Control of hyperhydricity in micropropagated apricot cultivars

The effects of different factors on the control and reversion of hyperhydri city during the in vitro propagation of Prunus armeniaca were studied. Trea tments that decreased the hyperhydricity but did not affect micropropagatio n rates were the use of the bottom cooling system for 1 or 2 wk and agargel as gelling agent in 'Helena', whereas the best results were obtained with the bottom cooling system for 2 wk and the use of 0.8% agar as gelling agen t in 'Lorna'. Hyperhydric shoots reverted to normal after keeping them for 3 wk in the bottom cooling system.