Peach Genotypes Research Articles

Seleção de genótipos de pessegueiro F1 com baixa necessidade de frio hibernal

A baixa necessidade de frio é característica fundamental para que se possa cultivar economicamente o pessegueiro em condições de clima subtropical, devendo ser este, portanto, o principal objetivo dos programas de melhoramento nestas regiões. o objetivo deste trabalho foi avaliar e selecionar progênies de pessegueiro com baixa necessidade de frio hibernal por meio do método de ramos destacados e indicar o melhor genitor para utilização em programas de melhoramento, visando a esta característica. Foram avaliados 180 genótipos pertencentes a 25 populações de pessegueiro, sendo que o número de genótipos em cada população variou de três a dezenove. os ramos foram submetidos a 50; 100; 150; 200 e 400 unidades de frio, e, ao término de cada tratamento, os ramos foram transferidos para o interior da casa de vegetação. Após 21 dias, foram avaliados quanto às porcentagens de floração e brotação,e com os resultados obtidos, 5 populações e 29 genótipos de pessegueiro com baixa necessidade de frio hibernal foram selecionados. A cultivar Real mostrou-se eficiente na obtenção de pessegueiros com baixa necessidade de frio hibernal, quando utilizada como genitor feminino.

Evaluation of the Antioxidant Capacity, Phenolic Compounds, and Vitamin C Content of Different Peach and Nectarine [Prunus persica (L.) Batsch] Breeding Progenies

Antioxidant capacity and contents of total phenolics, anthocyanins, flavonoids, and vitamin C were evaluated in 218 genotypes from 15 peach and nectarine breeding progenies. Significant differences were found among progenies on the fruit antioxidant profile, corroborated by the high contribution showed by cross to the phenotypic variance of each phytochemical trait analyzed (16-45%). Phytochemical profile varied depending on peach/nectarine and yellow/white flesh color qualitative traits. On the other hand, no significant effect of year was found on the bioactive profile of peaches and nectarines. Antioxidant capacity was linearly correlated to total phenolic content, but correlation varied depending on the progeny. No correlation was found for vitamin C versus any other phytochemical trait. The results suggest the importance of genetic background on the antioxidant profile of peaches and nectarines and stress its relevance for the ultimate objective of this work: selecting new peach and nectarine genotypes rich in bioactive compounds to benefit consumer's health.

Tolerância de frutos de pessegueiro a geadas

Este trabalho teve como objetivo avaliar a tolerância de frutos de pessegueiro aos danos ocasionados pela geada. A geada ocorreu no dia 5 de setembro de 2006, sendo que a temperatura mínima, a 1,5 m do solo, foi de - 1,06ºC. Foram avaliados 28 genótipos de pessegueiro em diferentes estádios fenológicos. O delineamento experimental foi o inteiramente casualizado, com três repetições (plantas de pessegueiro), procedendo-se à avaliação em seis ramos por planta. No dia em que ocorreu a geada, foram mensurados o número de frutos por ramo, diâmetro sutural médio dos frutos, número total de gemas vegetativas, percentual de brotação e percentual de brindilas formadas a partir das gemas brotadas. Uma segunda avaliação foi realizada 15 dias após a primeira, para avaliar o percentual de queda de frutos e o diâmetro sutural médio dos frutos remanescentes. Genótipos bem enfolhados e cujos frutos apresentavam endocarpo endurecido, no momento da ocorrência da geada, foram tolerantes ao dano ocasionado pelo frio; frutos com diâmetro sutural inferior a 20 mm foram suscetíveis à geada, enquanto frutos com diâmetro sutural superior a 30 mm apresentaram boa tolerância, independentemente do genótipo avaliado.

