Publications

Eighty-six almond accessions of diverse geographic origin, ranging from Central Asia to the USA, were genotyped in 15 simple sequence repeat (SSR) loci to compare genetic diversity parameters, characterize genetic differentiation, and examine factors responsible for the maintenance of genetic diversity and population structure in almond. The mean allele number was 18.86 alleles per locus. All but one primer demonstrated polymorphic information content higher than 0.7. Almond genotypes clustered according to their pedigree and geographic origin. STRUCTURE analysis determined nine genetically distinct subgroups within the studied genotypes including the Kyrgyz, Akdamar, Bademli, Hungarian, Monor, Italian, Moroccan, and Californian accessions and wild species and an admixed group. An AMOVA analysis confirmed that considerable genetic variation occurred within populations (71.30%), and genetic variation among populations was also significant (28.70%). The mean values of the fixation index (FST) varied between 0.38 and 0.55, indicating marked genetic differentiation among the populations. The among-population genetic differentiation based on allele sizes (RST) was significantly higher than that based on allele identities (FST) between the most groups, suggesting that stepwise mutations have also contributed to genetic differentiation. A Mantel test and a neighbor-joining tree showed no significant correlation between the geographic distance and the genetic distance (Rxy = 0.173, P = 0.226) and indicated that geographic distance among the assessed populations has little influence on their genetic differentiation (Rxy = 0.248, P = 0.194). Our data show drift, mutations, and massive gene exchange between several wild species and cultivated P. dulcis as crucial components of genetic differentiation. Slight losses of genetic diversity are attributable to geographic isolation, human selection and not to the relatively recent occurrence of self-compatibility. There was no indication of a major decrease in genetic variability in almond germplasm from Asia to Europe. The present results reveal that almond domestication avoided the occurrence of a genetic bottleneck although its risk is present in many subpopulations.

Diploid japanese plum ( Prunus salicina Lindl.) cultivars are commonly self-incompatible. To date, 14 incompatibility alleles ( S -alleles) have been identified and labeled with alphabetical ( S a - S n ) and 5 with numeric codes ( S 1 , S 3 - S 6 ). We applied polymerase chain reaction amplification of the S -RNase alleles with degenerate and allele-specific primers in 10 japanese plum cultivars and two pluots of unknown incompatibility alleles. Besides DNA sequencing, an additional method for the exact length determination of the first intron region was used for the first time for S -genotype japanese plums. The S 3 -allele was shown to correspond to S k in the alphabetic nomenclature, S 4 to S c , S 5 to S e , and S 6 to S f . The S 5 -allele-specific primer can be used as a reliable marker for self-compatibility in japanese plum. ‘Black Amber’, ‘October Sun’, ‘TC Sun’, and ‘Super Giant’ share the S b S c genotype, which was confirmed by test crosses. These cultivars belong to the widest incompatibility group currently known in japanese plum. An additional incompatibility group ( S c S h ) was established, including ‘Green Sun’ and ‘Queen Rosa’, a cultivar formerly known as a universal donor. By incorporating all previous and recent results, a table was assembled including 49 cultivars assigned to I–VII incompatibility groups, to the self-compatible group and to the group O of unique genotypes. These data may considerably contribute to further growing and breeding activities.

The effects of zirconium ascorbate (Zr-ASC), a water-soluble complex of Zr, were examined on wheat seedlings (Triticum aestivum L. cv. MV. 20). Hydroponically grown plants were exposed to 10, 33, 55, 100 and 550 µM Zr-ASC (Zr10, Zr33etc.). After 9 d of treatment inhibition of germination, retarded root and shoot growth, and increased activities of antioxidant enzymes (guaiacol peroxidase, ascorbate peroxidase, and glutathione reductase) showed that Zr-ASC was only harmful at and over a concentration limit of 100 µM. Chlorophyll (Chl) content of plants was only decreased by Zr550. Zr-ASC at lower concentrations was beneficial for plant development: Zr10 and Zr33 enhanced root elongation, Zr55 induced about 30 % increase in the total Chl content, while the activity of antioxidant enzymes was not elevated indicating that no oxidative stress was generated by the intracellularly accumulated Zr4+ ions.

