Effective temperature for overcoming dormancy of 'Fuyu' persimmon tree buds

The objective of this study was to evaluate the effective temperature for overcoming the dormancy of 'Fuyu' persimmon tree buds. Stem samples were collected three times between 2013 and 2014. Stems were maintained in a climate incubator chamber at 3, 6, 9, and 12 °C. For each temperature, five numbers of additional chilling hours (CH) (0, 240, 384, 528, and 672 CH) were studied. The experimental design was completely randomized in a 5 × 4 factorial design (chilling hours × temperatures) with four replications with 10 cuttings. The maintenance of branches at cold temperatures from 3 to 12 °C intensified endodormancy of the buds when the plants were at the beginning of endodormancy. The most effective temperatures for overcome dormancy when the buds were in transition from paradormancy to endodormancy were from 3 to 6 °C. When the buds were already in endodormancy, temperatures of 3, 6, 9, and 12 °C were effective for the accumulation of cold and overcoming dormancy. The increase in the number of chilling hours from 3 to 12 °C induced budburst and the temperature of 12 °C was able to slowly induce and overcome bud dormancy.

Identification of laccase gene family members in peach and its relationship with chilling induced browning / 生物工程学报

The laccase (PpLAC) gene family members in peach fruit were identified and the relationship between their expression pattern and chilling induced browning were investigated. The study was performed using two varieties of peaches with different chilling tolerance, treated with or without exogenous γ-aminobutyric acid (GABA) during cold storage. Twenty-six genes were screened from the peach fruit genome. These genes were distributed on 6 chromosomes and each contained 5-7 exons. The PpLAC gene family members shared relatively similar gene structure and conserved motifs, and they were classified into 7 subgroups based on the cluster analysis. Transcriptome sequencing revealed that the expression levels of PpLAC7 and PpLAC9 exhibited an increasing pattern under low temperature storage, and displayed a similar trend with the browning index of peach fruit. Notably, GABA treatment reduced the degree of browning and inhibited the expression of PpLAC7 and PpLAC9. These results suggested that PpLAC7 and PpLAC9 might be involved in the browning of peach fruit during cold storage.

Antimicrobial resistance of Escherichia coli isolates from spray‑chilled sheep carcasses during cooling / Resistencia antimicrobiana en aislados de Escherichia coli de canales de ovejas asperjadas durante la refrigeración / Resistência antimicrobiana de isolados de Escherichia coli de carcaças ovinas aspergidas durante o resfriamento

Abstract Background: Multidrug-resistant bacteria present in food of animal origin raise human and animal health concerns. Objective: To assess antimicrobial resistance of Escherichia coli isolates from sheep carcasses subjected to spray-chilling with water (4 and 10 hours) during cooling. Methods: Thirty surface swabs were collected from carcasses before and after the last water spray in two slaughter periods. In a first assessment (1st sampling), three spray-chilled carcasses (4 hours), three non-sprayed and one control carcass were sampled. In a second assessment (2nd sampling), the same number of carcasses and treatments were maintained, but spray-chilling was extended to 10 hours. All samples collected were isolated and submitted to susceptibility test using 16 (1st sampling) and 17 (2nd sampling) antimicrobials, respectively. Results: Overall, E. coli isolates were resistant most antimicrobials. Spray-chilled and control carcasses (10 hours) showed resistance to meropenem. Conclusion: E. coli isolates from carcasses subjected to spray-chilling with water for 10 hours had higher antimicrobial resistance to one, two, and four antimicrobial classes, characterizing a multidrug resistance profile. These results highlight the need to monitor health status throughout the meat production processes.

Resumen Antecedentes: las bacterias multirresistentes presentes en alimentos de origen animal son motivo de alerta para la salud humana y animal. Objetivo: verificar la resistencia a antimicrobianos de aislados de Escherichia coli en canales ovinas sometidas a aspersión (4 y 10 h) durante la refrigeración. Métodos: Luego de dos faenas de sacrificio, treinta hisopos fueron colectados en la superficie de las canales antes y después de la última aspersión. En un primer sacrificio (1era colecta) se recolectaron muestras de tres canales sometidas a aspersión (4 horas), tres sin aspersión y una canal como control. En un segundo sacrificio (2da colecta), el mismo número de canales y tratamientos se mantuvo, y el período de aspersión se extendió a 10 horas. Las muestras recogidas fueron aisladas y sometidas a la prueba de susceptibilidad utilizándo 16 (1.ª colecta) y 17 (2.ª colecta) antimicrobianos, respectivamente. Resultados: los aislamientos de E. coli fueron, en general, resistentes a las principales clases de antimicrobianos. Las canales con aspersión y el control (10 h) presentaron resistencia al meropenem. Conclusión: cuando la asperción duró 10 h, los aislados de E. coli presentaron mayor resistencia para una, dos y cuatro clases de antimicrobianos, es decir, fueron multirresistentes a los fármacos utilizados. Esto resalta la necesidad de monitorear el estado de salud durante todos los procesos de producción de carne.

