Patent Application
20200008334
Botanical denomination: Corylus avellana cultivar.
Variety designation: ‘PollyO’.
The present Invention relates to a new and distinct cultivar of Corylus plant, botanically known as Corylus avellana, and hereinafter referred to by the name ‘PollyO’.
The new Corylus resulted from a cross of OSU 684.104 x OSU 669.104 made in 2001 (
Hybrid seeds from the controlled cross were harvested in August 2001, stratified, and the resulting seedlings grown in a glasshouse during the summer of 2002. 99 seedlings from this cross were planted in the field in Corvallis, Oreg. in October 2002. The designation OSU 1108.001 indicates the row and tree location of the original seedling. Nuts were first observed on the original seedling in September 2006. The nuts were harvested from the original seedling tree and evaluated over four years (2006-2009).
‘PollyO’ was propagated by tie-off layerage of the suckers in the summer beginning in 2008. The rooted layers from the first propagation (2008) were lined out in a nursery row the year after layerage (2009), and used to plant a replicated yield trial the following spring (2010). The first trial included four trees of each variety. EFB-susceptible selections and check cultivars ‘Barcelona’, ‘Clark’ and ‘Sacajawea’ (unpatented) (Mehlenbacher et al., 2008. ‘Sacajawea’ hazelnut. HortScience 43:255-257) were planted on the same date in a trial adjacent to the first trial. Fungicides were applied to the trial of susceptible genotypes to reduce the incidence of EFB. The rooted layers from the second propagation (2009) were lined out in a nursery row in 2010 and used to plant a second trial in 2011. The second trial had seven blocks. Both trials were planted as randomized complete block designs with a single tree of each genotype in each block. EFB-resistant cultivars ‘Jefferson’ (unpatented) (Mehlenbacher et al., 2011. ‘Jefferson’ hazelnut. HortScience 46:662-664), ‘Yamhill’ (unpatented) (Mehlenbacher et al., 2009. ‘Yamhill’ hazelnut. HortScience 44:845-847) and ‘Gamma’ (unpatented) (Mehlenbacher and Smith. 2004. Hazelnut pollenizers ‘Gamma’, ‘Delta’, ‘Epsilon’ and ‘Zeta’. HortScience 39:1498-1499) served as checks in the first trial, while ‘Jefferson’ and ‘Yamhill’ were the checks in the second trial. Both trials included additional EFB-resistant selections.
The new cultivar was asexually reproduced by tie-off layerage of the suckers in the summer of 2008 and 2009 in Corvallis, Oreg. It was moved with a tree spade to the layer beds in spring, 2010. Of the 12 layers harvested in 2008, three were well-rooted, seven had a modest number of roots, and two had no roots. The size (caliper) was rated as medium. Layers harvested in 2009 showed improved rooting. Further propagation by layerage of about 28 suckers per year was performed in 2011-14, of which 39% were rated as well-rooted, 26% with fair rooting, 26% with poor rooting and 9% with no roots. In general, the layers rooted sufficiently well and size (caliper) was medium to small. The unique features of this new Corylus are stable and reproduced true-to-type in successive generations of asexual reproduction.
