MODIFICATION OF THE COLCHICINE TECHNIQUE FOR CHROMOSOME DOUBLING OF BARLEY HAPLOIDS

Abstract

Haploid barley plants, produced from the interspecific cross of barley (Hordeum vulgare) by H. bulbosum, were used to evaluate modifications of colchicine treatments for improved chromosome doubling. Plants were treated at the 3-leaf stage in culture vials. With the addition of Tween 20 (a wetting agent) to colchicine - DMSO [dimethyl sulfoxide] solutions, the percentage of surviving plants with doubled sectors was 54% compared to 33% for controls; plant survival decreased from 93% to 73%. The further addition of 10 mg/l GA3 to the treatment solution showed an increase from 54% to 72% plants with doubled sectors and a plant survival of 83%. The extent of doubling per plant as measured by the percentages of spikes and florets with seed increased in the presence of Tween 20 but was reduced when GA3 was included in the treatment solution. Cytological examination of diploid barley root-tips treated with colchicine, colchicine plus DSMO, and colchicine plus DMSO plus GA3 revealed a quicker recovery from C-metaphase in the presence of GA3. No difference in either the mitotic index or frequency of tetraploid cells was observed.