Feeding behaviour of brown planthopper, Nilaparvata lugens (Stal.) on rich double haploid lines

摘要

The Brown planthopper (BPH) Nilaparvata lugens (Stal.) damage to susceptible rice plants results in an excessive loss of sap from the vascular tissue particularly in phloem. Feeding rate of brown planthopper in rice lines was assessed by measuring the honeydew excretion (Paguia et al. 1980). The intake of the phloem sap by the brown planthopper was quantitatively less from resistant variety than susceptible ones (Saxena et al. 1974). The knowledge of mode of feeding in the rice varieties is usefulin evaluating their resistance to pest and the diseases transmitted by them. Feeding behaviour of brown planthopper Nilaparvata lugens was studied in rice Double Haploid (DH) lines. A total of 6 rice lines derived from a cross between IR 64 and Azucena were used in the present study. The parents, susceptible check (TN 1) and resistant check (Ptb 33) were also included The rice lines were mass screened for BPH resistance following standard seedbox screening method (IRRI, 1988). The damage rate was scoredfollowing "Standard Evaluation System (SES). The feeding rate of BPH on the rice lines were studied by honeydew excretion method. The mode of feeding i.e. phloem or xylem feeding of BPH was assessed using a selective dye safranine (Khan and Saxena, 1984). The selective dye can translocate on xylem vessels. Seedlings of 10 days old were removed without damaging their roots and washed thoroughly. The seedlings were immersed in an aqueous solution of 0.2 percent safranine for ca.6 h. The red dye was translocated in entire xylem vessels throughout the entire length of the seedlings. The seedlings were then removed and washed off. The seedlings were placed on medially perforated 10 cm plastic petridish through which the shoot of seedlings emerged. The roots of the seedlings were immersed in glass beaker containing enough water. A filterpaper disc of 9 cm was placed on Petridish at the base of seedling. Then the seedling was enclosed in a cylindrical mylar cage (15 X 9 cm). Five newly emerged female hoppers satiated in water for 4 h were released in to the cage. The honeydew excreted by the hoppers on the filter paper disc was readily absorbed. The area of honeydew dropped on the filter paper was measured after 24 h. The colour of the honey dew whether purple or red was noticed. Red spots on the filter paper disc indicate xylem feeding whereas bluish or purple spots indicate phloem feeding when the filterpaper was treated with 0.1 percent ninhydrin-acetone solution. The experiments were replicated four times and the data obtained were statistically analysed.