Development and Cultivar Improvement of Nut Crops

A special issue of Agriculture (ISSN 2077-0472). This special issue belongs to the section "Crop Production".

Deadline for manuscript submissions: closed (10 September 2021) | Viewed by 26474

Special Issue Editors

Department of Horticulture, Faculty of Agriculture Technology, Aburaihan Campus, University of Tehran, Tehran, Iran
Interests: fruit breeding; biotechnology; micropropagation; propagation; nut crops; walnut; pecan
Special Issues, Collections and Topics in MDPI journals
Department of Agronomy, University of Ljubljana, Biotechnical Faculty, Experimental Field for Nut Crops, Vinarska 14, 2000 Maribor, Slovenia
Interests: nut crops; walnut; hazelnut; chestnut; genetic resources; propagation; plant physiology; biochemical analysis
Fruit Production Programme, IRTA Institute of Agrifood Research and Technology, 08140 Caldes de Montbui, Spain
Interests: nuts (walnut, pecan, chestnut & stone pine); breeding; agroforestry; basic forest material; broadleaves

Special Issue Information

Dear Colleagues,

Nut fruits are among the most important horticultural crops, with production and consumption dramatically increasing due to their high nutritional and economic value. Therefore, the world's nut tree production has increased by 48% over the last 10 years (ca. 4.5 million metric tons). Almond and walnut were the top produced crops, accounting for 31% and 21% of the world share followed by cashews (17%), pistachios (14%), and hazelnuts (12%). The remaining 5% was distributed among pecans, macadamias, Brazil nuts, and pine nuts. Nut tree crops have a good economic return for countries investing in these products, so that export value of nut tree crops amounted to around 37.5 billion dollars (22.5% of total fruit export) in 2018 which was raised around 105% compared to the prior 10-year (INC, 2019; FAO, 2018). Technical knowledge of nut tree production has been rapidly increased in line with increasing demand for their production. One of the main issues to cause such extraordinary progress is the use of suitable cultivars and rootstocks for nut trees to increase yield, cultivate in poor soil and various climates, overcome stresses and improve their fruit quality. Considering the release of new cultivars and rootstocks of nut trees and the great advances in orchard management technology in the 21st century, this Special Issue focuses on the recent advancements in the development and cultivar improvement of nut crops.

Prof. Dr. Kourosh Vahdati
Dr. Anita Solar
Dr. Neus Aletà
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Agriculture is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Nut crops
  • Cultivars
  • Rootstocks
  • Breeding
  • Production
  • Stress tolerance
  • Orchard management
  • Water use efficiency

Published Papers (10 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

14 pages, 2498 KiB  
Article
Evaluation of Phenological and Agronomical Traits of Different Almond Grafting Combinations under Testing in Central Italy
by Aniello Luca Pica, Cristian Silvestri and Valerio Cristofori
Agriculture 2021, 11(12), 1252; https://doi.org/10.3390/agriculture11121252 - 10 Dec 2021
Cited by 5 | Viewed by 2058
Abstract
In the new introducing almond areas, it is necessary to test the more promising almond cultivar and rootstock combinations able to guarantee the best agronomic performances according to the specific pedoclimatic conditions. With this aim, two almond trials have been established in an [...] Read more.
In the new introducing almond areas, it is necessary to test the more promising almond cultivar and rootstock combinations able to guarantee the best agronomic performances according to the specific pedoclimatic conditions. With this aim, two almond trials have been established in an experimental farm located in the Latium region (Italy). The first trial (A) focused on the phenological, and agronomical influences induced by the clonal rootstock ‘GF677’ on the grafted cultivars ‘Tuono’, ‘Supernova’ and ‘Genco’, in comparison to those induced by peach seedling rootstocks, in order to identify the best grafting combination for developing “high density” plantings in this new growing area. The second trial (B) tested the phenological and agronomical influences induced by three different clonal rootstocks (‘GF677’, ‘Rootpac® 20’ and ‘Rootpac® R’), on the Spanish cultivar ‘Guara’ to identify suitable dwarfing rootstocks for “super high density” plantings in the same environment. Flowering and ripening calendars of the trial A highlighted as the medium-late flowering cultivars ‘Genco’, ‘Supernova’ and ‘Tuono’ could be subject to moderate risk of cold damages. The clonal rootstock ‘GF677’ seems to anticipate flowering and vegetative bud break by a few days in ‘Tuono’ when compared to the same cultivar grafted on peach seedling rootstocks. Furthermore, the yield per plant was always higher in plants grafted on ‘GF677’. The observations carried out in trial B highlighted as the flowering of cultivar ‘Guara’ were affected by the rootstock, with ‘Rootpac® 20’, which postponed its full bloom of about one week when compared to other rootstocks, whereas ‘GF677’ imposed more vigor to the cultivar than ‘Rootpac® 20’ and ‘Rootpac® R’. Full article
(This article belongs to the Special Issue Development and Cultivar Improvement of Nut Crops)
Show Figures