Resumo Antecedentes: bactérias multirresistentes presentes em alimentos de origem animal são motivo de preocupação e alerta na saúde humana e animal. Objetivo: verificar a resistência antimicrobiana em isolados de Escherichia coli de carcaças de ovinos pulverizadas ou não (4 e 10 horas) durante a refrigeração. Métodos: foram coletados trinta swabs de superfície em carcaças antes e após a última aspersão em dois abates. Em outubro do 2015, três carcaças aspergidas foram amostradas, três sem aspersão e uma carcaça para controle, por um período de 4 horas. Em julho de 2016 (2ª coleta), o mesmo número de carcaças e tratamentos foram mantidos e o período de aspersão foi prolongado em 10 horas. As amostras coletadas foram isoladas e submetidas ao teste de susceptibilidade em 16 (1ª coleta) e 17 (2ª coleta) antimicrobianos, respectivamente. Resultados: isolados de E. coli foram, em geral, resistentes às principais classes de antimicrobianos. As carcaças e o controle aspergidos (10 h) apresentaram resistência ao meropenem. Conclusão: quando a aspersão de água durou 10 horas, os isolados de E. coli apresentaram maior resistência antimicrobiana a uma, duas e quatro classes de antimicrobianos, o que é uma multirresistência aos fármacos testados. Isso alerta para a necessidade de monitorar os aspectos de saúde durante todos os processos de produção de carne.

Dormancy of Floral Buds of Rabbiteye Blueberry in a Mild Winter Climate

Abstract Blueberry is an important fruit crop, with many health benefits. Despite its importance, much remains to be studied concerning the dormancy dynamics in rabbiteye cultivars growing in a mild winter climate. In this research, the dormancy in blueberry, rabbiteye cultivars 'Bluegem', 'Climax', 'Delite', and 'Powderblue', was studied in a mild winter region. The single-node cuttings biological test and the evaluation of the hydric status were performed in dormant winter reproductive buds. These experiments were performed during fall and winter in one year (2016). Moreover, chilling hours under or equal to 7.2 ºC were measured, and chill units were calculated according to Utah Model [1], Modified Utah Model [2], and Blueberry Model [3]. In conclusion, the four cultivars showed a similar pattern, revealing a dormant state in the initial sampling dates and a released dormancy in the final treatments, showing the decrease of dormancy in June and July. However, Delite was earlier than the other cultivars. Bluegem and Delite required 134.0 chilling hours, 127.0 chill units (Utah Model), 198.5 chill units (Modified Utah Model), and 971.5 chill units (Blueberry Model) for 50% of their green tip buds reach the opened bud stage. Climax required 44.0, -11.0, 56.5, and 440.5, respectively. And Powderblue required 44.0, 5.5, 77.0, and 725.0 respectively. This study can bring some insights into crop management and production of this important fruit crop, especially in a global climate-changing scenario, related to flowering and dormancy control, as well as helping to select suitable cultivars to a region, concerning chilling requirements.

Induction and overcoming of dormancy of grapevine buds in response to thermal variations in the winter period / Indução e superação da dormência de gemas de videiras em resposta a variações térmicas no período hibernal

ABSTRACT: This study quantified the chilling requirements for the induction and overcoming of endodormancy (chilling-controlled physiological dormancy) of grapevines buds. Cuttings of the cultivars Chardonnay, Merlot and Cabernet Sauvignon were collected in vineyards in Veranópolis-RS in the winter period of 2019 and 2020. The cuttings were kept at a constant temperature of 7.2 °C or daily cycles of 7.2/18 °C for 6/18 h, 12/12 h or 18/6 h, up to 600 chilling hours (CH). Every 50 CH, part of the cuttings from each treatment was transferred to a temperature of 25 °C for daily assessment of the budburst in the green tip stage. The cultivars had different chilling requirements for inducing and overcoming endodormancy, reaching a total of 150 CH for 'Chardonnay', 300 CH for 'Merlot' and 400 CH for 'Cabernet Sauvignon'. Of these, 50 CH were required to induce endodormancy in cultivars Chardonnay and Merlot and 100 CH for cultivar Cabernet Sauvignon. Dormancy evolution did not differ between cultivars in response to thermal regimes, with a temperature of 18 °C inert to the accumulation of CH. Precocity and uniformity of budburst were higher after chilling requirements were met during endodormancy for each genotype.