Comparative analysis of expressed sequence tags from tissues in ripening stages of peach (Prunus persica L. Batsch)

Expressed sequence tag (EST) represents a resource for gene discovery, genome annotation and comparative genomics in plants. ESTs were derived by sequencing clones from five libraries created from two different fruit tissues (skin and mesocarp), at four ripening stages (from post-allegation to post-climacteric) in three different genotypes of peach (OroA, Bolero and Suncrest). A total of 10,847 EST sequences were produced (dataset A); in addition, 21,857 peach ESTs (dataset B) were obtained from public databases. Clustering and assembly of both datasets gave 17,858 unigenes. Analysis of the sequences allowed the assignment of a putative function to 70.8% of the ESTs. In order to define the relationship among fruit tissues transcriptome, a gene ontology analysis was performed. Differences among organs and among different maturation stages of the same organs were identified in organelle, signal transducer and antioxidant activity. A distance matrix of pairwise correlation coefficients analysis was applied between the libraries. Shoot appeared to outgroup and our analysis proved to be an efficient tool to parallel and complement gene expression studies (for example, based on microarray analysis). We conducted an analysis of the frequency of genes putatively involved in the metabolism of some volatiles, which pointed to a predominant presence of those transcripts in the skin. The metabolic pathways of esters and lactones were selected for further isolation and cloning of key genes. The EST database is available at the web site www.itb.cnr.it/estree.

Abundance and Consumption Rate of Glassy-Winged Sharpshooter (Hemiptera: Cicadellidae) on Peaches and Plums

Homalodisca vitripennis (Germar), the glassy-winged sharpshooter, is a primary vector of phony peach and plum leaf scald diseases caused by Xylella fastidiosa Wells et al. A survey of H. vitripennis on peach [Prunus persica (L.) Batsch] varieties established that leafhopper abundances varied from 0–13 per tree. Prunus persica cvs. Flordaking and June Gold and Prunus salicina Lindl. (cvs. Methley and Santa Rosa) were then budded on each of 3 P. persica rootstocks (cvs. Aldrighi, Lovell and Nemaguard). Leafhopper abundance was monitored on each of the two scions budded on each rootstock and on non budded rootstocks over a 2-yr period. The genotypes were container-grown in Year 1 and were planted in the field in Year 2. For both years leafhopper abundance was greatest during early June and on Methley and Santa Rosa cultivars compared with the peach genotypes. The feeding rates of leafhoppers were substantially higher on plum scions than on peach scions, and nocturnal feeding rates were often higher than daytime feeding rates. Mean leafhopper feeding rates were correlated with leafhopper abundance on Prunus genotypes from 3–8 June in a quadratic manner (F = 53.8; df = 2,12; R2 = 0.90; P < 0.0001); the mean nighttime feeding rate was best correlated linearly to mean cumulative leafhopper abundance (F= 446.9; df = 1,13; R2 = 0.972; P < 0.0001).

Qualidade pós-colheita de pêssegos de cultivares e seleções produzidos na microrregião de Jaboticabal-SP

O objetivo deste trabalho foi avaliar a qualidade pós-colheita de pêssegos das cultivares 'Aurora-1' e 'Régis' e das seleções 'Jab 484' e 'Jab 694', produzidos na microrregião de Jaboticabal-SP. As plantas foram enxertadas no porta-enxerto 'Okinawa', propagado por sementes, mantidas em condições de campo em Argissolo Vermelho-Amarelo eutrófico de textura arenosa média e conduzidas no espaçamento 6 x 4m. No segundo e terceiro anos após o transplantio das mudas (2005 e 2006), procedeu-se à colheita dos frutos no estádio maduro, conforme a época de maturação e a coloração de cada genótipo. No laboratório, foram realizadas análises de coloração (luminosidade, ângulo de cor e cromaticidade) do epicarpo e mesocarpo, firmeza, teor de sólidos solúveis e acidez titulável, além do índice de maturação. Adotou-se o delineamento experimental inteiramente casualizado, com quatro tratamentos e seis repetições de quatro frutos. Nas condições experimentais adotadas, conclui-se que os frutos da cultivar Aurora-1 apresentam epicarpo avermelhado (menor ângulo de cor), menor acidez e maior índice de maturação (gosto); dentre os genótipos de dupla finalidade, as seleções 'Jab 484' e 'Jab 694' apresentam frutos com maiores teores de sólidos solúveis e acidez titulável, conferindo-lhes melhor característica para a industrialização.

