Effect of soil, water regime and silicon on resistance of upland rice to blast
1989
Quijano, C.C. | Kuerschner, E. | Neue, H.U. (International Rice Research Inst., Los Banos, College, Laguna (Philippines). Soil Dept. and Plant Pathology Dept.)
A factorial pot experiment was conducted in the greenhouse to study the effects of soil, water regime and silicon addition on the resistance of rice to blast. Upland rice variety C22, susceptible to blast, was seeded in soil from upland sites at Sto. Tomas, Batangas and Cavinti, Laguna [Philippines]. Water treatment of saturated and field capacity and silicon treatment of without silica and with 100 mg/kg Si as sodium meta silicate were imposed. NPK fertilizers were incorporated in all pots at the following rates: 50 mg/kg as ammonium sulfate, 50 mg P/kg as solophos and 25 mg K/kg as muriate of potash. Rice plants were inoculated with a spore suspension of isolate P06-6 at 40 DAS [days after seeding]. Plants grew uniformly with normal appearance in all treatments before inoculation. Quantitative assessment of blast (total number of lesions/plant) one week after inoculation showed a 30 times higher rate of infection for plants grown in highly weathered soil from Cavinti, Laguna compared to plants in the young soil of volcanic origin from Sto. Thomas, Batangas in the saturated treatment. Keeping the water regime at filled capacity resulted in highest blast infection and lower plant silica content than saturating the soil, especially in the soil from Cavinti. Addition of silicon had no effect on the number of blast lesions and on silica in plant tissue. Silica content of plants was inversely correlated with the degree of infection with correlation coefficient of r=-.662**.
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