RESUMO: Este estudo visou quantificar as necessidades de frio para a indução e superação da endodormência (dormência fisiológica controlada por frio) de gemas de videiras. Estacas de das cultivares Chardonnay, Merlot e Cabernet Sauvignon foram coletadas em vinhedos em Veranópolis-RS, no período hibernal de 2019 e 2020. As estacas foram submetidas a temperatura de 7,2 ºC constante ou a ciclos diários de 7,2/18 °C por 6/18 h, 12/12 h ou 18/6 h, até 600 horas de frio (HF). A cada 50 HF, parte das estacas de cada tratamento foi transferida para a temperatura de 25°C, para avaliação diária da brotação das gemas, em estádio de ponta verde. As cultivares tiveram necessidades distintas de frio para indução e superação da endodormência, atingindo um total de 150 HF para 'Chardonnay', 300 HF para 'Merlot' e 400 HF para 'Cabernet Sauvignon'. Destes totais, 50 HF foram necessárias para indução da endodormência nas cultivares Chardonnay e Merlot e 100 HF na cultivar Cabernet Sauvignon. A evolução da dormência não diferiu entre cultivares em resposta aos regimes térmicos, sendo a temperatura de 18 °C inerte ao acúmulo de HF. A precocidade e uniformidade de brotação das gemas foram maiores após suprido o frio na dormência para cada genótipo.

Performance of blueberry cultivars under mild winter conditions / Desempenho de cultivares de mirtileiro em condição de inverno ameno

ABSTRACT: Evaluation of yield performance is important to find the most adapted blueberry cultivars in a particular region. This research aimed to evaluate the flowering and hasvesting periods, the production per plant, and fruit quality of eight rabbiteye blueberry cultivars (Aliceblue, Bluebelle, Bluegem, Briteblue, Climax, Delite, Powderblue, and Woodard) and two highbush blueberries (Georgiagem and O'Neal), in mild winter conditions in Pinhais-PR. Flowering and harvesting periods, production, berry weight, size, pH, soluble solids, titratable acidity, ratio and color of the fruits were evaluated in the 2013/2014 and 2014/2015 growing seasons, when the plants had two and three years old, respectively. Cultivars flowered from August to September, and harvest was concentrated in November and December. Berry weight, size, pH, soluble solids and acidity varied among the cultivars. The average ratios of 14.97 and 13.39 for each crop proved that the cultivars have good fruit quality. There was little variation in fruit color in the two years evaluated. Blueberry cultivars showed the staining characteristics and physical and chemical attributes of quality compatible to blueberry from other traditional regions. Under mild winter conditions, young plants of rabbiteye blueberry cultivars, Climax, Delite, Bluegem and Powderblue, are the most productive, while the highbusch cultivars bear few fruits.

RESUMO: A avaliação do desempenho produtivo é importante para encontrar as cultivares de mirtileiro mais adaptadas à uma determinada região. Este trabalho teve como objetivo avaliar o período de floração e de colheita, a produção por planta e a qualidade de frutos de oito cultivares de mirtileiro do grupo rabbiteye (Aliceblue, Bluebelle, Bluegem, Briteblue, Climax, Delite, Powderblue e Woodard) e duas do grupo highbush (Georgiagem e O'Neal) em condição de inverno ameno em Pinhais-PR. Foram avaliadas as datas de início e final de floração, início e final de colheita, produção por planta, massa, tamanho de fruto, pH, teor de sólidos solúveis, acidez titulável, ratio e coloração nos ciclos produtivos de 2013/2014 e 2014/2015, quando as plantas possuíam dois e três anos, respectivamente.As cultivares estudadas apresentaram floração nos meses de agosto e setembro, concentrando a colheita nos meses de novembro e dezembro. Houve diferenças entre as cultivares quanto a massa do fruto, tamanho, pH, teor de sólidos solúveis e a acidez. O ratio médio de 14,97 e 13,39 obtido em cada safra provou que as cultivares tem boa qualidade de frutos. A coloração dos frutos apresentou poucas variações nos dois anos avaliados. O mirtilo das cultivares avaliadas apresentou características de coloração e atributos físicos e químicos de qualidade compatível com o mirtilo de outras regiões tradicionalmente produtoras. Em região com inverno ameno, plantas jovens das cultivares Climax, Delite, Bluegem e Powderblue, do grupo rabbiteye, são as mais produtivas, enquanto as cultivares do grupo highbush produzem poucos frutos.

