Wine Grape Growing



RACHIS. The main axis of the inflorescence of Vitis vinifera is called a rachis. Flowers are borne on smaller stems called pedicels.

RAKE WIRE. A moveable trellis wire that is used to facilitate shoot positioning as in canopy division.

REFRACTOMETER. An optical instrument used to measure the solute (such as sugar) concentration of liquids such as grape juice.

RENEWAL SPUR. A cane pruned to one or two nodes, generally on an arm or cordon. Its primary purpose is to position a cane for fruiting the following season.

RENEWAL ZONE. A zone established by some growers, whereby the buds which will produce next year's shoots are assured proper positioning.

RESTRICTED ENTRY LEVEL (REI). The period of time after a field is treated with a pesticide during which restrictions on entry are in effect to protect persons from potential exposure to hazardous levels of pesticide residues.

ROOTSTOCK. A cutting taken from a vine (usually Native American or American hybrid) and cultivated to serve as a root system for a grafted vine. Hence a grafted vine consists of a scion (the above ground growth) and a rootstock (the below ground growth).