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A. Erez

Abstract

Magnesium chlorate [(Mg(C103)2] and hydrogen cyanamide (H2CN2) sprays defoliated one-year-old nursery trees of ‘Golden Delicious’ apple, ‘Spadona’ pear, ‘Canino’ apricot, ‘Harry Pickstone’ plum, and ‘Cabernet Sauvignon’ grapevine, with no or minimal phytotoxicity. Bearing Maravilha peach trees were defoliated completely in autumn using Mg(C103)2 at 0.36%.

Open access

A. Erez

Abstract

This workshop reviewed the problem of excessive vegetative growth in trees and its control by using dwarfing rootstocks, cultural methods, and growth retardants. Rootstocks are only partially satisfactory for apples, even though there is a wide choice of size control, and it is used along with less vigorous spur-type cultivars. All other species require some other means to control growth, since the number of dwarfing rootstocks is limited.

Open access

A. Erez

Abstract

Hardwood cuttings of peach [Prunus persica (L.) Batsch] treated with indolebutyric acid (IBA) and exposed to constant temperatures between 3° and 15°C for 44 to 47 days rooted well only at a temperature of 12° or higher. The medium temperature threshold for root formation seems to lie between 9° and 12°. Covering moist sand in winter outdoors at The Volcani Center, Bet Dagan, Israel, with polyethylene raised the temperature at a depth of 35 cm by over 1° on bright days and improved rooting of the cuttings.

Open access

S. Lavee and A. Erez

Abstract

Peach leaf and flower buds showed different light requirements for opening. Leaf bud opening required light, the active range for the process was 600 - 690 m. Flower bud opening was relatively light independent. Green light or low light intensities slightly promoted it, while red and white light or high intensities caused some inhibition.

Open access

A. Erez

Abstract

Thiourea will thin ‘Sunred’ nectarine and early peach cultivar flower buds effectively when sprayed at a concentration of 2 to 3% at the beginning of bud swell. Flower-bud thinning was not accompanied by any significant phytotoxicity at this period. Earlier and later application resulted in a reduced thinning effectivity with the latter also causing damage to leaf buds and young shoots. Fruit on chemically thinned trees were larger and matured earlier than those on hand-thinned trees.

Open access

B. Avidan and A. Erez

Abstract

The actinometric method, based on photolysis of uranyl oxalate, was adapted for measuring integrated light irradiance in plant canopies. The unique characteristics of the new actinometers are their small size, the avoidance of pressure build-up in the measuring cell, the good correlation with quantum sensors, and their response to the cosine law. The proposed system is inexpensive and reliable, integrates light measurement over a relatively long period, and needs little additional instrumentation. Numerous measurement points scattered in plant canopies can be determined simultaneously by this method, thus improving assessment of the light regime in fields and orchards. This paper describes such measurements in a peach meadow orchard planted at 2 densities, where 27 actinometers were dispersed in each density treatment and replicate

Open access

Gary A. Couvillon and A. Erez

Abstract

Rooted ‘Redhaven’ peach [Prunus persica (L.) Batsch] cuttings were exposed to diurnal temperature cycles. A severe reduction in lateral vegetative bud break was found in plants refrigerated at 4°C and given 8 hr daily exposure to 19° (±0.1°). Nearly complete chilling negation occurred in plants exposed to diurnal cycles including 8 hr of 20° or 21°. Also, effect decreased with increased time (0 to 8 hr per day) of exposure to 24°. Buds on plants exposed to cycles including 20° for 2 and 4 hr showed no chilling negation, but gradual increases in chilling negation occurred with longer exposures to 20°. ‘Harvester’ peach plants were exposed to 2, 7, or 12 days of 23° following the accumulation of one-fourth, one-half, or three-fourths of the chilling requirement. Chilling negation occurred only with the 12-day exposure to 23° when high temperatures were applied following the accumulation of one-fourth and one-half of the chilling requirement. No chilling negation was found after 12 days’ exposure to 23° if three-fourths of the chilling requirement had accumulated before exposure.

Open access

A. Erez and G.A. Couvillon

Abstract

The chilling enhancement effect of moderate temperature (15°C) on rest completion in ‘Redhaven’ peach was verified and observed only when the moderate temperature occurred followed exposure to chilling temperatures. Chilling efficiency rose with temperatures between 0° and 8° if no moderate temperatures were interspersed. Although 0° was an inefficient chilling temperature, cycling between 0° and 15° resulted in as efficient bud rest release as 6°. The most efficient moderate temperature level was 13°, and the effect of moderate temperatures on rest completion seemed to increase when received during the latter stages of rest. Leaf and flower buds reacted similarly, although the reaction of the former was more prominent. A two-step scheme is proposed for the effect of temperature on bud rest. The first step involves the conversion from the unchilled to the chilled state by chilling temperatures. This stage can be reversed by high temperatures. The second stage is not reversible and involves the conversion by moderate temperatures of the unstable intermediate formed by step 1 to a stable material, which, when accumulated to a certain level, will result in rest completion.

Open access

Gary A. Couvillon and A. Erez

Abstract

Shoots of apple (Malus domestica Borkh.), cherry (Prunus avium L.), peach [Prunus persica (L.) Batsch] and pear [Pyrus communis × Pyrus pyrifolia (Burm.) Nakai] were collected and used in these studies. In all instances, chilling beyond that required for 50% bud break within a 2-week period (prolonged chilling) resulted in a decrease in the growing degree hours required for bud break. In many cases, over 90% of the variation in each study could be attributed to the added chilling.

Open access

A. Erez and G. A. Couvillon

Abstract

Evaporative cooling (EC) of nectarine buds [Prunus persica (L.) Batsch] during rest by overhead sprinkling when day temperature exceeded 16°C lowered bud temperature in bright days by 3° to 5°C. EC resulted in an enhanced break of vegetative and floral buds.