SUITABILITY OF DIFFERENT VINEYARD PEACH GENOTYPES FOR GENERATIVE ROOTSTOCKS PRODUCTION

ISHS XXVII International Horticultural Congress - IHC2006: International Symposium on Seed Enhancement and Seedling Production Technology SUITABILITY OF DIFFERENT VINEYARD PEACH GENOTYPES FOR GENERATIVE ROOTSTOCKS PRODUCTION

Version VI of the ESTree db: an improved tool for peach transcriptome analysis

BackgroundThe ESTree database (db) is a collection of Prunus persica and Prunus dulcis EST sequences that in its current version encompasses 75,404 sequences from 3 almond and 19 peach libraries. Nine peach genotypes and four peach tissues are represented, from four fruit developmental stages. The aim of this work was to implement the already existing ESTree db by adding new sequences and analysis programs. Particular care was given to the implementation of the web interface, that allows querying each of the database features.ResultsA Perl modular pipeline is the backbone of sequence analysis in the ESTree db project. Outputs obtained during the pipeline steps are automatically arrayed into the fields of a MySQL database. Apart from standard clustering and annotation analyses, version VI of the ESTree db encompasses new tools for tandem repeat identification, annotation against genomic Rosaceae sequences, and positioning on the database of oligomer sequences that were used in a peach microarray study. Furthermore, known protein patterns and motifs were identified by comparison to PROSITE. Based on data retrieved from sequence annotation against the UniProtKB database, a script was prepared to track positions of homologous hits on the GO tree and build statistics on the ontologies distribution in GO functional categories. EST mapping data were also integrated in the database. The PHP-based web interface was upgraded and extended. The aim of the authors was to enable querying the database according to all the biological aspects that can be investigated from the analysis of data available in the ESTree db. This is achieved by allowing multiple searches on logical subsets of sequences that represent different biological situations or features.ConclusionsThe version VI of ESTree db offers a broad overview on peach gene expression. Sequence analyses results contained in the database, extensively linked to external related resources, represent a large amount of information that can be queried via the tools offered in the web interface. Flexibility and modularity of the ESTree analysis pipeline and of the web interface allowed the authors to set up similar structures for different datasets, with limited manual intervention.

Variability of vineyard peach tree characteristics

Vineyard peach seedlings are the most important rootstock for peach in Serbia and abroad. High variability is a characteristic of the vineyard peach planting material that is used as rootstock in nursery production. Through work of many years, vineyard peach genotypes with qualitative traits were selected and collected. Seedlings that are progeny of the nine selected genotypes and resulted from self and open pollination were examined. The vineyard peach seedlings resulted from uncontrolled pollination and with different geographical origin served as reference. A goal of research was to get vineyard peach genotypes that would give more uniform generative progeny with qualitative traits. This paper presents the results of two-year research of morphological traits of more than 500 vineyard seedlings. Based on the results, positive genotypes were selected for further inbreeding. Further, the seedlings of the selection 6 have the lowest coefficients of variation for trunk thickness, tree height and number of branches, which points to the self-pollination as a good method for getting more uniform progeny. .

Is competition between mesocarp cells of peach fruits affected by the percentage of wild species genome?

The number of cells and the mean cell volume in the mesocarps of fruits from peach genotypes with different percentages of the genome of Prunus davidiana, a wild, related, species, were evaluated. The mesocarp mass varied greatly between the four groups of genotypes. The mean cell volume and the number of cells were negatively correlated within each group. This correlation can be interpreted as a relationship of competition between cells. In order to describe the type of competition in the different groups, we tried to adjust a model of competition for resources proposed by Lescourret and Génard (Ecoscience 10:334-341, 2003). To estimate the values of the three parameters of the model for the different groups, we applied model selection. Within nested models, we identified a single best model with six parameter values. This model was roughly accurate, but it allowed us to describe the general relationship for each group. The parameter values revealed a strong and under-compensating density-dependence effect for all groups. The percentage of P. davidiana genome appeared to influence the maximal number of cells and the strength of the competition, but no effect was found on the maximal mean volume of cells.

