Long-term results of a tuber slice test for relative resistance to late blight

Darsow, Ulrich

doi:10.1007/bf02357680

Cited by 18 publications

(9 citation statements)

References 6 publications

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“…Black's differentials only detect a limited number of such factors and the postulated changes could remain undetected by these differentials. Such an interpretation may explain some of the results of DARSOW (1987). He found that the cvs.…”

mentioning

confidence: 86%

Potato Tuber Resistance to Phytophthora infestans and its Relation to Maturity

Świeżyński¹,

Krusiec²,

Osiecka³

et al. 1993

Plant Breeding

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Tuber resistance to P. infestans was evaluated in the progeny of potato genotypes differing in levels of resistance and maturity. Two methods of tuber evaluation were used: testing whole tubers and testing tuber slices.In the progeny, some genotypes were superior in resistance to the more resistant parent. This superiority was never associated with early maturity. The results of both tuber-testing methods were positively correlated but the interaction genotypes x years was more pronounced in the reaction of tuber slices.It is concluded that: (1) transgression in tuber resistance may be obtained, (2) a high level of tuber resistance is difficult to combine with early maturity and (3) the expression of genes for specific resistance was more pronounced in testing tuber slices than in testing whole tubers.A preliminary evaluation of potato families segregating for maturity and tuber resistance revealed that both characters were only weakly correlated (SWIE2YI^SKI et al. 1991). Continued testing of the parents and selected progeny provided new information on tuber resistance and its relation to maturity which is presented in this paper.Three groups of potato genotypes were evaluated: 14 parents and standard cultivars differing in tuber resistance and maturity, 12 progeny genotypes, selected in the first year of testing as outstanding in tuber resistance, and 15 progeny genotypes selected in the first year of testing as early maturing with the highest tuber resistance in this maturity group. Tuber resistance was evaluated, in the autumn, over a period of 3 years (1989)(1990)(1991). Two methods of tuber evaluation were used; testing whole tubers and testing tuber slices. Each genotype was evaluated in the first year in at least 2 replications, with 6 in the second year and 8 in the third year. In each replication 5 whole tubers and 5 tuber slices were tested. The results are presented in a 9-grade scale (9 = resistant). For inoculation, virulent fungus isolates collected from plants infected in nature were used. On Black's differentials their virulence at testing time was: 1.2.3.4.7.10 and 11; sometimes factors 5 and 8 also being expressed.Maturity was determined in plants growing in the field and was measured in days counted from the planting date.The origin of the evaluated potato genotypes and the description of the tuber testing methods are given by SwiE^YlNiSKi et al. (1991).Among parents and standard cultivars there were late maturing genotypes with resistant tubers and early maturing genotypes with susceptible tubers. In this group the correlation U.S.

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mentioning

confidence: 86%

Potato Tuber Resistance to Phytophthora infestans and its Relation to Maturity

Świeżyński¹,

Krusiec²,

Osiecka³

et al. 1993

Plant Breeding

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“…Darsow (1987) presented results of testing varieties for 12 years, and has shown how great these differences may be. depending on the year considerable differences in the evaluation of resistance to P. infestans was detected.…”

Section: Discussionmentioning

confidence: 99%

Comparison of resistance evaluation in potato variety assessment

et al. 2001

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Results of varietal assessment in France, Germany, Great Britain, The Netherlands and Poland have been compared for two characters: resistance to potato virus Y (PVY) and tuber resistance to Phytophthora infestans. In total 75 varieties were evaluated in more than one country. All evaluations were expressed or could be transformed into a 9-grade resistance scale. Evaluations did differ considerably due to two main reasons: countries differed in severity of evaluation (mean resistance level ascribed to varieties) and the relative resistance level ascribed to individual varieties depended on the country. Differences between countries in severity of the evaluation could exceed two grades in resistance to PVY and three grades in tuber resistance to P. infestans. In the relative resistance ascribed to individual varieties the differences between countries were larger, reaching up to 6 grades in evaluation of resistance to PVY and up to 8 grades in evaluation of tuber resistance to P. infestans. To achieve consistent variety assessment results from different countries, it will be necessary to use agreed standard varieties and more consistent evaluation methods.

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“…In many reports it is pointed out that results from laboratory tests in different years may differ considerably (Lapwood, 1967;Stewart et al, 1983;Darsow, 1987a). This may be due partly to the already reported differences between cultivars in the period of maximal resistance (Darsow, 1983;Swiezyriski et al, 1993aSwiezyriski et al, , 1997c.…”

Section: Evaluation Of Tuber Resistancementioning

confidence: 99%

“…The temperature at which the tubers are tested, inoculum concentration and mixtures of isolates versus single isolates could influence significantly the relative tuber resistance of individual potato genotypes (Darsow, 1987a). To overcome any specific resistance, an attempt is usually made to use a virulent fungus inoculum.…”

Section: Evaluation Of Tuber Resistancementioning

confidence: 99%

“…After preliminary evaluation of glasshouse-grown first year seedlings (Darsow, 1992), the seedlings are evaluated in the second to sixth years using tuber slice tests, according to Darsow (1987a). After preliminary evaluation of glasshouse-grown first year seedlings (Darsow, 1992), the seedlings are evaluated in the second to sixth years using tuber slice tests, according to Darsow (1987a).…”

Section: Breeding Potato Cultivars With Tubers Resistant To P Infestansmentioning

confidence: 99%

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Breeding potato cultivars with tubers resistant toPhytophthora infestans

Świeżyński

Zimnoch‐Guzowska

2001

Potato Res

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Available information has been reviewed on tuber resistance to P. infestans, its inheritance and breeding procedures used to obtain potato cultivars superior in this character.P. infestans is worldwide the most destructive potato pathogen. Tuber resistance is an essential component of potato resistance as this pathogen is often responsible for tuber rot in storage, and infected tubers of susceptible cultivars provide an important way for its overwintering.In Europe many cultivars and advanced breeders selections have been obtained with tuber resistance to P. infestans, but in the last decades no progress is noted in the mean level of this resistance in cultivars. The expression of tuber resistance depends to a large extent on testing conditions and therefore it can be difficult to evaluate. Consequently making progress in breeding is not easy, and also cultivar assessment data from various countries sometimes differ considerably. It is concluded from published data that it should be easier to make progress in breeding potato cultivars with resistant tubers if more attention is paid to combining the various types of resistance which are already known, and if the genetic determination of durable resistance to P.infestans is better understood.

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Long-term results of a tuber slice test for relative resistance to late blight

Cited by 18 publications

References 6 publications

Potato Tuber Resistance to Phytophthora infestans and its Relation to Maturity

Potato Tuber Resistance to Phytophthora infestans and its Relation to Maturity

Comparison of resistance evaluation in potato variety assessment

Breeding potato cultivars with tubers resistant toPhytophthora infestans

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