Produção e qualidade pós-colheita de cultivares de pereira nas condições subtropicais da região leste paulista / Production and postharvest quality of pear tree cultivars in subtropical conditions at eastern of São Paulo state, Brazil

Objetivou-se avaliar o desempenho produtivo e a qualidade pós-colheita de cultivares de pereira nas condições subtropicais da região leste paulista. Para tanto, um ensaio de competição de cultivares foi implantado no município de Jundiaí-SP, com cinco cultivares ('Centenária', 'Triunfo', 'Primorosa', 'Seleta' e 'Tenra'). O experimento foi implantado em 2007, no espaçamento de 3,0mx4,0m, com mudas enxertadas no porta-enxerto Pyrus calleryana. As avaliações foram realizadas em três ciclos vegetativos (2009/10, 2010/11 e 2011/12), analisando-se os aspectos fenológicos, produtivos e a qualidade pós-colheita das frutas. A pereira 'Tenra' apresentou a maior produção, com 6kg de frutos por planta. As cultivares estudadas produziram frutas com coloração típica e firmeza aceitável, porém pouco doces.

This research aimed to evaluate the production and postharvest quality of pear tree cultivars in subtropical conditions at eastern of São Paulo state. For such, an assay of competition among cultivars was implanted in the Jundiaí city-SP, with five cultivars ('Centenária', 'Triunfo', 'Primorosa', 'Seleta' and 'Tenra'). The experiment was implanted in 2007, the spacing was of 3.0mx4.0m, and the plants were grafting in Pyrus calleryana. The evaluations had been carried through in three vegetative cycle (2009/10, 2010/11 and 2011/12), the phenological stage, productive aspects and fruit postharvest quality were evaluated. The pear 'Tenra' presented highest production, with 6kg of fruits per plant. The cultivars produced fruits with typical coloring firmness and acceptable, but slightly sweet.

Effect of Desiccation and Chilling Treatment on Somatic Embryo Development and Germination in Rough Lemon (Citrus jambhiri Lush).

The goal of this study was to evaluate the effect of desiccation and chilling treatments on somatic embryogenesis of rough lemon (Citrus jambhiri Lush.). Styles were cultured on seven culture media (MS I-MS VII) containing Benzylaminopurine (BAP), Kinetin (KN) and Malt Extract for cell proliferation and somatic embryo development. Cell proliferation was maximum on MS IV media but maximum cultures showing somatic embryogenesis (52.08 %) was observed on MS VII media. Embryogenic callus proliferated on MS VII media was subjected to desiccation and chilling treatment for 24, 48, 72 and 96 hours. Embryogenic callus desiccated for 24 and 48 hours in sterile petriplates showed 58.33 and 56.94 % somatic embryogenesis respectively as compared to undesiccated callus (51.98%). Average number of cotyledonary embryos (6.80/culture) in embryogenic cultures from desiccated callus (48 hrs) was more as compared to untreated callus (2.26/culture). There was significantly less number of abnormal embryos (0.60-0.53/culture) in desiccated callus for 48, 72 and 96 hours as compared to untreated callus (7.20/culture). Chilling treatment also improves the average number of cotyledonary embryos and reduces the abnormal development of embryos. Among all the treatments desiccation of embryogenic callus for 48 hrs proved beneficial for improvement of somatic embryo development and germination.

An efficient method in breaking of dormancy from Bunium persicum (Boiss) Fedtsch seeds: A valuable herb of Middle East and Central Asia

Objective: To develop a protocol for breaking of seed dormancy and increasing the seed germination rate of Bunium persicum. Methods: The seeds were treated with 3.1, 6.3, 12.5, 25, 50 and 100 μmol/L of benzyl aminopurine, gibberellic acid (GA

Temperaturas e disponibilidades hídricas do substrato na germinação de sementes de niger / Temperatures and substrate water availability on niger seeds germination

O niger (Guizotia abyssinica Cass.) é uma oleaginosa com potencial para a produção de biodiesel com poucas informações a respeito da qualidade fisiológica com que suas sementes são produzidas. Objetivou-se avaliar a germinação e o crescimento das plântulas de niger sob diferentes temperaturas e disponibilidades hídricas no substrato. O primeiro experimento foi conduzido em câmaras de germinação do tipo B.O.D. com temperaturas constantes (5, 10, 15, 20 e 25 °C) e uma temperatura alternada (20-30 °C). Para o segundo experimento as sementes foram semeadas sobre substrato de papel umedecido com soluções de Polietileno Glicol 6000 em diferentes potenciais osmóticos (0,0; -0,2; -0,4; -0,8 e -1,2 MPa) e mantidas em câmara de germinação do tipo B.O.D. na temperatura de 25°C. Avaliou-se a porcentagem, o índice de velocidade e o tempo médio de germinação, os comprimentos da parte aérea e da raiz e as massas fresca e seca das plântulas. As temperaturas de 20, 25 e 20-30 °C aumentaram a porcentagem e a velocidade de germinação das sementes de niger, que são sensíveis a temperaturas inferiores a 15 °C. A redução da disponibilidade hídrica do substrato a partir do potencial osmótico de -0,2 MPa prejudica a germinação e o crescimento de plântulas.

