Mycorrhizae induced hardening of tissue culture raised grape (Vitis vinifera L.) plantlets

To minimize large-scale mortality of tissue culture raised grape plantlets during acclimatization, different mycorrhizal fungi viz., Glomus, Gigaspora, Aculospora, Enterophosphora, Scutellospora and a mixed strain were tried as biological hardening agents. Thirty-day-old in vitro rooted grape plantlets of cv. Pusa Seedless showed maximum root colonization with Glomus mossae, while Pusa Urvashi responded best with the mixed strain. Mycorrhizal plantlets were found to be faster in growth and possessed high shoot and root fresh and dry weights. The vines of the treated plants contained higher sugars and phenols, while the leaves had higher chlorophyll. Of the different nutrients analysed, P, Mg and Zn contents in the leaf were significantly higher compared to control. Mycorrhization resulted in higher plantlet survival, i.e. over 85.0% compared to 55.0% in non-mycorrhizal control.