Effect of low doses of gamma irradiation on in vitro growth of grapevine

Shoot tips and single node explants of two rootstocks (R.99 and 3309) and t wo varieties ('Helwani' and 'Cabernet Franc') of grapevine cultured on DSD1 media for a period of 60 days, were irradiated with 0, 2, 5 and 7 Gy doses of gamma irradiation. Shoot length of 'Helwani' and 'Cabernet Franc' was i ncreased by 7 Gy irradiation. The 5 Gy dose increased the number of roots i n plants of the two rootstocks and 'Helwani'. Root length of 'Helwani' and 'Cabernet Franc' at the 2 and 7 Gy doses were significantly higher than tho se of the non-irradiated control. A similar effect was noticed on R.99 root stock subjected to 5 Gy. Five Gy also increased the dry weight of the R.99 rootstock, whereas 2 and 7 Gy had a similar effect on 'Helwani' and 'Cabern et Franc'. Number of leaves of plants exposed to 5 and 7 Gy was increased w hen compared with the non-irradiated control.