Genetics of Karnal bunt resistance in a new set of bread wheat lines

Genetics of Karnal bunt resistance was studied in populations derived from crosses of ten resistant stocks (ALDAN, CMH77.308, H567.71, HD29, HD30, HP1531, W485, FRAME, CHIL and MRNG) and a highly susceptible cultivar, WH 542. F₂s from resistant x susceptible and resistant x resistant crosses, along with parents and F₁s, were screened for Karnal bunt response. The F₁ hybrids between resistant and susceptible parents were resistant indicating that resistance was dominant over susceptibility. ALDAN carried some minor genes for susceptibility while there is presence of some minor gene(s) for resistance in otherwise susceptible cultivar WH542. Genetic analysis revealed that Karnal bunt resistance is primarily controlled by few major gene(s) along with some minor genes/modifiers which ultimately affect the disease expression. One common gene for resistance was postulated in all the parents, thereby concluding that additive genes at eleven loci govern the Karnal bunt resistance.