Temperature Stress and Varietal Resistance in Rice: Effects on Whitebacked Planthopper
- M. Salim and
- R. C. Saxena
Temperature greatly influences fundamental plant and pest physiological processes and interactions. This phytotron study sought to determine how optimum (29/21 °C), low (24/16 and 26/18 °C), and high (3S/27 and 36/28 °C) day/night temperature expression of regimes affect resistance of ‘IR2035-117-3’ (IR2035) and susceptibility of ‘Taichung Native 1’ (TN1) rice (Oryza sativa L.) cultivars to the whitebacked planthopper, Sogatella furcifera (Horváth). Both low and high temperature stresses reduced plant growth and biomass, and influenced plant chemical composition. Insect food intake, growth, longevity, fecundity, and population increased significantly when IR2035 plants were grown at low and high (vs. optimum) temperature regimes (except 36/28 °C). Insect performance on temperature- stressed TN1 plants was similar or superior to that on TN1 plants grown at optimum temperature, but at low temperatures, developmental period and longevity increased, while population decreased. At 36/28 °C, the insect performed poorly on both resistant and susceptible plants. In spite of temperature-induced effects, the difference between resistance of IR2035 and susceptibility of TN1 remained distinct. Significantly more first instars died on TN1 plants painted with the steam-distillate extract of resistant IR2035 plants (grown at all temperatures studied) than on acetone-treated TN1 plants. Compared with unstressed plants, temperature-stressed plants had less allelochemicals. Since temperature-induced stresses enhance susceptibility of rice to insects, germplasm for S. furcifera resistance should be evaluated across a wide range of temperatures.
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