PLANT-REGENERATION FROM ISOLATED OVULES OF ITALIAN RYEGRASS (LOLIUM-MULTIFLORUM LAM) - EFFECT OF 2,4-DICHLOROPHENOXYACETIC ACID AND DIFFERENT CYTOKININS SUPPLEMENTED TO THE OVULE CULTURE-MEDIUM

Plantlet regeneration was obtained from culture of Lolium multiflorum ovules, excised 3 days post pollination. The response of ovules was in vestigated at various concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D) and of several cytokinins supplemented to the ovule culture m edium. A concentration of 0.2 mg 1(-1) 2,4-D stimulated regeneration v ia direct zygotic and/or secondary somatic embryogenesis, depending on genotype. Kinetin at a range of 0.04-1 mg 1(-1) was shown to be a gen erally suitable cytokinin in both tested genotypes. However, highest f requencies of plantlet regeneration per number of cultivated ovules we re recorded at 0.2 mg 2,4-D combined with 1 mg zeatin or 0.2 mg benzyl adenine per liter medium depending on genotype and resulted in 43.5 an d 57.8% plantlet regeneration, respectively, A high frequency regenera tion procedure for isolated ovules is desirable for further experiment s to overcome postzygotic crossing barriers and for the development of genetic manipulation techniques.