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Nutritional stresses and varietal resistance in rice: effects on whitebacked planthopper

Salim, M., Saxena, R.C.
Crop science 1991 v.31 no.3 pp. 797-805
Oryza sativa, pest resistance, Sogatella furcifera, cultivars, nutrient deficiencies, nitrogen, phosphorus, potassium, nutrient content, allelochemicals, fecundity, host-parasite relationships, chemical constituents of plants, varietal resistance, stress response
Nutritional disorders can affect plant growth and a plant's susceptibility to pests. Our objective was to evaluate the effects of N, P, and K stresses on resistance of 'IR2035-117-3' (IR2035) and susceptibility of 'Taichung Native 1' (TN1) rice (Oryza sativa L.) plants to whitebacked planthopper, Sogatella furcifera (Horvath), when grown in nutrient solution in a phytotron at 29/21 degrees C (day/night), minimum 70% relative humidity, and natural daylight of 12 h. Nitrogen, P, or K stresses altered the chemical composition of rice plants. Deficiency of N, P, or K significantly reduced growth of rice plants. Allelochemical production decreased at low K (3 mg/kg) concentration. Insect food intake and assimilation growth, adult longevity, fecundity, and population increased significantly as N increased. In contrast, increases in K application adversely affected the biology and behavior of S. furcifera. Insect response to P-stressed plants was not consistent. Regardless of the levels of N, P, or K, the difference between the resistance of IR2035 and susceptibility of TN1 remained distinct. Mortality of first-instar nymphs was high on TN1 plants treated with steam-distillate extracts of K-stressed or unstressed IR2035 plants when compared with plants treated with acetone or TN1 extract. Resistance to S. furcifera in rice cultivars thus may be enhanced by applying moderate rates of N and high doses of K.