scholarly journals Potato cultivars vary in susceptibility to blackleg (Erwinia carotovora subsp atroseptica)

2009 ◽  
Vol 62 ◽  
pp. 403-403
Author(s):  
P.J. Wright ◽  
J.A.D. Anderson

Ten potato cultivars were tested for susceptibility to infection by Erwinia carotovora subsp atroseptica (Eca) the causal agent of blackleg over two maincrop seasons in 200506 and 200607 The pathogen was inoculated into seed tubers using toothpicks charged with undiluted bacterial growth Blackleg incidence was assessed 56 weeks after planting The field experiments clearly confirmed that potato cultivars vary significantly in susceptibility to blackleg Some New Zealand cultivars had a lower susceptibility to blackleg than current commercial cultivars The new Plant Food Research release Summer Delight in particular had an exceptional level of resistance and will be used as a parent in efforts to develop potato cultivars with lower blackleg susceptibility than current local commercial cultivars Routine screening of Plant Food Research breeding lines and cultivars will continue to be carried out over several seasons to confirm results presented here and to determine further blacklegresistant germplasm

2009 ◽  
Vol 62 ◽  
pp. 403-403
Author(s):  
M. Jeram ◽  
P.J. Wright ◽  
J.A.D. Anderson ◽  
S.L. Lewthwaite

Bacterial soft rot of potato tubers in storage is an economically important postharvest disease worldwide Disease control measures include reduction of tuber damage at harvest provision of suitable storage conditions and breeding of resistant cultivars Tubers of 18 potato cultivars and breeding lines were assessed for susceptibility to infection by Erwinia carotovora subsp atroseptica (Eca) over three maincrop seasons between 2003 and 2007 Susceptibility to Ecainduced soft rot was determined by measuring the weight of rotted tissue in anaerobically incubated whole tubers 7 days after inoculation with Eca Potato lines differed in susceptibility to soft rot by a factor of >37 (weight of rotted tissue) Cultivars Crop 28 Ilam Hardy and 30975 were highly susceptible and 065/27 Crop 15 and Crop 16 were least susceptible to Ecainduced soft rot As a consequence of these trials several of these lines are now being used in Plant Food Researchs potato breeding programme in order to develop cultivars with lower soft rot susceptibility than cultivars currently grown


2011 ◽  
Vol 64 ◽  
pp. 292-292
Author(s):  
D. Park ◽  
D. Than ◽  
K.R. Everett ◽  
J. Rees-George ◽  
M.K. Romberg ◽  
...  

Subsequent to the detection of Pseudomonas syringae pv actinidiae (Psa) on kiwifruit in Te Puke (November 2010) isolates of Pseudomonas spp from kiwifruit stored in the International Collection of Microorganisms from Plants (ICMP) and at Plant Food Research (PFR) were tested by PCR for Psa A total of 139 isolates from ICMP were assayed with the previously published primer pairs PsaF1/PsaR2 and PAV1/P22 An amplicon of expected size for Psa was produced from 19 isolates using primers PAV1/P22 but no amplicons were obtained using the primers PsaF1/PsaR2 Amplicons produced by primers PAV1/P22 were sequenced and these isolates were identified as Pseudomonas viridiflava A further 52 Pseudomonas isolates collected from kiwifruit and stored at PFR did not amplify a PCR product with primers PsaF1/PsaR2 These PCR tests confirm that Psa was not detected in any of the cultures held in the ICMP or at PFR The screening of historical Pseudomonas isolates associated with kiwifruit suggests that Psa strains had not been isolated from New Zealand kiwifruit samples prior to the detection in 2010


