Tree growth
Rootstock affected scion growth rates that were reflected in both trunk
cross sectional area and shoot length. One year after planting, TCSA
ranged from 2.14 to 6.56 cm2 in 2018 and then, 3.55 to
8.90 cm2 in 2019 (Table 2). In both years, B.9 had
significantly smaller trunk cross sectional area (TCSA) than other
rootstocks. In 2018 and 2019, TCSA was greater for M.9, G.814, and G.890
among all rootstocks. In both years, CG.4292, G.210 and CG.5257 had
significantly higher shoot length compared to B.9 and G.969. There was a
significant effect on terminal shoot growth ranging from approximately
20 to 50 cm (Figure 1). Growth patterns were mostly consistent between
years with the exception of G.969 which had significantly lower shoot
growth in 2019 than 2018. For both years, shoot length was significantly
greater for G.890 than B.9. Greater growth was also observed for G.87,
CG.5257 and G.814 compared to B.9. There was a significant positive
relationship between trunk diameter and shoot growth in 2019 (r =
0.5182; P = < 0.01).