January 2014 Issue of
Wines & Vines
Vitis Hybrids: History and Current Status
Hybrid cultivars were key to the rapid changes in eastern and central vineyards during the 1970s
The full story of Vitis hybrids should involve biological sciences of genetics, plant pathology and physiology, entomology, soils, social sciences, economics, political science and that collective form of individualism we call nationalism. It’s impossible to address all of those topics in this space, but we hope to pick a thread that runs through these and reflects the history, current status and suggestions for future as a focus on the experiences of the authors in the state of Michigan in the Great Lakes region of the eastern United States. This is the first article in a two-part series, and it will address the history of hybrid grapes and their current status in the United States, while a second article will focus on hybrid grapes in Michigan and the outlook for those grapes in the future.
The grape and wine industry in the eastern U.S. is growing at a steady pace. In the early 1970s most of the grapes cultivated and wines produced were cultivars native to the Americas (Vitis labrusca such as Concord, Niagara, Catawba and Delaware). By 2010, the key grapegrowing states in the eastern U.S. had shown a historical change that was driven by factors mainly related to market demand and cultivar evolution through university and private grape-breeding efforts. Several trials, public and private, demonstrated that numerous hybrid cultivars were able to ripen in a short season and were sufficiently cold hardy to survive the winter in several existing viticultural regions.
Prime environmental factors for grapegrowing in the eastern U.S., and especially in the Great Lakes region, include frequency and severity of winter cold episodes, sufficient length of the growing season and its heat unit accumulation, and frequency of damaging spring freeze episodes. In the Great Lakes region, determination of suitability for cultivation of wine grapes mainly depends on winter cold events and disease pressure. Winter cold events are quite variable through the eastern U.S., with the result that there is a wide distribution of species cultivated and a ratio between hybrids (cold hardy) and vinifera (cold sensitive) that shows viticultural growing conditions favorable for different species.
Pre-hybrid history
Although there is considerable evidence that most European cultivars now called Vitis vinifera are actually hybrids of vinifera and the wild native species V. sylvestris, we will focus on the wider-based hybrids resulting from vinifera and non-European species. In the 18th and 19th centuries, transport of Vitis plant material between North America and Europe (primarily France) led to two undesired results: The vinifera vines transported to North America quickly died, and European viticulture suffered the introduction of serious grapevine pests for which the native European vines (Vitis vinifera) possessed no resistance. Among these introduced pests were the fungal diseases powdery mildew, downy mildew and black rot—and, most notably, the grape root and leaf aphid phylloxera. The impact of these pests was devastating, and thousands of acres of vineyards were destroyed.
Grafting for phylloxera
The story of phylloxera recently was well documented by Gale (2010), and it is a fascinating story of good and bad science coupled with examples of national chauvinism. Leo Laliman of Bordeaux, France, reputedly observed that phylloxera did not destroy Vitis aestivalis Michaux vines, and he argued that vine and insect had co-existed in their native habitat (Pongracz, 1988). That suggested that the vines possessed some characteristic that resulted in resistance or tolerance. The initial solution was to graft the desired vinifera scion cultivars to the roots of native American grape species, primarily V. riparia (Riparia Gloire) and V. rupestris (Rupestris du Lot, syn R. St. George).
There was, however, one important concern: The low soil pH-adapted riparia and rupestris rootstocks performed poorly on alkaline soils such as those in Graves (Galet, 2000; Wilson, 1999) and Cognac (Koscica, 2004). The Texas grape botanist T.V. Munson (1909) observed Vitis Berlandieri growing on alkali flats in Texas and northern Mexico (Galet, 1979) and proposed the species as a potential solution.
V. Berlandieri was very difficult to root and to graft, so crosses with more congenial species were necessary (Schmid et al., 2008), including the use of vinifera. However, rootstocks with vinifera parentage have been found to lack adequate phylloxera resistance after long trial (Pongracz, 1988) and, more recently, in California (Gale, 2010).
More successful results of vine grafting to phylloxera-resistant rootstocks rapidly followed, with employment of native American Vitis species of consequence (V. riparia, V. rupestris, V. Berlandieri, V. cordifolia, V. longii, V. champini, and others). Currently, the most commonly used rootstocks worldwide are the result of selections or crossings of riparia, rupestris and Berlandieri.
