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Girdling is an ancient agronomic technique that causes a change in the distribution of photosynthates, mineral nutrients and plant hormones. The aim of this study was to assess the effect of girdli...

The aim of this study was to analyze the mid-term influence of minimum tillage (MT) combined with early leaf removal (ELR) on the performance of the black grapevine variety Nerello Mascalese (Vitis vinifera L.). The research was carried out from 2015 to 2018 in a vineyard located in the Mount Etna area, East Sicily, Southern Italy. An average of about 8000 cm2 of leaves were removed from the ELR vines, corresponding to a canopy defoliation of 44% in 2017 and 30% in 2018. As for the stem water potential of both primary and lateral leaves, ELR-MT treatment showed the best performance (up to −0.4 MPa) among the four combinations. In 2017, no differences in yield/vine were found among treatments, whereas in 2018 the yield was significantly lower in ELR treatments. Among the different treatments performed, the ELR-MT showed the best results both in terms of physiological plant parameters (water status and photosynthetic activity) and fruit quality (higher concentration of sugars and total anthocyanins and polyphenols). ELR-MT treatment is also associated with a lower incidence of tillage operations from four to only one per year (−60–70 h/ha). In contrast to what was observed in the first 3 years of application (i.e., from 2015 to 2017), yield was heavily penalized during the fourth year of application (2018), probably due to the excessive depletion of nutritional reserves, the reduction of bud fertility and the unfavorable meteorological condition. For these reasons, the ELR-MT combination might require an interruption every 2–3 years of application.

In temperate climates, bud break and shoot and flower emission of deciduous fruit tree species are regulated by precise chilling and heating requirements. To investigate this aspect, sixty-one accessions of European pear (Pyrus communis L.) collected in Sicily were phenotyped for three consecutive years for harvest date, bud sprouting and blooming to determine both the chilling requirements and the threshold temperature using the Chill Days model. The whole germplasm collection was grown in two different experimental fields located at 10 and 850 m above sea level representing two Mediterranean-type climates in which pear is commonly cultivated. Results revealed a mean threshold temperature of 6.70 and 8.10 °C for the two experimental fields, respectively, with a mean chilling requirement ranging from −103 and −120 days. Through this approach, novel insights were gained on the differences in chilling requirement for early flowering cultivars to overcome dormancy. Furthermore, to better dissect differences in chilling requirement between accessions, the sprouting bud rate of six cultivars was assessed on excised twigs stored at 4 ± 0.1 °C from 300 to 900 h followed by a period at 25 ± 0.1 °C varying from seven to twenty-eight days. Results of both experiments highlighted that Sicilian pear germplasm is characterized by a low chilling requirement compared to other pear germplasm, making Sicilian local accessions valuable candidates to be used for selecting novel cultivars, coupling their low chilling requirements with other traits of agronomical interest.

The genus Pyrus is characterized by an S-RNase-based gametophytic self-incompatibility (GSI) system, a mechanism that promotes outbreeding and prevents self-fertilization. While the S-genotype of the most widely known pear cultivars was already described, little is known on the S-allele variability within local accessions. The study was conducted on 86 accessions encompassing most of the local Sicilian varieties selected for their traits of agronomic interest and complemented with some accessions of related wild species (P. pyrifolia Nakai, P. amygdaliformis Vill.) and some national and international cultivars used as references. The employment of consensus and specific primers enabled the detection of 24 S-alleles combined in 48 S-genotypes. Results shed light on the distribution of the S-alleles among accessions, with wild species and international cultivars characterized by a high diversity and local accessions showing a more heterogeneous distribution of the S-alleles, likely reflecting a more complex history of hybridization. The S-allele distribution was largely in agreement with the genetic structure of the studied collection. In particular, the &ldquo, wild&rdquo, genetic background was often characterized by the same S-alleles detected in P. pyrifolia and P. amygdaliformis. The analysis of the S-allele distribution provided novel insight into the contribution of the wild and international cultivars to the genetic background of the local Sicilian or national accessions. Furthermore, these results provide information that can be readily employed by breeders for the set-up of novel mating schemes.

The effect of basal zone defoliation on vines influences yield and ripening depending on the phenological stage and its intensity. Early basal defoliation (EBD) was carried out at flowering on the autochthonous Vitis vinifera (L.) cultivar ‘Nerello mascalese’ grown on the eastern slopes of Mount Etna, Sicily. The effects were evaluated over a two-year period. In the first year, the canopy retained 67 % of its original leaf area after EBD and in the second year, 58 %. Compared with control vines, mid-day leaf water potentials in the EBD vines enjoyed higher water status throughout the growing seasons in both years. EBD had no significant negative effects on yield but did have significant positive effects on the levels of total polyphenols, total flavonols and total anthocyanins. Yield and its components are conditioned by a number of factors mainly linked to climate and to the vines’ general condition during berry growth and ripening. Even after two consecutive years of treatment, EBD does not have any negative effects on yield. However, EBD does have strong positive effects on berry quality attributes as a consequence of the following: greater exposure of the cluster to sunlight, higher vine water status and avoidance of high temperature stresses in the last phase of ripening during the analysis of anthocyanin.

