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- Author or Editor: G.A. Couvillon x
Abstract
‘Concord’ grapes were harvested at weekly intervals from vines trained to either the Modified Munson (M.M.) or 4-arm Kniffin (4-A.K.) training systems. Total pectic substances and protopectin increased until about 7-9% soluble solids was reached and then decreased during further maturation. As maturity approached, water and oxalate soluble pectins increased. The M.M. system gave higher values for total pectic substances, protopectin, and water soluble pectins than the 4-arm Kniffin system.
Abstract
Softwood cuttings taken from phony peach disease-infected and uninfected trees of ‘Jefferson’ peach [Prunus persica (L.) Batsch] produced 80% or more well-rooted cuttings with no significant difference (5% level) between phony and non-phony cuttings.
Abstract
‘Redhaven’ peach (Prunus persica (L.) Batsch) that were in rest were exposed for 96 hours to 2.5, 5, 10.5, or 21% O2. A second group was exposed to 2.5% O2 for 1, 2, 4, or 6 days. Bud break was enhanced only by 2.5 or 5% O2. Rest release was also influenced by the duration of exposure to low O2. Plants exposed for 2, 4, or 6 days to 2.5% O2 showed faster bud break than did those exposed to the same concentration for 0 or 1 day.
Abstract
The effect of exposure of small peach plants (Prunus persica (L.) Batsch cvs. Redhaven and Redskin) to daily fluctuating temperatures (16 hours low: 8 hours high) of 6-15°, 6-18°, 6-21° and 6-24°C was examined in comparison with continuous chilling at 4° and a non-chilled control. Even though all chilling treatments received the same amount of chilling (weighted chilling hours), good leaf bud break was obtained only in the continuous 4°, 6-15° and 6-18° treatments. No lateral leaf buds opened in the 6-21°, 6-24° or the non-chilJed controls of both cultivars. The 6-15° temperature regime was more efficient than continuous chilling in breaking bud rest on a weighted chilling hour basis. ‘Redskin’ lateral buds were shown to have a higher chilling requirement than ‘Redhaven’. Terminal buds especially of ‘Redhaven’ showed a very low chilling requirement. Treating plants with 50 or 150 mg/liter GA3 slightly advanced bud break but did not affect the level of sprouting.
Abstract
Leaf bud break of ‘Redhaven’ and ‘Redskin’ peach (Prunus persica (L.) Batsch) following exposure of plants to temperature cycles of 1, 3, 6 and 9 days was examined. During each cycle the plants were exposed to 4°–6°C for 2/3 of the cycle length and 24° for the remaining 1/3 with all cycles repeated until the plants were exposed to a designated number of chilling hours. Thus, all plants within each treatment were exposed equally (in total) to chilling and heat. No lateral bud (LB) break occurred with ‘Redskin’ in the 1-day cycle, a low level was obtained in the 3-day cycle and good bud break occurred in the continuous chilling control and the 6 and 9 day cycles. With ‘Redhaven’ no LB break was evident in the 1 day cycle while the 3, 6, and 9 day cycles responded similar to the continuous chilling control. From these data it was concluded that chilling (4°-6°) accumulated during the 20 to 40 hrs prior to the onset of high temperature was susceptible to high temperature negation.
Abstract
Energy dispersive X-ray analysis of Ca and K was conducted in apple (Malus domestica Borkh.) leaves. Larger amounts of Ca and K were detected in the xylem than in the mesophyll tissue. The X-ray images of both the elements increased in intensities in samples from trees receiving gypsum and foliar sprays with CaCl2. Conversion of the X-ray images into graphical data produced a better quantitative comparison of element concentrations. The range of Ca concentration in the xylem of 206 to 350 ppm compared favorably with that reported in the literature for xylem sap of assorted tree species, including apple trees.
Abstract
[14C-ethyl] labeled (2-chloroethyl)methylbis(phenylmethoxy)silane (CGA-15281) was applied to fruit and leaves of 4-year-old ‘Bicentennial’ peach trees [Prunus persica (L.) Batsch]. Virtually none of the parent material moved into the fruit or was taken up and transported in vegetative tissue. Of the small amount found within the vegetative tissue, there was equal distribution between acropetal and basipetal movement. The compound appears to act through the release of ethylene which penetrates the tissue rather than uptake of the parent molecule and subsequent release.
Abstract
A method for obtaining small (15-25 cm) plants of peach [Prunus persica (L.) Batsch] with all bud types present was developed by rooting peach cuttings following flower bud initiation. These small plants permit studies to be carried out in controlled-environmental chambers. The rest and dormancy periods of the rooted cuttings were similar to large field-grown trees of the same cultivar.
Abstract
Peach seed (Prunus persica (L.) Batsch, cv. Elberta) were stratified at 0°C in peat moss and analyzed for GA3 and GA7 at weekly intervals for 4 weeks and at 4 week intervals for 16 weeks. Percentage germination increased as GA3 and GA7 increased during stratification. The suggestion is made that there is a conversion of GA7 to GA3 during stratification and the biosynthesis is temperature dependent.
Abstract
Dormant cuttings of muscadine grape, Vitis rotundifolia Michx., rooted best early in the dormant season, although root quality was poor and the percentage rooting was low. Large-diameter cuttings rooted better than small-diameter cuttings. A high percentage of cuttings with aerial roots produced additional root growth. Medium heating was necessary for root formation. No significant rooting response was observed with indolebutyric acid (IBA), (2-chloroethyl) phosphonic acid (ethephon), precallousing, sucrose treatments, or with mallet cuttings.