Development of protective sprays for fungal diseases
After many trial and error attempts to find a way to protect of vines from fungal diseases, Pierre-Marie-Alexis Millardet discovered that Bordeaux mixture proved effective against the mildews. While the fungicide materials have changed, variants of the fungicide spray approach are those most often employed today. Still, spray protection has required a careful, well-planned program. Spray effectiveness can be reduced by inclement weather, pest mutation and subsequent resistance or vine phytotoxicity to the spray material itself (Bostanian, et al., 2012). Diverse parentage of hybrid vines has led to damage from new chemicals.
Pest management efforts have been made more reliable through multiple improvements. New and varied spray compounds have reduced the development of pest resistance and precise weather monitoring, and online reporting tools have helped scientists increase their understanding of pest ecology. Further, the development and utilization of integrated pest management approaches have added much to viticulture—especially for vineyards employing more ecologically sustainable methods. These have resulted in improved responses of vine growth, fruit ripening, and yield and vine survival.
History of hybrids
Like so much in viticulture and enology, the history of grapevine hybrids began in France. In the mid-20th century Phillip Wagner (1955) presented a paper at the annual meeting of the American Society for Enology and Viticulture titled “The French Hybrids.” The impact of that presentation was congruent with a change in cultivars used for wine in the Great Lakes region of North America. The change was a shift from strongly flavored cultivars with primary genetic background in labrusca to cultivars of a mixed-species background capable of producing table wines (Schiller, 2010). An example of this shift was observed in Michigan. In 1970, 95% of wines produced were from labrusca-based cultivars Concord, Niagara and Delaware; by 1990, less than 5% of wines were produced from these varieties. The issues influencing this shift relate to the national evolution of the appreciation of wine to accompany meals.
Although much of North America was not and is still not the most wine-friendly culture, the American experience with European culture and its wines during the first five decades of the 20th century led to an expanded appreciation for table wines. This interest in table wines, while severely retarded by the U.S. government policy of Prohibition during the 1920s, was later reinforced by experiences during the 1930s and ’40s, particularly through the exposure of American military personnel during World War II.
At the same time, major cultivar changes occurred in now-renowned California locales such as the Napa and Sonoma valleys. The impact of the growing degree-day assessment on wine quality (Amerine and Winkler, 1944) resulted in a shift to table wine production. These locales underwent a significant cultivar change as dessert wines like Angelica (made from Mission grapes syn. Listan Negro [LaMar, 2002; Robinson, et al., 2012]) were replaced with Cabernet Sauvignon, Chardonnay, Sauvignon Blanc and Zinfandel. In the Great Lakes region, the strong flavors and aromas characteristic of labrusca-based cultivars such as Concord, Niagara, Catawba, Delaware, Elvira, Diamond, Agawam and others produced as dessert wines were similarly challenged by the group of cultivars Wagner (1955) called French hybrids, interspecific, resistant cultivars of both European and North American origin. In many ways, hybrid cultivars were a key to the rapid changes that took place in the Great Lakes region and paved the way for the current mixed viticulture there that includes both vinifera and the new interspecifics.
Interspecific hybrids
The subject of interspecific hybrids among Vitis species has an interesting history. It appears to have occurred as the result of efforts to solve two vexing problems: 1) lime-induced iron chlorosis demonstrated the need for lime tolerance lacking in the low-pH adapted species riparia and rupestris (Gale, 2011); and 2) the poor rooting efficiency and graft compatibility with vinifera of the V. Berlandieri species even though it was selected for its ability to thrive in calcareous soils (Schmid, et al., 2008).
Attempts to solve both concerns often involved the use of vinifera parents and the progeny, occasionally produced fruiting offspring. Importantly, this result offered a possibility that interspecific crosses could produce vines with the greater disease tolerance of the American parent and possibly the fruit and subsequent wine qualities of the vinifera parent in a single cultivar. If there was also phylloxera tolerance, the result could be a non-grafted, productive, resistant cultivar; a hybrid direct producer (HDP) capable of culture with fewer pest control inputs and thus lower production costs.
Wagner (1955) makes much of this. He points to the rapid inclusion of many HDP selections for production of vin du pays and vin du table. With the difficult periods of the second through fifth decades of the 20th century, when war and economic upheaval reduced the ability of vineyardists to get the materials and equipment necessary to protect susceptible standard vinifera grape cultivars, hybrids appeared a reasonable solution for the production of everyday table wines. To fill that gap in wine-production volume, the HDP cultivars and selections became widely grown (Galet, 1977).