Background and Aims Generally, grapevine roots have been less studied than the above‐ground parts of the plant. Here we analyse scion–rootstock interactions in mature vines growing in a heavy clay soil in a climate characterised by severe summer drought to investigate the effect of the scion–rootstock interaction in a suboptimal soil. Methods and Results The rootstocks, 34 Ecole de Montpellier, 140 Ruggeri and 1103 Paulsen, were grafted onto Nerello Mascalese and Nero d'Avola scions and assessed along with self‐rooted vines. Root distribution and root architecture were analysed using the profile wall method at 0, 60 and 120 cm from the row midline. Root density was greatest at a depth between 21 and 60 cm. The cumulative root fraction for root density registered a β value, a numerical quantity that summarises depth distribution, ranging between 0.932 and 0.962. Root number and density were significantly lower for the self‐rooted vines compared to that of the grafted vines. Conclusions The scion genotypes affected most developmental parameters, including the diameter of the root system, the root density at 21–80 cm depth and the ratio of fine roots to coarse roots. Significance of the Study The scion plays an important role in grapevine root growth, development and distribution in a heavy clay soil, although the mechanism remains unclear.

Blood oranges have been cultivated in Italy since the early 19th century. Growers and breeders were able to identify and collect many somatic mutants, which differed in their major pomological traits, such as fruit size and firmness, pulp and peel pigmentation, and ripening period. Recently, in the framework of a genetic resource conservation program, most of the accessions collected at CREA in recent decades were planted in a single block to evaluate their characteristics. The presence of many selections in the same block, of the same age and grafted on the same rootstock is extremely important for a reliable characterization of the pomological characters, particularly pigmentation, which is strongly influenced by both the environment and the rootstock. The collection consists of 88 genotypes, including old lines and nucellar selections. Some commercial Tarocco, Moro and Sanguinello varieties were also included in the collection to facilitate comparison among clones. Moreover, the pomological features of 20 elite Tarocco clones cultivated nearby in the same experimental station were used as a further reference. The pomological characterization, based on 13 traits and performed in two consecutive years, revealed significant variability. Some genotypes showed strong year-to-year variability, mainly in fruit pigmentation, probably due to different climatic conditions during winter. Similarly, other traits such as fruit size, total soluble solids and acidity also varied among and within the varietal groups. These findings have a potential utility in identifying promising clones, which might fulfil the growing market needs such as higher anthocyanin content and longer shelf life.

One of the leading goals in novel breeding programs on table grapevine is the set-up of novel seedless varieties. Seedlessness has a strong impact on consumers’ choices representing an important added economic value compared to traditional cultivars. Breeding in tree crops greatly benefits from the use of molecular markers associated to a trait of interest. Nevertheless, one of the main limitations hampering marker assisted breeding is the lack of marker validation on multiple genetic backgrounds. To this extent, we evaluated the efficiency of four markers linked to seedlessness on 97 F1 genotypes derived from 16 cross combinations obtained through in vitro embryo rescue. Our results confirmed that the four markers were associated to seedlessness even though all, to a different extent, showed marker-trait inconsistencies. Marker efficiency was then tested on the different genetic backgrounds composing the entire germplasm providing a more acurate overview of the marker performances when the genetic background changes. Overall, the most efficient markers were VMC7f2 and p3_VvAGL11 even though their effectiveness changed remarkably from one genetic background to another. This work reports a marker validation assay on a germplasm created to encompass the actual allelic variability employed by breeders. The results could represent a valuable tool to guide the choice of the best markers to assist selection, a choice that should be based, more than on the absolute efficiency of the marker, on a careful evaluation of its performance on the genetic backgrounds in analysis.

The pear (genus Pyrus) is one of the most ancient and widely cultivated tree fruit crops in temperate climates. The Mount Etna area claims a large number of pear varieties differentiated due to a long history of cultivation and environmental variability, making this area particularly suitable for genetic studies. Ninety-five pear individuals were genotyped using the simple sequence repeat (SSR) methodology interrogating both the nuclear (nDNA) and chloroplast DNA (cpDNA) to combine an investigation of maternal inheritance of chloroplast SSRs (cpSSRs) with the high informativity of nuclear SSRs (nSSRs). The germplasm was selected ad hoc to include wild genotypes, local varieties, and national and international cultivated varieties. The objectives of this study were as follows: (i) estimate the level of differentiation within local varieties; (ii) elucidate the phylogenetic relationships between the cultivated genotypes and wild accessions; and (iii) estimate the potential genetic flow and the relationship among the germplasms in our analysis. Eight nSSRs detected a total of 136 alleles with an average minor allelic frequency and observed heterozygosity of 0.29 and 0.65, respectively, whereas cpSSRs allowed identification of eight haplotypes (S4 Table). These results shed light on the genetic relatedness between Italian varieties and wild genotypes. Among the wild species, compared with P. amygdaliformis, few P. pyraster genotypes exhibited higher genetic similarity to local pear varieties. Our analysis revealed the presence of genetic stratification with a 'wild' subpopulation characterizing the genetic makeup of wild species and the international cultivated varieties exhibiting the predominance of the 'cultivated' subpopulation.