Figure 1

9 pages, 1213 KiB  
Article
Evaluation of Chestnut Susceptibility to Cryphonectria parasitica: Screening under Controlled Conditions
by Emigdio Jordán Muñoz-Adalia, Andreu Meijer, Joan Abel, Carlos Colinas, Neus Aletà and Mercè Guàrdia
Agriculture 2021, 11(11), 1158; https://doi.org/10.3390/agriculture11111158 - 18 Nov 2021
Viewed by 1765
Abstract
Cryphonectria parasitica (Murrill) M.E. Barr (Sordariomycetes, Valsaceae) is the causal agent of chestnut blight. This disease is a major concern for chestnut cultivation in Europe. The fungus colonizes vascular tissues and evolves generating cankers causing severe dieback and the death of the tree. [...] Read more.
Cryphonectria parasitica (Murrill) M.E. Barr (Sordariomycetes, Valsaceae) is the causal agent of chestnut blight. This disease is a major concern for chestnut cultivation in Europe. The fungus colonizes vascular tissues and evolves generating cankers causing severe dieback and the death of the tree. Excised and debarked well-lignified shoots of 28 C. sativa genotypes (assay A) and of 10 progenies (assay B) were inoculated with C. parasitica strain FMT3bc2 (vcg: EU2). Fungal growth was measured along the longitudinal axis on the 3rd and 6th days after inoculation. Results indicated the inoculation methodology works and the results were clear after 6 days. Differences in susceptibility to chestnut blight among C. sativa trees of Montseny have been detected both at the individual genotype level and at the progeny level. Nineteen genotypes and four progenies showed a susceptibility to Blight not significantly different from C. mollissima. The methodology was easy to apply in extensive/preliminary selection screenings to assess the susceptibility of C. sativa materials to the Blight. Full article
(This article belongs to the Special Issue Development and Cultivar Improvement of Nut Crops)
Show Figures

