Elina Coneva1, Patrick Conner2, Margaret Worthington3, Sushan Ru1, and Melba Salazar-Gutierrez1
1Auburn University, 2University of Georgia, 3University of Arkansas
There is a high demand for fresh grapes on the domestic market. According to the 2022 Census of Agriculture, there are 628 acres of grapes in Alabama, while the grape acreage is about four times larger in neighboring Georgia (2084 acres), a state with a similar climatic condition.
Furthermore, current advances in fresh market muscadine breeding have yielded new fresh market cultivars with larger and more uniform berries, thinner skins, crisp flesh, and skins that adhere to the flesh. These advances have set the stage for the expansion of the muscadine grape industry and to a wider production area and the introduction of new, high-quality cultivars to the consumer. The list of UGA’s currently released perfect-flowered, large fruited muscadine varieties with crisp flesh includes ‘Lane’, ‘Hall’, ‘Paulk’, ‘Ruby Crisp’. ‘Razzmatazz’ is another recent release from a private breeding program that produces seedless berries with thin skin and crisp flesh. Science-based information is currently lacking on the new cultivars’ productivity and fruit quality attributes in Alabama’s environment; therefore this study was set up to evaluate the performance of newly released muscadine grape cultivars and advanced selections with improved qualities from the UGA and the University of AR breeding programs in Alabama and develop recommendations for the best adapted muscadine cultivars.
‘Paulk’, ‘Lane’, ‘Hall’, ‘Ruby Crisp’, ‘Razzmatazz’, ‘Southern Home’, ‘Supreme’ (standard) muscadine grape cultivars and eight advanced selections from the UGA and UA breeding programs have been planted as a RCBD experiment with four single-vine replications at the Chilton Research and Extension Center (CREC), Clanton, AL (Fig. 1). Cultivars ‘Paulk’, ‘Lane’, ‘Hall’, ‘Razzmatazz’, ‘Southern Home’, ‘Supreme’ (standard) were planted in fall of 2019 and the advanced selections ‘AM-26’, ‘AM-70’, ‘AM-77’, ‘AM-195’, ‘GA10-1-222’, ‘GA 6-1-269’, ‘GA 13-4-2’, ‘GA 10-1-294’ and cultivar ‘Ruby Crisp’ were planted in spring of 2021. Vines are trained to the single wire bilateral training system at a planting distance of 20 ft. x 12 ft. Vine phenological development was recorded periodically starting at bud break. Inflorescence emergence and flowering were recorded to determine the critical flowering stages. Full bloom was determined when 50% of flower caps fell. Veraison and ripening of berries were assessed throughout the changes of berry color and softening of fruit. Harvest was conducted by hand and yield per vine was recorded for each experimental vine. For each individual vine, average berry weight was determined based on a 50-berry subsample per vine. Following harvest evaluations, grape berries were maintained in a 4 ℃ cooler until fruit quality analysis was conducted. Fruit quality analysis included measurements of soluble solid content (SSC) using a 50-berry subsample/vine and counting the number of berries with wet stem scar at each harvest date to determine the percentage of berries with wet stem scar. The number of berries with wet stem scar is an important trait of muscadine varieties as the large number of berries with wet stem scar means short shelf life as pathogens invade and spoil the berries. Cultivars with high number of dry stem scar berries is preferred and better kept in storage.
Soluble solids content (SSC) was measured at room temperature using extracted juice analyzed via a digital refractometer. Standard statistical analyses were performed to compare the results. Muscadine cultivars and selections were analyzed separately based on their age.
During the spring of 2023, muscadine vines started to flower in mid-May and flowering and fruit set continued until the end of June. ‘Razzmatazz’ was the earliest flowering followed by ‘Lane’ and ‘Hall’, while ‘Paulk’ and ‘Eudora’ had a delayed flowering among the cultivars in our study (Figure 2). Muscadine grape elections ‘AM-26’, ‘AM-70’ and ‘GA-13-4-2’, kg, had an advanced flowering (70% open flowers on June 6), while ‘AM-77’ had 40% open flowers on the same date (Fig. 3).
