Apple production depends on the fulfilment of a chilling requirement for bud dormancy release. Insufficient winter chilling results in irregular and suboptimal bud break in the spring, with negative impacts on apple yield. Trees from apple cultivars with contrasting chilling requirements for bud break were used to investigate the expression of the entire set of apple genes in response to chilling accumulation in the field and controlled conditions. Total RNA was analysed on the AryANE v.1.0 oligonucleotide microarray chip representing 57,000 apple genes. The data were tested for functional enrichment, and differential expression was confirmed by real-time PCR. The largest number of differentially expressed genes was found in samples treated with cold temperatures. Cold exposure mostly repressed expression of transcripts related to photosynthesis, and long-term cold exposure repressed flavonoid biosynthesis genes. Among the differentially expressed selected candidates, we identified genes whose annotations were related to the circadian clock, hormonal signalling, regulation of growth, and flower development. Two genes, annotated as FLOWERING LOCUS C-like and MADS AFFECTING FLOWERING, showed strong differential expression in several comparisons. One of these two genes was upregulated in most comparisons involving dormancy release, and this gene's chromosomal position co-localized with the confidence interval of a major quantitative trait locus for the timing of bud break. These results indicate that photosynthesis and auxin transport are major regulatory nodes of apple dormancy and unveil strong candidates for the control of bud dormancy.

The molecular control of bud dormancy establishment and release is still not well understood, although some genes have already been demonstrated to play important roles in this process. The dormancy-associated MADS-box (DAM) genes were first identified in the peach EVERGROWING locus and are considered the main regulators of bud dormancy control. In this work, the apple (Malus × domestica Borkh.), a perennial plant adapted to temperate climates that displays cycles of growth and bud dormancy, was screened for the presence of DAM genes. The candidate genes retrieved were characterized in comparison to DAM genes from other species. Four of them (MdDAM1-4) are structurally very similar to the reported DAM genes. When apple genomic segments containing these candidates were compared to the peach EVERGROWING locus, a highly conserved noncoding region was detected inside their largest intron. Similar sequences were also identified inside introns of apricot and pear DAM genes. Organ expression patterns revealed that MdDAM1-4 are mainly expressed in dormant buds and seeds, with low transcript accumulation in vegetative structures. In addition, the MdDAM genes showed seasonally oscillating patterns of steady-state messenger RNA (mRNA) levels and were downregulated by artificial chilling. Motif analyses in the promoter and in the intronic conserved region of the MdDAM genes disclosed some clues to the regulation of the expression patterns observed. Possible roles for the conserved intronic sequence in dormancy regulation are discussed.

RESUMO -Objetivou-se com este trabalho determinar as curvas de crescimento de aves de postura das linhagens semipesadas Hy Line Marrom (HLM) e Hisex Marrom (HSM) e leves Hy Line W36 (HLW36) e Hisex Branca (HSB). Foram utilizadas 300 aves de cada linhagem, distribuídas em um delineamento experimental inteiramente casualizado, com quatro repetições de 75 aves por tratamento. Semanalmente, foram avaliados o peso vivo (PV), o peso de pena (PP) e a composição corporal de proteína, gordura, cinzas e água. As curvas de crescimento foram determinadas aplicando-se os dados na função Growth curves and deposition of body components in pullets of different strains ABSTRACT -The growth curves of egg pullets of semi heavy: Hy Line Brown (HLB) and Hisex Brown (HSB) and light strains: Hy Line W36 (HLW36) and Hisex White (HSW) were evaluated. Three hundred birds of each strain were assigned to a completely randomized design with four replicates of 75 birds. Body weight (BW), feather weight (FW) and body depositions of protein, fat, ash and water were weekly measured. The growth curves were determined by Gompertz function with data collections. The semi heavy birds were later than the light ones for BW, with greater body growth rates and weights at maturity.The HLW36 were 64.23 g lighter at maturity than the HSW. Data obtained for feather growth and protein deposition were similar, but the semi heavy birds showed greater weight at maturity (WM) than the light ones. However, for these components, the birds Hy Line had larger depositions than Hisex. HLW36 strain had smaller feather rate at maturity, making it three days later than HSW. The lowest protein deposition in the end of growth period caused the deviation of energy ingested for fat deposition in HSB birds and overestimated the WM in relation to HLB birds. Hy Line birds had later body ash composition and showed greater WM than Hisex. Among the studied variables, Hy Line birds had always heavier WM, however, the body water content of Hisex birds was greater and the maximum rates at maturity were later. This fact explains the similarity in the weight gain among the studied strains, once other body components were greater for Hy Line birds.Key Words: body composition, Gompertz function, laying birds, pullets IntroduçãoAs linhagens de postura utilizadas atualmente, em virtude do constante melhoramento genético, estão aumentando continuamente a produção de ovos, diminuindo o peso à maturidade fisiológica, a idade de pico de produção, o consumo de alimento e o ganho de peso. Desta forma, os programas nutricionais destas aves devem ser reavaliados

