. Plant Dis. 91:908, 2007. (4) Q. Yu et al. Can. J. Plant Pathol. 32:264, 2010.


1982 ◽  
Vol 99 (1) ◽  
pp. 67-70 ◽  
Author(s):  
M. S. Phillips ◽  
M. F. B. Dale

SUMMARYA bulk seedling test is described which can be applied shortly after completion of a crossing programme. The test assesses resistance to G. pallida in progeny derived from crossing programmes involving S. luberosum, S. vernei and S. tuberosum spp. andigena. It provides good estimates of both the mean level of resistance within progenies and the breeding value of the parents. The test was applied to a crossing schedule involving a half-diallel and a North Carolina 2 design utilizing a range of material. The results and their implications are discussed.


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