MUTATION BREEDING IN CULTIVAR IAC-24 OF W HEAT AIMING AT RESISTANCE TO DISEASES

The objective of the present work was to obtain mutants with disease r esistance in the wheat cultivar IAC-24. Seeds were irradiated with gam ma-rays (25 and 35 krad) and the selection was started in the M(2) gen eration. Eight selected lines were compared with the control IAC-24 du ring three years (M(6), M(7) and M(8) generations) in nine trials carr ied out in several locations with and without irrigation. Four mutant lines were immune to leaf rust and one of them showed also moderate re sistance to powdery mildew. Another mutant line showed better reaction to leaf spot. Two of these mutant lines maintained the same yield, pl ant height and tolerance to aluminum toxicity as the control. These re sults show the usefulness of mutation breeding approach to correct def ects in outstanding cultivars.