Abstract
Root production of four cultivars of flue-cured tobacco was quantified in the field, greenhouse and phytotron. The cultivars ranged in level of partial resistance to the black shank pathogen, Phytophthora parasitica var. nicotianae, from susceptible to highly resistant. In the field, root-observation plates were installed approximately 10 cm from plants, and in greenhouse and phytotron studies, plants were grown in 4-liter containers with one sloping transparent side for root observation. Root growth was determined weekly for four weeks after transplanting in the field and daily up to 14 days after transplanting in the greenhouse and phytotron. Root tracings were made on acetate sheets placed against the sloping transparent side of the containers or against the transparent observation plates in the field following removal of soil from the outside of the observation plate. Root growth was quantified by retracing the root pattern on the acetate sheets over a digitizing tablet attached to a personal computer. Numbers of roots, root length, and mean and maximum rate of root growth were determined. Cultivars Hicks (susceptible) and K-326 (low level of resistance) had significantly larger root systems than moderately resistant G-28 or highly resistant NC 82. Differences in total root length were due to increased branching that resulted in development of significantly greater numbers of roots in Hicks and K-326. For example, between day 21 and 28, Hicks produced more than three times the number of new roots as NC 82 in the field. The mean rate of root extension observed (2.17 mm hr−1) was similar in all four cultivars. Infection efficiency on the different cultivars was determined in the field by inoculating roots with zoospores of P. p. nicotianae. Lesions were visible as water soaked areas within 24 hr of inoculation. At 48 hr after inoculation, percentages of inoculations that resulted in lesion formation were 57, 46, 23, and 16% for Hicks, K-326, G-28 and NC 82, respectively. The possible role of rooting intensity as a mechanism of avoidance to P. p. nicotianae in tobacco cultivars is discussed.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Aycock M K and Mc Kee C G 1975 Root size variability among several cultivars and breeding lines of Maryland tobacco. Agron. J. 67, 604–606.
Aycock M K, Skoog H A, Morgan O D, Mc Kee C G, Hoyert J H and Mulchi C L 1973 Performance of Maryland tobacco and breeding lines, 1971–72. Md. Agric. Exp. Stn., Misc. Publ. 839.
Berthod T 1931 Effect of topping and suckering on development of the tobacco plant. Conn. Agric. Exp. Stn. Bull. 326.
Blaker N S and Hewitt J D 1987 A comparison of resistance to Phytophthora parasitica in tomato. Phytopathology 77, 1113–1116.
Bohm W 1979 Methods of Studying Root Systems. Springer-Verlag, New York.
Bruner W E 1932 Root development of cotton, peanuts and tobacco. Okla. Acad. Sci. Proc. 12, 20–37.
De Roo H C 1961 Deep tillage and root growth. A study of tobacco growing in sandy loam soil. Conn. Agric. Exp. Stn. Bull. 644.
English J T and Mitchell D J 1989 Use of morphometric analysis for characterization of tobacco root growth in relation to infection by Phytophthora parasitica var. nicotianae. Plant and Soil 113, 243–249.
Ferrin D M and Mitchell D J 1986 Influence of initial density and distribution of inoculum on the epidemiology of tobacco black shank. Phytopathology 76, 1153–1158.
Ferriss R S 1984 Effects of microwave oven treatment on microorganisms in soil. Phytopathology 74, 121–126.
Fitter A H 1982 Morphometric analysis of root systems: application of the technique and influence of soil fertility on root system development in two herbaceous species. Plant Cell Environ. 5, 313–322.
Gerard C J 1978 Root growth along plexiglas surfaces by sugarcane under different soil salinity conditions. Agron. J. 70, 639–643.
Gier L J 1940 Root systems of bright belt tobacco. Am. J. Bot. 27, 780–787.
Jones K J 1984 Inhibition of root production as the mechanism of pathogenicity of Glomus macrocarpum to tobacco, and the variability in single spore isolations of G. macrocarpum. M.S. Thesis, University of Kentucky, Lexington, KY, USA.
Jones K J 1990 Components of resistance in Nicotiana tabacum to Phytophthora parasitica var. nicotianae. Ph. D. Thesis, Department of Plant Pathology, North Carolina State University, 79 p.
Lucas G B 1975 Diseases of Tobacco, 3rd ed. Biological Consulting Associates, Raleigh. 621 p.
McKee C G 1967 Root growth in relation to top growth in Catterton and Wilson varieties of Maryland tobacco. Univ. Md. Agric. Exp. Stn, Bull. 478.
McMichael B L and Taylor H M 1987 Applications and limitations of rhizotrons and minirhizotrons. ASA Special Publication No. 50, 1–15.
Melton T A, Porter D and Wood K 1992 Disease Management Practices. In Tobacco Information 1992. Agricultural Extension Service, North Carolina State University, Ag 187, pp 82–106.
Menchey E K, Aycock M K and Mc Intosh M S 1993 Morphological characteristics associated with lodging of tobacco. Crop. Sci. 33, 58–62.
Osmond D L and Raper C D 1982 Root development of field-grown flue-cured tobacco. Agron. J. 74, 541–546.
Shew H D and Shew B B 1994 Host resistance. In Epidemiology and Management of Root Diseases. Eds. C LCampbell and D MBenson. pp 244–275. Springer-Verlag, Heidelburg.
Vepraskas M J and Hoyt G D 1988 Comparison of the trench profile and core methods for evaluating root distributions in tillage studies. Agron. J. 80, 166–172.
Vepraskas M J and Miner G S 1986 Effects of subsoiling and mechanical impedance on tobacco root growth. Soil Sci. Soc. Am. J. 50, 423–427.
Vepraskas M J, Miner G S and Peedin G F 1986 Relationships of tillage pans, soil properties, and subsoiling to root growth. Soil Sci. Soc. Am. J. 50, 1541–1546.
Voorhees W B 1976 Root elongation along a soil-plastic container interface. Agron. J. 68, 143.
Walton L R and Casada J H 1979 Physical characteristics of burley varieties affecting lodging resistance. Tob. Sci. 23, 83–86.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Jones, K.J., Shew, H.D. Early season root production and zoospore infection of cultivars of flue-cured tobacco that differ in level of partial resistance to Phytophthora parasitica var. nicotianae . Plant Soil 172, 55–61 (1995). https://doi.org/10.1007/BF00020859
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00020859