Hazelnuts (Corylus avellana L.) from Spontaneous Flora of the West Part of Romania: A Source of Nutrients for Locals

In this study, the nutritional potential of some hazelnut varieties from the spontaneous flora of Romania was analyzed as a means to increase the sustainability of the local production. The chemical composition from hazelnuts (Corylus avellana L.) from spontaneous flora was determined in terms of mineral substances, protein, as well as essential and non-essential amino acids. The eight amino acids investigated had the following average values: Arg—0.68 g/100 g, Phe—0.415 g/100 g, Ser—0.277 g/100 g, Glu—0.188 g/100 g, Asp—0.133 g/100 g, Pro—0.038 g/100 g, and Lys—0.031 g/100 g. The average values of metal content were in the ranges: 88.39–146.98 µg·g−1 (Fe); 96.93–123.23 µg·g−1(Zn); 46.68–100.38 µg·g−1 (Cu); 26.00–87.78 µg·g−1 (Mn); 4.87–32.19 µg·g−1 (Ni); 1.87–2.84 µg·g−1 (Cr); and 1.29–1.86 µg·g−1 (Cd). Crude protein content values were in the range 16.33–22.31%. In order to harness this nutritional potential, the variety with superior quality indices was included, in the form of flour, in biscuit-type baked goods that were characterized from nutritional and sensory points of view. The results showed that the content of polyphenols increased with the addition of hazelnut flour, as did the content of polyunsaturated fatty acids.

Association Between Flaming Efficiency and Liquefied Petroleum Gas Pressure and Flaming Time in Hazelnut Sucker Control Done Using a Flame Torch

Turkish hazelnut (Corylus avellana L.) is naturally grown as a multi-stemmed shrub. This hazelnut produces lots of suckers. Suckers compete with the main branches for nutrients and water. Because the emergence of suckers negatively affects crop management in the hazelnut orchards are required to eliminate at least twice a year. Flaming is an alternative method to chemical and mechanical control methods. In this study, the effect of gas pressure, flaming time on fuel consumption and flaming efficiency in hazelnut sucker control were evaluated. The trials were carried out in an shrub ocak (in Turkish) type hazelnut orchard The results show that the torch flaming method is a useable method for hazelnut basal sucker cleaning. Gas pressure and flaming time had significant effects on fuel consumption and flaming efficiency. 150 s flaming duration and 3 bar pressure is sufficient for the flaming application. Durations above this time will increase fuel consumption and time loss.

Mapping the Genetic Regions Responsible for Key Phenology-Related Traits in the European Hazelnut

An increasing interest in the cultivation of (European) hazelnut (Corylus avellana) is driving a demand to breed cultivars adapted to non-conventional environments, particularly in the context of incipient climate change. Given that plant phenology is so strongly determined by genotype, a rational approach to support these breeding efforts will be to identify quantitative trait loci (QTLs) and the genes underlying the basis for adaptation. The present study was designed to map QTLs for phenology-related traits, such as the timing of both male and female flowering, dichogamy, and the period required for nuts to reach maturity. The analysis took advantage of an existing linkage map developed from a population of F1 progeny bred from the cross “Tonda Gentile delle Langhe” × “Merveille de Bollwiller,” consisting in 11 LG. A total of 42 QTL-harboring regions were identified. Overall, 71 QTLs were detected, 49 on the TGdL map and 22 on the MB map; among these, 21 were classified as major; 13 were detected in at least two of the seasons (stable-major QTL). In detail, 20 QTLs were identified as contributing to the time of male flowering, 15 to time of female flowering, 25 to dichogamy, and 11 to time of nut maturity. LG02 was found to harbor 16 QTLs, while 15 QTLs mapped to LG10 and 14 to LG03. Many of the QTLs were clustered with one another. The major cluster was located on TGdL_02 and consisted of mainly major QTLs governing all the analyzed traits. A search of the key genomic regions revealed 22 candidate genes underlying the set of traits being investigated. Many of them have been described in the literature as involved in processes related to flowering, control of dormancy, budburst, the switch from vegetative to reproductive growth, or the morphogenesis of flowers and seeds.

Susceptibility of Some Corylus avellana L. Cultivars to Xanthomonas arboricola pv. corylina

Bacterial blight of hazelnut (Corylus avellana L.) is caused by Xanthomonas arboricola pv. corylina (Xac). In the past, bacterial blight has been a key disease impacting the Oregon hazelnut industry where 99% of the United States hazelnut crop is grown. The disease is re-emerging in young orchards, as acreage of newly released hazelnut cultivars rapidly increases. This increase in hazelnut acreage is accompanied by renewed interest in developing control strategies for bacterial blight. Information on susceptibility of hazelnut cultivars to Xac is limited, partially due to lack of verified methods to quantify hazelnut cultivar response to artificial inoculation. In this research, Xac inoculation protocols were adapted to two hazelnut growing environments to evaluate cultivar susceptibility: in vitro tissue culture under sterile and controlled conditions, and in vivo potted tree conditions. Five hazelnut cultivars were evaluated using the in vitro inoculation protocol and seven hazelnut cultivars were evaluated using the in vivo inoculation protocol. Under in vitro conditions, there were severe bacterial blight symptoms on each cultivar consistent with those seen in the field, but no significant differences in the susceptibility of the newly released cultivars were observed compared to known Xac-susceptible cultivar (“Barcelona”). Under in vivo conditions, the proportion of necrotic buds were significantly higher in “Jefferson” and “Dorris” compared to all of the other tested cultivars, including “Barcelona.” The symptom progression seen in vivo mirrored the timing and symptom progression of bacterial blight reported from field observations. The in vitro conditions significantly reduced the amount of time required to measure the inoculation efficiency compared to the in vivo environment and allowed for greater replication. Further studies on the effects of Xac can use the results of these experiments to establish a dose–response model for bacterial blight, a wider range of germplasm can be tested under in vitro conditions, and management strategies that can be evaluated on large populations of new cultivars using the in vivo methods.

