Inheritance of seedling and adult plant resistance to Alternaria leaf spot in safflower (Carthamus tinctorius L.)

The present study on safflower (Carthamus tinetorius L.) was undertaken to workout inheritance pattern of seedling as well adult plant resistance to alternaria leaf spot caused by Alternaria earthami. Two genetically male sterile lines, GMS-104 and GMS-105, susceptible to leaf spot, were crossed with a resistant accession GMU-1825. Evaluation of the parents and the F₁, F₂, BC₁ and BC₂ derived from the two crosses under polyhouse condition, showed that the seedling resistance was monogenic recessive. The adult plant resistance under field condition, was under the control of two duplicate loci where atleast one locus at homozygous recessive condition confers the adult plant resistance.