| Muscadine Cultivar | Open Flowers |
|---|---|
| Lane | 50% |
| Hall | 40% |
| Supreme | 35% |
| Eudora | 20% |
| S. Home | 25% |
| Paulk | 15% |
| Razzmatazz | 80% |
| Muscadine Selection | Open Flowers |
|---|---|
| GA-10-1-294 | 60% |
| GA-10-1-222 | 50% |
| AM-195 | 60% |
| AM-77 | 40% |
| GA-6-1-269 | 50% |
| AM-26 | 70% |
| AM-70 | 70% |
| Ruby Crisp | 60% |
| GA-13-4-2 | 70% |
Harvest of the cultivars began on July 28 and continued until October 11. There were a total number of eleven harvest dates and data collection points this season. ‘Razzmatazz’ first harvest occurred on July 28, two weeks before any other cultivar had mature berries. The average ‘Razzmatazz’ yield per vine (3.6 kg/vine) was over two folds higher on the second harvest date (August 9th) (Table 1) and was the highest (4.6 kg/vine) on August 23rd (Table 2, Fig. 4). The mean number of clusters per vine varied between 34 and 158.5 for each of the harvest dates, with a season mean number of clusters/vines of 128.5 and mean berry weight of 1.5 g.
Table 1. ‘Razzmatazz’ muscadine early yield and fruit quality attributes, 2023.
| Harvest | Yield, kg/vine | No. Clusters/vine | Mean Cluster Weight, g | Mean Berry Weight, g | Average Brix, % |
|---|---|---|---|---|---|
| July 28 | 1.4 | 34 | 48.5 | 1.3 | 17.2 |
| August 9 | 3.6 | 113 | 40.4 | 1.6 | 18.5 |
‘Lane’, ‘Hall’ (Figure 5 A, B), ‘Supreme’ and ‘Eudora’ were harvested for the first time on August 16th. Although these cultivars were not significantly different in terms of their first yield of the season, ‘Lane’ produced the highest early crop of 9.7 kg/vine, followed by ‘Hall’ with 6.6 kg/vine (Table 2). ‘Hall’s yield of 13.3 kg/vine was significantly higher in comparison with all other cultivars on August 23rd. ‘Southern Home’ and ‘Paulk’ had a delayed harvest season starting on August 23rd. Significant differences were found among studied muscadine cultivars in terms of their total yield for the season with ‘Supreme’ and ‘Hall’ producing the highest yield.
No significant differences were found between the total yield of the advanced selections (Table 2). The highest productivity of 20.1 kg/vine was recorded for the ‘GA-13-4-2’ vines, followed by Vines of ‘GA-13-4-2’ produced 20.1 kg/vine on average, followed by ‘GA-10-1-222’ with 19.8 kg/vine and ‘GA-6-1-269’ yielding 17.6 kg/vine.
Table 2. Selected muscadine cultivars and advanced selections yield (kg/vine) by harvest date, CREC, Clanton, AL, 2023.
| Cultivar | 16-Aug | 23-Aug | 30-Aug | 6-Sep | 13-Sep | 20-Sep | 27-Sep | 4-Oct | 11-Oct | Total yield |
|---|---|---|---|---|---|---|---|---|---|---|
| Lane | 9.7 | 2.6 B | 1.5 B | 1.0 C | 0.9 | 0.5 | 0.2 | 0.4 | 0.4 | 15.9 B |
| Hall | 6.6 | 13.3 A | 5.3 AB | 2.3 BC | 0.7 | 1.3 | 0.5 | 0.7 | 0.5 | 30.2 A |
| Supreme | 5.8 | 4.9 B | 8.4 A | 6.5 AB | 2.9 | 1.8 | 1.3 | 0.3 | 0.6 | 32.5 A |
| Razzmatazz | 3.4 | 4.6 B | 1.8 B | — | — | — | — | — | — | 14.8 B |