European attitudes about French hybrids
According to Wagner (1955), French hybrids were always grown for vin de table or vin de pays and never suggested for “quality wine.” However, there was one unintended but significant result of the interspecific crossing, especially with V. riparia, and that was improved cold hardiness of the subsequent Vitis selections. This enhanced characteristic, along with the earlier improved resistance to fungal diseases and phylloxera, now made it possible to grow the selections and cultivars successfully in geographic regions outside the established, delineated wine districts initially codified by the Bordeaux laws of 1855 and subsequently promulgated through most wine regions. This ability to produce wine in “non-traditional” wine regions, and at lower cost per ton (and thus per gallon) than in traditional regions, resulted in increased competition and set the stage for conflict.
Competition rooted in these vine characteristics remains a concern in Europe today. There have been serious gluts of French wine, and active efforts have been taken to address it. In 1988 growers were paid to remove hybrid vines, and in the following five years 790,400 acres were removed from southern France and northern Italy (Anson, 2008). To put that into perspective, that area is equivalent to all U.S. vineyard acreage combined. Further excess production led Bordeaux-based ONIVINS to propose a goal of removing an additional 41,990 acres (or 14% of 306,280 total acres). The plan was based on two considerations: 1) In 2004 alone, exports of Bordeaux wines to the U.S. and Britain declined 50% and 33%, respectively; and 2) Per-capita consumption fell among French wine drinkers (Anson, 2008). Hybrids having use as vin de table (now vin de France) and vin de pays (now Indication Geographic Protégé; IGP) were easy targets.
Toxicity of hybrids
The English translation of Galet (1979) noted that early HDP cultivars came to France as the country’s vineyards were being reconstructed following devastation from phylloxera and other vine diseases. The early selections included Isabella, Clinton, Noah, Othello, Black Spanish and Herbemont. These grapes were predominantly hybrids of the Vitis species labrusca, aestivalis and riparia with occasional vinifera, and they were quickly rejected for unacceptable fruit and wine flavors. Breeding efforts continued, and both vine performance and fruit and wine quality improved.
As a result, more than 900,000 acres of these cultivars were planted in France by 1958 (Galet, 1971). The disease resistance, direct producer status and unanticipated improved tolerance to low winter temperatures resulted not only in replacing dead or dying vineyards in traditional viticultural regions, but it also opened previously “unacceptable” geographic areas to wine-grape production. Once grafting and sprays for disease control allowed the re-establishment of traditional production areas, such new areas could only be viewed as economic competition.
The economic impact on established regions was so great as to be judged unacceptable, with calls for corrective action. A detailed cultivar-by-cultivar comparison would be tedious and too lengthy in achieving the desired goal, so the result was a campaign to discredit the whole group of HDP cultivars. It could not be admitted, even if true, that a specific HDP might have superior vineyard qualities and could produce wine superior to a number of “acceptable” cultivars; all must be proscribed.
Further, many of the popular expressions were based on nationalistic viewpoints. If the United States was disliked, it showed. If Germany disliked France, it showed. The language used was often rooted in chauvinism, and occasionally even racism. These views found their peak of absurdity in the work of H. Breider (1971; Breider and Wolf 1967; Breider, et al., 1971), who declared wines and juices with native American species in their genetic background to be toxic; furthermore, he said, the basis for the toxicity were the same constituents that made the American species and their crosses resistant to parasites and pathogens. Cornell University scientists (Stoewsand, et al., 1969, Stoewsand and Robinson, 1971, 1972) demonstrated that the toxic effects found by Breider in the German experiments were due to an inadequate diet that lacked required vitamins and minerals, and not to the presence of hybrid grapes. However, the “toxic” bell had been rung and fueled the destructive campaign.
Current status of French hybrids in the U.S.
Those who appreciate the mixed species American/European hybrids owe a debt to the New York Agricultural Experiment Station at Geneva, N.Y. The greatest effort and impact regarding the evaluation of hybrid grape selections and cultivars was at Geneva. The collected works published by Pool, et al. (1976) show a focused and dedicated effort that included both vineyard and cellar evaluation. More than 200 named hybrids and hybrid selections were evaluated for both vineyard and cellar micro-vin characteristics over many years. This endeavor made the subsequent evaluations in Michigan, other Great Lakes wine states and other regions where additional cold hardiness was an advantage much less demanding, as many of the selections lacking necessary viticultural or wine qualities had been winnowed out.
