Selection and characterisation of sugarcane mutants with improved resistance to brown rust obtained by induced mutation

Abstract

The brown rust susceptible sugarcane genotype B4362 was subjected to in vitro tissue culture and physical and chemical mutation induction procedures. Five brown rust resistant mutants with hypersensitive response to Puccinia melanocephala were selected out of a total population of 11 167 regenerated plants. High selection frequency was obtained with both mutagenic treatments, although chemical mutagenesis (NaN3) resulted in higher selection frequencies for brown rust resistance than gamma irradiation (60Co). The brown rust resistant mutants showed variations in molecular, morphological, and agronomic traits. Traits such as internode shape, bud shape, leaf sheath hairiness, outer auricule shape, intensity of flowering, stool growth habit, number of stalks per stool, and smut susceptibility were modified in brown rust resistant mutants. In addition, sugar yield was improved in two mutants with increments in stalk length, stalk number, and stalk diameter. Mutation induction proved to be suitable for the generation of new sources of brown rust resistance in sugarcane.