| Eudora | 3.3 | 4.9 B | 5.2 AB | 8.2 A | 4.7 | 1.4 | — | — | — | 25.4 AB |
| S. Home | — | 2.1 B | 3.9 B | 7.0 AB | 4.2 | 4.0 | 3.2 | 0.5 | 0.7 | 22.5 AB |
| Paulk | — | 1.0 B | 5.8 AB | 6.8 AB | 2.8 | 1.9 | 1.6 | 1.2 | 0.8 | 19.9 AB |
| Selection | ||||||||||
| GA-10-1-294 | 6.5 | 3.8 ABC | — | — | 1.0 | — | 0.5 | — | — | 11.8 |
| GA-10-1-222 | 5.0 | 8.1 A | 6.3 A | 1.2 B | 0.9 | — | — | — | — | 19.8 |
| AM-195 | 3.9 | 4.2 AB | 5.4 A | 1.0 B | — | — | 1.0 | 1.7 | 1.3 | 14.5 |
| AM-77 | 3.4 | 2.8 BC | 1.4 BC | 0.6 B | — | — | — | — | — | 7.7 |
| GA-6-1-269 | 3.0 | 4.3 AB | 1.3 C | 2.3 B | 1.4 | 4.7 A | 2.7 | 1.5 | 1.5 | 17.6 |
| AM-26 | 2.6 | 2.7 BC | 1.7 BC | 1.1 B | — | 1.1 B | 0.7 | 0.7 | 0.3 | 7.5 |
| AM-70 | 1.4 | 2.0 BC | 1.4 CB | 0.4 B | — | 1.7 B | 3.6 | 1.3 | 0.1 | 7.9 |
| Ruby Crisp | — | 3.5 BC | 5.2 AB | 4.8 AB | 2.0 | 0.9 B | 0.6 | 0.8 | 0.6 | 16.4 |
| GA-13-4-2 | — | 0.6 C | 3.6 ABC | 7.3 A | 4.6 | 2.3 AB | 1.6 | 0.6 | 0.2 | 20.1 |
Mean berry weight varied significantly between the cultivars and selections. ‘Supreme’ and ‘Paulk’ had the largest berries of 14.7 and 14.2 g respectively, while ‘Razzmatazz’ average berry weight was 1.5 g (Table 3). Berry size of selection ‘GA-6-1-269’ was similar to the size of ‘Ruby Crisp’ control. ‘Razzmatazz’, ‘Eudora’ and selection ‘AM-195’ produced the sweetest berries. Percent of berries with a wet stem scar varied between 8.7 and 32.6% respectively for ‘Hall’ and ‘Paulk’ and between 3.0 and 19.8% for ‘GA-10-1-294’ and ‘Ruby Crisp’ respectively.
Table 3. Mean berry weight, total soluble solids and percent wet stem scar of selected muscadine varieties, CREC, Clanton, AL, 2023.
| Variety | Mean Berry Weight, g | TSC, % | Wet Stem Scar, % |
|---|---|---|---|
| Lane | 9.0 B | 16.9 AB | 19.8 AB |
| Hall | 10.2 B | 17.1 AB | 8.7 B |
| Supreme | 14.7 A | 14.9 C | 9.5 B |
| Razzmatazz | 1.5 D | 17.9 A | — |
| Eudora | 10.0 B | 17.9 A | 19.6 AB |
| Paulk | 14.2 A | 15.9 BC | 32.6 A |
| S. Home | 6.5 C | 15.8 BC | 19.0 AB |
| Selection | |||
| GA-10-1-294 | 11.6 AB | 17.0 AB | 3.0 |
| GA-10-1-222 | 11.0 AB | 14.9 BC | 11.7 |
| AM-195 | 10.9 AB | 17.6 A | 12.4 |
| AM-77 | 8.3 B | 13.7 C | 16.2 |
| GA-6-1-269 | 12.4 A | 16.6 AB | 7.9 |
| AM-26 | 10.1 AB | 16.4 AB | 6.7 |
| AM-70 | 10.2 AB | 16.8 AB | 4.0 |
| Ruby Crisp | 13.0 A | 16.3 AB | 19.8 |
| GA-13-4-2 | 10.3 AB | 15.5 B | 14.5 |
The 2023 results of this study demonstrate the cultivation of newly released self-fertile muscadine cultivars can lead to improved muscadine grape sustainability by producing increased yield, improved fruit quality, and increased economic benefits to the grower. The newly generated knowledge can directly impact crop production and grower success and can enhance the competitiveness of small fruits. Outcomes from this trial can aid in muscadine grape production expansion in Alabama and the Southeast.