Niger (Guizotia abyssinica Cass.) is an oilplant with biodiesel potential production. However, there is little information about the seeds physiological quality production. This work aimed to evaluate niger germination and seedlings growth submitted to different temperature and substrate water availability. The first experiment was carried out in a germination chamber as B.O.D. with constants temperatures (5, 10, 15, 20 e 25 °C) and an alternated temperature (20-30 °C). For the second experiment seeds were sowed on paper substrate Polyethylene Glicol 6000 different osmotic potentials moisture solutions (0.0; -0.2; -0.4; -0.8 e -1.2 MPa) and it were kept in the germination chamber as B.O.D. at 25°C. Evaluated the germination percentage, germination speed index, germination medium time, aerial part and root length and fresh and dry seedlings mass. Results showed the 20-30, 25 e 20 °C temperatures favored the niger seeds germination percentage and speed index. Niger seeds are sensitive to temperatures below 15 °C and the substrate water availability decrease from -0.2 MPa prejudice seeds germination and seedlings growth.

An efficient method in breaking of dormancy from Bunium persicum (Boiss) Fedtsch seeds: a valuable herb of Middle East and Central Asia

<p><b>OBJECTIVE</b>To develop a protocol for breaking of seed dormancy and increasing the seed germination rate of Bunium persicum.</p><p><b>METHODS</b>The seeds were treated with 3.1, 6.3, 12.5, 25, 50 and 100 µmol/L of benzyl aminopurine, gibberellic acid (GA3), thidiazuron (TDZ) and forchlorfenuron. Then, seeds were transferred to two different temperature conditions including room temperature (25 °C) and chilling temperature (2-5 °C).</p><p><b>RESULTS</b>The treatment of moist seeds with chilling temperature (2-5 °C) broke seed dormancy and showed maximum germination, which was 54.7% after 60 d treatment. Also, the treatment of dry seeds with chilling temperature broke seed dormancy with 9.3% germination rate after 120 d. Treatment of seeds with different level of plant growth regulators showed that under moist-room condition, there was evidence of higher and lower seed germination rate: GA3 (100 µmol/L) with 46.7% and TDZ (50 µmol/L) with 6.67% respectively. In addition, the results showed that under moist-chilling condition, TDZ (6.3 µmol/L) with 53.3% seed germination rate had higher influence on breaking seed dormancy. Treatment of seeds with combination of TDZ and GA3 under moist-chilling condition revealed higher rate of breaking of seed dormancy when 6.3 µmol/L TDZ was combined with 100 µmol/L GA3, showing 93.7% germination rate.</p><p><b>CONCLUSIONS</b>The effect of plant growth regulators coupled with chilling temperature on breaking of seed dormancy could provide a large number of seedlings while the long juvenile time which is the next restricting factor of plantation still remained. Thus, the subsequent growth of seedlings to provide a large number of corms is necessary for successful plantation.</p>

An efficient method in breaking of dormancy from Bunium persicum (Boiss) Fedtsch seeds:a valuable herb of Middle East and Central Asia

Objective: To develop a protocol for breaking of seed dormancy and increasing the seed germination rate of Bunium persicum. Methods:The seeds were treated with 3.1, 6.3, 12.5, 25, 50 and 100 μmol/L of benzyl aminopurine, gibberellic acid (GA3), thidiazuron (TDZ) and forchlorfenuron. Then, seeds were transferred to two different temperature conditions including room temperature (25 °C) and chilling temperature (2-5 °C). Results: The treatment of moist seeds with chilling temperature (2-5 °C) broke seed dormancy and showed maximum germination, which was 54.7%after 60 d treatment. Also, the treatment of dry seeds with chilling temperature broke seed dormancy with 9.3%germination rate after 120 d. Treatment of seeds with different level of plant growth regulators showed that under moist-room condition, there was evidence of higher and lower seed germination rate:GA3 (100 μmol/L) with 46.7%and TDZ (50 μmol/L) with 6.67%respectively. In addition, the results showed that under moist-chilling condition, TDZ (6.3 μmol/L) with 53.3%seed germination rate had higher influence on breaking seed dormancy. Treatment of seeds with combination of TDZ and GA3 under moist-chilling condition revealed higher rate of breaking of seed dormancy when 6.3 μmol/L TDZ was combined with 100 μmol/L GA3, showing 93.7%germination rate. Conclusions:The effect of plant growth regulators coupled with chilling temperature on breaking of seed dormancy could provide a large number of seedlings while the long juvenile time which is the next restricting factor of plantation still remained. Thus, the subsequent growth of seedlings to provide a large number of corms is necessary for successful plantation.

