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  • Author or Editor: James A. Wolpert x
  • Journal of the American Society for Horticultural Science x
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Abstract

Two photoperiod regimes, natural daylength (ND) and night interruption (NI) of ND with a white light source, were used to test the importance of photoperiod on growth parameters, cold acclimation, and root conductance of potted ‘Concord’ grapevines (Vitis labruscana Bailey). By 3 Sept., NI-treated plants had a greater percentage of shoots with actively growing apices and a greater number of nodes per shoot than those untreated. No differences were seen in effect of light treatment on the extent of shoot maturation, as evidenced by shoot color change from green to brown. No consistent differences in hardiness of primary buds or canes of the first 12 nodes could be attributed to light regime. Apical tissues were less hardy than basal tissues for all regimes early in the acclimation period (10 Sept.). Root conductance, measured as suction-induced water flow, decreased throughout the acclimation period but did not differ between light treatments. Results are discussed in light of current hypotheses and of evidence of interrelationships among photoperiod, shoot growth cessation, shoot maturation, and cold acclimation.

Open Access

Abstract

Variability of cluster weight, soluble solids, and titratable acidity of ‘Concord’ grapes (Vitis labruscana Bailey) was quantified with respect to several fixed and random factors. All 3 measurements were affected by cluster position while only cluster weight and soluble solids were affected by sunlight exposure. Estimates of variance components indicated that the greatest percentage variability was among vines. Variance components were used to examine efficient sampling plans that would detect a specified difference at a selected level of Type I error. Graphs illustrate various schemes of sample allocation which would achieve the desired level of precision.

Open Access