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Planting Distance Can Increase the Yield of PD Resistant Predominately Vitis Vinifera Grapevine ‘502-20’

Applied Research

Elina Coneva


Vitis vinifera grape acreage is limited in Alabama due to Pierce’s disease (PD) caused by the bacterium Xylella fastidiosa (Xf) and vectored by insects from the family Cicadellidae. UC Davis breeding program has developed PD resistant germplasm and has released 5 predominantly V. vinifera cultivars. Although PD resistant V. vinifera cultivars are currently available, no V. vinifera grapes management recommendations exist for production in Alabama.  An experimental vineyard was planted at the Chilton Research Extension Center, AL in 2017 to determine the effect of planting distance on PD resistant 94% V. vinifera selection ‘502-20’ growth and productivity. The experiment utilizes a randomized complete block design consisting of three replications and three vines per replication. Vines were planted at distances of 1.8m x 3.7m, 2.1m x 3.7m, and 2.4m x 3.7m. Total yield and number of clusters was measured at harvest for each vine. Fruit samples were collected to determine fruit total soluble solids (TSS), titratable acidity and pH.  Our results suggest that 2.4m x 3.7m treatment resulted in the highest yield of 17.4 kg/vine in 2022, significantly higher than yields from other treatments (12.6 kg/vine and 9.6 kg/vine for 2.1m x 3.7m and 1.8m x 3.7m respectively). Planting distance of 2.4m x 3.7m resulted in the highest number of clusters/vine (53), while vines planted at 1.8m x 3.7m responded with the lowest number (38) of clusters/vine. Planting distance of 2.4m x 3.7m resulted in the largest cluster weight of 540g and also had the highest TSS. No significant differences were found among titratable acidity or juice pH. Current results indicate planting distance 2.4m x 3.7m is optimal for sustainable production of PD resistant 94% V. vinifera grape ‘502-20’. Further research will be conducted to expand current knowledge, and develop management recommendations for the successful production of V. vinifera grapes in Alabama.


Poster has NOT been presented at any previous NACAA AM/PIC

This poster is being submitted for judging. It will be displayed at the AM/PIC if not selected as a State winner. The abstract will be published in the proceedings.

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Authors: Elina Coneva, Jarrett Price
  1. Coneva, E. EXTENSION SPECIALIST & PROFESSOR, Auburn University, Alabama, 36849
  2. Price, J. Graduate Research Assistant, AUBURN UNIVERSITY, Alabama, 36849