Figure 1

16 pages, 6590 KiB  
Article
Hazelnut Kernel Size and Industrial Aptitude
by Agusti Romero-Aroca, Mercè Rovira, Valerio Cristofori and Cristian Silvestri
Agriculture 2021, 11(11), 1115; https://doi.org/10.3390/agriculture11111115 - 09 Nov 2021
Cited by 6 | Viewed by 2611
Abstract
Kernel size is the main hazelnut quality parameter for the consumption market. However, industrial purposes are the main destination for the main hazelnut cultivars. This work aims to identify industrial aptitude relationships to kernel size, and qualitative nut and kernel traits eligible to [...] Read more.
Kernel size is the main hazelnut quality parameter for the consumption market. However, industrial purposes are the main destination for the main hazelnut cultivars. This work aims to identify industrial aptitude relationships to kernel size, and qualitative nut and kernel traits eligible to enhance hazelnut’s commercial value. The qualitative hazelnut traits of cv “Negret” and “Pauetet” were assessed via in-shell and shelled nut sizes for two years. In-shell hazelnuts were tested for weight, shape, percent kernel, yield and shell thickness. Kernels were measured for shape, weight, roasting aptitude, skin color, moisture content and water activity, free acidity, fat content, crude protein, total sugars, minerals, fatty acid composition, α-tocopherol and oil stability. In-shell hazelnut traits significantly differed between cultivars, sizes and storage period. Shell thickness and nut roundness increased almost linearly with nut caliber, whereas kernel percentage decreased. Kernel roundness increased linearly with caliber. The blanching and roasting aptitude of “Negret” increased linearly with caliber, whereas no significant trend was observed for “Pauetet”. Significant differences between cultivars were confirmed for water activity, oil acidity and skin color. Regarding chemical composition, fat content increased linearly with caliber in both cultivars, and α-tocopherol followed the same trend in “Negret”. The sugar content tended to decrease with caliber, whereas crude protein, fiber and minerals did not show any significant relationship with kernel size. Unsaturated and polyunsaturated fatty acids fitted to linear models related to caliber, showing differences between cultivars. Unsaturated fatty acids increased with caliber, whereas polyunsaturated fatty acids decreased, and the oil stability increased linearly with kernel size. These results show that some hazelnut key traits change significantly with kernel size. The linear models presented could be a powerful tool for the confectionery industry to modulate the industrial value of given hazelnut batches. Full article
(This article belongs to the Special Issue Development and Cultivar Improvement of Nut Crops)
Show Figures

Figure 1

12 pages, 807 KiB  
Article
An Agronomic Approach to Pine Nut Production by Grafting Stone Pine on Two Rootstocks
by Mercè Guàrdia, Anna Teixidó, Rut Sanchez-Bragado and Neus Aletà
Agriculture 2021, 11(11), 1034; https://doi.org/10.3390/agriculture11111034 - 22 Oct 2021
Cited by 5 | Viewed by 1631
Abstract
Stone pine (Pinus pinea) grows in natural stands within the Mediterranean basin and its nut is highly appreciated for its nutritional profile. Nevertheless, a decline in this species due to biotic and abiotic damages is currently being clearly observed. This situation has [...] Read more.
Stone pine (Pinus pinea) grows in natural stands within the Mediterranean basin and its nut is highly appreciated for its nutritional profile. Nevertheless, a decline in this species due to biotic and abiotic damages is currently being clearly observed. This situation has led to its development as a nut crop, to try to save its production and obtain regular harvests over the years. Under this agronomic scenario, the aim of this work was to compare the behavior of the stone pine grafted onto two rootstocks, P. pinea (PP) and P. halepensis (PH), by evaluating cone productivity, tree growth response, mast seeding patterns and pine nut composition. The field test was composed of 14 PH and 14 PP, randomly distributed into groups of 4–5 trees/rootstock. Data were from seven productive growing seasons. The results show higher growth and ripe cone production on PP rather than PH, although the productivity (cones/m2 canopy) was similar. Any effect of rootstock was observed on the mast seeding pattern and weight of cones, while the pine nut composition showed differences in the fatty acids content. The global quality of production was similar in PH and PP. Full article
(This article belongs to the Special Issue Development and Cultivar Improvement of Nut Crops)
Show Figures