Disponibilidades climáticas para macieira na região de Vacaria, RS / Climate availability for apple trees in Vacaria, southern Brazil

O objetivo deste trabalho foi avaliar a variabilidade e as tendências temporais das principais variáveis climáticas - temperaturas máxima, mínima e média do ar, horas de frio (abaixo de 7°C), precipitação pluvial e umidade relativa do ar - no período 1983-2009 e confrontá-las com as necessidades de macieiras dos grupos Gala e Fuji, na região de Vacaria, RS. Foram utilizados dados diários de estação meteorológica da Embrapa, do período de 1983 a 2009, e comparados com as normais 1931-1960 e 1961-1990, para análise de tendência temporal. A precipitação pluvial apresentou diferenças significativas entre a média do período 1983-2009 e as normais, com aumentos de 479 e 256mm, respectivamente. Não houve diferenças significativas na temperatura do ar mensal entre os períodos analisados. A precipitação pluvial da primavera e a temperatura mínima do ar mensal apresentaram tendência significativa de aumento. O número médio de horas de frio foi de 657 de maio-agosto. O número mínimo de horas de frio delimitado no zoneamento agroclimático é atingido, na maioria dos anos, na região de Vacaria, no entanto, não significa a superação natural da dormência de gemas de macieiras. Além disso, o número de horas de frio apresentou tendência temporal de redução.

This study aimed to evaluate the variability and temporal tendency for the main climate parameters - air maximum, minimum and mean temperatures, chilling hours (bellow to 7°C), pluvial precipitation, and relative air humidity - in the 1983-2009 period, focusing to evaluate the climate conditions for Gala and Fuji apple groups, in Vacaria, Brazil. Daily weather data in the 1983-2009 series were compared to climate means of the 1931-1960 and 1961-1990 periods, for analyzing the temporal trends. The annual pluvial precipitation showed significant differences in comparing the 1983-2009 series to both the climate means, with increments of 479 and 256mm, respectively. There were no significant differences in monthly air temperatures among the analyzed periods. The pluvial precipitation in spring season and the annual mean of minimum air temperature showed significant tendencies for increasing. The mean number of 657chilling hours was from May to August. The minimum number of chilling hours defined zoning of agroclimatic is achieved in most of the years, in Vacaria, however, does not mean the natural breaking of bud dormancy the apple tree. Otherwise, the number of chilling hours had a significant tendency for reducing.

Produção e atributos de qualidade de cultivares de macieira nas condições subtropicais da região Leste paulista / Production and quality attributes of apple tree cultivars in subtropical conditions at eastern of São Paulo state

Objetivou-se avaliar o desempenho adaptativo, produtivo e atributos de qualidade de cultivares de macieira nas condições subtropicais da região leste paulista. Para tal, um ensaio de competição de cultivares foi implantado no município de Jundiaí, SP, com sete cultivares ('Eva', 'Condessa', 'Princesa', 'Rainha', 'Imperial Gala', 'Daiane', e 'Baronesa'). O experimento foi implantado em 2006, no espaçamento de 3,0mx1,5m, com mudas enxertadas no porta-enxerto Marubakaido e interenxerto M9. As avaliações foram realizadas em dois ciclos produtivos (2008/09 e 2009/10), analisando-se os aspectos fenológicos, produtivos e atributos de qualidade do fruto. As cultivares de macieira 'Eva', 'Baronesa' e 'Princesa' apresentaram maior produção de frutos. A cultivar 'Baronesa' apresentou atributos de qualidade mais adequados ao consumo ao natural, com menor acidez titulável e boa firmeza de polpa e ratio mais elevado.

