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Local germplasm may be the basis for genetic improvement for sustainability and resilience, yet little is known about Greek peach [Prunus persica (L.) Batsch] local genetic resources. The aims of the present study were to entail a prospection in the mainland and islands of Greece for local traditional and underutilized germplasm and study their genetic and morphological variation and susceptibility to shoot blight from Cylindrocarpon destructans and Monilinia laxa. A total of 32 peach cultivars/accessions were prospected from the mainland (Imathia and Magnesia) and islands (Andros, Ikaria, Kythira, Lesvos and Samos) of Greece. Leaf and fruit morphological characterization was made in situ and ex situ using 42 qualitative and quantitative morphological descriptors. Nine clones of ‘Lemonato’, isolated in Magnesia, with differing ripening times, were found to vary in leaf and fruit phenotypic traits. The local peach genotypes were separated from 12 old foreign cultivars, in 8 out of the 42 leaf and fruit phenotypic traits studied. We observed greater lesion damages from C. destructans than M. laxa. Local cultivars had greater resistance to Cylindrocarpon destructans than foreign cultivars, with ‘Lemonato Andrea’, ‘Daggalakou’ and ‘Papagianni’ exhibiting the greatest resistance. Genetic characterization was performed in the studied local and foreign peach cultivars/accessions, using eight Inter Simple Sequence Repeats (ISSRs), resulting in a total of 404 bands. Analysis of molecular variance and principal coordinates analysis revealed moderate to low genetic diversity among the peach cultivars, and three distinct clusters were formed. Furthermore, multiple regression analysis was implemented for the association study between morphological traits and the ISSR markers, revealing several markers that are statistically and significantly correlated with fruits’ traits. The obtained results could be valuable for breeding programs and future research on peach.

The present study aims to generalize cultivar-specific tree phenology responses to winter and spring temperatures and assess the effectiveness of the Tabuenca test and various chill and heat accumulation models in predicting bloom dates for a wide range of climatic conditions and years. To this end, we estimated the dates of rest completion and blooming and correlated them with observed bloom dates for 14 peach and nectarine cultivars that were evaluated in 11 locations across Europe (Greece, France, Italy, Romania and Spain), within the EUFRIN cultivar testing trial network. Chill accumulation varied considerably among the studied sites, ranging from 45 Chill Portions (CP) in Murcia-Torre Pacheco (Spain) to 97–98 CP in Cuneo (Italy) and Bucharest (Romania). Rest completion occurred latest or was not achieved at all for some cultivars in the southern sites in Murcia. Dormancy release happened earliest in Bucharest and Cuneo, sites where heat accumulation had a strong influence on the regulation of bloom time. Blooming occurred earliest in the moderately cold regions of Lleida (Spain) and Bellegarde (France), and 7–11 days later in the warmer locations of Rome (Italy) and Naoussa (Greece), suggesting that bloom timing is strongly influenced by delayed rest completion in these locations. The Dynamic Model resulted in both more homogeneous chill accumulation across years and better predictions of bloom dates, compared with the Utah, Positive Utah and Chilling Hours models. Prediction of bloom dates was less successful for low-chill cultivars than for medium- and high-chill cultivars. Further climatic and experimental data are needed to make estimates of the climatic needs of peach cultivars more robust and to generate reliable advice for enhancing the resilience of peach production under varying and changing climatic conditions.

Herein, we studied the variation in leaf and fruit morphological traits and antioxidant contents in 43 local and foreign cultivars (cvs) grown under the same experimental conditions in the widely cultivated plum species Prunus domestica and Prunus salicina. The peel contribution of fruit bioactive compounds in a serving portion, correlations among the examined parameters, and group patterns in each plum species were also studied. The species and cvs were sufficiently separated. Compared to Japanese cvs, European cvs had less elongated leaves and smaller and sweeter fruit with less total phenol and antioxidant capacities. The Japanese cvs ‘Red ace’ and the widely grown ‘Black Amber’, together with the European ‘Tuleu Dulce’, ‘BlueFre’, and the landrace ‘Asvestochoriou’ make up groups with rich dietary sources of phytochemicals. The peel tissue contained higher total phenols and antioxidant capacities compared to the flesh, while the peel/flesh ratios varied widely among the cvs (6.6-fold). The variation in the antioxidant contents was lower among the cvs calculated per serving portion (3.7-fold); yet the peel tissue contribution was equal to that of the flesh (48.6%), signifying its high nutritive value. We observed increased sweetness in the fruit in the later-harvested cultivars, while cvs with more blue- and red-colored peel generally contained higher antioxidant contents mainly in the European plums. Moreover, larger fruit sizes were positively correlated with larger and more elliptic leaf shapes. In conclusion, the significant role of the genotype and the peel tissue as a source of bioactive compounds in plums were outlined with prospects of utilization in future breeding programs.

Pomegranate is one of the oldest known fruit crops, well adapted to hot and dry areas and successfully grown in Mediterranean countries. During the last two decades, numerous publications have revealed the traditionally known associations between pomegranate consumption and health benefits, which led to increased demand by consumers and expansion in cultivation areas. Pomegranate is well adapted to areas with diverse pedoclimatic conditions and local cultivars could provide an essential source of genes for breeding. In this study, fruit phenotypic and genetic variability, and relationships, were studied in 26 Greek and foreign pomegranate cultivars/accessions grown in an ex situ collection located in Naoussa Greece, using Inter Simple Sequence Repeat (ISSR) and Start Codon Targeted (SCoT) molecular markers. Results from the principal component analysis made on fruit phenotypic characters revealed five components that accounted for 74.8% of the total variance, the first being related to skin color parameters and the second to juice antioxidant contents and aril color. Clustering from phenotypic data allocated individuals into four clusters. A total of 184 bands were generated for all markers applied across the 26 pomegranate cultivars/accessions, with an average of 77 bands per ISSR markers and 82 bands for SCoT markers. Low variability in the phenotypic and genotypic level was indicated; nevertheless, results from the association study between phenotypic traits and molecular markers that were obtained using Multiple Regression Analysis (MRA) could prove valuable for marker-assisted breeding programs, especially from SCoT markers that were found to be strongly or averagely associated with the morphological traits and chemical components.