Figure 1

10 pages, 3187 KiB  
Article
‘Helete Güneşi’, a New Walnut Cultivar with Late Leafing, Early Harvest Date, and Superior Nut Traits
by Mehmet Sütyemez, Şakir Burak Bükücü and Akide Özcan
Agriculture 2021, 11(10), 991; https://doi.org/10.3390/agriculture11100991 - 12 Oct 2021
Cited by 19 | Viewed by 2525
Abstract
‘Helete Güneşi’ was selected among different genotypes obtained from crossing ‘Maraş 18’ × ‘Chandler’ in Turkey. The present study compares phenological and pomological traits of ‘Helete Güneşi’ with those of its parents so as to scale their performances. ‘Helete Güneşi’ staged leaf out [...] Read more.
‘Helete Güneşi’ was selected among different genotypes obtained from crossing ‘Maraş 18’ × ‘Chandler’ in Turkey. The present study compares phenological and pomological traits of ‘Helete Güneşi’ with those of its parents so as to scale their performances. ‘Helete Güneşi’ staged leaf out on 22 April, whereas its parents, ‘Chandler’ and ‘Maraş 18’, did on 20 and 12 April, respectively. The harvest date of ‘Helete Güneşi’ was as early as 17 September, whereas ‘Chandler’ and ‘Maraş 18’ began to be harvested on 5 October and 15 September, respectively. Defoliation in ‘Helete Güneşi’ occurred about 1 month earlier than ‘Chandler’. The nut weight and kernel percentage of ‘Helete Güneşi’ were 13.41 g and 53.39%, respectively, whereas in ‘Chandler’ the values were 12.73 g and 48.23%, respectively, but were 14.62 g and 53.76% in ‘Maraş 18’. ‘Helete Güneşi’ had a higher yield value compared to its parents. The results demonstrated that ‘Helete Güneşi’ has superior traits in being selected for late leafing date, early harvest date, high yield, and good nut quality. Therefore, it can be considered as a valuable genetic resource in future breeding programs around the world. Full article
(This article belongs to the Special Issue Development and Cultivar Improvement of Nut Crops)
Show Figures

Figure 1

13 pages, 3268 KiB  
Article
Osmolyte Accumulation and Sodium Compartmentation Has a Key Role in Salinity Tolerance of Pistachios Rootstocks
by Pegah Behzadi Rad, Mahmoud Reza Roozban, Soheil Karimi, Reza Ghahremani and Kourosh Vahdati
Agriculture 2021, 11(8), 708; https://doi.org/10.3390/agriculture11080708 - 27 Jul 2021
Cited by 46 | Viewed by 2733
Abstract
Physio-biochemical responses of pistachio varieties including Pistacia vera L. ‘Ghazvini’ (GH), P. vera ‘Ghermez-Pesteh’ (GP) and P. atlantica subsp. mutica (M) were assessed under salt stress to understand the common mechanisms of salt tolerance in two popular Pistacia species. In the experiment, half-sib [...] Read more.
Physio-biochemical responses of pistachio varieties including Pistacia vera L. ‘Ghazvini’ (GH), P. vera ‘Ghermez-Pesteh’ (GP) and P. atlantica subsp. mutica (M) were assessed under salt stress to understand the common mechanisms of salt tolerance in two popular Pistacia species. In the experiment, half-sib seedlings of the varieties were subjected to high (100 mM) and severe (200 mM) levels of NaCl-induced salinity for 90 days. Growth, physiological, biochemical and ionic parameters in the roots and shoots of plants were measured in the experiment. Salinity markedly declined plant growth, and increased the number of necrotic leaves (NL) and leaf abscission. In terms of physiological responses, salinity reduced the relative water content (RWC), membrane stability index (MSI) and the concentrations of photosynthetic pigments, but increased carbohydrates and proline content in the leaves. MSI of the leaves was positively correlated with the concentrations of anthocyanins and carotenoids. Salinity increased sodium content in root and shoot tissues of the plants, and decreased potassium concentration and K/Na ratio. Among the rootstocks, GH had better performance on all parameters. Despite the high concentration of Na+ and low K/Na ratio in the shoots, the lowest number of NL was found in GH under both salinity levels. The results indicated that salt tolerance in GH was most likely related to compartmentation of Na+ ions. Finally, accumulation of osmolytes and sodium compartmentation were considered to be the most important mechanisms in the salt tolerance of pistachio rootstocks. Full article
(This article belongs to the Special Issue Development and Cultivar Improvement of Nut Crops)
Show Figures