These research aimed evaluate the production and quality attributes of apple tree cultivars in subtropical conditions at eastern of São Paulo state. For such, an assay of competition among cultivars was implanted in the Jundiaí city, SP, with seven cultivars ('Eva', 'Condessa', 'Princesa', 'Rainha', 'Imperial Gala', 'Daiane', and 'Baronesa'). The experiment was implanted in 2006, the spacing was 3,0mx1,5m, and the plants were grafting in Marubakaido roostock and M9 inter-grafting. The evaluations had been carried through in two production cycle (2008/09 and 2009/10), the phenological stage, productive aspects and fruit quality attributes were evaluated. 'Eva', 'Baronesa' and 'Princesa' showed higher productive performance. The 'Baronesa' apple presented fruit quality attributes most suitable for the fresh market, i.e., lower acidity and good firmness, and the highest ratio.

Effect of sodium nitroprusside on morphological characters under chilling stress in chickpea (Cicer arietinum L.).

An experiment was conducted with chilling tolerant (IC-424234) and sensitive (PBG-1) chickpea (Cicer arietinum L.) genotypes to study the effect of sodium nitroprusside (SNP) – nitric oxide donor applied as foliar spray of 150 and 300 µM concentrations at 45 DAS (vegetative stage), 85 DAS (flowering stage) and 125 DAS (post flowering stage). Both the concentrations of SNP (150 and 300 µM) resulted in significant increase in all the morphological characters viz. plant height, number of leaves plant-1, leaf area plant-1 and leaf area index (LAI) over the control at all the stages, though lower concentration (150 µM) was more effective. Chilling sensitive (CS) genotype PBG-1 responded more effectively to SNP treatment. Electrolyte leakage percentage was effectively reduced by SNP treatments in both the genotypes at low temperature (15 DAA). Chilling sensitive genotype PBG-1 treated with SNP (150 µM) recorded significantly higher yield contributing characters viz. number of pods plant-1, number of seeds pod-1, seed yield plant-1(g), pod setting percentage (%), 100 seed weight (g) and yield (kg ha-1) over the chilling tolerant (IC-424234).

Ablandamiento d frutos de pitaya amarilla (acathocereus pitajaya) a temperatuura ambiente y en refrigeración: actividad de poligalacturonasa, celulasa y xilanasa / Yellow Pitaya (Acanthocereus pitajaya) Fruit Softening During its Storage at Room Temperature and on Refrigerated Conditions: Polygalacturonase, Celualase and Xilanase Activities

Una de las mayores causas de pérdidas poscosecha de frutos de pitaya amarilla es su ablandamiento excesivo, el cual ha sido documentado previamente cuando la fruta es almacenada a temperaturas de cosecha o después de refrigeración. Además, tratamientos de choque térmico antes del almacenamiento refrigerado ofrecen control en el ablandamiento de estos frutos. Diferentes experimentos fueron llevados a cabo para evaluar el papel de algunas enzimas degradadoras de pared celular en el ablandamiento de frutos de pitaya amarilla: almacenamiento a 18 °C (TA) y refrigeración con choque térmico previo (ChT-R). Se incluyó también un tratamiento refrigerado control, sin choque térmico (control-R). Si midió el color de la corteza, la firmeza y las actividades de poligalacturonasa (PG), celulasa (CEL) y xilanasa (XIL). La evaluación del color indicó que los frutos almacenados a TA alcanzaron su madurez comercial luego de seis días. Luego de 12 días de almacenamiento a TA el pardeamiento y ablandamiento excesivo afectaron negativamente la calidad de los frutos. El pardeamiento y ablandamiento excesivo fueron detectados también en los frutos control-R cuando se movieron de 2 a 18 °C. Un ligero pardeamieno fue observado en los frutos ChT-R. Estos frutos alcanzaron su madurez comercial luego de 24 días de almacenamiento (nueve días luego de terminado el almacenamiento refrigerado). La actividad de XIL se asoció al ablandamiento en los frutos almacenados a TA y ChT-R. No se observó una clara correlación entre las actividades de PG y el ablandamiento, como tampoco entre CEL y el ablandamiento.

One of the major causes of yellow pitaya fruit loss during its marketing is its excessive softening, which has been previously documented when the fruit is stored at harvest temperature or after refrigeration. Furthermore, its excessive softening has been controlled by the application of heat shock treatments before refrigeration. Different experiments were carried out to evaluate the role of cell wall degrading enzymes on yellow pitaya fruit softening: storage at 18 °C (RT) as well as refrigeration with previous heat shock treatment (HS-R). A refrigerated control, without heat shock, was included (control-R). Peel color, firmness, poligalacturonase (PG), celulase (CEL) and xilanase (XIL) activities were measured. RT fruits reached the commercial ripeness after six days, as indicated by the color evaluation. After 12 days of storage at RT browning and excessive softening negatively affected the fruit quality. Browning and excessive softening were also detected in the control-R fruit when moving from 2 to 18°C. Minor browning was found in the HS- R fruit. HS-R fruit was full ripe 24 days of storage (nine days after finishing the refrigerated storage). XIL activity was associated to the softening in the RT and HS-R fruits. No clear correlation was observed between PG and softening neither between CEL and softening.