The area committed to viticulture since 1970 has increased significantly. This increase occurred across nearly all states east of the Rocky Mountains, including some that had no previous history of commercial wine-grape production. provides a recent compilation of area by state and the relative percentage of the area planted to American (largely based on labrusca), hybrid and vinifera cultivars. Several points are clear: 1) New York, Michigan, Pennsylvania and Ohio have the most significant area under cultivation; 2) They maintain the highest percentages of American cultivars, largely for use as non-fermented juices or confections; and 3) They have the largest area of vinifera. The first case is due to a long history of American production of non-fermented products, and, in the latter case, the influence of the Great Lakes, which serve to create milder, “maritime” climates needed for vinifera (not really maritime, but a degree of maritime buffering). Indeed, of the Great Lakes states only New York and Michigan have a ratio of vinifera to hybrids favoring vinifera. This is borne out by the data regarding Missouri and the states adjacent to the Great Lakes with minimal lake moderation of winter cold. Illinois, Minnesota and Wisconsin have hardy hybrids as their top five cultivars.
Of equal note is the impact of hybrids in developing wine-production regions. Although the area is currently small, it is increasing at a rapid rate because of existing hardy hybrids and very cold-hardy cultivars produced by Elmer Swenson and Peter Hemstad. No hybrid is as susceptible to cold damage as the most cold-hardy vinifera, and the three hardiest cultivars are from the Minnesota-breeding efforts.
The New York efforts, under the guidance of Dr. Bruce Reisch, continue the productive tradition established by Reisch’s predecessors, Robert Pool and John Einset (Pool, et al., 1976). Additionally, the efforts of Hemstad and Swenson expanded on the cold hardiness available in French hybrids, allowing the development of commercial wine grape production in areas where it was formerly not possible.
Lack of strong color is a common problem for many cool-climate hybrid cultivars, and many of the breeding programs specifically select for parents with deeply colored juice. Harold Olmo used this characteristic to breed the mixed species hybrid red cultivars for California’s Central Valley, where heat makes development of adequate color particularly problematic. There, Olmo bred hybrids Rubired and Royalty (Robinson, et al., 2012) to address this concern.
Part two of this series will examine at hybrid grape cultivars in Michigan and the challenges and opportunities for the future of hybrid viticulture.
Dr. Paolo Sabbatini is an associate professor of horticulture at Michigan State University with research (60%) and extension (40%) responsibilities in viticulture. His primary objective is to identify environmental, physiological and cultural factors that limit vine growth and development, fruit maturity and quality of grapes grown in Michigan. Sabbatini received his Ph.D. in 2002 from the University of Ancona (Italy).
The grape and wine industry in the eastern U.S. is growing at a steady pace. In the early 1970s most of the grapes cultivated and wines produced were cultivars native to the Americas (Vitis labrusca such as Concord, Niagara, Catawba and Delaware). By 2010, the key grapegrowing states in the eastern U.S. had shown a historical change that was driven by factors mainly related to market demand and cultivar evolution through university and private grape-breeding efforts. Several trials, public and private, demonstrated that numerous hybrid cultivars were able to ripen in a short season and were sufficiently cold hardy to survive the winter in several existing viticultural regions.
Prime environmental factors for grapegrowing in the eastern U.S., and especially in the Great Lakes region, include frequency and severity of winter cold episodes, sufficient length of the growing season and its heat unit accumulation, and frequency of damaging spring freeze episodes. In the Great Lakes region, determination of suitability for cultivation of wine grapes mainly depends on winter cold events and disease pressure. Winter cold events are quite variable through the eastern U.S., with the result that there is a wide distribution of species cultivated and a ratio between hybrids (cold hardy) and vinifera (cold sensitive) that shows viticultural growing conditions favorable for different species.
Pre-hybrid history
Although there is considerable evidence that most European cultivars now called Vitis vinifera are actually hybrids of vinifera and the wild native species V. sylvestris, we will focus on the wider-based hybrids resulting from vinifera and non-European species. In the 18th and 19th centuries, transport of Vitis plant material between North America and Europe (primarily France) led to two undesired results: The vinifera vines transported to North America quickly died, and European viticulture suffered the introduction of serious grapevine pests for which the native European vines (Vitis vinifera) possessed no resistance. Among these introduced pests were the fungal diseases powdery mildew, downy mildew and black rot—and, most notably, the grape root and leaf aphid phylloxera. The impact of these pests was devastating, and thousands of acres of vineyards were destroyed.
