Genetic control of biennial bearing in apple

Although flowering in mature fruit trees is recurrent, floral induction can be strongly inhibited by concurrent fruiting, leading to a pattern of irregular fruiting across consecutive years referred to as biennial bearing. The genetic determinants of biennial bearing in apple were investigated using the 114 flowering individuals from an F1 population of 122 genotypes, from a ‘Starkrimson’ (strong biennial bearer)בGranny Smith’ (regular bearer) cross. The number of inflorescences, and the number and the mass of harvested fruit were recorded over 6 years and used to calculate 26 variables and indices quantifying yield, precocity of production, and biennial bearing. Inflorescence traits exhibited the highest genotypic effect, and three quantitative trait loci (QTLs) on linkage group (LG) 4, LG8, and LG10 explained 50% of the phenotypic variability for biennial bearing. Apple orthologues of flowering and hormone-related genes were retrieved from the whole-genome assembly of ‘Golden Delicious’ and their position was compared with QTLs. Four main genomic regions that contain floral integrator genes, meristem identity genes, and gibberellin oxidase genes co-located with QTLs. The results indicated that flowering genes are less likely to be responsible for biennial bearing than hormone-related genes. New hypotheses for the control of biennial bearing emerged from QTL and candidate gene co-locations and suggest the involvement of different physiological processes such as the regulation of flowering genes by hormones. The correlation between tree architecture and biennial bearing is also discussed

Detecting QTLs and putative candidate genes involved in budbreak and flowering time in an apple multiparental population

UMR AGAP - équipe AFEF - Architecture et fonctionnement des espèces fruitièresIn temperate trees, growth resumption in spring time results from chilling and heat requirements, and is an adaptive trait under global warming. Here, the genetic determinism of budbreak and flowering time was deciphered using five related full-sib apple families. Both traits were observed over 3 years and two sites and expressed in calendar and degree-days. Best linear unbiased predictors of genotypic effect or interaction with climatic year were extracted from mixed linear models and used for quantitative trait locus (QTL) mapping, performed with an integrated genetic map containing 6849 single nucleotide polymorphisms (SNPs), grouped into haplotypes, and with a Bayesian pedigree-based analysis. Four major regions, on linkage group (LG) 7, LG10, LG12, and LG9, the latter being the most stable across families, sites, and years, explained 5.6–21.3% of trait variance. Co-localizations for traits in calendar days or growing degree hours (GDH) suggested common genetic determinism for chilling and heating requirements. Homologs of two major flowering genes, AGL24 and FT, were predicted close to LG9 and LG12 QTLs, respectively, whereas Dormancy Associated MADs-box (DAM) genes were near additional QTLs on LG8 and LG15. This suggests that chilling perception mechanisms could be common among perennial and annual plants. Progenitors with favorable alleles depending on trait and LG were identified and could benefit new breeding strategies for apple adaptation to temperature increase

Espaço Público: Espetáculo, vigilância e controle

3º congresso – As múltiplas Faces da Arquitetura Contemporânea de 2016 – As múltiplas Faces da Arquitetura Contemporânea – foram apresentados pelos/as estudantes da disciplina de Crítica e História da Arquitetura e da Cidade IV sob orientação da professora Andreia Moassab, do curso de Arquitetura e Urbanismo da Universidade Federal da Integração Latino-americana – UNILA. O congresso é parte da avaliação final da disciplina, no qual os/as estudantes apresentam a sua versão e dialogam com autores/as e textos de referência sobre a arquitetura nas últimas décadasO espaço público tem como característica o coletivo, segundo a pesquisadora Diane Ghirardo. A autora demonstra como este espaço, após a segunda guerra mundial foi repensado. Se no período antecedente o espaço público constituía uma esfera otimista, voltado ao povo, a partir das décadas de 50 e 60, ele passa a ter uma concepção exclusivista, barrado às diferenças que compõem a sociedad

Evaluer la sélection génomique au sein de croisements bi-parentaux d’espèces pérennes fruitières génotypés par séquençage : point d’étape du projet FruitSelGen

Poste

Mais pourquoi donc mon arbre fruitier ne revient-il pas à fleur chaque année ?

La floraison des arbres fruitiers est essentielle pour obtenir une production de fruits. Chaque année, l’arbre doit produire des fleurs pour assurer une régularité de productioN. De nombreux facteurs peuvent perturber cette production de fleurs et de fruits. Pour certaines espèces, notamment les fruitiers à pépins (pommiers, poiriers), il est même fréquemment observé une alternance de production. Cela se caractérise par une fructification abondante une anéne, suivie par une année très peu florifère, puis à nouveau une année productive. La connaissance du cycle de production de l’espèce est importante pour comprendre les mécanismes sousjacents à ce comportement, notamment il est nécessaire de connaître la période de l’induction florale sur ce cycle. Pour la plupart des arbres fruitiers tempérés, els bourgeons en hiver ont déjà les fleurs préparées pour la floraison printanière. La période de l’induction florale dans les bourgeons est située durant la saison végétative précédant la floraison. Durant cette période, certains méristèmes végétatifs reçoivent une information qui les conduit à modifier leur fonctionnement pour élaborer des fleurs. L’étude des mécanismes physiologiques et génétiques favorisant l’induction florale s’appuie sur les travaux effectués sur les plantes modèles. Pour le pommier, les recherches en génétique sont conduites pour contribuer à la sélection de variétés nouvelles peu alternantes. En atendant, des opérations culturales peuvent être mises en œuvre pour favoriser la régularité de floraison des variétés sensibles à l’alternance

Variations saisonnieres du transport et de la distribution de l'acide abscissique et de quelques nutriments dans les rameaux de hetre (Fagus sylvatica L.)

SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : T 78701 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Shoot type demography and dry matter partitioning: a morphometric approach in apple (Malus xdomestica)

International audienc

The shoot system architecture of Vitis vinifera ssp. sativa

International audienceConversely to many other woody perennial crops, the Vitis vinifera grapevine does not display self-supporting and limited-in-space aerial architectures, but rather develops extended shoot systems relying on external mechanical supports. This behavior results from both structural factors, i.e. stem anatomy, bud and phytomer organisation, and also specificities in the modulation of primary growth and branching, i.e. phyllotaxis, apical dominance and acrotony. To mitigate the most limiting biological properties for cultivation, the grapevine domestication need a range of practices to facilitate plant management and improve agronomic performances. The structure and the functioning of the shoot system regulate not only the potential of biomass accumulation and source/sink balance and but also the canopy microclimate with effects on fruit quality and organ fungus susceptibility. This paper reviews the main biological processes and management practices that regulate grapevine shoot system architecture and development, revisiting the associated terminology

Transcriptional analyses of root responses under soil water stress of one-year old apple cultivars

UMR AGAP - équipe AFEF - Architecture et fonctionnement des espèces fruitièresGlobal climate change may lead to longer or more frequent episodes of extreme temperatures and drought, thus threatening plant crops. Thus, we focused on apple tree aiming to identify the molecular mechanisms that are triggered when trees face water soil deficit. We focused on differentially expressed transcripts (DET) in roots, between well-watered trees compared to trees grown under soil water deficit either moderate (MS) and severe (SS). Two apple cultivars, ‘Starkrimson’ (ST) and ‘Granny Smith’ (GS), with contrasted behavior under water deficit, were grafted on M9 rootstock and grown in pots under controlled conditions. Roots were sampled when transpirable soil water (FTSW)=0.5 and FTSW=0.2 were reached, for MS and SS stress, respectively. RNA was extracted and analyzed using the AryANE micro-array apple chip to identify DET response to moderate and severe soil water deprivation. Among DET in roots, 209 up and 137 down-regulated genes were common to both cultivars under MS while 148 up and 542 down-regulated genes were common to both cultivars under SS. DET linked to the response to osmotic stress were observed at MS, especially signal sensors proteins kinases and phosphatases which were up-regulated. As expected, DET related to abscissic acid (ABA) were highly expressed under water deficit conditions, both ABA-dependent (ADP) and ABA-independent pathways (AIP) being stimulated. ABA biosynthesis was activated in both genotypes in MS, even though to a lesser extent in ST than in GS. However, these transcripts were no more differentially expressed in SS, suggesting that other mechanisms are involved under SS. Specific DET to each genotype were also observed. ST had a higher number of upregulated DET at MS and downregulated DET at SS than GS. Such results prove that even when grafted on the same rootstock, we notice a significant difference on the ST and GS roots system response to the soil water deficit evidencing that root systems (here M9) response to the soil water deficit depends on the grafted scion, probably because of different transpiration and regulation in response to soil water deprivation of the two scion genotypes. Further analyses are currently performed to decipher DET in aerial organs

Multispectral airborne imagery in the field reveals genetic determinisms of morphological and transpiration traits of an apple tree hybrid population in response to water deficit

UMR AGAP - équipe AFEF - Architecture et fonctionnement des espèces fruitièresGenetic studies of response to water deficit in adult trees are limited by low throughput of the usual phenotyping methods in the field. Here, we aimed at overcoming this bottleneck, applying a new methodology using airborne multispectral imagery and in planta measurements to compare a high number of individuals.An apple tree population, grafted on the same rootstock, was submitted to contrasting summer water regimes over two years. Aerial images acquired in visible, near- and thermal-infrared at three dates each year allowed calculation of vegetation and water stress indices. Tree vigour and fruit production were also assessed. Linear mixed models were built accounting for date and year effects on several variables and including the differential response of genotypes between control and drought conditions.Broad-sense heritability of most variables was high and 18 quantitative trait loci (QTLs) independent of the dates were detected on nine linkage groups of the consensus apple genetic map. For vegetation and stress indices, QTLs were related to the means, the intra-crown heterogeneity, and differences induced by water regimes. Most QTLs explained 15−20% of variance.Airborne multispectral imaging proved relevant to acquire simultaneous information on a whole tree population and to decipher genetic determinisms involved in response to water deficit