Peach Rootstock/Scion Hardiness Effects1

Cold resistance of current season shoots of ‘Redhaven’ peach in the nursery as affected by 4 rootstocks was determined by electrical conductance. Significant conductance differences were noted on scion due to rootstock effects, and the most effective time for determining this difference appeared to be in early winter. There were significant differences due to late N applications. Late winter determinations showed that rootstock effects tend to diminish except at critical temperatures. There was variance in relative hardiness of stocks from 1 temperature to another or on different dates but, in general, ‘New’ and ‘Harrow Blood’ transmitted more hardiness to scions that did ‘Siberian C’ or ‘Rutgers Red Leaf’. ‘Siberian C’ was generally better than ‘Rutgers Red Leaf’.