Graphical abstract

14 pages, 714 KiB  
Article
Phenotypic Characterisation for Growth and Nut Characteristics Revealed the Extent of Genetic Diversity in Wild Macadamia Germplasm
by Thuy T. P. Mai, Craig M. Hardner, Mobashwer M. Alam, Robert J. Henry and Bruce L. Topp
Agriculture 2021, 11(7), 680; https://doi.org/10.3390/agriculture11070680 - 19 Jul 2021
Cited by 11 | Viewed by 2775
Abstract
Macadamia is a recently domesticated Australian native nut crop, and a large proportion of its wild germplasm is unexploited. Aiming to explore the existing diversity, 247 wild accessions from four species and inter-specific hybrids were phenotyped. A wide range of variation was found [...] Read more.
Macadamia is a recently domesticated Australian native nut crop, and a large proportion of its wild germplasm is unexploited. Aiming to explore the existing diversity, 247 wild accessions from four species and inter-specific hybrids were phenotyped. A wide range of variation was found in growth and nut traits. Broad-sense heritability of traits were moderate (0.43–0.64), which suggested that both genetic and environmental factors are equally important for the variability of the traits. Correlations among the growth traits were significantly positive (0.49–0.76). There were significant positive correlations among the nut traits except for kernel recovery. The association between kernel recovery and shell thickness was highly significant and negative. Principal component analysis of the traits separated representative species groups. Accessions from Macadamia integrifolia Maiden and Betche, M. tetraphylla L.A.S. Johnson, and admixtures were clustered into one group and those of M. ternifolia F. Muell were separated into another group. In both M. integrifolia and M. tetraphylla groups, variation within site was greater than across sites, which suggested that the conservation strategies should concentrate on increased sampling within sites to capture wide genetic diversity. This study provides a background on the utilisation of wild germplasm as a genetic resource to be used in breeding programs and the direction for gene pool conservation. Full article
(This article belongs to the Special Issue Development and Cultivar Improvement of Nut Crops)
Show Figures

Figure 1

12 pages, 2396 KiB  
Article
Phenolic Response to Walnut Anthracnose (Ophiognomonia leptostyla) Infection in Different Parts of Juglans regia Husks, Using HPLC-MS/MS
by Aljaz Medic, Anita Solar, Metka Hudina and Robert Veberic
Agriculture 2021, 11(7), 659; https://doi.org/10.3390/agriculture11070659 - 13 Jul 2021
Cited by 13 | Viewed by 3234
Abstract
This study compares the individual phenolic response of husk tissues of Juglans regia L., infected to different degrees of severity with walnut anthracnose, which is one of the most serious and widespread walnut diseases worldwide. A comparison among three differently susceptible cultivars, ‘Franquette’, [...] Read more.
This study compares the individual phenolic response of husk tissues of Juglans regia L., infected to different degrees of severity with walnut anthracnose, which is one of the most serious and widespread walnut diseases worldwide. A comparison among three differently susceptible cultivars, ‘Franquette’, ‘Milotai 10’ (‘M10’), and ‘Milotai intenziv’ (‘M10-37’), is made. In our methodology, high performance liquid chromatography coupled with mass spectrometry is used to identify and quantify the compounds. Our results show that flavanols, flavonols, and naphthoquinones account for more than 95% of the phenolic compounds identified in the walnut husk. The higher total analyzed phenolic content in tissues is more affected by walnut anthracnose confirmed that phenolics play a major role in the plant’s response against pathogens. A difference between cultivars is observed, since French cultivar ‘Franquette’ responds differently to walnut anthracnose infection than Hungarian cultivars ‘M10’ and ‘M10-37’. Naphthoquinones and flavanols have a very similar response to walnut anthracnose infection. The resistance of cultivars may be due to the reaction time of the plant and the speed with which it recognizes the pathogen and responds quickly to the infection by containing it while it has not yet spread. Flavonols may be the most important phenolic compounds in disease control, since they respond more rapidly to infection than flavanols and naphthoquinones. They also play an inhibitory role in the early stages of viral and bacterial infections. Full article
(This article belongs to the Special Issue Development and Cultivar Improvement of Nut Crops)
Show Figures

