Rootstock and Scion Interact to Affect 

 Apple Tree Performance 



Wesley R. Autio, J. LaMar Anderson, John A. Barden, 

 Gerald R. Brown, Paul A. Domoto, David C. Ferree, Alvan Gaus, 

 Richard A. Hayden, Frank Morrison, Charles A. MuUins, 

 Curt R. Rom, James R. Schupp, and Loren D. Tukey 

 NC-140 1990 CultivarlRootstock Trial Cooperators 



For about 20 years, the NC-140 Regional 

 Research Committee has been stud3dng the 

 effects of rootstock on the performance of 

 various tree-fruit crops. The first and second 

 cooperative plantings of NC-140 included 

 Delicious apple on a variety of rootstocks from 

 subdwarf to vigorous. Much useful information 

 was generated from these trials, particularly 

 because of the rigorous, systematic evaluation 

 of performance and the large number of sites 

 and conditions that trees were exposed to. A 

 total of 25 to 30 sites were included, ranging 

 from Mexico and the southern United States to 

 several Canadian provinces. 



Delicious was the cultivar of choice for 

 these early plantings, because it was important 

 for all growing regions; however, little 

 information was generated on how rootstocks 

 may affect different cultivars. In fact, no large- 

 scale trial had looked at the interaction of 

 rootstock and scion in a systematic way. 

 Therefore, planning began in 1987 to establish 

 such a trial. 



Trees for the 1990 NC-140 Cultivar/ 

 Rootstock Trial were propagated by Stark Bro's 

 Nurseries during the winter of 1989 and were 

 grown in Selma, CA during the 1989 growing 

 season. Trees were dug in the fall and shipped 

 to cooperative sites (see tables for a list of 

 locations) in the late winter and early spring of 

 1990. Each site included six replications of four 

 cultivars (Smoothee Golden Delicious, Nicobel 

 Jonagold, Empire, and Law Rome) on five 

 rootstocks (M.9 EMLA, B.9, Mark, 0.3, and 

 M.26 EMLA). The four cultivars were chosen 



with different growth habits, ranging from the 

 basitonic (spur-type) Empire to the acrotonic 

 (tip-bearing) Rome. The rootstocks were the 

 most promising from the first two NC-140 

 cooperative trials. 



Trees were individually staked and man- 

 aged as slender spindles with a standard 

 protocol. Pest management, irrigation, and 

 fertilization were per local recommendations. 

 Yield and tree size were measured annually. 

 Data reported here are through the seventh 

 growing season (1996). 



Using trunk cross-sectional area as a 

 measure of tree size (Table 1), it is clear that 

 rootstock affected trees size differently, 

 depending on cultivar. M.26 EMLA, however, 

 resulted in the largest tree, regardless of 

 cultivar. Golden Delicious and Empire trees on 

 M.9 EMLA were significantly smaller than 

 those on 0.3, but Rome trees on the two 

 rootstock were similar in size, and Jonagold 

 trees on M.9 EMLA were signficantly larger 

 than those on 0.3. Jonagold, Empire, and 

 Rome trees on B.9 were similar in size to those 

 on Mark, however. Golden Delicious trees on 

 B.9 were larger than comparable trees on 

 Mark. The cultivars also differed overall. 

 Specifically, Jonagold trees were the largest 

 and Empire trees were the smallest. Site 

 differences were very dramatic. Trees in 

 Wichata, Kansas were the largest, and those in 

 Maine were the smallest, less than 1/3 of the 

 size of the Kansas trees. Massachusetts trees 

 were not significantly larger than those in 

 Maine. 



Fruit Notes, Volume 63 (Number 1), Winter, 1998 



