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Evaluation of the Concord Crop Load Response for Current Commercial Production in New York

Terry Bates, Rhiann Jakubowski, James A. Taylor
Am J Enol Vitic.  2021  72: 1-11  ; DOI: 10.5344/ajev.2020.20026

Article Figures & Data

Figures

  • Figure 1
    Figure 1

    The effect of Concord pruning weight (PW) on fresh fruit yield at two variable node and two fixed node pruning severities. Vines were balanced pruned to retain 33 (open circles) or 66 (closed circles) nodes for the first 500 g pruning weight plus an additional 11 nodes for each additional 500 g or pruned to retain 100 (open triangles) or 120 (closed triangles) nodes per vine, regardless of pruning weight. Individual vine observations (n = 36 per year) from 2001 to 2004 were combined by pruning treatment and binned by 0.1 kg pruning weight (bars = ±SE). Fitted curves for 33 + 11: Yield = 11.8 - ([11.8] * EXP[-1.1 * PW]), R2 = 0.91; 66 + 11: Yield = 14.9 - ([14.9] * EXP[-1.3 * PW]), R2 = 0.94; 100 nodes: Yield = 13.6 - ([13.6] * EXP[-3.1 * PW]), R2 = 0.87; 120 nodes: Yield = 17.6 - ([17.6] * EXP[-3.6 * PW]), R2 = 0.88.

  • Figure 2
    Figure 2

    The effect of Concord yield:pruning weight (Y:PW) on harvest juice soluble solids from 2001 to 2004. Vines were grouped by pruning severity (33 + 11, 66 + 11, or 100 nodes: open symbols) or by 120-node pruning with midseason fruit-thinning (closed symbols). There were 108 pruning observations per year (36 per pruning level) and 75 thinning observations per year. Data was binned by crop load in intervals of 2 Y:PW (bars = ±SE).

  • Figure 3
    Figure 3

    The effect of Concord yield:pruning weight (Y:PW) on the seasonal change in pruning weight from 2001 to 2004. Vines were grouped by pruning severity (33 + 11, 66 + 11, or 100 nodes: open symbols) or by 120-node pruning with midseason fruit-thinning (closed symbols). There were 108 pruning observations per year (36 per pruning level) and 75 thinning observations per year. Data was binned by crop load in intervals of 2 Y:PW (bars = ±SE).

  • Figure 4
    Figure 4

    The general four-year Concord crop load response on harvest juice soluble solids (A) and seasonal change in vine pruning weight (B). Pruning severity (open circles) or midseason fruit-thinning (closed circles) was used to generate a range of yield:pruning weight. Each point is the mean of four years (n = 4). Pruning and thinning data were combined for the mean response. A broken-stick model was fitted to illustrate the inflection point on the juice soluble solids response (see Equation 1). For the pruning weight response, a linear model was used (see Equation 2). Dashed lines indicate 95% mean confidence limits.

  • Figure 5
    Figure 5

    The effect of Concord yield:pruning weight on harvest juice soluble solids (A) and the seasonal change in vine pruning weight (B) from 1999 to 2009. Dashed lines are individual year trend lines and the solid lines are the mean response for all years. (n = 75 for 1999 to 2004, 2006, and 2010; 18 for 2005; and 42 for 2007 to 2009). The solid lines are the mean response (n = 11 years).

  • Figure 6
    Figure 6

    The effect of growing degree day (base 10°C) and precipitation (mm) accumulation on the yield:pruning weight (Y:PW) needed to achieve 16 Brix at harvest (A and B) or no seasonal pruning weight change (C and D) in New York Concord from 1999 to 2009. Data labels indicate year.

  • Figure 7
    Figure 7

    The relationship of year 1 yield:pruning weight (Y:PW) on year 2 yield on small (0 to 0.6 kg), medium (0.6 to 1.2 kg), and large (1.2 to 1.8 kg) vine size classes in Concord grapevines. Data was pooled from an 11-year fruit-thinning study, grouped by vine size class, and binned in intervals of Y:PW = 2 (each point n = 10, bars = ±SE).

Tables

  • Table 1

    Weather and phenology from Cornell’s Taschenberg Vineyard Laboratory, Fredonia, NY, from 1999 to 2009. GDD, growing degree day.

    Table 1
  • Table 2

    Multivariate analysis of yield:pruning weight (Y:PW) and treatment (pruning or thinning) on harvest juice soluble solids or the seasonal change in pruning weight in New York Concord from 2001 to 2004. Model used standard least squares and effect tests (Prob > F) are shown.

    Table 2
  • Table 3

    Multivariate regression effect tests of seasonal growing degree days or precipitation on the yield:pruning weight (Y:PW) needed to reach harvest juice soluble solids of 16 Brix or no seasonal change in vine pruning weight in New York-grown Concord from 1999 to 2009. GDD, growing degree days.

    Table 3
  • Table 4

    General crop load descriptions and management recommendations for Concord production in the Lake Erie AVA.

    Table 4
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Evaluation of the Concord Crop Load Response for Current Commercial Production in New York
Terry Bates, Rhiann Jakubowski, James A. Taylor
Am J Enol Vitic.  2021  72: 1-11  ; DOI: 10.5344/ajev.2020.20026
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