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- Author or Editor: H. B. Lagerstedt x
Abstract
There are various problems associated with hot-callusing graft unions of dormant fruit and nut trees. Since the whole plant is exposed to elevated temperatures, growth is promoted not only at the graft union, but also from the scion buds and the roots. Translocation demands are placed on the graft union once growth of scion buds starts and leafing out occurs. Scion buds and leaves will desiccate if a callus bridge between rootstocks and scion is inadequately formed (1).
Abstract
‘Ennis’ and ‘Butler’ are the first filbert (Corylus avellana L.) introductions to be made from the Pacific Northwest in over 40 years. Cultivars more recently introduced from the northeastern U.S. and Canada have not proved to be satisfactory in Oregon and Washington. About 85% of the U.S. filbert production comes from a single cultivar, ‘Barcelona’, introduced from Europe in 1885. Another 10% of the production comes from ‘Daviana’, a cultivar which functions primarily as a pollinizer for ‘Barcelona’. ‘Ennis’ is being introduced as a main crop cultivar to replace ‘Barcelona’ for the in-shell trade. ‘Butler’ is introduced as a pollinizer to replace ‘Daviana’. The new introductions will, in part, be described by comparing them to the cultivars they are expected to replace (Fig. 1 and 2).
Abstract
The application of exterior white latex paint has proved useful in protecting young fruit and nut trees from summer sunscald. The common methods of paint application are by brush or spray, but brushing is time consuming and not always fully effective and spraying is wasteful of paint and the equipment is difficult to clean. The construction and use of new application ideas such as edge rollers, shake paint applicators, and paint mittens are presented.
Abstract
Exterior white latex paint has been satisfactory in protecting young orchard trees against summer sunscald. Brush application of latex paint to tree trunks has proved to be slow and sometimes thorough coverage at the groundline is not obtained. A 3-nozzle spray boom has been developed to solve these application problems. Directions for its construction are given.
Abstract
Concentrations of 750 to 1,000 ppm of (2-chlorethyl)phosphonic acid (ethephon) will accelerate filbert nut drop by 2-3 weeks without causing excessive premature foliage drop, reduction in nut quality, or plant injury. When ethephon was applied in dilute and concentrate air-carrier sprays at 250, 500, and 750 ppm, responses were found to be a function of concn regardless of total amount of material applied. Results from 4-year trials indicate that over 90% nut drop can usually be attained approximately 3 weeks after treatment. Treatment should be applied as nuts start changing color from green to brown and begin their normal abscission from the base of the husk. Ethephon accelerates maturation of the filbert husk and causes its early release.
Abstract
For commercial nut production the filbert (Corylus avellana L.) is trained as a tree in the U.S., but is commonly grown as a bush in other countries. In a 12 year conparitive test, growth was similar for both methods of training, but the bush form produced slightly fewer nuts. Suggested causes for the reduced yields are the additional pruning the bush receives to keep traffic lanes open, the location of its bearing wood, the nuts lost within the stem mass, and the effect of shading.
Abstract
Branch treatments with (2-chloroethyl)phosphonic acid (ethephon) on fruiting filbert trees showed that ethephon was equally effective in accelerating nut drop from bagged and treated clusters. Ethylene production in husks increased significantly after ethephon application to leaves. Ethylene production did not differ between husk applications and leaf-plus-husk applications of ethephon. Results from radioactive-tracer studies showed the presence of radioactivity in stem tips, buds, and husks when 14C-ethephon was applied to leaves. The data indicate that ethephon, or its active derivative, translocates rapidly in the filbert, as shown by radioactivity and ethylene evolution, being completed within 1 day of foliar application.
Abstract
Translocation of (2-chloroethyl) phosphonic acid (ethephon) was studied in 14-day old bean plants (Phaseolus vulgaris L. cv. Black Valentine) and 7-day old pea seedlings (Pisum sativum L. cv. Alaska). Both foliar and root applications of ethephon caused abscission of the primary leaves and stem terminals, promotion of lateral bud growth, and stem enlargement in bean plants. With pea seedlings, the typical triple responses, normally caused by ethylene, were observed. When 14C-ethephon was applied to the primary leaves of bean plants, recovery of evolved 14C-labelled ethylene, from other parts of the plant, was obtained within 1 hour. Radioautography of the plant showed accumulation of radioactivity in stem tips and nodal regions. The translocated material was identified by instant thin layer chromatography (ITLC) to be ethephon. It is concluded that ethephon translocates readily throughout the plant and accumulates in rapidly growing sinks.
Abstract
Foliar sprays of paraquat, dinoseb, and (2,4-dichlorophenoxy) acetic acid (2,4-D) each provided satisfactory control of filbert suckers. Paraquat and 2,4-D controlled vegetative regrowth to a greater extent than dinoseb. Use of oil with dinoseb increased its phytotoxicity towards filbert suckers.
Suckers should be treated when less than 1 foot in height and thoroughly wetted with spray. The herbicide 2,4-D controlled large suckers better than either paraquat or dinoseb. There was no evidence of injury to the mature trees following the use of these materials.
Abstract
Shoot tip explants from tissue culture plantlets of five Rubus accessions (Rubus leucodermis Torr. & Gray, R. spectabilis Pursh, R. idaeus L. ‘Heritage’, Rubus spp. ‘Logan Thornless’ and ‘Merton Thornless’) were frozen slowly (0.8°C/min) to -40° and then rapidly to -196° in the presence of cryoprotectants. Following rapid thawing, regrowth as organized apical growth or as callus occurred on agar media. A combination of polyethylene glycol (PEG), glucose, and dimethylsulfoxide (PGD) was the most successful cryoprotectant.