ISHS Acta Horticulturae 367: VI International Symposium on Pear Growing
SHOOT POSITIONING |
| Authors: | Eugene A. Mielke, L. Smith |
| Abstract:
In 1986, d'Anjou trees on eight Old Home by Farmingdale (OHxF) rootstocks and seedling Bartlett were established in a 2.4 x 5.5 m (8 x 18 ft) planting, with eight replicates. The trees were trained to a central leader, with all lateral shoots allowed to develop, unless they exceeded 50% of the diameter of the central leader. The lateral shoots on half of the replicates were trained at 15 degrees above horizontal. Shoots on the other half of the trees were trained at 45 degrees above horizontal. As the trees came into bearing, or the lateral shoots interfered with each other, lateral branches were selectively removed. In 1993, trees on OHxF 97 roots had the largest trunk cross sectional area (TCSA) (Table 1). This was true regardless if the shoots were positioned at 15 or 45 degrees from horizontal. Trees on Bartlett seedling roots had the smallest TCSA at the flatter (15 degree) angle, and trees on OHxF 51 had the smallest TCSA at the more upright (45 degree) angle. Generally trees trained to the more upright angle had slightly larger TSCAs. Trees on OHxF 97 and OHxF 51 had respectively the largest and smallest percentage increase in TCSA in 1993 when trained to the flatter angle, while trees on OHxF 217 and OHxF 333 had respectively the largest and smallest percentage increases in TCSA when trained to the more upright angle. Trees on OHxF 361 roots produced the greatest yields in 1993 (Table 1). This was true at both degrees of shoot positioning. Trees on OHxF 333 produced the lowest yields at both degrees of shoot positioning. Yield on trees with five of the nine rootstocks (OHxF 40, OHxF 87, OHxF 97, OHxF 217, and OHxF 361) produced greater yields when shoots were positioned at the flatter angle. Trees on the remaining four rootstocks produced greater yields when positioned at the more upright angle. This is somewhat in agreement with last year in which trees on OHxF 51 and seedling Bartlett produced more fruit when trained at the more upright angle. Cumulative production was greater at the flatter training angle with trees on all rootstocks except seedling Bartlett, OHxF 51 and OHxF 333 (Table 2). Trees on OHxF 87 were the most productive at both training angles. Fruit pressure at harvest was generally greater when the trees were trained at the more upright angle (Table 2). Trees on seedling Bartlett roots generally produced the softest fruit. The number of flower clusters was generally higher when the shoots were trained to the more upright angle. This was true for both limbs on the north and south sides of the tree. There was generally more flower clusters on the north side of the tree as compared to the south side of the tree. No consistent pattern was found for the number of fruit initially or finally set, or for the percentage of initial or final set. Branch yield efficiency was generally (but not always) greater on shoots trained to the | |
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