Grafting for phylloxera
The story of phylloxera recently was well documented by Gale (2010), and it is a fascinating story of good and bad science coupled with examples of national chauvinism. Leo Laliman of Bordeaux, France, reputedly observed that phylloxera did not destroy Vitis aestivalis Michaux vines, and he argued that vine and insect had co-existed in their native habitat (Pongracz, 1988). That suggested that the vines possessed some characteristic that resulted in resistance or tolerance. The initial solution was to graft the desired vinifera scion cultivars to the roots of native American grape species, primarily V. riparia (Riparia Gloire) and V. rupestris (Rupestris du Lot, syn R. St. George).
There was, however, one important concern: The low soil pH-adapted riparia and rupestris rootstocks performed poorly on alkaline soils such as those in Graves (Galet, 2000; Wilson, 1999) and Cognac (Koscica, 2004). The Texas grape botanist T.V. Munson (1909) observed Vitis Berlandieri growing on alkali flats in Texas and northern Mexico (Galet, 1979) and proposed the species as a potential solution.
V. Berlandieri was very difficult to root and to graft, so crosses with more congenial species were necessary (Schmid et al., 2008), including the use of vinifera. However, rootstocks with vinifera parentage have been found to lack adequate phylloxera resistance after long trial (Pongracz, 1988) and, more recently, in California (Gale, 2010).
More successful results of vine grafting to phylloxera-resistant rootstocks rapidly followed, with employment of native American Vitis species of consequence (V. riparia, V. rupestris, V. Berlandieri, V. cordifolia, V. longii, V. champini, and others). Currently, the most commonly used rootstocks worldwide are the result of selections or crossings of riparia, rupestris and Berlandieri.
Development of protective sprays for fungal diseases
After many trial and error attempts to find a way to protect of vines from fungal diseases, Pierre-Marie-Alexis Millardet discovered that Bordeaux mixture proved effective against the mildews. While the fungicide materials have changed, variants of the fungicide spray approach are those most often employed today. Still, spray protection has required a careful, well-planned program. Spray effectiveness can be reduced by inclement weather, pest mutation and subsequent resistance or vine phytotoxicity to the spray material itself (Bostanian, et al., 2012). Diverse parentage of hybrid vines has led to damage from new chemicals.
Pest management efforts have been made more reliable through multiple improvements. New and varied spray compounds have reduced the development of pest resistance and precise weather monitoring, and online reporting tools have helped scientists increase their understanding of pest ecology. Further, the development and utilization of integrated pest management approaches have added much to viticulture—especially for vineyards employing more ecologically sustainable methods. These have resulted in improved responses of vine growth, fruit ripening, and yield and vine survival.
History of hybrids
Like so much in viticulture and enology, the history of grapevine hybrids began in France. In the mid-20th century Phillip Wagner (1955) presented a paper at the annual meeting of the American Society for Enology and Viticulture titled “The French Hybrids.” The impact of that presentation was congruent with a change in cultivars used for wine in the Great Lakes region of North America. The change was a shift from strongly flavored cultivars with primary genetic background in labrusca to cultivars of a mixed-species background capable of producing table wines (Schiller, 2010). An example of this shift was observed in Michigan. In 1970, 95% of wines produced were from labrusca-based cultivars Concord, Niagara and Delaware; by 1990, less than 5% of wines were produced from these varieties. The issues influencing this shift relate to the national evolution of the appreciation of wine to accompany meals.
Although much of North America was not and is still not the most wine-friendly culture, the American experience with European culture and its wines during the first five decades of the 20th century led to an expanded appreciation for table wines. This interest in table wines, while severely retarded by the U.S. government policy of Prohibition during the 1920s, was later reinforced by experiences during the 1930s and ’40s, particularly through the exposure of American military personnel during World War II.
At the same time, major cultivar changes occurred in now-renowned California locales such as the Napa and Sonoma valleys. The impact of the growing degree-day assessment on wine quality (Amerine and Winkler, 1944) resulted in a shift to table wine production. These locales underwent a significant cultivar change as dessert wines like Angelica (made from Mission grapes syn. Listan Negro [LaMar, 2002; Robinson, et al., 2012]) were replaced with Cabernet Sauvignon, Chardonnay, Sauvignon Blanc and Zinfandel. In the Great Lakes region, the strong flavors and aromas characteristic of labrusca-based cultivars such as Concord, Niagara, Catawba, Delaware, Elvira, Diamond, Agawam and others produced as dessert wines were similarly challenged by the group of cultivars Wagner (1955) called French hybrids, interspecific, resistant cultivars of both European and North American origin. In many ways, hybrid cultivars were a key to the rapid changes that took place in the Great Lakes region and paved the way for the current mixed viticulture there that includes both vinifera and the new interspecifics.