EFFICIENCY OF PRUNUS TRANSFORMATION FOR PPV-RESISTANCE BY GENE SILENCING AND PPV COAT PROTEIN GENE STRATEGIES

ISHS XXVII International Horticultural Congress - IHC2006: International Symposium on Plant Biotechnology: From Bench to Commercialization EFFICIENCY OF PRUNUS TRANSFORMATION FOR PPV-RESISTANCE BY GENE SILENCING AND PPV COAT PROTEIN GENE STRATEGIES

THE INFLUENCE OF GENOTYPE ON THE INDUCTION OF SOMATIC EMBRYOS FROM IN VITRO CULTURED ZYGOTIC EMBRYOS AND ADVENTITIOUS SHOOT REGENERATION FROM COTYLEDONS OF PEACH AND NECTARINE

Genotype-independent transformation of peach (Prunus persica (L.) Batsch) is difficult to achieve, primarily due to its high recalcitrance to produce adventitious shoots or somatic embryos in vitro. In spite of sporadic reports of adventitious shoot organogenesis or somatic embryogenesis from peach tissue cultures, there is no universal method for peach regeneration that can be reliably used for peach transformation. In order to determine the relative efficacy of regenerative competence in peach, one to three mm long immature zygotic embryos excised from 25 peach and nectarine genotypes were cultured on Raj Bhansali et al. (1990) medium containing 2,4-dichloro phenoxy acetic acid (2,4-D). Somatic embryos were produced from 23 peach and nectarine genotypes, but the number of explants forming somatic embryos varied widely between genotypes. In general, those zygotic embryos that were small in size produced the highest numbers of somatic embryos. Accordingly, zygotic embryos of 1 mm in size are more regenerative than 2 or 3 mm in size. Thirty-seven percent of 1 mm size zygotic embryos produced somatic embryos, whereas only 27 percent of 2 mm and 16 percent of 3 mm size zygotic embryos produced somatic embryos. Among genotypes, high percentages of somatic embryos were obtained from 'Bell of Georgia', 'Bailey', 'Tennessee Natural' and 'Nemaguard'. Besides 2,4-D, other synthetic auxins such as dicamba (3,6-dichlo-o-anisic acid), picloram (4-amino 3,5,6-trichloroapicolinic acid), and centrophenoxine (4-chlorophenoxyacetic acid 2-dimethylaminoethyl ester) also induced somatic embryogenesis from zygotic embryos of 'Encore'. A 1-week pre-culture of 5-7 mm long cotyledons in dark on MS (Murashige and Skoog, 1962) medium + 5 μM 2,4-D + 0.5 μM benzyladenine (BA) followed by subculture onto MS + 12.5 μM thidiazuron (TDZ) + 0.4 μM α-naphthaleneacetic acid (NAA) induced adventitious shoots upon transfer to light in the peach genotypes 'Bounty' and 'Bailey'.

The effects of the parents’ genotype on susceptibility to leaf curl (Taphrina deformans (Berk.) Tul) of vineyard peach hybrid seedlings

Leaf curl is one of the peach diseases with the most economically important impact, because very strong infection can cause total defoliation. Susceptibility to a leaf curl was examined from the period 1994-1998 in a collection of selected vineyard peach genotypes and newly peach and nectarine cultivars. Selected low susceptible genotypes (vineyard peach GR/65/87 and processing peach Villa Ada) were used in cross-pollination with differently susceptible genotypes. The process produced more than 250 seedlings of F1 progeny from few combinations of the parents. Susceptibility of hybrid seedlings to the leaf curl pathogen was investigated several years in the open field, without application of pesticide. More types of inheritance of examined characteristic were determinate in the progenies from different combinations of the parents. The results agree with polygenic inheritance. .

A set of EST‐SSRs isolated from peach fruit transcriptome and their transportability across Prunus species

AbstractTwenty‐one expressed sequence tag–simple sequence repeat (EST–SSR) markers were developed in peach from a mesocarp cDNA library. Eighteen of them gave successful amplification in 22 peach genotypes and produced one to three alleles each with an average of 1.8 alleles per locus. The average value of expected and observed heterozygosities was 0.24 and 0.20, respectively. All the primers gave successful amplification in other six Prunus species (almond, apricot, sweet cherry, Japanese plum, European plum and Prunus ferganensis).