Figure 1

18 pages, 2919 KiB  
Article
Almond Fruit Drop Patterns under Mediterranean Conditions
by Jaume Lordan, Lourdes Zazurca, Mercè Rovira, Laura Torguet, Ignasi Batlle, Theodore DeJong and Xavier Miarnau
Agriculture 2021, 11(6), 544; https://doi.org/10.3390/agriculture11060544 - 12 Jun 2021
Cited by 2 | Viewed by 2933
Abstract
Almond is an important tree nut crop worldwide, and planted areas have been increasing year after year. While self-fertility is one of the key factors when it comes to improved almond productivity of new cultivars, yield is also affected by the number of [...] Read more.
Almond is an important tree nut crop worldwide, and planted areas have been increasing year after year. While self-fertility is one of the key factors when it comes to improved almond productivity of new cultivars, yield is also affected by the number of flowers produced, pollination, fruit set, fruit drop, and fruit weight. Almond fruit drop patterns of 20 Mediterranean almond cultivars were studied over three years. In addition, fruit drop patterns of two scion cultivars ‘Marinada’ and ‘Vairo’ budded onto eight to 10 different rootstocks managed with three different pruning strategies were studied for two years. Cumulative flower and fruit drop ranged from 50% to 90% among cultivars and treatments, and there were up to four fruit drop events during the growing season, the main one occurring from 20–60 days from full bloom (DFFB). Subsequent drops were at 100 DFFB, 120–140 DFFB, and the last one at 160–180 DFFB. The later drops were less apparent. In general, about half of the cumulative drop was comprised of buds and flowers, and the remaining percentage was fruit that dropped 20 or more days after full bloom. Furthermore, different fruit drop patterns were observed depending on the cultivar. For late- and extra-late flowering cultivars, cumulative fruit drop began to decrease earlier, with most of the drops occurred already at full bloom, whereas the opposite was observed for the early flowering cultivars. Rootstocks also had an important effect on the fruit drop pattern, with different effects depending on the scion cultivar. Tree management, such as type of pruning, also had an important effect on the rate of fruit drop and cumulative drop. Therefore, each combination of cultivar × rootstock × pruning type will require different strategies in order to reduce the fruit drop and optimize crop loads. Full article
(This article belongs to the Special Issue Development and Cultivar Improvement of Nut Crops)
Show Figures

Figure 1

10 pages, 1416 KiB  
Article
Effects of Branch Number on Quality Traits and Yield Properties of European Hazelnut (Corylus avellana L.)
by Tuba Bak and Turan Karadeniz
Agriculture 2021, 11(5), 437; https://doi.org/10.3390/agriculture11050437 - 12 May 2021
Cited by 13 | Viewed by 2338
Abstract
Despite being the world leader in the production of hazelnuts, Turkey’s nut yield per hectare is quite behind other producer countries. The main reasons for low yield are the completion of the economic life of hazelnut orchards and the lack of pruning following [...] Read more.
Despite being the world leader in the production of hazelnuts, Turkey’s nut yield per hectare is quite behind other producer countries. The main reasons for low yield are the completion of the economic life of hazelnut orchards and the lack of pruning following the technique. Hazelnuts are being grown with the ‘ocak’ system in Turkey. The ocak system is a bush-like growing technique that does not contain the main trunk but consists of shoots instead. It is necessary to maintain the optimum number of shoots per ocak to increase yield and quality in this system. The effects of different branch numbers on yield and fruit quality parameters of ‘Tombul’ and ‘Palaz’ hazelnut cultivars were investigated in Ordu ecological conditions. ‘Palaz’ had the highest yield per ocak in 8 branches (1460.19 g), while ‘Tombul’ had in the 5 branched ocak (2170.47 g). ‘Palaz’ and ‘Tombul’ had the highest fruit weights in 4 and 4–6 branches, respectively. The highest oil ratio of ‘Palaz’ was observed in 4 branches, while ‘Tombul’ had the highest in 5 branches. The highest kernel ratio was determined in 6 and 5 branches in ‘Palaz’ and ‘Tombul’, respectively. The ocaks with 4 and 5 branches were mostly expressed higher values, and it is foreseen that the number of branches should not exceed 6 to reduce the competition of the branches and to obtain good quality products. Full article
(This article belongs to the Special Issue Development and Cultivar Improvement of Nut Crops)
Show Figures

Figure 1

Back to TopTop