Author(s):  
W.M. Williams ◽  
L.B. Anderson ◽  
B.M. Cooper

In evaluations of clover performances on summer-dry Himatangi sandy soil, it was found that none could match lucerne over summer. Emphasis was therefore placed on production in autumn-winter- early spring when lucerne growth was slow. Evaluations of some winter annual clover species suggested that Trifolium spumosum, T. pallidum, T. resupinatum, and T. vesiculosum would justify further investigation, along with T. subterraneum which is already used in pastures on this soil type. Among the perennial clover species, Kenya white clover (7'. semipilosum) showed outstanding recovery from drought and was the only species to produce significantly in autumn. However, it failed to grow in winter-early spring. Within red clover, materials of New Zealand x Moroccan origin substantially outproduced the commercial cultivars. Within white clover, material from Israel, Italy and Lebanon, as well as progeny of a selected New Zealand plant, showed more rapid recovery from drought stress and subsequently better winter growth than New Zealand commercial material ('Grasslands Huia'). The wider use of plant material of Mediterranean origin and of plants collected in New Zealand dryland pastures is advocated in development of clover cultivars for New Zealand dryland situations.


HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 483a-483
Author(s):  
Roy N. Keys ◽  
Dennis T. Ray ◽  
David A. Dierig

Guayule (Parthenium argentatum Gray, Asteraceae) is a latex-producing perennial desert shrub that is potentially of economic importance as an industrial crop for the desert Southwest. It is known to possess complex reproductive modes. Diploids are predominantly sexual and self-incompatible, while polyploids show a range of apomictic potential and self-compatibility. This paper describes the development of a relatively rapid and simple technique for characterizing reproductive modes of breeding lines of P. argentatum. Initial field experiments were based on an auxin test used successfully to characterize reproductive mode in the Poaceae. The application of 2,4-dichlorophenoxyacetic acid inhibited embryo formation in P. argentatum, but this was not the case with other auxins tested. Results of field experiments were ambiguous because: 1) the floral structure of P. argentatum is such that auxins might not have penetrated to the ovules, and 2) there was potential self-fertilization by pollen released within isolation bags. Therefore, in vitro culture of flower heads was tested because it provided much better control of environmental conditions, growth regulator application, and pollen release. Auxin alone, or in combination with gibberellic acid or kinetin, inhibited parthenogenesis in vitro. Embryo production did not vary using two substantially different nutrient media. In vitro flower head culture using a (Nitsch and Nitsch) liquid nutrient medium without growth regulators, enabled characterization of the reproductive mode of seven breeding lines, ranging from predominantly sexual to predominantly apomictic. The results of this technique were substantiated using RAPD analyzes of progeny arrays from controlled crosses.


Foods ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 414
Author(s):  
Victoria Purdy ◽  
Biniam Kebede ◽  
Ron Beatson ◽  
Kerry Templeton ◽  
Patrick Silcock ◽  
...  

Hop aroma characteristics originate from hop essential oils, which have complex chemical profiles that remain poorly understood, particularly for New Zealand hops. The aim of this study was to determine volatile compounds that distinguish New Zealand hop cultivars. Untargeted fingerprinting methods based on headspace gas chromatography mass spectrometry (GC-MS) were used to analyse nine hop cultivars. A total of 61 volatile compounds were identified as compounds that differentiated the commercial hop varieties using advanced chemometrics and feature selection techniques. Similarities in volatile composition were found between Wakatu, Wai-iti™ and Kohatu®, which are rich in alcohols. Another grouping was found between Waimea™ and Nelson Sauvin™, where ketones and esters were commonly found. Rakau™ was distinct from the other eight cultivars, distinguished by 2-methylbutyl 3-methylbutanoate and methanethiol hexanoate. Riwaka™ contained the greatest number of discriminating volatile compounds when compared to other cultivars, which was dominated by terpenoids, such as geranyl 2-methylbutanoate, perillene and D-limonene. The chemical fingerprinting approach successfully identified volatile compounds that had not been previously found in New Zealand hop cultivars and that discriminated the commercial cultivars. The data obtained in the present study further extend the knowledge of New Zealand hops and will help facilitate targeted breeding.


Plant Disease ◽  
2011 ◽  
Vol 95 (3) ◽  
pp. 263-268 ◽  
Author(s):  
S. K. Gremillion ◽  
A. K. Culbreath ◽  
D. W. Gorbet ◽  
B. G. Mullinix ◽  
R. N. Pittman ◽  
...  

