Searching for Resistance to Eastern Filbert Blight: Hazelnuts from the Republic of the moderate climate of the Willamette Thomas Molnar1 and Michele Pisetta2 Valley is well suited to cultivars from 1Plant Biology and Pathology Department Europe. Rutgers University, 59 Dudley Road Our native American hazelnuts, C. New Brunswick, NJ 08901 americana, and its cousin the beaked [email protected] hazel, C. cornuta, are very resistant to 2Hazelnut Business Development - R&D EFB, due to having evolved alongside Ferrero S.p.A., Piazzale P. Ferrero 1 the fungus that causes the disease over 12051 ALBA (Cuneo), Italy millennia. While the American spe- [email protected] cies can be productive, their tiny, thick- shelled nuts do not compete with their European relative and for the most part azelnuts are a favorite nut crop gia), and chestnuts (Castanea spp.). have only been harvested from the wild of many NNGA members. The The top hazelnut producing country H for local consumption. Corylus ameri- plants are adapted to a wide range of in the world is Turkey, which gener- cana can be found growing over a wide climates and soils and their smaller ally produces more than 70 percent of area of eastern North America, and be- stature makes them suitable for back- the world’s crop (776,890 metric tons cause of its ability to harbor non-lethal yard orchards. They are easy to grow in 2007). Turkey is followed by Italy, EFB infections it acts as a reservoir of and harvest and require relatively little which produces around 17-20 percent inoculum to infect European hazelnuts in terms of pesticides or other chemical of the total, and then the U.S., which planted across its range. Fortunately, it inputs to produce tasty crops of nuts. produces less than five percent. Other also acts as a pool of genetic resources Currently, there is renewed interest in producing countries include Spain, useful for breeding EFB resistant, cold- growing them for personal consump- Georgia, Azerbaijan, Iran, France, hardy hybrid hazels, as demonstrated tion, as well as for large-scale produc- Greece, Russia and China (FaoStat, by the early successes of J.F. Jones, tion across much of the eastern U.S. 2009). G.H. Slate, C. Weschcke and others and southern Canada. There are now As many NNGA members already when crossing C. americana with culti- hazelnut breeding programs located at know, a native fungal disease called vars of C. avellana (Crane et al., 1937; Oregon State University (OSU) and Eastern Filbert Blight (EFB), caused Weschcke, 1954; Slate, 1969; Rutter, Rutgers University, as well as hazelnut by Anisogramma anomala, makes most 1987). However, when C. americana research underway at the University of European hazelnut cultivars nearly im- is used as a parent in breeding, it takes Nebraska, Lincoln, Minnesota State possible to grow across much of North several generations (amounting to many University, the University of Guelph, America, the only continent where this decades) to recover EFB-resistant, and the Arbor Day Foundation. disease is found. The European ha- cold-hardy hybrid plants with nut quali- The European hazelnut, Corylus zelnut is very susceptible to EFB and ties and yields suitable for commercial avellana, is the most coveted of the the disease is blamed for why there production. For example, the early first Corylus genus because of its large, has been no commercial production generation hybrids developed by Slate, thin-shelled nuts. It is an economically of hazelnuts in the eastern U.S. in the while suitable for backyard produc- valuable crop, ranking fifth in world past. Conversely, commercial hazelnut tion, did not produce consistent yields tree nut production behind cashews production has thrived in the Pacific of high-quality kernels in the amounts (Anacardium occidentale), almonds Northwest, as EFB was not found in needed to support a commercially vi- (Prunus dulcis), walnuts (Juglans re- this region until relatively recently and 16 THE NUTSHELL, December 2009 able industry (Slate, 1961). Further the acreage of hazelnut orchards in the bazaars, road side stands, research sta- generations of breeding were needed. Willamette Valley is increasing for the tions and botanical gardens. Over 4,000 While work to develop advanced gen- first time in decades. The power of nuts were brought back to Rutgers, with eration C. avellana x C. americana systematic plant breeding is clearly vi- a comparable group brought back to hybrids continues at Oregon State sualized when comparing the poor nut OSU. From this collection, over 1,200 University, Rutgers University and at quality of ‘Gasaway’ with that of the seedlings were grown at Rutgers and several private nurseries, it will likely new excellent quality EFB resistant re- inoculated with spores of A. anomala. be a decade or more before a suitable leases. This breeding success at OSU, In less than four years, a large major- proven hybrid cultivar is released to the besides saving the U.S. hazelnut indus- ity of these plants quickly succumbed public for commercial production. try, provides much tangible evidence to to the disease. However, after several One way to speed development of demonstrate the genetic improvement more years of continued evaluation and EFB resistant commercial quality ha- potential of Corylus, a genus that has constant disease pressure in the field, zelnuts is to search for resistance within undergone very little breeding and con- we were successful in identifying a the European species itself. While in tains a great deal of genetic diversity. small number that were highly resistant general the species is highly suscep- This evidence greatly bolsters enthusi- (Molnar et al., 2007). To our surprise, tible, rare plants exist that are resistant asm to develop improved C. avellana several of these plants produced large to EFB, as demonstrated by the obso- and hybrid hazelnuts for colder regions nuts of relatively high quality repre- lete pollinizer C. avellana ‘Gasaway’. across North America. senting great improvement over those While ‘Gasaway’ produces low yields The identification of ‘Gasaway’ from ‘Gasaway’ (Fig. 1). of very tiny, poor quality nuts (mak- spurred the search for other resistant We are currently using our best re- ing it a less than ideal parent in terms C. avellana cultivars and selections to sistant Russian plants in controlled of nut characteristics), it was the first provide a diversity of resistance genes crosses with pollen from elite but EFB and only source of C. avellana resis- to combat EFB. Shawn Mehlenbacher susceptible hazelnuts from the OSU tance identified at a time when hazelnut and his team at OSU closely evalu- breeding program. Our goal is to con- production in Washington and Oregon ated much of the large Corylus germ- currently investigate how the resistance was being devastated by EFB after plasm collection at the USDA Clonal genes are transmitted to the next gener- its inadvertent introduction in the late Germplasm Repository in Corvallis, ation while also working towards rapid- 1960s. ‘Gasaway’ was shown to carry Oregon, as well as their own diverse ly developing new resistant plants with a dominant allele at a single locus that collections, for resistance to this dis- much improved nut quality. This work transmits EFB resistance to its progeny ease. By developing and using both was funded in part by a NNGA research (Mehlenbacher and Thompson, 1991). greenhouse and field inoculation tech- grant. We hope that by identifying and Simply stated, ‘Gasaway’ transmits a niques, they were successful in identi- using EFB resistant parents that have gene for EFB resistance to fifty-per- fying a number of plants that did not decent nut size and quality, crossed cent of its offspring. Due to its predict- succumb to EFB, with several repre- with parents having excellent nut qual- able inheritance, a concerted effort was senting improvements over ‘Gasaway’ ity from the OSU breeding program, we made at OSU to use ‘Gasaway’ and its in many respects (Coyne et al., 1998; will produce improved EFB-resistant offspring in controlled crosses to devel- Lunde et al., 2000; Chen et al., 2005 & offspring in a shorter period of time op improved EFB resistant C. avellana 2007). They are currently using the best compared to the work with ‘Gasaway’. cultivars. While EFB resistance was of these resistant plants in their breed- From our efforts, we now have over inherited in a simple manner, the poor ing program to develop future releases one thousand plants in the greenhouse nut quality of ‘Gasaway’ still required for the Oregon hazelnut industry. and field representing the first genera- several generations of breeding, equat- Following the successful approach tion of new hybrids from these Russian ing to over 30 years, to finally develop of OSU, in 2002 a trip was made to parents. We also have several thousand EFB resistant plants that produce high southern Russia and the Crimean pen- hybrid seeds in stratification from simi- yields and kernels of proper quality for insula of Ukraine to collect hazelnut lar crosses made in 2009 that will be commercial markets. Nevertheless, germplasm to search for additional germinated and grown at Rutgers, as the most recent OSU introductions sources of EFB resistance and other well as at OSU and the University of (‘Yamhill’ for the kernel market and traits needed for breeding efforts in the Nebraska, Lincoln. ‘Jefferson’ for the inshell market,) as U.S. This was the first time hazelnuts Based on the success of the Russian well as several new compatible polliniz- were collected from this region for collection, we recently initiated a new ers, can be credited for revitalizing the evaluation on such a large scale. Nuts project to identify resistant plants from hazelnut industry in Oregon. Currently, were collected from local markets and a different geographic location to add

