Date of Graduation

7-2020

Document Type

Thesis

Degree Name

Master of Science in Horticulture (MS)

Degree Level

Graduate

Department

Horticulture

Advisor/Mentor

Garcia, Maria E.

Committee Member

Threlfall, Renee T.

Second Committee Member

Lee, Jacquelyn A.

Third Committee Member

McWhirt, Amanda L.

Keywords

Canopy Management; High Tunnel; Horticulture; Plant Physiology; Table Grape; Viticulture

Abstract

Grapevines (Vitis vinifera L.) are one of the most important horticultural crops world-wide. In the southern U.S. region, hot and humid climate accompanied by high pest pressure requires high levels of labor and pesticide inputs, making open field table grape production unsustainable. Previous research at University of Arkansas has demonstrated that table grape production under high tunnels (HTs) is a viable option to overcome biotic and abiotic challenges in the region. This project evaluated two HTs established in Arkansas. In the spring of 2014, at Fayetteville, three table grape cultivars (Faith, Gratitude, and Jupiter) were established in an 8 x 61m Haygrove Super Solo HT. In the spring of 2017, at Cabot, three table grape cultivars (Gratitude, Hope, and Jupiter) were established in an 8 x 76m Haygrove Multi-bay HT. Both tunnels had the same trellis systems: modified double high cordon on the east and west side, MDHCW and MDHCE, and Geneva double curtain in the middle, GDC. The objectives of this study were to evaluate trellis systems on vine performance and yield characteristics and to evaluate cluster thinning responses for crop load management. In 2018 and 2019 cluster thinning was implemented during different stages of fruit development (pea-size and onset of veraison) to control excessive yields. Two treatments were applied to Fayetteville vines: no cluster removal and clusters thinned at pea-size. At Cabot, vines were treated with three treatments: no cluster removal, pea-size, and cluster removal at the onset of veraison. In 2018, at Fayetteville, the yield for ‘Jupiter’ was 22.28 kg per vine and with 90 clusters per vine. In 2019, yield per vine increased to 42.50 kg and the cluster count rose to 197 clusters per vine. In 2018 at Cabot, the year after plating, ‘Jupiter’ had a yield of 10.84 kg per vine with 39.40 clusters per vine. In 2019, ‘Jupiter’ had higher yield than the previous year (26.89 kg) per vine. The cluster number also increased to 157.07 clusters per vine. Cluster thinning during either year of the study did not reduce yields. At Fayetteville during both years of this project, a CIRAS-3 portable CO2/H2O gas analyzer was used, three times per growing season (June, July, and August) on the cultivar Faith. In 2018, assimilation (A) rate was significantly higher in July (25.17 µmol CO2 m-2 s-1) than June and August (14.01 and 13.24 µmol CO2 m-2 s-1, respectively). During the two years of the study, weather data were also collected utilizing a Watchdog 2700 series weather station to evaluate the HT microclimate and compare it to open-field conditions. The microclimate temperatures inside the HT were 1-3 ⁰C warmer compared to open-field conditions. Daily light integral (DLI) varied throughout the growing season, but generally was lower inside the high tunnel. The results from this data has shown that table grape production under HT systems is feasible and results in increased yields but may require increased labor inputs due to excessive vigor and increased productivity of vines.

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