Mario Fregoni

Effect of some biological methods to improve Fe-efficiency in grafted grapevine

Vitis vinifera L. cv. “Chardonnay” clone R8 was grafted on three hybrid rootstocks with a decreasing degree of tolerance to lime-induced chlorosis, as follows: V Berlandieri Planch, × V. rupestris Scheele “140 Ru”; V. Berlandieri Planch, × V. riparia Michx. “S04”; V. riparia Michx. × V. rupestris Scheele “101-14”. Before potting the plants in unsterile calcareous soil, the roots were infected with Pseudomonas fluorescens cell suspension and Glomus mosseae (Nicol. and Gerd.) Gerd, and Trappe inoculum. The aim of the trial was to test, during the annual growing cycle, the effects of these organisms on some physiological parameters involved in the occurrence of lime-induced chlorosis. The most significant findings were: a) the root infection with Pseudomonas fluorescens and Glomus mosseae affected in a positive way the iron leaf concentration of cv. “Chardonnay” grafted on the chlorosis susceptible “104–14” rootstock; b) the “101–14” rootstock showed a low natural VAM infection, while the chlorosis tolerant “S04” and “140 Ru” rootstocks had a high percentage of natural VAM infection; c) chlorophyll leaf concentrations were related to the extent of root VAM infection in the three rootstocks.