THE NUTSHELL, December 2009 17 cause most of the hazelnuts collected in Georgia were purposely selected from plants with above average to excellent nut quality, with many having round, well-filled kernels with a high ratio of kernel to shell. Georgia holds a wealth and diversi- ty of hazelnut germplasm that has only recently been available for evaluation in the west, with very little imported to the eastern U.S. prior to this study. This new project is a wonderful oppor- tunity to not only find new EFB resis- tant germplasm, but also to learn about, connect with and possibly give back to the Republic of Georgia. For one, the best of the resistant plants identified here will be returned to Georgia to be held in a repository for use in breeding locally adapted EFB resistant plants, if Figure 1. Comparison of nut size of new EFB resistant Russian and Crimean hazelnut it is ever necessary. Due to their wealth selections H3R13P40 and H3R14P26 with that of ‘Gasaway’. of genetic resources, rich soils and ex- cellent climate, great opportunities exist to our arsenal of EFB resistant germ- material will also be grown at OSU for in Georgia for increasing acreage and plasm with improved nut quality. In evaluation in their breeding program. modernizing the production of hazel- August 2009, an extensive collection Due to the high disease pressure at nuts. In this small country, which local of hazelnuts was made in the Republic Rutgers, we expect over 95% of the legends indicate as the “Garden chosen of Georgia by Michele Pisetta with help plants to die from EFB in less than by God for his own needs”, Georgians from local expert Dr. Nana Mirotadze. five years. Of the remaining plants, it are very fond of the hazelnut plant, Georgia is a small country approxi- is likely a small percent will express which plays an important role as a sec- mately 70,000 sq. km in size (slightly a high level of resistance to EFB. If ondary agricultural crop. However, the smaller than South Carolina) that bor- we are able to grow a large number of country’s location next to Turkey, the ders the Black Sea on the west, Russia plants (over 2,500), we hope to identify largest world producer, it has not been on the north and east, and Turkey, resistant selections that also produce easy for the Georgian hazelnut sector Armenia, and Azerbaijan on the south high quality nuts. Only time will tell to establish itself as a leading entity in (CIA, 2009). Over 4,000 seeds were if our assumptions are correct. Once both quality and quantity. collected from 62 different accessions, we identify the surviving plants we will In 2006, a survey on cropland including local cultivars, selections, evaluate them for nut characteristics was carried out by the Ministry of and wild plants from across the coun- (size, shape, kernel quality, kernel per- Agriculture indicating that out of the try representing a wide spectrum of the cent, etc.) and yield for several seasons. approximately 100,000 hectares dedi- diversity present in the region (Table We will then propagate the best of these cated to agriculture in the country about 1; Figure 2). The seeds were shipped plants and grow them in multiple loca- 15,000 were planted to hazelnut or- under proper permits to the U.S. in tions to assess how they perform under chards. This figure has been increasing October and are now undergoing strati- different climates and soils. We will due to the extensive planting that fol- fication at Rutgers for germination in also use them in controlled crosses lowed the strong demand for hazelnuts spring 2010. The resulting plants will with susceptible parents to evaluate if in 2004; this dynamic originated due to be inoculated with spores of the EFB and how resistance is transmitted to an unexpected frost event that decimat- fungus in the greenhouse and will also their offspring. If we are lucky, we will ed Turkish production to a point where be grown under severe disease pressure identify new dominant genes for resis- world demand could not entirely be in the research fields at Rutgers, simi- tance in some of the plants that also matched by the decreased supply. Since lar to the Russian and Crimean material produce decent quality nuts. We are then, many small-size orchards have described above. A large subset of this hopeful that this will be the case, be- been planted in Georgia, with the ma-

