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Loss of genetic variability is an increasing challenge in tree breeding programs due to the repeated use of a reduced number of founder genotypes. However, in almond, little is known about the genetic variability in current breeding stocks, although several cases of inbreeding depression have been reported. To gain insights into the genetic structure in modern breeding programs worldwide, marker-verified pedigree data of 220 almond cultivars and breeding selections were analyzed. Inbreeding coefficients, pairwise relatedness, and genetic contribution were calculated for these genotypes. The results reveal two mainstream breeding lines based on three cultivars: "Tuono", "Cristomorto", and "Nonpareil". Descendants from "Tuono" or "Cristomorto" number 76 (sharing 34 descendants), while "Nonpareil" has 71 descendants. The mean inbreeding coefficient of the analyzed genotypes was 0.041, with 14 genotypes presenting a high inbreeding coefficient, over 0.250. Breeding programs from France, the USA, and Spain showed inbreeding coefficients of 0.075, 0.070, and 0.037, respectively. According to their genetic contribution, modern cultivars from Israel, France, the USA, Spain, and Australia trace back to a maximum of six main founding genotypes. Among the group of 65 genotypes carrying the Sf allele for self-compatibility, the mean relatedness coefficient was 0.125, with "Tuono" as the main founding genotype (24.7% of total genetic contribution). The results broaden our understanding about the tendencies followed in almond breeding over the last 50 years and will have a large impact into breeding decision-making process worldwide. Increasing current genetic variability is required in almond breeding programs to assure genetic gain and continuing breeding progress.

BACKGROUND:The outer peels of pomegranate (Punica granatum L.) possess two groups of polyphenols that have health beneficial properties: anthocyanins (ATs, which also affect peel color); and hydrolysable tannins (HTs). Their biosynthesis intersects at 3-dehydroshikimate (3-DHS) in the shikimate pathway by the activity of shikimate dehydrogenase (SDH), which converts 3-DHS to shikimate (providing the precursor for AT biosynthesis) or to gallic acid (the precursor for HTs biosynthesis) using NADPH or NADP+ as a cofactor. The aim of this study is to gain more knowledge about the factors that regulate the levels of HTs and ATs, and the role of SDH. RESULTS:The results have shown that the levels of ATs and HTs are negatively correlated in the outer fruit peels of 33 pomegranate accessions, in the outer peels of two fruits exposed to sunlight, and in those covered by paper bags. When calli obtained from the outer fruit peel were subjected to light/dark treatment and osmotic stresses (imposed by different sucrose concentrations), it was shown that light with high sucrose promotes the synthesis of ATs, while dark at the same sucrose concentration promotes the synthesis of HTs. To verify the role of SDH, six PgSDHs (PgSDH1, PgSDH3-1,2, PgSDH3a-1,2 and PgSDH4) were identified in pomegranate. The expression of PgSDH1, which presumably contributes to shikimate biosynthesis, was relatively constant at different sucrose concentrations. However, the transcript levels of PgSDH3s and PgSDH4 increased with the accumulation of gallic acid and HTs under osmotic stress, which apparently accumulates to protect the cells from the stress. CONCLUSIONS:The results strongly suggest that the biosynthesis of HTs and ATs competes for the same substrate, 3-DHS, and that SDH activity is regulated not only by the NADPH/NADP+ ratio, but also by the expression of the PgSDHs. Since the outer peel affects the customer's decision regarding fruit consumption, such knowledge could be utilized for the development of new genetic markers for breeding pomegranates having higher levels of both ATs and HTs.

