Survival and Growth of ‘Empire’ Apple Trees Chip Budded onto Mark or M.9 Rootstock

Abstract

‘Empire’ apple ( Malus domesticaBorkh.) was budded onto Mark or M.9 rootstock on 16 July, 9 Aug., 30 Aug., or 23 Sept. 1990 in Illinois and Washington to determine the effect of time of chip budding on tree survival, scion growth, and union overgrowth. Most of the trees (≥ 68%) propagated in July or August produced scion growth by 5 May 1991. However, scion wilting occurred subsequently, resulting in substantial tree loss. By October 1991, scions that were budded on Mark rootstock on 30 Aug. 1990 generally had the greatest survival at both locations. In contrast, ‘Empire’/M.9 trees chip budded in Illinois on 23 Sept. tended to have the greatest scion survival and growth and number of branches. In Washington, M.9 rootstocks budded on 16 July had greater scion survival than those budded on 30 Aug. or 23 Sept.