Interspecific hybrids
The subject of interspecific hybrids among Vitis species has an interesting history. It appears to have occurred as the result of efforts to solve two vexing problems: 1) lime-induced iron chlorosis demonstrated the need for lime tolerance lacking in the low-pH adapted species riparia and rupestris (Gale, 2011); and 2) the poor rooting efficiency and graft compatibility with vinifera of the V. Berlandieri species even though it was selected for its ability to thrive in calcareous soils (Schmid, et al., 2008).
Attempts to solve both concerns often involved the use of vinifera parents and the progeny, occasionally produced fruiting offspring. Importantly, this result offered a possibility that interspecific crosses could produce vines with the greater disease tolerance of the American parent and possibly the fruit and subsequent wine qualities of the vinifera parent in a single cultivar. If there was also phylloxera tolerance, the result could be a non-grafted, productive, resistant cultivar; a hybrid direct producer (HDP) capable of culture with fewer pest control inputs and thus lower production costs.
Wagner (1955) makes much of this. He points to the rapid inclusion of many HDP selections for production of vin du pays and vin du table. With the difficult periods of the second through fifth decades of the 20th century, when war and economic upheaval reduced the ability of vineyardists to get the materials and equipment necessary to protect susceptible standard vinifera grape cultivars, hybrids appeared a reasonable solution for the production of everyday table wines. To fill that gap in wine-production volume, the HDP cultivars and selections became widely grown (Galet, 1977).
European attitudes about French hybrids
According to Wagner (1955), French hybrids were always grown for vin de table or vin de pays and never suggested for “quality wine.” However, there was one unintended but significant result of the interspecific crossing, especially with V. riparia, and that was improved cold hardiness of the subsequent Vitis selections. This enhanced characteristic, along with the earlier improved resistance to fungal diseases and phylloxera, now made it possible to grow the selections and cultivars successfully in geographic regions outside the established, delineated wine districts initially codified by the Bordeaux laws of 1855 and subsequently promulgated through most wine regions. This ability to produce wine in “non-traditional” wine regions, and at lower cost per ton (and thus per gallon) than in traditional regions, resulted in increased competition and set the stage for conflict.
Competition rooted in these vine characteristics remains a concern in Europe today. There have been serious gluts of French wine, and active efforts have been taken to address it. In 1988 growers were paid to remove hybrid vines, and in the following five years 790,400 acres were removed from southern France and northern Italy (Anson, 2008). To put that into perspective, that area is equivalent to all U.S. vineyard acreage combined. Further excess production led Bordeaux-based ONIVINS to propose a goal of removing an additional 41,990 acres (or 14% of 306,280 total acres). The plan was based on two considerations: 1) In 2004 alone, exports of Bordeaux wines to the U.S. and Britain declined 50% and 33%, respectively; and 2) Per-capita consumption fell among French wine drinkers (Anson, 2008). Hybrids having use as vin de table (now vin de France) and vin de pays (now Indication Geographic Protégé; IGP) were easy targets.
Toxicity of hybrids
The English translation of Galet (1979) noted that early HDP cultivars came to France as the country’s vineyards were being reconstructed following devastation from phylloxera and other vine diseases. The early selections included Isabella, Clinton, Noah, Othello, Black Spanish and Herbemont. These grapes were predominantly hybrids of the Vitis species labrusca, aestivalis and riparia with occasional vinifera, and they were quickly rejected for unacceptable fruit and wine flavors. Breeding efforts continued, and both vine performance and fruit and wine quality improved.
As a result, more than 900,000 acres of these cultivars were planted in France by 1958 (Galet, 1971). The disease resistance, direct producer status and unanticipated improved tolerance to low winter temperatures resulted not only in replacing dead or dying vineyards in traditional viticultural regions, but it also opened previously “unacceptable” geographic areas to wine-grape production. Once grafting and sprays for disease control allowed the re-establishment of traditional production areas, such new areas could only be viewed as economic competition.
