Nutfruit Magazine

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21 July, 2020 Feature Articles

Five Hazelnut Cultivars from Oregon State University for the Kernel Market

Five Hazelnut Cultivars from Oregon State University for the Kernel Market


Hazelnut is an economically important tree nut for which demand currently exceeds supply. Plantings have expanded in many current production areas, and orchards have been established in areas new to hazelnut production. Nearly all world production is based on selections from the local, wild vegetation, but new cultivars from the Oregon State University breeding program with ‘Gasaway’ resistance to eastern filbert blight (EFB) are now being widely planted. This article describes five cultivars for the kernel market: ‘Tonda Pacifica’, ‘Dorris’, ‘Wepster’, ‘McDonald’, and ‘PollyO’. All have high yields, high kernel quality and nuts that are nearly round with few defects. 


Shawn Mehlenbacher earned his Ph.D. in Plant Breeding at Cornell University in 1982 after graduating from Pennsylvania State University in 1978 with a B.S. in Horticulture. Mehlenbacher has held tree crop breeding responsibilities at Oregon State University Department of Horticulture since 1986, beginning as an Assistant Professor and since 2000 serving as Oregon Hazelnut Industry Professor.

‘Tonda Pacifica’ was released in 2010 for its exceptional kernel quality and ease of pellicle removal, but is highly susceptible to EFB. It is from a cross of ‘Tonda Gentile delle Langhe’ x OSU 23.024 and its kernel quality is similar to that of its female parent. Trees are less precocious than other recent releases, but nut yields in years 3-7 are slightly higher than ‘Barcelona’. Tree size is about 77% of ‘Barcelona’ but yield efficiency is considerably higher. In Chile, ‘Tonda Pacifica’ trees appear to be more sensitive to sunburn and strong wind than those of other cultivars. Although the husks are long, they are slit and open as they dry. Nut maturity is 7-10 days earlier than ‘Barcelona’. Percent kernel is about 48%.
 
‘Dorris’ was released in 2012 for its exceptional kernel quality, ease of pellicle removal, and high yield efficiency but small tree size. It is from a cross of OSU 309.074 x ‘Delta’ and carries EFB resistance from ‘Gasaway’. ‘Dorris’ nut and kernel size is larger than those of most kernel cultivars, and there is a range in nut sizes from a single tree. Kernel texture and flavor is similar to that of its grandparent ‘Tonda Gentile delle Langhe’. Nut yields per tree are similar to ‘Barcelona’ but the tree size is only about 60% of ‘Barcelona’. Yield efficiency is 58% higher than ‘Barcelona’, and the small tree size makes it suitable for high-density plantings. Nut maturity is with ‘Barcelona’. Percent kernel is 43%, the same as ‘Barcelona’. The pellicle is easily removed from the kernel with dry heat. 
 
‘Wepster’ was released in 2013 for the kernel market. It is from a cross of ‘Tonda Pacifica’ x OSU 440.005 and carries EFB resistance from ‘Gasaway’. The trees are considerably more vigorous than ‘Yamhill’, have an open but globose growth habit, and yield efficiency is high. Most of its kernels are the size (1.1 g) desired by the confectionery industry, and the pellicle on the kernels is easily removed by dry heat. Kernel texture and flavor are very good, and the pellicle is easily removed from the kernel with dry heat. Percent kernel is 46%, a bit higher than ‘Barcelona’. Nut maturity is 7-10 days before ‘Barcelona’.
 
‘McDonald’ was released in 2014 for the kernel market. It is from a cross of ‘Tonda Pacifica’ x ‘Santiam’ and carries EFB resistance from ‘Gasaway’. The trees are intermediate in vigor between ‘Yamhill’ and ‘Wepster’, and have an open but globose growth habit. Yield efficiency is similar to ‘Wepster’. The kernel size is similar to ‘Sacajawea’ and larger than ‘Wepster’, and kernel texture, flavor and ease of pellicle removal are excellent. The nuts have thin shells and are 52% kernel by weight, and they mature and drop two weeks before ‘Barcelona’.
 
‘PollyO’ was released in 2018 for the kernel market as a complement to ‘Wepster’, ‘McDonald’ and ‘Yamhill’. It is from a cross of OSU 684.104 x OSU 669.104 and carries EFB resistance from ‘Gasaway’ through the grower selection ‘Zimmerman’. The pedigree includes ‘Mortarella’ from southern Italy and ‘Negret’ from Spain. The trees are vigorous and productive, and have a globose shape. The yield efficiency is similar to ‘Jefferson’ but less than ‘Yamhill’. The kernel size is similar to ‘McDonald’. The kernel texture, flavor and ease of pellicle removal are excellent. Nuts are 48% kernel by weight, and nuts mature and drop two weeks before ‘Barcelona’.
 
All of the cultivars listed above have been described in publications in HortScience. These publications give additional information on performance, frequency of defects, incompatibility alleles, and flowering time.
 
Legal protection has been sought for these five and additional cultivars in the USA, Chile, European Union and a few other countries. A list of nurseries licensed to propagate and sell trees may be obtained from Oregon State University. These cultivars should be attractive additions to the assortment available in producing countries. Growers and end-users will be pleased by their high yields of round nuts with high kernel quality and few defects.
 
In addition to the five cultivars described above, ‘Jefferson’ was released in 2009 for the in-shell market, and ‘Sacajawea’ and ‘Yamhill’ for the kernel market. A series of pollinizers has also been released, of which ‘York’, ‘Felix’ and ‘Theta’ are the most interesting. These three set large quantities of catkins that shed pollen with high viability. ‘York’ has a medium-size tree and sheds pollen in mid-season with ‘Daviana’. ‘Felix’ has a vigorous tree and sheds pollen in late mid-season with ‘Hall’s Giant’. ‘Theta’ has a moderately vigorous tree and sheds pollen very late in the season. In addition, some of the cultivars described above could be used as pollinizers.
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