Genetics of Resistance to Bacterial Blight in Cultivars Pr111, Pr113 and Pr115 of Rice (Oryza Sativa L.)

Cultivar PR106 was used as susceptible parent and crossed with PR111, PR113 and PR115 to develop F₁’s, F₂’s, BC₁F₁P₁ and BCF₁P₂ generations. The Xoo pathotype PbXo7 causing bacterial blight was used in the study. The F₁’s of all the crosses of PR106 with the resistant parents PR111, PR113 and PR115 showed susceptible reaction, thereby indicating that the resistance in these cultivars is recessive. In the F₂’s there was a 3:1 ratio of susceptible:resistant plants which shows that the resistance was controlled by a single recessive gene. The backcrosses with the susceptible parent produced all susceptible plants and backcrosses with the resistant parent gave 1:1 ratio of susceptible and resistant plants thereby confirming that the resistance was governed by a single recessive gene.