Ten-Year Summary of the 2003 NC-140 Dwarf Apple Rootstock Trial

摘要

This is a 10 year summary report about the NC-140 trial. The coordinators also submitted compiled reports, but that would not fit in Compact Fruit Tree. It is available in the research library on the IFTA website. You must be a 2014 member and be logged in to access it.Rootstock can influence many aspects of apple tree performance including preciosity, yield, fruit size, tree size, biennial bearing, and tree survival from pests, and extremes in temperature and soil moisture. NC-140 is a USDA-funded multistate researchproject that was established in the 1970s to evaluate root-stocks and other aspects of orchard systems. In 2003 a trial was established at 8 locations (Table 1) with Golden Delicious on 23 dwarf rootstocks and trees were trained to the vertical axe system. Cooperators at all locations received trees on 11 rootstocks: industry standards included B.9, M.9 NAKBT337, M.26 EM LA, and M.9 Pajam 2, along with B.62396 from Russia, G. 16, G.41, and G.935 from Cornell-Geneva, J-TE-H from the Czech Republic, and PiAu 5-14 and PiAu 56-83 from Germany. These 11 rootstocks were considered to be "core" rootstocks because they were grown at all locations. Some locations also received two additional CG rootstocks, seven Japanese (JM) rootstocks, one Czech rootstock, and two German rootstocks. Each year trunk cross-sectional area (TCA) was measured and the number and weight of fruit harvested from each tree was recorded. Average fruit weight (FW) was estimated by dividing yield (kg of fruit/tree) by the number of fruitper tree, and crop density (CD; number of fruit per cm2 TCA) and yield efficiency (YE; kg fruit per cm2 TCA)were also estimated. YE is considered an important characteristic because it is a ratio of fruit to wood. Biennial bearing index (I) was also calculated, where a value of 0.0 indicates no alternate bearing and a value of 1.0 indicates complete alternatebearing.