The following traits have been observed and are determined to be the unique characteristics of ‘PollyO’. ‘PollyO’ is well-suited to the blanched kernel market for use in chocolate products and baked goods. ‘PollyO’ combines high nut yield, early nut maturity, small round nuts and kernels, high kernel percentage, good kernel blanching and excellent flavor. The tree is vigorous and has a desirable growth habit. ‘PollyO’ is resistant to bud mite (primarily Phytoptus avellanae Nal.). DNA markers and field exposure indicate that it is highly resistant to eastern filbert blight (EFB) caused by Anisogramma anomala (Peck) E. Müller. The resistance is conferred by a dominant allele from ‘Zimmerman’, which microsatellite markers indicate is from a cross of ‘Barcelona’ x ‘Gasaway’ (Gökirmak et al., Characterization of European hazelnut (Corylus avellana) cultivars using SSR markers. Genetic Resources and Crop Evolution 56:147-172, 2009). EFB is now present throughout the Willamette Valley where 99% of the U.S. hazelnut crop is grown. Pruning to remove cankers and fungicide applications are currently used to manage the disease in orchards of ‘Barcelona’ and other susceptible cultivars. ‘PollyO’ is suitable for planting in areas with high disease pressure, as are previous releases ‘Yamhill’ (2008, unpatented), ‘Jefferson’ (2009, unpatented), ‘Dorris’ (2012, U.S. Plant Pat. No. 25,022) (Mehlenbacher et al., 2013. ‘Dorris’ hazelnut. HortScience 48:796-799), ‘Wepster’ (2013, U.S. Plant Pat. No. 27,141) (Mehlenbacher et al., 2014. ‘Wepster’ hazelnut. HortScience 49:346-349) and ‘McDonald’ (2014, U.S. Plant Pat. No. 28,200) (Mehlenbacher et al., 2016. ‘McDonald’ hazelnut. HortScience 51:757-760).
‘PollyO’ has incompatibility alleles S2 and S10. Both alleles are expressed in the stigmas, but only S10 is expressed in the pollen because of dominance. Female receptivity is early, with ‘Wepster’ and ‘McDonald’, while pollen is shed by ‘PollyO’ about ten days later than the other two. Pollen germination is high and similar to ‘Wepster’ and ‘McDonald’. Recommended pollinizers include ‘Wepster’ (S1 S2), ‘McDonald’ (S2 S15) and ‘York’ (S2 S21) (U.S. Plant Pat. No. 24,972).
‘PollyO’ can serve as a companion for ‘Wepster’ and ‘McDonald’, and an alternative to ‘Yamhill’. Many growers find ‘Yamhill’ trees difficult to manage because of low vigor, and the kernels do not blanch well. ‘Wepster’ and ‘McDonald’ are cross-compatible with ‘PollyO’ in all directions, giving growers additional options in orchard design. All three cultivars (‘Wepster’, ‘McDonald’ and ‘PollyO’) could be planted together with each serving as a pollinizer for the others.
Comparisons in two replicated trials conducted in Corvallis, Oreg., plants of ‘PollyO’ differed from plants of other cultivars and selections of Corylus avellana known to the Inventors primarily in nut yield, time of nut maturity, nut size, and kernel percentage (ratio of kernel weight to nut weight). For example:
The accompanying colored photographs illustrate the overall appearance of the new cultivar, showing the colors as true as it is reasonably possible to obtain in colored reproductions of this type. Foliage colors in the photographs may differ slightly from the color values cited in the detailed botanical description which accurately describe the colors of the new Corylus.
The cultivar ‘PollyO’ has not been observed under all possible environmental conditions. The phenotype may vary somewhat with variations in environment such as temperature and light intensity, without, however, any variance in genotype. The aforementioned photographs and following observations and measurements describe trees grown in Corvallis, Oreg. under commercial practice outdoors in the field during the fall, winter and spring. Plants used for the photographs and description were propagated by tie-off layerage and growing on their own roots, and seven or eight years old. In the following description, color references are made to The Royal Horticultural Society Colour Chart, 1966 Edition, except where general terms of ordinary dictionary significance are used. The list of UPOV descriptors are from the Mar. 28, 1979 Hazelnut guidelines from UPOV.
