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- Author or Editor: G.A. Couvillon x
Abstract
Dormant ‘Redhaven’ peach [Prunus persica (L.) Batsch.] cuttings with flower, lateral vegetative, and terminal vegetative buds were exposed to either 7.2°, 3°, or 2°C for 600, 1340 or 2040 hr. Terminal vegetative (TV) buds had the shortest chilling requirement and showed less differential response to the various temperature levels than the other bud types. ‘Redhaven’ lateral vegetative (LV) and flower buds (FL) had similar chilling requirements. In general, 7.2° was more effective in releasing buds from rest than 3° or 2°. Prolonged chilling (2040 hr) decreased the growing degree hours (GDH°C) required for vegetative bud opening regardless of temperature. However, the GDH°C required for flower bud opening was decreased only by prolonged chilling at 7.2°C.
Abstract
Semi-hardwood peach cuttings of 13 cultivars of peach (Prunus persica (L.) Batsch) collected in 2 locations were successfully rooted and transplanted to the field. Rooting was influenced by indolebutyric acid (IBA) concentration and basal wounding.
Abstract
The rabbiteye blueberry, V. ashei, is planted to a limited extent in the Southeast, although it is adapted to an area extending from Virginia to Texas. The difficulty in propagating the species is one factor limiting the planting of improved selections (1). Many factors are known to influence root initiation and development in cuttings of rabbiteve, lowbush, and highbush blueberry species (2,4,5,7,8,9,10), but the effect of extended photoperiods on the rooting of the rabbiteye species is lacking. This study was conducted in 1963 and 1964 to investigate the effect of photoperiod and IBA on the rooting of cuttings of the rabbiteye blueberry, ‘Woodard’.
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.
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.
Abstract
Fruits on uniform peach shoots selected from the periphery of trees were thinned to leave only those nodes of the terminal, intermediate, or basal regions of the shoot, or at 6” spacings along the shoot. The control consisted of unthinned shoots. During one year of the study the date of 90% bloom of buds at the various node positions and size of the subsequent fruit was determined. During the second year fruit volume and mean ovule length were determined for each thinning treatment.
Flower buds from the terminal nodes were the first to bloom the resulting fruit were the largest at harvest. Conversely, buds at the basal nodes were the last to bloom and produced the smallest fruit. In treatments that included fruit from all node positions, the mean fruit volume was smaller than for shoots having fruit only at the terminal nodes. Mean ovule length was also influenced by node position.
Abstract
‘Loring’ peach trees (Prunus persica (L.) Batsch) were treated with a 1% thiourea + 2% KNO3 (TUK) mixture during “late rest” when 589 chill units had accumulated and 1 week following rest completion, when 691 chill units had accumulated. Applications made during “late rest” terminated rest of both flower and lateral vegetative buds before the control and significantly reduced growing degree hour celsius (GHD°C required for bud break. Applications of TUK a week later resulted in a significant reduction in GDH°C for bud break over the control. The late treatment was intermediate between the control and the earlier treatment for bloom date and GDH°C accumulation.
Abstract
Thiourea (TU) at 0.5 or 1% in combination with KNO3 at 2% sprayed on peach trees (Prunus persica (L.) Batsch cv. Washington) with delayed dormant symptoms 1 month after full bloom failed to alleviate the prolonged dormant conditions, were phytotoxic to the foliage, and resulted in severe aberrant fruit.
Abstract
Unrooted hardwood cuttings of ‘Harvester’, ‘Redhaven’, and ‘Bicentennial’ peach [Prunus persica (L.) Batsch] were planted directly in the field. Survival decreased with planting dates from November to January. Basal wounding increased survival of all cultivars. Survival of cultivars varied significantly.
Abstract
The “after-rest” and “post-rest” quiescent periods of flower buds of 2 peach cultivars of different chilling requirements were characterized by a period of reduced inhibition during which the degree of inhibition decreased each succeeding week. Buds within this reduced period of inhibition appeared to be quiescent since they broke and grew during 2 weeks in a greenhouse. However, during this period the buds responded to GA3 and chilling temp. The “post-rest” quiescent period was not reached until mid-February, at which time the buds no longer responded to GA3 or additional chilling and bud break occurred within 72 to 84 hours after exposure to the greenhouse environment.
The degree of inhibition of buds of the 2 cultivars varied throughout this study. ‘Redhaven’ buds were more inhibited than buds of ‘Redskin’ throughout the period studied.