Genetic studies on collar rot resistance in opium poppy (Papaver somniferum L.).

The collar rot disease has been reported recently and occurs at the 10-12-leaf stage of plants of opium poppy. Infected plants topple down and dry prematurely due to fast rotting at the collar region. The inoculum for this study was multiplied on the cornmeal-sand culture. Genetic ratios were calculated by the chi-square test. Inheritance studies on this disease show a monogenic pattern of segregation with the ratio of 3 : 1 at F2, 1 : 2 : 1 at F3 and 1 : 1 at the backcross. Such genetic ratios clearly indicate that a single recessive gene (rs-1) is responsible for disease resistance in opium poppy. The inference drawn on the basis of the present study will be a great help in the future breeding programme of opium poppy for collar rot resistance.