In vitro chemical mutagenesis improves the turf quality of bahiagrass

Abstract

Bahiagrass (Paspalum notatum Flugge) is a warm season, low-input, perennial turfgrass used for residential lawns and sides of road ways. The turf quality of bahiagrass is limited by its open growth habit, light green color, and prolific production of tall seedheads. Genetic improvement of the tetraploid bahiagrass turf cultivar ‘Argentine’ by conventional breeding is difficult due to its apomictic mode of reproduction. Our objective was to explore the potential of in vitro chemical mutagenesis for the generation of uniform, mutant seed progeny with improved turf quality. Scarified, surface sterilized bahiagrass seeds were treated with different concentrations of the chemical mutagen ‘sodium azide’. Callus was induced from these seeds and 19,630 plants were regenerated via somatic embryogenesis. 2,035 of these plants were selected based on their morphological characteristics and transferred to soil. Wildtype bahiagrass and 46 mutant lines (M1 lines) with reduced stem lengths, higher tiller densities or reduced or delayed seedhead formation were established under field conditions. Mutant lines with improved traits and production of viable apomictic seeds were identified and their apomictic M2 progeny was evaluated. A superior line displayed higher density, finer leaves, an upright growth habit, dark green color, reduced seedhead formation and uniform seed progeny in replicated, two location field trials. Beside this improved turf quality, this line also retained the superior drought tolerance and persistence that make bahiagrass a popular low-input turfgrass.