Minimally processed table grapes have traditionally been used as a component of fruit salads; only recently has been taken into account the possibility of producing single-portion packages in small containers. The aim of this research was to assess the shelf-life of small table grape clusters, including some of the most utilized varieties in Italy, such as ‘Vittoria’, ‘Superior seedless®’, ‘Italia’, ‘Crimson seedless’, ‘Red Globe’ and ‘Black Pearl’, packed in polyethylene containers. Chemometric techniques including principal component analysis (PCA) and linear discriminant analysis (LDA) were carried out on six parameters to develop discriminant models. The berry firmness remained satisfactory until the 15th day of storage, especially in seedless cultivars such as ‘Superior seedless®’ and ‘Crimson seedless’. Variations of weight loss and colour were almost absent in all cultivars. A significant increase in CO2 and a decrease in O2 inside the packages were observed during the second week of storage. During the cold storage period, most of the quality parameters remained stable in all cultivars. LDA achieved satisfactory discrimination of grape fruits according to the variety and the storage time. The results indicated the possibility of packaging small clusters of table grapes that could maintain good quality parameters for a rather long storage period without excessive reduction of the antioxidant activity of the product.

Introduction . Plum cultivation in Southern Italy is of great interest due to the possibility of obtaining produce over an extended period using early and late varieties. The objective of this study was to choose the best combination of cultivars and rootstock to make the production period as long as possible. Materials and methods. The influence of two rootstocks i.e. Myrobalan 29C (Prunus cerasifera Ehrn.) and Montclar® [Prunus persica (L.) Batsch] on growth, yield and fruit quality of nine Japanese and three European plum cultivars was evaluated. Results and discussion. Four years after planting, the trees on Montclar® rootstock displayed higher vigour. The highest yield was recorded on Shiro and Obilnaya grafted on both rootstocks. Black Amber produced the largest fruit and Obilnaya the smallest. Conclusion. This research contributed to identifying the most promising cultivars to be successfully grown in Southern Italy.

The integration of Agroecological Service Crops (ASCs) into agroecosystems can provide several ecological services, such as nutrient cycling and disease and weed management. A two-year experiment on an organic orchard was carried out to compare barley (B) and horse bean (HB) ASCs with a control without ASC (Cont) in combination with fertilizers. Their effects on soil fertility and weed- and soil-borne fungi communities were evaluated by direct measurements, visual estimation, and indicators computation. A Principal Component Analysis (PCA) was used to identify latent patterns and redundancy among variables, whereas a correlation analysis was used to discriminate the compared systems within the PCA matrix. The empirical results of this study put in evidence the correlation among soil, weed, and fungal variables. A slight contribution of fertilizers on the system&rsquo, s variability was observed, whereas a clear effect of ASCs was highlighted. The systems differed in weed communities, with the lowest density associated to B and the highest to Cont. B showed the highest fungal diversity, with changes in community compared to HB. HB showed a contribution on soil fertility, being associated to organic matter increase and N availability, and evidencing mixed impacts on soil quality and ecosystem functioning. Overall, the above-ground diversity and below-ground community results were inter-correlated.

The effect of minimum tillage on two autochthonous Vitis vinifera L. varieties, namely Nerello mascalese and Carricante, established on the eastern and northern aspect slopes of the volcano Mount Etna in Sicily, was evaluated over two seasons. The objective was to determine whether conventional tillage and minimum tillage affect the vegetative growth, bud fertility, total leaf area, leaf nutritional status and fruit yield components. The ratio of bunches/retained buds was strongly influenced by aspect. Yield per vine was significantly different within cultivars and seasons depending on cultivar, tillage treatment and aspect. Due to its natural plasticity in marginal conditions, yields were consistently higher in Nerello mascalese. The yield reduction with minimal tillage was excessive in Carricante. As a consequence of the yield reduction in the second season, total soluble solids in particular were increased in Nerello mascalese. Linear discriminant analysis revealed the highest discrimination va...

Early leaf removal is an innovative viticultural practice for regulating yield components and improving grape quality. Direct sunlight interception by fruit has been associated with improved fruit quality and is generally desirable to some degree in most vineyards. The effects of early defoliation on four indigenous and international grapevines in Sicily were monitored. The experiment was conducted in a commercial Vitis vinifera L. vineyard located in the Ragusa district of Sicily over two consecutive years (2010 and 2011). The grapevines studied were Frappato, Nero d’Avola, Syrah and Cabernet Sauvignon grafted onto 140 Ru. rootstock. The treatments consisted of a control (no leaf removal) and of their removal from the cordon up to the leaf of the last cluster per shoot. Leaf removal at the earlier stages of cluster development appears to be an effective strategy in order to obtain smaller clusters and, therefore, control the vine crop load when coupled with other agronomic strategies.