VARIETAL DIFFERENCES IN PLANT-REGENERATION FROM SOLID AND SUSPENSION-CULTURES IN ONION (ALLIUM-CEPA L.)

Seeds of 22 onion (Allium cepa L.) cultivars were cultured on solid Mu rashige and Skoog (MS) medium containing 50 mu M 4-fluorophenoxyacetic acid (4-FPA) and 1 mu M N-6 (2-isopentenyl) adenine (2iP). Callus for mation was observed in all cultivars. Some of the calli in solid cultu re were transferred into liquid MS medium containing 50 mu M 4-FPA and 1 mu M 2iP and were cultured in suspension. After subculturing in a l iquid medium of 0.2M of sucrose, light yellow and large (LL) type cell clumps were obtained. To investigate the varietal differences in plan t regeneration from solid and suspension cultures, the calli in solid culture and LL type clumps in suspension culture were transferred onto solid MS medium containing 1 mu M 2iP. Plantlets were regenerated dir ectly from the calli and the LL type clumps. The frequency of plantlet regeneration from suspension cultures tended to be higher than that f rom solid cultures. Significant differences were observed among the cu ltivars in the frequencies of plantlet regeneration from solid culture s and from suspension cultures. After suspension culture, 'Kurenai' sh owed the highest regeneration frequency (98%).