ISHS Acta Horticulturae 481: International Symposium on Growing Media and Hydroponics
THE RELATIONSHIP OF PYTHIUM ROOT ROT AND RHIZOSPHERE MICROORGANISMS IN A CLOSED CIRCULATING AND AN OPEN SYSTEM IN ROCKWOOL CULTURE OF TOMATO |
| Authors: | J.C. Tu, A.P. Papadopoulos, X. Hao, J. Zheng |
| Abstract:
The relationship of Pythium root rot and rhizosphere microorganisms was investigated in rockwool culture of tomato using three systems: (A) closed circulating with rockwool feeding formula, (B) closed circulating with modified NFT feeding formula and (C) open system with rockwool feeding formula. Although the populations of bacteria, Pythium and other fungi increased with time, A & B supported higher bacterial population and lower Pythium and other fungal populations than C. Similarly, the percent root segments with Pythium infection increased with time in all treatments and the disease progression was nearly three-times slower in A & B as compared to C. There were a significant quadratic relationship between Pythium infection and bacterial population, and a linear relationship between Pythium infection and Pythium and other fungal populations. The results clearly showed that higher bacterial population reduced Pythium root rot in the closed rockwool system. The final root rot severity for A, B and C were 4.56, 4.39 and 6.44, respectively. The results indicated strongly that resident bacteria might play a role in the biosuppression of Pythium, and the suppressiveness was most evident in the closed rockwool system using NFT feeding formula. | |
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