The economic impact on established regions was so great as to be judged unacceptable, with calls for corrective action. A detailed cultivar-by-cultivar comparison would be tedious and too lengthy in achieving the desired goal, so the result was a campaign to discredit the whole group of HDP cultivars. It could not be admitted, even if true, that a specific HDP might have superior vineyard qualities and could produce wine superior to a number of “acceptable” cultivars; all must be proscribed.
Further, many of the popular expressions were based on nationalistic viewpoints. If the United States was disliked, it showed. If Germany disliked France, it showed. The language used was often rooted in chauvinism, and occasionally even racism. These views found their peak of absurdity in the work of H. Breider (1971; Breider and Wolf 1967; Breider, et al., 1971), who declared wines and juices with native American species in their genetic background to be toxic; furthermore, he said, the basis for the toxicity were the same constituents that made the American species and their crosses resistant to parasites and pathogens. Cornell University scientists (Stoewsand, et al., 1969, Stoewsand and Robinson, 1971, 1972) demonstrated that the toxic effects found by Breider in the German experiments were due to an inadequate diet that lacked required vitamins and minerals, and not to the presence of hybrid grapes. However, the “toxic” bell had been rung and fueled the destructive campaign.
Current status of French hybrids in the U.S.
Those who appreciate the mixed species American/European hybrids owe a debt to the New York Agricultural Experiment Station at Geneva, N.Y. The greatest effort and impact regarding the evaluation of hybrid grape selections and cultivars was at Geneva. The collected works published by Pool, et al. (1976) show a focused and dedicated effort that included both vineyard and cellar evaluation. More than 200 named hybrids and hybrid selections were evaluated for both vineyard and cellar micro-vin characteristics over many years. This endeavor made the subsequent evaluations in Michigan, other Great Lakes wine states and other regions where additional cold hardiness was an advantage much less demanding, as many of the selections lacking necessary viticultural or wine qualities had been winnowed out.
The area committed to viticulture since 1970 has increased significantly. This increase occurred across nearly all states east of the Rocky Mountains, including some that had no previous history of commercial wine-grape production. provides a recent compilation of area by state and the relative percentage of the area planted to American (largely based on labrusca), hybrid and vinifera cultivars. Several points are clear: 1) New York, Michigan, Pennsylvania and Ohio have the most significant area under cultivation; 2) They maintain the highest percentages of American cultivars, largely for use as non-fermented juices or confections; and 3) They have the largest area of vinifera. The first case is due to a long history of American production of non-fermented products, and, in the latter case, the influence of the Great Lakes, which serve to create milder, “maritime” climates needed for vinifera (not really maritime, but a degree of maritime buffering). Indeed, of the Great Lakes states only New York and Michigan have a ratio of vinifera to hybrids favoring vinifera. This is borne out by the data regarding Missouri and the states adjacent to the Great Lakes with minimal lake moderation of winter cold. Illinois, Minnesota and Wisconsin have hardy hybrids as their top five cultivars.
Of equal note is the impact of hybrids in developing wine-production regions. Although the area is currently small, it is increasing at a rapid rate because of existing hardy hybrids and very cold-hardy cultivars produced by Elmer Swenson and Peter Hemstad. No hybrid is as susceptible to cold damage as the most cold-hardy vinifera, and the three hardiest cultivars are from the Minnesota-breeding efforts.
The New York efforts, under the guidance of Dr. Bruce Reisch, continue the productive tradition established by Reisch’s predecessors, Robert Pool and John Einset (Pool, et al., 1976). Additionally, the efforts of Hemstad and Swenson expanded on the cold hardiness available in French hybrids, allowing the development of commercial wine grape production in areas where it was formerly not possible.
Lack of strong color is a common problem for many cool-climate hybrid cultivars, and many of the breeding programs specifically select for parents with deeply colored juice. Harold Olmo used this characteristic to breed the mixed species hybrid red cultivars for California’s Central Valley, where heat makes development of adequate color particularly problematic. There, Olmo bred hybrids Rubired and Royalty (Robinson, et al., 2012) to address this concern.
Part two of this series will examine at hybrid grape cultivars in Michigan and the challenges and opportunities for the future of hybrid viticulture.
Dr. Paolo Sabbatini is an associate professor of horticulture at Michigan State University with research (60%) and extension (40%) responsibilities in viticulture. His primary objective is to identify environmental, physiological and cultural factors that limit vine growth and development, fruit maturity and quality of grapes grown in Michigan. Sabbatini received his Ph.D. in 2002 from the University of Ancona (Italy).
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