Inheritance of resistance to rice tungro virus disease*

The genetics of resistance to tungro rice virus disease was studied under severe tungro pressure in field in five crosses involving 3 resistant ((Kataribhog, Kamod 253 and Pankhari 203) and 3 susceptible varieties (T.N. 1., Bala and Cauvery). In crosses involving Kataribhog and Kamod 253 a ratio of 13 susceptible: 3 resistant was obtained whereas in crosses with Pankhari 203 a complementary gene ratio (9 resistant: 7 susceptible) was recorded. It was inferred from available information that in all 3 genes for resistance were involved besides an inhibitor. The concept of “symptomless carrier” and breeding for resistance to tungro virus disease is briefly discussed.