Good Fruit Grower

December 2011

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Manufacturing Excellence for over 60 years. Prunings a problem? The Edwards Brush Spider makes a clean sweep of prunings, leaves, and other debris from the difficult area between trees or vines. When combined with shredding, the Brush Spider makes a time-consuming job a fast, one-pass opera- tion. Brush Spiders can be mounted on shred- ders or mowers, or on the Edwards Front Mount 3-Point Hitch. Edwards also manufactures the Brush Rake for orchardists who prefer to push out the brush. Online catalog: 4312 Main Street Union Gap WA 98903 800-452-5151 509-248-1770 Web Site: E-mail: Self-rooted trees CUT COSTS In an experiment, self-rooted pear trees were as productive as trees on rootstocks and cost much less. by Bas van den Ende T his is not a story out of a horticultural book of fables. It is a story to ruffle your imagination. While the search goes on unabated for the elu- sive size-controlling precocious pear rootstock, an experiment at the Tatura Research Institute in Victoria, Australia, has shown that pear trees propa- gated on their own roots can match the productivity of trees on a rootstock. The cost of trees represents a large proportion (often more than 50 percent) of the total cost of establishing a Tatura Trellis planting. The experiment showed that pear trees can be propagated cheaply from softwood cuttings and made productive at an early age. The aim was to sub- stantially reduce the cost of trees and so increase interest in the Tatura system of growing pears. Leafy (softwood) cuttings of Packham's Triumph taken in December (midsummer), treated with a root- promoting hormone, and then placed under a mist propagation unit, produced roots within 60 days. The cuttings were then potted up, and in August (early spring), they were planted on Tatura Trellis as dormant rooted cuttings 1 meter (3 feet) apart in the rows with 4.5 meters (15 feet) between rows, for a total of 2,222 trees per hectare (968 trees per acre). Each tree developed a leader to the left and to the right at 30 degrees to vertical (60 degrees in the V). Branches were trained to the wires with small plastic ties. Initial training and pruning were done in spring and summer. A dormant rooted cutting of Winter Nelis was planted as pollinizer at each trellis frame (15 meters, or 50 feet, apart). Trees were irrigated with microjets. Export standards Adjacent to the Packham's experiment was the first Tatura Trellis with Bartlett on Pyrus calleryanaD.6 seedling rootstock planted at the same tree and row spacing. Packham's were grown for the fresh market and Bartletts for the cannery. Packham yields were compared with those of Bartletts for ten years (see Table 1). The cost of raising a self-rooted tree was estimated to be less than one-eighth the cost of raising a tree with a rootstock. Australian export standards were followed when fruit quality and fruit size of Packham's were assessed. An aver- age assessment for the last six years is as follows: unblem- ished fruit fit for export, 67 percent (ranged from 59 to 79%); limb rub, 8 percent; sunburn, 4 percent; misshapes, 8 percent; russet, 6 percent; and undersized fruit less than 57 mm (2.25 inches) in diameter, 7 percent. Bartlett yields are shown as canning grade (larger than 57 mm diameter). Well-managed productive orchards of Packham's on Tatura Trellis in Australia (on P. calleryanaD.6) and South Africa (on BP.1 and BP.3) produced between 72 and 81 tons per hectare annually. Yields in Table 1 are equal to or better than those obtained from overseas reports of yields of different pear varieties on Old Home by Farmingdale and quince rootstocks at approximately the same tree density. Propagating pear trees on their own roots has not been adopted by nurseries in Australia. Perhaps it was too rad- ical. Perhaps the logic and persuasion were not convinc- ing enough for a traditional nursery industry dealing with fruit trees. With the ever-increasing cost of nursery trees, and a continuous emphasis on high-density planting, this exper- iment with self-rooted pear trees has shown that thinking outside the box can have boundless possibilities. • 64 DECEMBER 2011 GOOD FRUIT GROWER Four-year-old Packham's Triumph trees grown from cuttings starting their fifth year. The trees had already produced 24 tons per hectare (24 bins per acre) from two harvests. Van den Ende is a tree fruit consultant in Australia's Goulburn Valley. The propagating mist unit. Table 1. Yields of 10-year-old Packham's Triumph on their own roots and Bartlett on Pyrus calleryana D.6 seedling rootstock, planted at 2,222 trees per hectare. (tons per hectare or bins per acre) Yield Year 23 4 5 6 7 8 9 10 Total Packham 0 17 7 64 87 68 88 78 78 460 on own roots Bartlett 0 14 60 17 63 61 79 71 86 451 on rootstock SOURCE: Bas van den Ende Softwood cuttings struck roots within 60 days. photos courtesy of bas van den ende

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