Article

Densidade populacional de Ralstonia solanacearum em cultivares de batata a campo

Ciência Rural (Impact Factor: 0.4). 01/2004; 34(1). DOI: 10.1590/S0103-84782004000100004
Source: DOAJ

ABSTRACT A ocorrência de populações latentes de Ralstonia solanacearum em plantas de batata (Solanum tuberosum) pode representar fonte de inóculo de potencial desconhecido. Além disso, também é desconhecido se a população latente da bactéria é menor em cultivares resistentes do que em cultivares suscetíveis. Com a finalidade de estudar estes aspectos, um experimento foi conduzido a campo em dois locais no Estado do Rio Grande do Sul, Brasil. O objetivo foi verificar se havia relação entre a densidade populacional e o grau de resistência de cultivares de batata. O experimento foi conduzido em Eldorado do Sul, durante o período de primavera, e em Caxias do Sul, durante o período de outono. Tubérculos das cultivares Achat, Baronesa, Elvira, Macaca, Monte Bonito e Trapeira foram inoculados com uma estirpe de R. solanacearum, biovar II, e plantados a campo. A densidade populacional da bactéria foi estimada em plantas com e sem sintomas de murcha, através de ELISA e imunofluorescência. Não houve evidência da relação entre densidade populacional da bactéria e cultivar. Além disso, a densidade populacional na cultivar Achat, caracterizada como a mais resistente entre as cultivares testadas, foi igual à registrada nas outras cultivares.

0 Followers
 · 
177 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Historically, Canada has been among the world's foremost exporters of seed potatoes, and has had long standing markets in the Mediterranean Basin and in the Americas. Overseas exports have come, almost entirely, from two provinces, Prince Edward Island and New Brunswick, and these provinces account for 85 % of Canada's seed potato production. Approximately 70% of Canada's exports go to countries other than the United States. In recent years, total exports have amounted to about 125,000 tons, for a value of about $37 million (Cdn). By the late 1970s there was growing apprehension within the export industry as markets for Canadian seed declined. The reasons for this were complex and included such factors as lack of demand for Canadian cultivars, and market preference for smaller seed. In addition, there were concerns about Canada's lack of a post harvest control system (particularly for virus diseases), comparable to those used by other seed exporting countries. Furthermore, a number of countries in the European Economic Community (EEC) were becoming concerned at the potential for spreading Corynebacterium sepedonicum (Syn. Clavibacter michiganense subsp, sepedonicus) (6) and potato spindle tuber viroid (PSTV) in seed being imported from North America.
    American Journal of Potato Research 02/1991; 68(2):115-121. DOI:10.1007/BF02853930 · 0.95 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The survival of Pseudomonas solanacearum biovars 2 and 3 in three soils, a Nambour clay loam, a Beerwah sandy loam and a Redland Bay clay, was compared at pressure potentials of −0.003, −0.05 and −0.15 kPa. The soils were inoculated with mutants of P. solanacearum biovars 2 and 3, resistant to 2000 μg streptomycin sulphate ml−1 and their survival measured every 6 weeks for 86 weeks in the clay loam and clay and for 52 weeks in the sandy loam. Soil populations declined with the initial drying necessary to bring the soil moisture to the specific pressure potentials; the initial counts for biovar 2 varied between 0.20 and 2.00 × 109 cfu g−1 soil and for biovar 3 between 0.17 and 1.29 × 109 cfu g−1 soil.The population decline in soil maintained at a constant pressure potential was expressed as the rate of population decline. Biovar 2 declined more rapidly than biovar 3. The rate of population decline of each biovar at −0.003 and −0.05 kPa was greater in clay loam than in sandy loam and at all pressure potentials it was greater in clay loam and sandy loam than in clay. There was also a tendency for the rate of population decline of both biovars to decrease in the drier soil treatments.
    Soil Biology and Biochemistry 01/1983; 15(5):587–591. DOI:10.1016/0038-0717(83)90054-8 · 4.41 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Ten tomato cultivars, from the USA, Taiwan and French Antilles, were compared for resistance to bacterial wilt as measured by disease and pathogen population invasiveness and density in the stem at the collar and midstem regions. On the basis of disease incidence, cultivars ranked from highly susceptible to totally resistant. By contrast, no significant difference was observed in bacterial population in wilting plants, regardless of the cultivar. All symptomless plants were latently infected at the collar level. Percentage of symptomless plants with bacteria at the midstem level was significantly correlated with the degree of resistance; the more resistant, the lower the stem colonization. Restriction of Pseudomonas solanacearum invasiveness in the vascular tissues of the stem is associated with resistance properties in tomato. This observation may be useful in developing improved criteria for selecting stable resistance to the disease.
    Plant Pathology 07/1994; 43(4):663 - 668. DOI:10.1111/j.1365-3059.1994.tb01604.x · 2.97 Impact Factor

Preview

Download
3 Downloads
Available from