RESUMO -No presente estudo, determinaram-se as influências da cobertura plástica impermeável (CP) sobre a demanda evaporativa atmosférica e o potencial da água no solo, bem como as conseqüências destas sobre as trocas gasosas foliares (fotossíntese, condutância estomática e transpiração) e o potencial da água na folha da videira. As avaliações foram realizadas nos ciclos 2005/06 e 2006/07, em um vinhedo da cv. Moscato Giallo, conduzido em "Y", com cobertura plástica impermeável tipo ráfia (160 μm), em 12 fileiras com 35 m, deixando-se cinco fileiras sem cobertura (controle). Em ambas as áreas, avaliou-se o microclima quanto à temperatura do ar, umidade relativa do ar, radiação fotossinteticamente ativa e velocidade do vento, próximos ao dossel vegetativo. A CP aumentou a disponibilidade hídrica no solo nas entrelinhas e restringiu-a nas linhas, sobretudo em profundidades mais superficiais (0-10 cm). A CP também diminuiu a demanda evaporativa atmosférica, principalmente pela redução da velocidade do vento (-90%), aumentando o potencial da água na folha e a condutância estomática. De modo geral, a CP pode favorecer a condição hídrica e elevar a capacidade de assimilação de carbono em videiras. Termos para indexação: Condutância estomática, transpiração, demanda evaporativa, cultivo protegido, videira. WATER RELATIONS AND LEAF GAS EXCHANGE IN VINEYARD WITH PLASTIC OVERHEAD COVERABSTRACT -This study evaluated the plastic overhead cover (POC) effect on evaporative demand of atmosphere and soil water content, as well as their consequences on gas exchange (photosynthesis, stomatal conductance and transpiration) and leaf water potential in grapevine. The experiment was carried out during the 2005/06 and 2006/07 seasons, in a vineyard of 'Moscato Giallo', trained in "Y" and covered with an impermeable plastic cloth (2.65 m x 160 μm), in 12 rows with 35 m, with five rows left uncovered (control). In both areas, the microclimate was evaluated, in terms of air temperature, air relative humidity, radiation photosynthetically active and wind speed above the canopy. The POC increased the soil water content between rows and restricted it in the most superficial depths of rows (0-10 cm). The POC also decreased the evaporative demand of atmosphere, mainly by reducing wind speed (-90%), which increased the leaf water potential and stomatal conductance. In this way, POC can favor water conditions and increase leaf carbon assimilation in grapevines.

Fluctuations in winter chilling availability impact bud dormancy and budburst. The objective of this work was to determine chilling requirements to induce and overcome endodormancy (dormancy controlled by chilling) of buds in different grape cultivars. ‘Chardonnay’, ‘Merlot’ and ‘Cabernet Sauvignon’ shoots were collected in Veranópolis-RS vineyards in 2010, and submitted to a constant 3 °C temperature or daily cycles of 3/15 °C for 12/12h or 18/6h, until reaching 1120 chilling hours (CH, sum of hours with temperature ≤ 7.2 °C). Periodically, part of the samples in each treatment was transferred to 25 °C for budburst evaluation (green tip). Chilling requirements to induce and overcome endodormancy vary among cultivars, reaching a total of 136 CH for ‘Chardonnay’, 298 CH for ‘Merlot’ and 392 CH for ‘Cabernet Sauvignon’. Of these, approximately 39, 53 and 91 CH are required for induction of endodormancy in the three cultivars, respectively. The thermal regimes tested (constant or alternating) do not influence the response pattern of each cultivar to cold, with 15 °C being inert in the CH accumulation process. In addition, time required to start budburst reduces with the increase in CH, at a rate of one day per 62 CH, without significant impacts on budburst uniformity.