18 THE NUTSHELL, December 2009 Table 1. Accessions of hazelnut seeds collected in the Republic of Georgia. Identification numbers correspond to placement on map in Fig. 2.

Cultivar name or ID number Region Village description Source 1 Adjara Kopuleti Berzula(Anakliuri) roadside vendor 2 Adjara Kopuleti Gulshishvela roadside vendor 3 Samegrelo Anakliuri market 4 Adjara Kopuleti Dedopolis titi private garden 5 Guria Muhalistate Skheniskbili market 6 Abkhazia Gali Anakliuri private garden 7 Adjara Dedopolis titi market 8 Adjara Kedo vaio Giresum market 9 Guria Lanchuti Cincia market 10 Guria Muhalistate Kharistvala market 11 Guria Khasarula private garden 12 Samegrelo Daracheni mixture of nuts private garden 13 Imereti 5 private garden 14 Guria Surebi Shvelis Kura private garden 15 Imereti Nottingham private garden 16 Imereti Ganja(azj) experimental garden 17 Imereti Samtredia KTN 30b (azj) experimental garden 18 Imereti Samtredia Lewis experimental garden 19 Imereti Samtredia Cosford experimental garden 20 Kakheti Lagodekhi Ashera(azj) market 21 Belakani(azj) Belakani Belakani market 22 Belakani(azj) Zakatala Belakani market 23 Kakheti Gurjani-Kotechi Kharistvala roadside vendor 24 Kakheti Gurjani-Bakuri Chkvistava private garden 25 Kakheti Gurjani-Bakuri Lombarda red and white private garden 26 Kakheti Gurjani-Bakuri Anakliuri roadside vendor 27 Kakheti Mekutkasheni private garden 28 Kakheti Pshaveli Pshauri private garden 29 Kakheti Hikhalto Hogi private garden 30 Kakheti Pshaveli Shvelis Kura private garden 31 Kakheti Gurjani-Bakuri Nemsa roadside vendor 32 Kakheti Pshaveli Pshauri 2 private garden 33 Kakheti Gurjani-Bakuri Kachapura market 34 Kakheti Gurjani-Kotechi AZJ Mix market 35 Kakheti Pshaveli Pshauri 5 private garden 36 Belakani(azj) Belakani Gawasuria market 37 Kakheti Pshaveli Hybrids private garden 38 Kakheti Pshaveli Pshauri 3 private garden 39 Kakheti Pshaveli Unknown private garden 40 Svaneti Unknown Wild handpicked 41 Kakheti Akhalsheni Kerasuli private garden