Pomegranate (Punica granatum L.) is an important and interesting fruit tree that is cultivated in many parts of the world. In recent years, along with the increase in its cultivation and consumption there has been a dramatic increase in the scientific interest in its biology, methods of cultivation, adaptation to environmental cues and its health-promoting properties. Quite a large proportion of the various metabolites produced in the pomegranate were determined and their content in the bark, roots, leaves, and fruit was reported. Many reviews on polyphenolic compound content, antioxidant activity and health-promoting compounds were published recently. However, only very few recent reports were dedicated to primary metabolites, despite the fact that much work was done on organic acids, sugars, proteins, lipids, and amino acids of the pomegranate fruit. In this review, a special effort was made to present these recent studies and the review is devoted to primary metabolites. The reported data show high variation in the content of primary metabolites within the pomegranate fruit; therefore the data is presented (whenever possible) according to fruit tissues (peel, arils, and seeds), developmental stages of the fruit, environmental and climatic conditions, and genetic background. Most of the data on pomegranate is based on metabolic content and contains no genetic or molecular analysis except for work done on anthocyanins and hydrolyzable tannins. In those cases, gene assignment and genetic control studies were pointed out in the review. The recent publication of the genome sequences from several pomegranate varieties and transcriptomic data from fruits, flowers, and leaves is expected to facilitate the understanding of genetic control of metabolites in pomegranate.

Commercial production of apricot is severely affected by sensitivity to climatic conditions, an adaptive feature essential for cycling between vegetative or floral growth and dormancy. Yield losses are due to late winter or early spring frosts and inhibited vegetative or floral growth caused by unfulfilled chilling requirement (CR). Two apricot cultivars, Perfection and A.1740, were selected for high and low CR, respectively, to develop a mapping population of [F.sub.1] individuals using a two-way pseudo-testcross mapping strategy. High-density male and female maps were constructed using, respectively, 655 and 592 markers (SSR and AFLP) spanning 550.6 and 454.9 cM with average marker intervals of 0.84 and 0.77 cM. CR was evaluated in two seasons on potted trees forced to break buds after cold treatments ranging from 100 to 900 h. A total of 12 putative CR quantitative trait loci (QTLs) were detected on six linkage groups using composite interval mapping and a simultaneous multiple regression fit. QTL main effects of additive and additive x additive interactions accounted for 58.5% ± 6.7% and 66.1% ± 5.8% of the total phenotypic variance in the Perfection and A.1740 maps, respectively. We report two apricot high-density maps and QTLs corresponding to map positions of differentially expressed transcripts and suggested candidate genes controlling CR. Key words: dormancy, budbreak, peach, QTL. La production commerciale de l'abricot est grandement affectee par sa sensibilite aux conditions climatiques, une caracteristique adaptative essentielle pour alterner entre les phases de croissance vegetative ou floraison et de dormance. Des baisses de rendement sont enregistrees lorsque surviennent des gelees a la fin de l'hiver ou au debut du printemps ou encore lorsque le froid necessaire pour lever la dormance (CR) n'est pas obtenu, ce qui entraine une inhibition de la croissance vegetative et de la floraison. Deux cultivars de l'abricotier, Perfection et A.1740, ont ete choisis en raison de leur grande et faible exigence en froid, afin de developper une population de cartographie [F.sub.1] a l'aide d'une strategie de pseudo-testcross reciproque. Des cartes male et femelle a haute densite ont ete produites avec respectivement 655 et 592 marqueurs (SSR et AFLP), s'etendant sur 550,6 et 454,9 cM pour une distance moyenne de 0,84 et 0,77 cM. L'exigence en froid a ete evaluee sur deux saisons sur des arbres cultives en pots et dont le debourrement des bourgeons a ete force apres des traitements au froid variant entre 100 et 900 h. Au total, 12 QTL putatifs pour l'exigence en froid ont ete detecte s sur six groupes de liaison par analyse composite des intervalles et une regression multiple simultanee. Les effets principaux des composantes additives et des interactions additive x additive expliquaient 58,5 [+ o -] 6,7 % et 66,1 [+ o -] 5,8 % de la variance phenotypique au sein des cartes respectives de Perfection et A.1740. Les auteurs rapportent deux cartes genetiques a haute densite pour l'abricotier ainsi que des QTL dont la position coincide avec celle de transcrits exprimes de manie re differentielle, ce qui en fait des genes candidats pour le controle de l'exigence en froid pour lever la dormance. Mots-cles: dormance, debourrement des bourgeons, peche, QTL. [Traduit par la Redaction], Introduction Apricots, like other temperate stone fruit crops, are grown in climates with well-differentiated seasons where species have adapted mechanisms to survive low winter temperatures and frost damage (Ruiz et [...]