Articles
INDUCTION OF PROLEPTIC SHOOT FORMATION ON POME FRUIT NURSERY TREES
Article number
514_27
Pages
235 – 244
Language
Abstract
High establishment costs of new orchards necessitate early cropping to ensure an early return on investment.
Feathered trees come into production earlier than whip trees, but are expensive to produce.
Trees branched via prolepsis may be more precocious and less expensive to produce than syllepticly feathered trees.
One-year-old ‘Abate Fetel’ pear nursery trees on BP3 rootstock were thinned to 7, 14 or 21 cm within the row and 1.2 m between rows.
Half of the trees were bent to a horizontal wire at 45 cm above the bud union and compared to unbent trees.
Bending lasted for a fortnight from just prior to bud break (3 October 1996), whereafter trees were headed at a height of 80 cm.
DNOC (3%) was applied to all trees prior to bud swell.
Proleptic shoot formation was evaluated and trees scored according to their acceptability as ‘feathered’ trees.
No interaction occurred between spacing and bending.
Tree diameter, and the number and length of useful laterals (appropriate length and height above the bud union) increased with spacing.
This resulted in more trees being classified as ‘acceptable’ with an increase in spacing.
The number of ‘acceptable’ trees did not differ between spacing at 14 or 21 cm.
Bending did not influence the acceptability of trees.
In another trial one-year-old ‘Royal Gala’, ‘Fuji’ (Akifu strain) and ‘Golden Delicious’ apple nursery trees on M793 rootstock were either left unheaded or headed at 80 cm above the bud union.
Trees were headed either in winter (5 August 1996), two weeks after bud break (31 October 1996) or six weeks after bud break (29 November 1996). DNOC (4%) was applied to all trees at bud swell.
Proleptic shoot formation was assessed and trees evaluated as described for pear trees.
Tree height decreased linearly with the time of heading.
Unheaded ‘Fuji’ trees were taller than headed trees.
Unheaded ‘Royal Gala’ and ‘Fuji’ trees were thicker than headed trees.
Unheaded trees had more, but shorter laterals.
Heading of ‘Royal Gala’ and ‘Fuji’ trees in October increased the laterals per meter shoot length.
Heading trees in November resulted in an unacceptable bend at the base of the leader.
Leaving ‘Royal Gala’ and ‘Fuji’ trees unheaded, or heading them in October resulted in high percentage ‘acceptable’ trees.
The acceptability of ‘Golden Delicious’ trees decreased linearly with time of heading.
Feathered trees come into production earlier than whip trees, but are expensive to produce.
Trees branched via prolepsis may be more precocious and less expensive to produce than syllepticly feathered trees.
One-year-old ‘Abate Fetel’ pear nursery trees on BP3 rootstock were thinned to 7, 14 or 21 cm within the row and 1.2 m between rows.
Half of the trees were bent to a horizontal wire at 45 cm above the bud union and compared to unbent trees.
Bending lasted for a fortnight from just prior to bud break (3 October 1996), whereafter trees were headed at a height of 80 cm.
DNOC (3%) was applied to all trees prior to bud swell.
Proleptic shoot formation was evaluated and trees scored according to their acceptability as ‘feathered’ trees.
No interaction occurred between spacing and bending.
Tree diameter, and the number and length of useful laterals (appropriate length and height above the bud union) increased with spacing.
This resulted in more trees being classified as ‘acceptable’ with an increase in spacing.
The number of ‘acceptable’ trees did not differ between spacing at 14 or 21 cm.
Bending did not influence the acceptability of trees.
In another trial one-year-old ‘Royal Gala’, ‘Fuji’ (Akifu strain) and ‘Golden Delicious’ apple nursery trees on M793 rootstock were either left unheaded or headed at 80 cm above the bud union.
Trees were headed either in winter (5 August 1996), two weeks after bud break (31 October 1996) or six weeks after bud break (29 November 1996). DNOC (4%) was applied to all trees at bud swell.
Proleptic shoot formation was assessed and trees evaluated as described for pear trees.
Tree height decreased linearly with the time of heading.
Unheaded ‘Fuji’ trees were taller than headed trees.
Unheaded ‘Royal Gala’ and ‘Fuji’ trees were thicker than headed trees.
Unheaded trees had more, but shorter laterals.
Heading of ‘Royal Gala’ and ‘Fuji’ trees in October increased the laterals per meter shoot length.
Heading trees in November resulted in an unacceptable bend at the base of the leader.
Leaving ‘Royal Gala’ and ‘Fuji’ trees unheaded, or heading them in October resulted in high percentage ‘acceptable’ trees.
The acceptability of ‘Golden Delicious’ trees decreased linearly with time of heading.
Authors
K.I. Theron, W.J. Steyn, G. Jacobs
Keywords
prolepsis, feathered trees, apple nursery trees, pear nursery trees, branching
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