Tree size, growth habit, yield, and yield efficiency. Tree sizes in the two trials were estimated by measuring trunk circumference 30 cm above the soil line, at the end of the 7th growing season (December 2016 and November 2017, respectively). Trunk cross-sectional area (TCA) was calculated from trunk circumference. In the first trial, TCA of ‘PollyO’ (OSU 1108.001) was 118 cm2 or 126% of ‘Jefferson’ and 91% of ‘Barcelona’ in the adjacent trial of EFB-susceptible selections. In the second trial, TCA of ‘PollyO’ (OSU 1108.001) was 117.6 cm2, or 146% of ‘Jefferson’. In previous trials, TCA of ‘Jefferson’ has been about 65-70% of the vigorous standard ‘Barcelona’, a size that pleases Oregon growers. Trees of ‘PollyO’ (OSU 1108.001) are vigorous, and their globose growth habit (
In the first trial, mean total nut yield (2013-16) of ‘PollyO’ (OSU 1108.001) was 29.4 kg compared to 24.3 kg for ‘Jefferson’ (Table 1). Yield efficiency, the ratio of yield to TCA, adjusts yield for differences in tree size. Yield efficiency of ‘PollyO’ (OSU 1108.001) was 0.251 kg/cm2 which is not significantly different from ‘Jefferson’ (0.261 kg/cm2). In the second trial, mean total nut yield was 23.46 kg for ‘PollyO’ (OSU 1108.001) which is significantly higher than the 16.91 kg for ‘Jefferson’ (Table 2). Yield efficiency was 0.201 kg/cm2 for ‘PollyO’ (OSU 1108.001) which is not significantly different from ‘Jefferson’ (0.210 kg/cm2).
zTCA = Trunk cross-sectional area calculated from trunk circumference measured 30 cm above the soil line in November 2017.
yCumulative kernel yield and yield efficiency are based on field-run samples, with defects not removed.
Nut and kernel defects. Samples of 100 nuts were cracked from each tree in each year. No problems were noted in either trial, although many differences among selections in the trials lack statistical significance because of the small number of replications. In both trials (Tables 3-5), ‘PollyO’ (OSU 1108.001) showed a high percentage of good nuts, and low percentages of blanks, brown stain, poorly filled nuts, twins, and kernels with black tips. In the first trial, the frequency of moldy kernels (2.56%) was similar to ‘Yamhill’ and lower than ‘Jefferson’. In the second trial, the frequency of moldy kernels (3.4%) was similar to ‘Jefferson’ (4.3%). Percent kernel (the ratio of kernel weight to nut weight) for ‘PollyO’ (OSU 1108.001) was 47.9% in the first trial based on well-filled nuts, and 46.9% in the second trial based on field-run nuts. In the same trials, the percent kernel for ‘Jefferson’ was 45.7% and 44.4%, respectively. Yields of kernels per acre would be high for ‘PollyO’ (OSU 1108.001). In the two trials, nut yields of ‘PollyO’ (OSU 1108.001) were consistently good and the nuts consistently well-filled. In contrast, ‘Yamhill’ trees occasionally set very heavy nut crops, and the nuts can be so poorly filled that the kernels are not marketable. This was the case for ‘Yamhill’ in the final year of the first trial, when 27% of the nuts were poorly filled.
zData from seven replications of each selection (2013-17) unless otherwise noted, with a single tree of each selection in each block.
Nut and kernel characteristics. ‘PollyO’ can be used for the blanched kernel market as a companion for ‘Wepster’ and ‘McDonald’, and an alternative to ‘Yamhill’. The nut shape is nearly round and lends itself well to sizing and cracking (
Nut maturity date. The nuts of ‘PollyO’ are borne in clusters of 3-4 in husks about 25% longer than the nuts (
Incompatibility and pollinizers. Trees of ‘PollyO’ set a moderate to high amount of catkins that shed copious amounts of pollen in early mid-season, with ‘McDonald’, ‘Wepster’, ‘York’ and ‘Yamhill’. Pollen has been collected and used in several controlled pollinations, and both quantity and viability appear to be very good. Pollen of ‘PollyO’ has germinated well on agar plates (85% in 2014, 81% in 2015 and 48% in 2017), in contrast to ‘Barcelona (36%, 36% and 40%, respectively). ‘PollyO’ has incompatibility alleles S2 and S10 as determined by fluorescence microscopy. Both alleles are expressed in the females, but only S10 is expressed in the pollen because of dominance. By convention, alleles expressed in the pollen are underlined.
