Shijian Zhuang,* Qun Sun, and Matthew Fidelibus
*University of California Cooperative Extension, 550 E Shaw Ave, suite 210-B, Fresno, CA, 93710 (gzhuang@ucanr.edu)

Pinot gris has the sixth-largest variety in CA based on the crush volume and the growing interest in Pinot gris in the San Joaquin Valley (SJV) has encouraged grow­ers to look for a more productive clone to improve profitability. A field trial under a randomized complete block design evaluating 10 clones, replicated six times, was es­tablished near Mendota, CA. Quadrilateral cordon, spur-pruned, Pinot gris vines were planted in 2017 and went through the normal training in 2018 and 2019. Yield and ber­ry chemistry data were collected in 2020 and 2021. Two adjacent vines from the same clone were designated as an experimental unit. Pinot gris FPS 10 yielded the most in two consecutive seasons: 21.1 kg/vine in 2020 and 11.0 kg/vine in 2021. The main driver for the increased yield was cluster number per vine: 208 cluster/vine in 2020 and 219 cluster/vine in 2021. A significant year-to-year variation was found and the overcropping in 2020, with a significant higher Ravaz index (>15), may have led to the 50% yield reduction in 2021. No significant difference in berry chemistry was found among clones. The varietal tendency to overcrop from the quadrilateral cordon, spur-pruned system may require growers to adopt: 1) additional crop load management; 2) switch to bilateral cordon, spur pruning; or 3) cane pruning to achieve consistent yield of Pinot gris in the SJV.

Funding Support: American Vineyard Foundation