THE NUTSHELL, December 2009 19 Table 1. continued

Cultivar name or ID number Region Village description Source 42 Raja Orbeli-Lechkhumi Pollinizers private garden 43 Imereti Zoureti Zoureti 3 private garden 44 Imereti Zoureti Zoureti 4 private garden 45 Samegrelo Zugdidi Dedopolis titi market 46 Imereti Shorapani Nemsa private garden 47 Adjara Chaqui Kharistvala market 48 Samegrelo mixture of nuts market 49 Samegrelo Marani Dedopolis titi private garden 50 Adjara Kopuleti Mshavala roadside vendor 51 Kakheti Bakurzi-Gurjani Gulshishvela private garden 52 Guria Lanchuti Anakliuri market 53 Raja Orbeli Vanis tetri private garden 54 Imereti Zoureti Zoureti 2 private garden 55 Raja Gori Cia private garden 56 Imereti Samtredia Kx 29(azj) market 57 Imereti Samtredia Willamette experimental garden 58 Kakheti Lagodekhi C. colurna woods 59 Imereti Ata Baba private garden 60 Samegrelo Marani Red Corylus private garden 61 Imereti Chiatura Legimari private garden 62 Imereti Samtredia Ganja(azj) experimental garden jority of them coming into full produc- tendency could change in the region of ‘Anakliuri’, a round-shaped small tion between 2008 and 2012. Presently, Kakheti where droughts are becoming nut that is believed to have originated the estimated hazelnut growing area in more frequent. The main problem re- in the area of on the coast of Georgia of 15,000 hectares is unequally lated to water is flooding especially in Samegrelo region. This cultivar is con- divided among five production regions. the western part of the country where sidered to be moderately productive Samegrelo is by far the most important hazelnut often suffers root asphyxia (1.5 tons/Ha) and while it grows simi- of the regions, with over 10,000 esti- during abundant precipitation in the fall larly in habit to the Turkish cultivars on mated hectares and about 15,000 tons season. Cultivation techniques are still the Black Sea coast, its husks drop their of production, while national produc- primitive with a vast majority of farm- nuts on maturity facilitating handpick- tion is over 25,000 tons. Guria, Imereti, ers not using mineral fertilizers nor ing or eventually mechanized harvest. Kakheti and Adjara follow with much pruning the plants, which can produce Although ‘Anakliuri’ has proved to be a less production, although cultivated ar- an abundance of unproductive suckers reliable cultivar in terms of productiv- eas are rapidly growing in each region, (Fig. 4 and 5). Pollination is typically ity and resistance to diseases, it carries especially close to the Black Sea coast provided by the great number of wild some traits such as a early drop of cat- (Adjara) (Mirotadze, pers. com.) (Fig. hazelnuts that grow around cultivated kins and intensive production of suck- 3). orchards, although in recent years a ers that suggest it needs some genetic Hazelnut is found growing at differ- need of pollinizers for the Samegrelo improvement to increase production. ent altitudes across Georgia, from sea region has been assessed in order to Other local cultivars are ‘Gulshishvela’, level up to 1600 meters in the moun- solve problems related with over pro- ‘Kachapura’, ‘Hogi’, ‘Dedopolis titi’, tains of the Little Caucasus. Most or- duction of twin kernels and blanks. ‘Shveliskura’ and ‘Nemsa’ with the last chards are not irrigated, although this The main cultivar in Georgia is being more suitable for the climatic

