Genetic analysis of resistance to whitebacked planthopper in twenty-one varieties of rice, Oryza sativa L.

The inheritance of resistance to whitebacked planthopper Sogatella furcifera (Horvath) was studied in 21 rice varieties. Reactions of F1; F2 and F3 progenies of the crosses of 21 resistant varieties with the susceptible variety 'TN 1' revealed that a single dominant gene governs resistance in 'Mushkan 41', 'Santhi', 'Siahnakidar 195', 'SM2-34', 'Tirisurkh 251', 'Zirijowaian 245', '18', '24A', '39', '76 S', '78', '180', '213 B', '267', '293', 'CI 6037-4', 'NP97', 'S39 JKW' and 'Bansphul'. In varieties '65' and '274 A', resistance is governed by one dominant and one recessive gene which segregate independently of each other. Tests for allelism with the Wbph 1 gene originally identified in 'N 22' revealed that the dominant gene present in all the test varieties is the same as Wbph 1. Further studies are required to determine the allelic relationships of the recessive gene found in varieties '65' and '274 A'.