First report of nut rot caused by Neofusicoccum parvum on hazelnut (Corylus avellana) in Italy

Hazelnut (Corylus avellana L.), which is native to Europe and Western Asia, is a widely distributed and economically important crop in Italy, cultivated on 82,104 ha and its production is 110,618 t (ISTAT 2021). A total of one hundred and eleven black rotted nuts (incidence: 41%) with sunken lesions from Lu and Cuccaro (45°00'21.8"N/8°28'59.6"E), north-western Italy, were collected during the ripening stage of hazelnuts during October-December 2020. Symptomatic half cut kernels were sterilized in 1% NaClO for 1 min, washed in sterile water twice, and dried on sterile filter paper. The fragments were placed onto potato dextrose agar (PDA) containing streptomycin. After 48 to 72 h of incubation at 25°C, fast-growing white colonies with abundant aerial mycelia were observed. On the opposite side of the plates, colonies were initially white, then turned to dark-grayish olive after one week of incubation. Dark colonies produced globose, hyaline, ellipsoidal, unicellular conidia ranging from 12.23-15 μm x 5-6.71 μm. Morphologically, the causal agent was identified as Neofusicoccum parvum (Pennycook & Samuels) Crous, Slippers & A.J.L. Phillips (Crous et al. 2006; Zhang et al. 2021). The DNA from the isolates HMa-19-2 and Hwb-4b-2 was extracted with the E.Z.N.A. Fungal DNA mini kit (Omega Bio-tek) according to manufacturer instructions. Molecular identification was confirmed by sequencing of rDNA internal transcribed spacer (ITS) using primers ITS1/ITS4 (White et al. 1990) and translation elongation factor 1-alpha (tef-1α) gene by using the primers EF1-728F/EF1-986R (Carbone & Kohn, 1999). The sequences of both isolates were deposited in GenBank for ITS (accession numbers MZ848132 and MZ848133) and for tef-1α gene (accession numbers MZ913266 and MZ913267). The BLAST analysis showed 99% identity with ex-type strain of N. parvum (CMW9081) for ITS and tef-1α. Maximum likelihood method based on combined sequences of ITS and tef-1α genes was performed and the isolates of N. parvum clustered with ex-type strain of N. parvum (CMW9081; eXtra file). Pathogenicity of both isolates were tested on ripening hazelnuts (BBCH: 85) to evaluate Koch’s postulates. Three nuts per isolate, and per three replicates, were surface disinfected with 1% NaClO. A piece of shell (5 mm diameter) from nuts was removed with a sterile cork borer, then nuts were inoculated with PDA mycelium plugs of the same diameter cut from 7 days old PDA colony (Seddaiu et al. 2021). The control nuts were treated with sterilized PDA plugs. All inoculated nuts produced black lesions with softening pulp (eXtra file). Additionally, abundant white-gray mycelium developed on the inoculation sites. Control nuts showed no symptoms. Neofusicoccum parvuwas recently reported in Italy on chestnut (Seddaiu et al. 2021) and blueberry (Guarnaccia et al. 2021). The fungal pathogen was also reported as agent of grey necrosis of hazelnut in Chile (Duran et al. 2020). However, this is the first report of N. parvum on hazelnut nut in Italy. The findings suggest that N. parvum could severely affect hazelnut production in Italy. Accurate identification of the pathogen will support the growers to manage the disease.

1-Naphthaleneacetic Acid (NAA) Reduces Sucker Growth in European Hazelnut (Corylus avellana L.)

Three 2-year field studies were conducted to evaluate 1-naphthaleneacetic acid (NAA) as a suppressant of suckers in European hazelnut (Corylus avellana L.). Treatments were basal-directed applications of NAA at 5, 10, and 20 g·L−1 a.i. applied once per season, and two sequential applications of NAA 10 g·L−1 a.i., 28 days apart, compared with 2,4-D (3.8 g·L−1 acid equivalent), and a nontreated control. Treatments were applied early in spring and repeated the following year. Both NAA and 2,4-D delayed sucker growth by 1.2- to 3.0-fold compared with the nontreated control, and response varied with experimental site and year. Sequential treatments of NAA significantly reduced sucker height and fresh weight 120 days after treatment. NAA applied in sequential treatments increased tree trunk cross-sectional area and canopy volume in two of the three experimental sites. Yield of hazelnuts increased when suckers were removed with NAA or 2,4-D compared with nontreated. Results indicate that NAA is an effective option to control suckers in hazelnuts and can help reduce herbicide and labor in sucker control.