20 THE NUTSHELL, December 2009 exports. Many cracking facilities sup- plied with modern machinery arose in western Georgia during the last decade but a great number of them went out of business when Turkey recovered from the catastrophic 2004 harvest with out- standing crops in the last two seasons (2007-2008). Georgia, like all the hazelnut-grow- ing countries in Eurasia, has no pres- ence of EFB. However, scientists recognize the danger of this pathogen and make efforts to exclude it from the country via strict quarantine efforts. As a precaution, we strive to identify lo- cal Georgian plants that are resistant to EFB for use in future genetic improve- ment efforts in the country should the disease be introduced. Other sources of infestation can be of significant Figure 2. Collection locations of hazelnut accessions from Georgia corresponding to immediate concern especially where identification numbers in Table 1. not treated properly. Nationwide, fil- bert bud mite (Phytoptus avellanae) can be found thriving on any age of stand, while bacterial blights such as Xanthomonas spp. and Pseudomonas spp. are more common in the western side where conspicuous precipitation combine with acidic (pH less than 6) soils. Sudden summer outbreaks of fall webworm (Hyphantria cunea) are generally promptly treated by Georgian environmental protection services in order to preserve not only hazelnut, but all the susceptible tree species. While current social and economic situations and governmental policies hinder opportunities for enhancing ha- zelnut production in Georgia, the coun- try’s wealth of high quality hazelnut ge- netic resources, fertile soils, excellent climate and hardworking great people set the stage for a bright future. It is our hope this study leads to the identifica- tion of new sources of EFB resistance Figure 3. Map of the Republic of Georgia with corresponding regions. coupled to plants that produce large yields of high-quality kernels. These conditions in the east of the country ing nuts from the ground by hand and new plants can provide a means to has- (Kakheti region) producing tiny, pointy drying them in open air under the sun. ten the development of new cultivars nuts but withstanding a drier climate. Unlike Turkey, no cases of aflatoxins suitable for colder areas of the world Harvest is generally carried out by pick- have been reported for Georgian kernel where EFB is present, while enhancing

THE NUTSHELL, December 2009 21 Figures 4 and 5. Typical hazelnut orchards in Georgia. the pool of resistance genes available to Coyne, C.J., Mehlenbacher, S.A., Rutter, P.A. (1987). “Badgersett Re- combat this devastating disease in the Smith, D.C. (1998). “Sources of re- search Farm – plantings, projects, future.  sistance to eastern filbert blight,” J. and goals,” Annual Report of the Amer. Soc. Hort. Sci., 124:253-257 Northern Nut Growers Assoc., References FAOStat. (2009). http://faostat.fao.org/ 78:173-186. Chen, H., Mehlenbacher, S.A., Smith, site/567/default.aspx#ancor Ac- Slate, G.L. (1961). “The present status D.C. (2005). “AFLP markers linked cessed December 17, 2009 of filbert breeding,” Annual Report to eastern filbert blight resistance Lunde, C.F., Mehlenbacher, S.A., of the Northern Nut Growers Assoc., from OSU 408.040 hazelnut,” J. Smith, D.C. (2000). “Survey of 52:24-26. Amer. Soc. Hort. Sci., 130:412-417. hazelnut cultivars for response to Slate, G.L. (1969). “Filberts-including Chen, H., Mehlenbacher, S.A., Smith, eastern filbert blight inoculation,” varieties grown in the east,” p.287- D.C. (2007). „Hazelnut accessions HortScience, 35:729-73 293. In: R.A. Jaynes (ed.), Hand- provide new sources of resistance to Mehlenbacher, S.A., Thompson, M.M. book of North American Nut Trees, eastern filbert blight,” HortScience, (1991). „Occurrence and inheri- Northern Nut Growers Assoc., 42:466-469. tance of resistance to eastern filbert Knoxville, Tennessee CIA (2009). The World Factbook. blight in ‘Gasaway’ hazelnut,” Hort- Weschcke, C. (1954). p. 24-28. In: https://www.cia.gov/library/publi- Science, 26:410–411. Growing huts in the north, Webb, cations/the-world-factbook/geos/ Molnar, T.J., Mehlenbacher, S.A., Zau- St. Paul gg.html. Accessed December 17, rov, D.E., Goffreda, J.C. (2007). 2009. “Survey of hazelnut germplasm from Crane, H.L., Reed, C.A., Wood, M.N. Russia and Crimea for response to (1937). “Nut breeding,” p. 827-889. eastern filbert blight,” HortScience, In: USDA Yearbook of Agriculture. 42:51-56.

Notes: ______

22 THE NUTSHELL, December 2009