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- Author or Editor: P. Spiegel-Roy x
Abstract
‘Kochba’ is a high yielding, semi-hard shelled, well-sealed cultivar of almond, with an attractive light colored kernel.
Abstract
In fruit thinning experiments performed during the June, 1970 drop period in mandarin (Citrus reticulata Blanco cv. Wilking), both 200 and 400 ppm naphthalene acetic acid (NAA), applied 6 days before extremely onset of hot weather, increased fruit size without significantly decreasing yield. Under other conditions, NAA sprays did not cause enough additional fruit drop to thin the crop. In 1972, 400 and 600 ppm NAA proved ineffective. A new thinning agent, 1-(α-naphthaleneacetyl)-3,5 dimethyl-pyrazole (TH656) applied at 160 ppm, brought about a significant increase in fruit size without decreasing yield.
Abstract
Resistance to the root-knot nematode (Meloidogyne javanica Chitwood) was established for 7 bitter almond (Prunus amygdalus Batsch. var. amara DC) F1 progenies selected from trees in a heavily infested nursery soil and subjected to repeated inoculations in containers. Resistance was very high; (complete in some open-pollinated progenies) suggesting dominance or the presence of a cytoplasmic factor. F1 hybrid progenies of 2 highly susceptible almond cultivars crossed with ‘Okinawa’ peach showed almost complete dominance of resistance to M. javanica.
Abstract
Avocado pollen was germinated in vitro without recourse to germination on the style. The technique employed involved inclusion of pollen grains in liquid medium of 15% sucrose and minerals and application of 1 or 2 drops on 1% agar plus 15% sucrose and minerals. No germination was obtained on agar plus sucrose without placement of pollen in liquid first. Of the cultivars tested, ‘Ettinger’ and ‘Nabal’ pollen germinated best, and ‘Fuerte’ was the poorest. The optimum temperature for germination was 25° to 27°C. Addition of Ca to the liquid proved beneficial.
Grapevine (Vitis vinifera L.) explant shoots indexed forcorky-bark and rootstocks from healthy LN33 indicator plants were sterilized and maintained in vitro. When infected shoot tips were micrografted onto LN33 shoots, typical corky-bark symptoms appeared in 8 to 12 weeks. We suggest developing this method further to replace the regular, 2-year indexing procedure.
In many cases the diagnosis of a viral disease in perennial woody plants requires indexing by grafting on indicator plants. In the case of grapevine leafroll and corky-bark diseases, indexing requires 2 to 3 years for symptom recording. Both diseases are found in all grapevine-growing countries. It would therefore be advantageous to develop a sensitive, quick, and reliable diagnostic technique. Explant shoots infected with corky-bark were micrografted onto healthy indicator rootstocks and maintained in vitro. Typical corky-bark symptoms appeared on the indicator within 8 to 12 weeks. Osmotic stress, in vitro, induced by sorbitol, enhanced leafroll symptoms. Explants expressed symptoms after 2 to 3 months of growth on these media. The advantages of these techniques are: Rapid indexing, saving of space and labor, could be performed year-round. Further experiments are underway for adaptation of the micrografting to leafroll disease and the stress method for corky-bark disease.
Abstract
In a breeding program for table grapes (Vitis vinifera L.) initiated in 1968 at Bet Dagan, Israel, one objective has been to breed large-berried, better-flavored grape cultivars for replacement of ‘Ribier’ (syn. Alphonse Lavallee). A selection with large black berries has been made and named ‘Nava’ (Fig. 1.). The fruit is well-adapted for the fresh market.
Abstract
In examining the adenosine triphosphate (ATP) synthesizing system in seeds, an inhibitory effect of seeds on luciferase activity was detected (4). This study describes possible use of the luciferin-luciferase system for a better definition of the amount of seed traces in grape berries. With growing consumer preference for seedless table grapes and raisins, breeding of stenospermocarpic grape cultivars is of great interest. Stenospermocarpic grapes yield considerably larger seedless berries than parthenocarpic ones, but also often possess seedcoats that develop into hard, stony tissue (2). An objective definition of the amount of seed rudiments would be of considerable value in breeding for seedlessness and in assessing environmental or plant growth regulator effects.
Abstract
In a breeding program for table grapes initiated in 1968 at Bet Dagan, one of the objectives has been to breed late-ripening cultivars of Vitis vinifera. A late-ripening plant selected from a cross of ‘Zeni’ and ‘Toufahi’, made in 1969, is being named ‘Odem’.
Abstract
Alnem rootstocks constitute a series of cultivars of bitter almond (Prunus amygdalus Batch var. amara) resistant to the root-knot nematode Meloidogyne javanica Chitwood. Root-knot nematodes are a great hazard to almond trees in warm climates, especially on light and medium irrigated soils. To the best of our knowledge, no other source of resistance in almond has been reported.