Identification of chilling-responsive transcripts in peanut (Arachis hypogaea L. )

To isolate differentially expressed peanut genes responsive to chilling, a suppression subtractive hybridization (SSH) cDNA library was constructed for a chilling tolerant peanut cultivar A4 with mRNAs extracted from the seeds imbibed at 2ºC and 15ºC, respectively, for 24 hrs. A total of 466 cDNA clones were sequenced, from which 193 unique transcripts (73 contigs and 120 singlets) were assembled. Of these unique transcripts, 132 (68.4 percent) were significantly similar to the sequences in GenBank non-redundant (nr) protein database, which belonged to diverse functional categories including metabolism, signal transduction, stress response, cell defense and transcriptional regulation. The remaining 61 (31.6 percent) showed no similarity to either hypothetical or known proteins. Six differentially expressed transcripts were further confirmed with real-time quantitative PCR (RT-qPCR).

Comparative studies on morphological and biochemical characters of chickpea genotypes under chilling stress.

Comparison of chickpea (Cicer arietinum L.) genotypes for morphological and biochemical attributes was done. Morphological characters viz. Plant height, number of branches and number of leaves were recorded highest in chilling tolerant genotypes at early stages of development (30 and 60 DAS) whereas at later stages (90 and 120 DAS) these characters were recorded highest in chilling sensitive genotypes. Pollen viability percentage at 5 and 10oC temperatures were recorded highest in chilling tolerant genotypes as compared to sensitive genotypes. Biochemical characters viz. electrolyte leakage (%), total soluble sugars and total free amino acids were recorded highest in chilling tolerant genotypes as compared to sensitive genotypes.

Effect of exogenous H2O2 on antioxidant enzymes of Brassica juncea L. seedlings in relation to 24-epibrassinolide under chilling stress.

Hydrogen peroxide is most stable molecule among reactive oxygen species, which play a vital role in growth and development of plant as signaling molecule at low concentration in response to various abiotic and biotic stresses. Exogenous application of H2O2 is known to induce chilling tolerance in plants. Brassinosteroids are plant steroid hormones known for their anti-stress properties. In this study, effect of exogenous H2O2 on antioxidant defense system of Brassica juncea L. seedlings was investigated in 24-epibrassinolide (24-EBL) treated and untreated seedlings under chilling stress. The surface sterilized seeds of B. juncea L. were germinated in petriplates containing different concentrations of H2O2 alone and in combination with 10-8 M 24-EBL. Chilling treatment (4 ºC) was given to 10-days old seedlings grown in different treatments for 6 h daily up to 3 days. 24 h recovery period was given to chilling treated seedlings by placing at 25ºC ± 2ºC and harvested for antioxidant enzymes on 14th day after sowing (DAS). Treatment of 24-EBL in combination with H2O2 (15 and 20 mM) helped in reducing the toxicity of seed and seedlings due to H2O2 exposure on their germination rate, shoot and root length respectively. 24-EBL treatment at seed and seedling stage helped in alleviating the toxic effect of H2O2 through antioxidant defense system by increasing the activities of various enzymes involved in antioxidant defense system such as catalase (CAT, E.C. 1.11.1.6), ascorbate peroxidase (APOX, E.C. 1.11.1.11), and superoxide dismutase (SOD, E.C. 1.15.1.1). In conclusion, exogenous pretreatment of H2O2 to seeds of B. juncea L. adapted the seedlings to tolerate chilling stress, which was further ameliorated in combination of H2O2 with 24-EBL.

Reinstate hydrogen peroxide as the product of alternative oxidase of plant mitochondria.

Chill treatment of potato tubers for 8 days induced mitochondrial O2 consumption by cyanide-insensitive alternative oxidase (AOX). About half of the total O2 consumption in such mitochondria was found to be sensitive to salicylhydroxamate (SHAM), a known inhibitor of AOX activity. Addition of catalase to the reaction mixture of AOX during the reaction decreased the rate of SHAM-sensitive O2 consumption by nearly half, and addition at the end of the reaction released half of the O2 consumed by AOX, both typical of catalase action on H2O2. This reaffirmed that the product of reduction of O2 by plant AOX was H2O2 as found earlier and not H2O as reported in some recent reviews.