(267) The Effects of Media Types on Rescued Peach Embryos

A major obstacle faced by programs that breed early-ripening peach cultivars [Prunus persica (L.) Batsch] is the low viability of the embryos from the early-ripening parents that are used as females. Embryo culture techniques have been developed to allow embryos to mature in vitro, thus increasing the chances of germination and survivability. Several media types exist for Prunus embryo culture. Two types, Woody Plant Medium (WPM) and Smith, Bailey, and Hough (SBH) were investigated for this report. The WPM type was studied in two forms, one made from scratch and the other in a prepackaged form. The SBH type was studied with the addition of vitamins and without vitamins. Eight peach genotypes with embryo lengths ranging from 9.6 to 12.7 mm were used. Surprisingly enough, it was found that WPM from scratch performed better than WPM from a prepackaged mix. For all eight genotypes studied, WPM from scratch resulted in as good as or better germination than SBH with or without vitamins. A large media by genotype effect was found, which is partially attributed to the embryo size. The genotypes with larger embryos (>11 mm) tended to perform equally on all media tested whereas the embryos <10.5 mm germinated better on WPM as compared to SBH.

Changes in endopolygalacturonase levels and characterization of a putative endo‐PG gene during fruit softening in peach genotypes with nonmelting and melting flesh fruit phenotypes

The changes in endopolygalacturonase (endo-PG) levels and endo-PG expression in nonmelting flesh (NMF) and melting flesh (MF) peach fruits (Prunus persica) during softening were studied. The endo-PG gene was analysed to identify polymorphisms exploitable for early marker-assisted selection (MAS) of flesh texture. The role of endo-PG in softening was assessed by western and northern blotting and by biochemical analyses. Polymorphisms in the endo-PG gene were revealed by reverse transcription-polymerase chain reaction (RT-PCR) and sequencing. An endo-PG protein was detected in both NMF and MF fruits. The levels of this endo-PG protein were higher and increased with softening in MF fruits, but remained lower and were constant in NMF fruits. The different levels of endo-PG appeared to be caused by the differential expression of an endo-PG gene, whose open-reading frame (ORF) showed five single nucleotide polymorphisms (SNPs) in NMF 'Oro A' compared with MF 'Bolero'. One of these SNPs allowed us to determine the allelic configuration at the melting flesh (M) locus and also seemed to be exploitable for early MAS in other NMF/MF phenotypes. The NMF phenotype does not seem to be caused by a large deletion of the endo-PG gene.

Genotypic variation in induced resistance and induced susceptibility in the peach‐Myzus persicae aphid system

In response to herbivore damage or stress, plants may express physiological or morphological changes known as induced responses. We tested whether previous herbivory by the aphid Myzus persicae differentially altered the expression of resistance and susceptibility among five genotypes of peach that differ in their resistance phenotype (avoidance resistance, antibiosis resistance or susceptibility). We measured behavioural and performance parameters of aphid success on plants previously infested by conspecifics as compared to uninfested controls. Significant variation was found both among genotypes and among resistance phenotype, including between genotypes showing a same resistance phenotype. Genotypes with avoidance resistance showed either induced resistance to aphid settling or no response. Genotypes with antibiosis resistance showed induced susceptibility to aphid settling, but the effects of previous herbivory on aphid development were either positive or negative depending on the genotype. In the susceptible genotype, most parameters of aphid settlement and performance, including reproduction, were positively influenced by previous herbivory. Using electronic recording, the aphid probing behaviour was examined to tentatively identify host plant tissues most likely to play a role in induced defenses. Probing behaviour was significantly affected by plant genotype, previous herbivory, and their interaction, indicating complex relations between the two factors. In the genotypes with avoidance resistance, aphids were deterred before they reach the phloem. In the genotypes expressing susceptibility or antibiosis resistance, previous herbivory triggered instead the induction of a phloem‐mediated response, that however diverged depending on the resistance status (facilitation or reduction of phloem sap uptake respectively). Genotypic variation in induction found in the peach‐M. persicae system establishes a useful framework to improve our knowledge of the ecological role of induced plant responses to aphids.