Field experiments were conducted in 2002 to 2006 to characterize yield potential and disease resistance in the Bolivian landrace peanut (Arachis hypogaea) cv. Bayo Grande, and breeding lines developed from crosses of Bayo Grande and U.S. cv. Florida MDR-98. Diseases of interest included early leaf spot, caused by the fungus Cercospora arachidicola, and late leaf spot, caused by the fungus Cercosporidium personatum. Bayo Grande, MDR-98, and three breeding lines, along with U.S. cvs. C-99R and Georgia Green, were included in split-plot field experiments in six locations across the United States and Bolivia. Whole-plot treatments consisted of two tebuconazole applications and a nontreated control. Genotypes were the subplot treatments. Area under the disease progress curve (AUDPC) for percent defoliation due to leaf spot was lower for Bayo Grande and all breeding lines than for Georgia Green at all U.S. locations across years. AUDPC for disease incidence from one U.S. location indicated similar results. Severity of leaf spot epidemics and relative effects of the genotypes were less consistent in the Bolivian experiments. In Bolivia, there were no indications of greater levels of disease resistance in any of the breeding lines than in Bayo Grande. In the United States, yields of Bayo Grande and the breeding lines were greater than those of the other genotypes in 1 of 2 years. In Bolivia, low disease intensity resulted in the highest yields in Georgia Green, while high disease intensity resulted in comparable yields among the breeding lines, MDR-98, and C-99R. Leaf spot suppression by tebuconazole was greater in Bolivia than in the United States. This result indicates a possible higher level of fungicide resistance in the U.S. population of leaf spot pathogens. Overall, data from this study suggest that Bayo Grande and the breeding lines may be desirable germplasm for U.S. and Bolivian breeding programs or production.


Plant Disease ◽  
2017 ◽  
Vol 101 (11) ◽  
pp. 1843-1850 ◽  
Author(s):  
Brian S. Jordan ◽  
Albert K. Culbreath ◽  
Timothy B. Brenneman ◽  
Robert C. Kemerait ◽  
William D. Branch

Peanut (Arachis hypogaea) cultivars with resistance or tolerance to Cercospora arachidicola and/or Cercosporidium personatum, the causes of early and late leaf spot, respectively, are needed for organic production in the southeastern U.S. To determine the potential of new breeding lines for use in such production systems, field experiments were conducted in Tifton, GA, in 2014 and 2015 in which nine breeding lines and two cultivars, Georgia-06G and Georgia-12Y, were grown without foliar fungicide applications. In one set of trials, cultivar Georgia-12Y and most of the breeding lines evaluated had early season vigor ratings, early-season canopy width measurements, final plant populations, and pod yield that were greater than those of standard cultivar Georgia-06G. In those trials, final late leaf spot Florida scale ratings were lower and canopy reflectance measured as the normalized difference vegetation index (NDVI), was higher all the breeding lines than those of Georgia-06G. In another set of trials, two of those same breeding lines had final late leaf spot ratings similar to those of Georgia-12Y in 2014, whereas in 2015, six of those breeding lines had final leaf spot ratings that were lower than those of Georgia-12Y. Yields were similar for Georgia-12Y and all the breeding lines in the Gibbs Farm trials. Across years and breeding lines at the Lang Farm, the relationship between visual estimates of defoliation and NDVI was described by a two sector piecewise regression with NDVI decreasing more rapidly with increasing defoliation above approximately 89%. The utility of NDVI for spot comparisons among breeding lines appears to be limited to situations where there are differences in defoliation. Georgia-12Y and multiple breeding lines evaluated show potential for use in situations such as organic production where acceptable fungicides available for seed treatment and leaf spot control are limited.


1988 ◽  
Vol 31 (1) ◽  
pp. 67-72 ◽  
Author(s):  
R. L. Wastie ◽  
G. J. Jellis ◽  
D. H. Lapwood ◽  
C. Logan ◽  
G. Little ◽  
...  

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