Quince (Cydonia oblonga Mill.) has been long regarded to be a health-promoting fruit. Although it is mainlyconsumed in processed form, its relatively heat-stable polyphenolics were confirmed to be responsible for most of the beneficial effects. This review aims to show basic nutritional information on quince fruit such as carbohydrate, fibre, pectin and mineral element contents. In addition, vitamin and polyphenolic contents and composition as well as the physiological effects of quince consumption were also surveyed. Information on presumable protective effects against several diseases including infl ammation, atopic dermatitis, ulcers and cancer is summarized. Potential antibacterial effects of quince polyphenolics were also considered. Polyphenolics are supposed to be responsible for the major part of benefi cial health-effects, and phenolic compounds predominantly accumulate in peel. There exists a considerable extent of genetic variation in phytochemical composition among cultivars, which might be exploited in designing future breeding programs for quince improvement and opening new ways for health-related uses.

In the present study, we identified and characterized the apricot (Prunus armeniaca L.) homologs of three dormancy-related genes, namely the ParCBF1 (C-repeat binding factor), ParDAM5 (dormancy-associated MADS-BOX) and ParDAM6 genes. All highly conserved structural motifs and the 3D model of the DNA-binding domain indicate an unimpaired DNA-binding ability of ParCBF1. A phylogenetic analysis showed that ParCBF1 was most likely homologous to Prunus mume and Prunus dulcis CBF1. ParDAM5 also contained all characteristic domains of the type II (MIKCC) subfamily of MADS-box transcription factors. The homology modelling of protein domains and a phylogenetic analysis of ParDAM5 suggest its functional integrity. The amino acid positions or small motifs that are diagnostic characteristics of DAM5 and DAM6 were determined. For ParDAM6, only a small part of the cDNA was sequenced, which was sufficient for the quantification of gene expression. The expression of ParCBF1 showed close association with decreasing ambient temperatures in autumn and winter. The expression levels of ParDAM5 and ParDAM6 changed according to CBF1 expression rates and the fulfilment of cultivar chilling requirements. The concomitant decrease of gene expression with endodormancy release is consistent with a role of ParDAM5 and 6 genes in dormancy induction and maintenance. Cultivars with higher chilling requirements and delayed flowering time showed higher expression levels of ParDAM5 and ParDAM6 toward the end of endodormancy. Differences in the timing of anther developmental stages between early- and late-flowering cultivars and two dormant seasons confirmed the genetically and environmentally controlled mechanisms of dormancy release in apricot generative buds. These results support that the newly identified apricot gene homologs have a crucial role in dormancy-associated physiological mechanisms.

Fruits are rich sources of flavonoid polyphenolic compounds that seem to be associated with favourable healtheffects. Commonalities and differences are well known in the flavonoid contents of different fruit crops, which suggest alterations in the flavonoid biosynthesis pathway of fruit tissues. This review aims to collect data from molecular genetic studies on the structural and regulatory genes in grape, berries, citrus, pomes and stone fruits to get impression on the state of the art of this field of science. Results indicate that the expression of flavonoid genes is a genotype-dependent and developmentally regulated process. In addition, genetic alterations resulting in specific changes in flavonoid composition are also highlighted. Analysis of colour mutants of grape, bilberry and orange identified the genes responsible for the altered phenotype, and this strategy might offer valuable tools to identify several other candidate genes in different fruits. The application of such data is also discussed in relation with the development of molecular markers.

Fruit crops have a growing economic importance worldwide and molecular genetics might be useful in solving many problems that arise during commercial production. One of the fields that have attracted intense attention is the molecular basis of self-incompatibility that may result in low fruit set. In tree fruits of the Rosaceae family, the incompatibility reactions take place between the pistil S-ribonuclease (S-RNase) and the pollen-expressed S-haplotype specific F-box (SFB) proteins. In most cases, the loss of self-incompatibility was associated with mutations in the S-RNase or SFB genes. A total of 27 non-functional S-haplotypes have been identified and characterized, most (24) of which emerged as a consequence of natural mutations. In the Prunoideae, most haplotypes are pollen-part mutants (50 %), while 8 are stylar-part mutants (36 %), one haplotype shows both pollen- and stylar-part mutations, and molecular changes for two haplotypes still have not been clarified. In contrast, non-functional natural haplotypes in the Maloideae are all stylar-part mutants. The analysis of such mutants may shed light on underlying molecular mechanisms as was the case with the establishment of the general inhibitor model that describes interactions between pollen and pistil S-proteins. However, several other molecules were supposed to contribute to the molecular interactions, at least in Solanaceae, a family with a similar self-incompatibility system. This review also endeavours to delineate the evolutionary implications of the S-locus mutations and collect limited data on non-S-locus molecular interactions and signaling events after self- and cross-pollination of fruit tree species.