Comparison of flower bud development in almond, apricot and peach genotypes

The phenological processes of flower bud development of stone fruits during dormancy are not thoroughly known. The yield of these species, especially of almond, apricot and peach is determined basically by dormancy of flower buds, the survival rate of buds during winter frosts and by their ability to develop normal floral organs in the next spring. After the initiation of floral primordia, flower bud development is taking place in continuous space until blooming, though at different speed characteristic to the species. To study flower bud development during dormancy we applied two alternative methods in different genotypes of almond, apricot and peach: (1) examination of pollen development (microsporogenesis), and (2) the measurement of pistil length. The samples were collected from the central part of Hungary during the dormancy period of 2004/2005. The three fruit species differed significantly in the speed of flower bud development, it was the quickest in almond, followed by apricot and peach. In addition to the species, there were significant differences in the process of microsporogenesis and pistil development between genotypes within species and also between the different types of shoots on which the buds were located. On short shoots buds developed at a higher speed, than on long shoots. Based on our observations, on the short shoots the period of endodormancy was shorter with 5-30 days, according to genotypes, compared to the long shoots. This difference, however, decreased to 2-3 days by the time of blooming.

Variabilidad anatómica de los sistemas de conducción y estomático de genotipos de Prunus spp. de diferentes orígenes

El propósito de esta investigación fue estudiar las relaciones ambientales de disponibilidad de humedad, con las características anatómicas del sistema de conducción de agua y estomático, en cinco genotipos de duraznos mexicanos con diferentes orígenes (Jalatzingo y Misantla, Veracruz; Temascaltepec, México; Tulancingo, Oaxaca; Sombrerete, Zacatecas), un almendro y el portainjerto Nemaguard. Fueron caracterizados anatómicamente brotes, hojas y estomas de plántulas de seis meses de edad, mediante 25 caracteres. El almendro y el portainjerto Nemaguard presentaron diferencias con respecto a los duraznos, los cuales tuvieron mayor similitud, aunque mantuvieron una separación acorde con su origen. Los caracteres que diferenciaron los grupos fueron: densidad estomática, grosor de la epidermis superior, número, frecuencia y perímetro de vasos, el índice de vulnerabilidad de la nervadura central, y el porcentaje de médula, xilema y floema del brote. Las condiciones de disponibilidad de humedad del origen presentaron fuerte asociación con las características anatómicas estudiadas, debido a que los ambientes con mayor déficit de humedad (Tulancingo y Sombrerete) presentaron mayor tamaño y menor frecuencia de vasos de xilema, así como bajo porcentaje de xilema y floema en brote, lo que puede interpretarse como adaptaciones de resistencia a sequía. La zona donde es rara la ocurrencia de sequía (Jalatzingo) presentó características opuestas.

Evaluation of transformation in peach Prunus persica explants using green fluorescent protein (GFP) and beta-glucuronidase (GUS) reporter genes

To determine the optimum conditions for Agrobacterium-mediated gene transfer, peach explants including cotyledons, embryonic axes and hypocotyl slices from non-germinated seeds and epicotyl internode slices from germinating seeds were exposed to Agrobacterium-mediated transformation treatments. The GUS (uidA) marker gene was tested using two different A. tumefaciens strains, three plasmids and four promoters [CaMV35s, (Aocs)3AmasPmas (“super-promoter”), mas-CaMV35s, and CAB]. GFP was tested with six A.␣tumefaciens strains, one plasmid (pLC101) and the doubleCaMV35s (dCaMV35s) promoter. The CaMV35s promoter produced more GUS expression than the CAB promoter. A. tumefaciens strains EHA105 and LBA4404 harboring the same plasmid (pBIN19) differed in their effects on GUS expression suggesting an interaction between A. tumefaciens strain and plasmid. A combination of A. tumefaciens EHA105, plasmid pBIN19 and the CaMV35s promoter produced the highest rates of transformation in peach epicotyl internodes (56.8%), cotyledons (52.7%), leaves (20%), and embryonic axes (46.7%) as evaluated by the percentage of explants expressing GUS 14 days after co-cultivation. GFP expression under the control of the dCaMV35s promoter was highest for internode explants but only reached levels of 18–19%. When GFP-containing plasmid pCL101 was combined with each of five A. tumefaciens strains the highest levels of transformation were 20–21% (internode and cotyledons, respectively). When nine peach genotypes were co-cultivated with A. tumefaciens strain EHA105 and GFP-containing plasmid pCL101 the highest levels of transformation were 26–28% (cotyledons and internodes, respectively). While GFP represents a potentially useful transformation marker that allows the non-destructive evaluation of transformation, rates of GFP transformation under the conditions of this study were low. It will be necessary to optimize expression of this marker gene in peach.