ISHS Acta Horticulturae 635: XXVI International Horticultural Congress: Managing Soil-Borne Pathogens: A Sound Rhizosphere to Improve Productivity in Intensive Horticultural Systems
POTATO GENOTYPES, A TOOL FOR MANAGING SOILBORNE PATHOGENS - A SUMMARY |
| Authors: | J.R. Davis, J.J. Pavek, D.L. Corsini |
| Keywords: | bacterial antagonists, nitrogen-fixing bacteria, resistance, soil ecology, root lesion nematodes, Verticillium dahliae, V. tricorpus, Verticillium wilt |
| Abstract:
Verticillium resistant potato clones [A68113-4(-4) and A66107-51(-51)] reduced increases of inoculum densities (ID) of Verticillium dahliae in soil and Verticillium wilt of potato >50% when susceptible varieties were grown in the same locations following resistant clones (-4 and –51). Suppression occurred even though V. dahliae ID was sufficiently high for maximum disease development (>80 cfu g-1 of soil). Significant increases of suppressive factors occurred with the growing of the resistant –51 clone. The cropping of –51 was accompanied by significant increases of bacterial antagonists in both the rhizosphere and on roots along with increases of populations of nitrogen-fixing bacteria (Azotobacter and Azomonas) in both the soil and rhizoplane. In addition to increases of beneficial bacteria, the growing of resistant clones (-4 and –51) resulted in 8-50 fold increases of Verticillium tricorpus, a potential biocontrol agent, compared to the susceptible Russet Burbank. These studies demonstrate the effects of potato genotypes on both soil ecology and Verticillium wilt control. In addition to effects on bacterial and fungal populations, the Butte potato also suppressed root lesion nematode populations to a degree that was similar to either of two nematocides (isophenphos and aldicarb) at recommended rates, and showed biocontrol against both Pratylenchus neglectus and P. penetrans. These results are based on over 15 years of research at the University of Idaho Research Center, Aberdeen. | |
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