Time of pollen shed and female receptivity were recorded weekly from mid-December to mid-March and are shown for three years (2014-2017) (
Pests and diseases. Based on DNA marker data, ‘PollyO’, like ‘McDonald’, ‘Wepster’ and ‘Yamhill’, has a very high level of resistance to EFB conferred by a dominant allele from ‘Gasaway’ through the grower selection ‘Zimmermean’, so fungicide applications are not needed. RAPD markers 152-800 and 268-580 that flank the resistance allele in ‘Gasaway’ are present in ‘PollyO’, and these markers are transmitted to its seedlings. Additional RAPD markers linked to resistance are also present. No cankers have been observed on the 11 trees of ‘PollyO’ in the yield trials, while several cankers have been noted on adjacent trees of susceptible genotypes. During the trials, a nearby heavily infected commercial orchard provided high EFB disease pressure on all plantings. ‘PollyO’ and many other selections were propagated by tie-off layerage of the suckers in 2013. Eight trees of ‘PollyO’ were potted and grown in the lathhouse in the summer of 2014 and exposed to EFB under a structure topped with diseased branches in spring 2015. Unfortunately, inspection in December 2016 showed that very few trees became infected, even the highly susceptible check ‘Ennis’ (unpatented). It seems that the diseased branches were of low-quality inoculum due to freeze injury, as no useful data were provided by this exposure.
Susceptibility to bacterial blight caused by Xanthomonas campestris pv. corylina has not been quantified, but no trees in the two trials were affected.
Susceptibility to big bud mite (primarily Phytoptus avellanae Nal.) was rated in the first trial (Table 3) after leaf fall once per year for five years (December 2012-2016). The scale was from 1 (no blasted buds) to 5 (many blasted buds), with chemical control considered unnecessary for cultivars with a mean rating <3.3. The average ratings indicate high resistance for ‘PollyO’ (1.15) and ‘Jefferson’ (1.34), and an intermediate rating for ‘Gamma’ (2.96). Blasted buds are very rare on ‘PollyO’, so chemical applications should not be necessary to control bud mite.
Microsatellite Marker Analysis: Twenty microsatellite (simple sequence repeat) markers were used. PCR products were multiplexed post-PCR and sized using capillary electrophoresis (Table 6, and see for example Bassil et al., Acta Horticulturae 686:105-110, 2005; Gökirmak et al., Genetic Resources and Crop Evolution 56:147-172, 2009; Gürcan and Mehlenbacher. Molecular Breeding 26:551-559, 2010; Gürcan et al. Tree Genetics and Genomes 6:513-531, 2010).
Table 7 shows allele sizes at 20 microsatellite markers for ‘PollyO’, its parents ‘OSU 684.104’ and ‘OSU 669.104’, cultivars and selections that appear in the pedigree of ‘PollyO’ (‘Mortarella’ to ‘Montebello’), and four kernel cultivars (‘Yamhill’, ‘Tonda Pacifica’, ‘McDonald’ and ‘Wepster’). ‘PollyO’ is easily distinguished from all others shown in Table 7. ‘PollyO’ is different from its female parent ‘OSU 684.104’ at 11 of the 20 marker loci. ‘PollyO’ is different from its male parent ‘OSU 669.104’ at 14 of the 20 marker loci. ‘PollyO’ is the same as both parents at 3 loci. ‘PollyO’ is the same as one parent at 9 loci. ‘PollyO’ is different from both parents at 8 loci. Allele A614-125, Allele A616-144, Allele B617-285, Alleles B709-223 and B709-227, and Allele KG807-238 observed in ‘PollyO’ are not found any of ‘Yamhill’, ‘Tonda Pacifica’, ‘McDonald’, and ‘Wepster’.
This invention was made with government support under USDA-NIFA-SCRI 2009-51181-06028, USDA-NIFA-AFRI 2014-67013-22421, and USDA-NIFA-SCRI 2016-04991 awarded by the United States Department of Agriculture. The government has certain rights in the invention.
