Research summary

MSU WARC's current research vineyard was planted in 2014, with an additional planting in 2016. The cultivars chosen at WARC are 'Marquette,' 'Frontenac,' 'Petite Pearl,' 'Frontenac Gris,' 'LaCrescent,' and 'St.Pepin' as wine grapes, with 'Somerset Seedless' and 'Bluebell' for table grapes. The 2016 planting included 'Crimson Pearl,' 'Verona,' 'Baltica,' and three yet unnamed 'Tom Plocher' cultivars, 'TP B-3-40,' 'TP 1-1-12,' and 'TP 2-3-51' (http://www.petitepearlplus.com/). These vines are studied for their cold hardiness and winter survival rates, as well as their phenology, to monitor bud burst, fruit set, and harvest in this area of the state.

Results

The most popular red wine varieties currently planted in Montana include 'Marquette,' 'Petite Pearl,' 'Marechal Foch,' and 'Frontenac,' while the most widely planted white variety is 'St. Pepin,' followed by 'Prairie Star.' Some of the many other cold hardy varietals include 'Frontenac Gris,' 'Crimson Pearl,' 'St.Croix,' 'Verona,' 'LaCrescent,' 'Leon Millot,' 'Louise Swenson,' 'Itasca,' and 'Sabrevois.' In our research vineyard, all varieties planted in 2014 have grown well. Among the red wine varieties, 'Frontenac' has larger clusters (Table 1) and is very vigorous and productive (Table 2). 'Marquette' has experienced higher mortality (Table 2, as seen in other vineyards in the state), but produces quality juice. 'Petite Pearl' has lower sugar content and lower total acidity (TA, Table 2).

Our results also emphasize the balance between production and quality in grapes. In 2018, an average of 128 clusters per vine were left to ripen (more than twice the number compared to the year before). The increase in production was associated with a large increase in total acidity (Tables 2 and 3).

Table 1. Cluster and berry weights for grape varieties in trials planted in 2014 at WARC
Type
Variety
Cluster Wt (g)
Berry Wt (g)

 

 

Red
Frontenac

70.8

0.9
Marquette
44.6
0.9
Petite Pearl
44.7
0.9

 

Table
Bluebell
64.4
2.5
Table/White
Somerset Seedless
25
0.9

 

White
Frontenac Gris
73.3
0.9
LaCrescent
52.9
1
St. Pepin
66.3
1.8
Table 2. Performance of three cold-hardy, red wine grape varieties planted in 2014 over 3 years at WARC.
Variety
Year
% Fruiting
Harvest Date
Clusters per vine
Yield (lbs/plant)
Yield (lbs/acre)
Brix
pH
TA
Frontenac
2016

83

9/27
5
0.4
285
30.7
3.0
2.4
2017

100

9/21
50
9.2
5995
23.8
3.0
1.9
2018
100
10/3
149
19.3
12645
18.0
2.9
3.6
Marquette
2016
50
9/27
7
0.4
287
29.0
3.1
1.8
2017
67
9/21
63
6.3
4157
23.7
3.0
1.7
2018
67
10/3
126
12.1
7939
22.5
3.0
2.6
Petite Pearl
2016
92
9/27
7
0.6
384
21.9
3.1
1.3
2017
92
9/29
72
7.6
4961
19.1
3.1
1.0
2018
92
10/3
123
11.2
7368
17.0
3.0
2.4

 

All white wine varieties have been hardy and productive (Table 3). 'La Crescent' and 'St. Pepin' have had lower total acidity than 'Frontenac Gris' when production is lower than 10 lbs/vine.

Table 3. Performance of three cold-hardy, white wine grape varieties planted in 2014 over 3 years at WARC.
Variety
Year
% Fruiting
Harvest Date
Clusters per Vine
Yield (lbs/plant)
Yield (lbs/acre)
Brix
pH
TA

Frontenac Gris
2016

67

9/27
3
0.3
185
29.9
3.0
2.3
2017
75
9/21
41
7.3
4784
25.5
3.0
2.0
2018
83
10/3
124
17.8
11658
18.4
3.0
3.2
La Crescent
2016
75
9/27
5
0.4
291
25.4
3.0
2.3
2017
100
9/29
63
9.0
5867
24.4
3.0
1.8
2018
100
10/3
143
13.0
8530
21.7
3.0
3.0
St. Pepin
2016
58
9/27
2
0.2
101
23.7
3.1
1.2
2017
83
9/29
51
7.3
4812
21.3
3.1
1.2
2018
83
10/3
103
15.2
9981
18.1
3.1
2.4

 

Both table grape varieties have grown well, although 'Bluebell' experienced higher mortality rates in the first few years. Both are productive and have excellent flavor. 'Bluebell' has large purple grapes (Table 1) with a 'Concord' grape flavor. 'Somerset Seedless' has small, peach colored grapes with a flavor reminiscent of peach and raspberry that ripen 3 to 4 weeks before 'Bluebell' (Table 4).

Table 4. Performance of two cold-hardy, table grape varieties planted in 2014 over 3 years at WARC.
Variety
Year
% Fruiting
Harvest Date
Clusters per Vine
Yield (lbs/plant)
Yield (lbs/acre)
Brix
pH
TA

Bluebell
2016

50

9/19
2
0.2
142
22.1
ND
ND
2017
50
9/21
44
6.7
4381
21.3
3.1
0.9
2018
86
10/3
76
10
6531
16.7
3.1
2.3
Somerset Seedless
2016
50
9/19
4
0.2
139
25.6
ND
ND
2017
100
9/6
42
4.0
2651
23.3
3.2
1.0
2018
100
9/9
161
9.0
5870
22.9
3.4
1.5

Conclusions

Quality table and wine grapes can be grown in warmer sites in Montana. MSU-WARC will continue to work with growers and winemakers to exploit the agro-tourism opportunities in the state.