PRODUCTION OF LARGE NUMBER OF DOUBLED HAPLOID PLANTS FROM BARLEY ANTHERS PRETREATED WITH HIGH-CONCENTRATIONS OF MANNITOL

Pretreatment with increasing concentrations of mannitol, form 0.3 to 0 .7 M, was used to induce stress in cultured anthers of barley (Hordeum vulgare L.). Three cultivars with varying degrees of androgenetic abi lity were studied. A positive linear relationship was found between co ncentration of mannitol in the pretreatment medium and the number of r egenerated green doubled haploid plants in all the cultivars. The pret reatment also resulted in an increasing proportion of embryos to divid ing microspores, and in green to albino plantlets. The optimum length of the pretreatment seemed to be genotyped dependent. When Ficoll was used as an alternative stress agent a differential genotype response w as observed.