Efecto del aclareo de frutos sobre la composición mineral del fruto del níspero japonés (Eriobotrya japonica Lindl.) y su relación con la mancha púrpura

This work studies the effect of competition among developing fruits on the mineral concentration of the flesh and rind tissues of loquat fruit and its relation to the incidence of purple spot. When fruit reached 10 mm in diameter, the trees were hand-thinned to 1, 3 or 5 fruits per panicle, using non-thinned trees as control trees. In flesh tissue, K concentration significantly increased and Fe concentration significantly decreased at colour break in response to thinning. In rind tissue, N, K, Mg and Fe concentration diminished at colour break, depending on the thinning intensity, down to 23%, 21%, 27% and 41%, respectively, for one fruit per panicle treatment. Changes in the mineral composition of fruits caused by thinning significantly increased the gradient of concentration of N, K, Ca and Mg between the rind and the flesh tissue. This increase in the mineral gradient correlates positively and significantly with the percentage of purple-spotted fruit.En este trabajo se estudia el efecto de la competencia entre frutos de níspero en desarrollo sobre la concentración de elementos minerales en la piel y en la pulpa y su relación con la incidencia de la mancha púrpura. Cuando los frutos alcanzaron 10 mm de diámetro, los árboles se aclararon a 1, 3 ó 5 frutos por panícula, dejando árboles sin aclarar como controles. Como consecuencia del aclareo, la concentración de K y de Fe de la pulpa aumentó y disminuyó, respectivamente, alcanzando la significación estadística en el momento del cambio de color. En la piel, y en el momento del cambio de color, la concentración de N, K, Mg y Fe disminuyó con la intensidad de aclareo hasta un 23%, 21%, 27% y 41%, respectivamente, para el tratamiento de un fruto por panícula. Estos cambios en la composición mineral del fruto debidos al aclareo incrementaron significativamente el gradiente de concentraciones de N, K, Ca y Mg entre la pulpa y la piel que, a su vez, se correlacionaron positiva y significativamente con el porcentaje de frutos afectados de mancha púrpura

Relacje między różnymi fizycznymi właściwościami owoców pomidora a utratą wody po zbiorze

Water loss contributes to acceleration of postharvest senescence of tomato (Solanum lycopersicum L.). Ten cultivars representing two fruit types were studied. Fruit were stored at 25ºC and 75% relative humidity. Physical characteristics were examined to determine relationships between physical properties and water loss rate in tomato fruit. Water loss rate increased almost linearly with storage time and was different for each cultivar. When the vapour pressure deficit was increased the fruit water loss rate was affected among cultivars. Water loss rate was positively correlated with initial fruit water content. An increase in the surface are a to volume of fruit may explain the differences in water loss that was observed between cultivars. The cuticle thickness did not influence the differences in the fruit water loss during storage. However, it was observed the existence of a positive correlation between Surface Area of the Peduncle Scar to Fruit Surface Area ratio and water loss of the tomato fruit.Utrata wody przyczynia się do przyspieszenia starzenia się pomidorów (Solanum lycopersicum L.). Badano 10 odmian reprezentujących dwa typy owoców. Owoce przechowywano w temperaturze 25ºC przy 75% wilgotności względnej. Badano cechy fizyczne w celu określenia związków między fizycznymi cechami a wskaźnikiem utraty wody w owocach pomidora. Wskaźnik utraty wody wzrastał prawie w sposób liniowy wraz z czasem przechowywania i był inny dla każdej odmiany. Zwiększony deficyt ciśnienia pary wpływał na wskaźnik utraty wody w owocach poszczególnych odmianach.Wskaźnik utraty wody był pozytywnie skorelowany z początkową zawartością wody w owocach. Zwiększenie powierzchni do objętości owocu może wyjaśniać różnice w utracie wody zaobserwowane pomiędzy odmianami. Grubość skórki nie wpływała na różnice w utracie wody podczas przechowywania. Zaobserwowano jednak dodatnią korelację między stosunkiem powierzchni blizny po szypułce a powierzchnią owocu w stosunku do utraty wody w owocach pomidora

Phenology and reproductive traits of peaches and nectarines in Central-East Argentina Fenologia e comportamento reprodutivo de pêssego no centro-leste da Argentina

In Santa Fe, the central-east area of Argentina, the expansion of fruit tree crops requires the introduction and evaluation of low chilling varieties. The aims of this study was to characterize the phenological behaviour and the reproductive traits of peach (Prunus persica L. Batsch) and nectarine varieties with chilling requirements ranging from 150 to 650 chilling hours (CH). Low chilling varieties (< 450 CH) had higher flower density (22.0-56.5 flowers m-1), fruit set (26.0-56.7%), fruit yield (9.3-36.6 kg per plant), and low coefficient of fruit yield variability than varieties with a higher chilling requirement (>500 CH). The phenology of high chilling requirement varieties had the advantage that blooming and fruit set happened after the period of late frost occurrence. However, they did not satisfy their chilling requirement, showing an inadequate vegetative and reproductive behaviour. Low chilling varieties began to sprout during July, and the period of full bloom occurred from July 14th to August 4th. Fruit harvest was initiated on October 19th with the cv. 'Flordastar' and it extended for 58 days. However, on low chilling varieties the harvest time was reduced in ten days. Flower density, fruit set and fruit yield showed a negative relationship with the chilling requirement of the variety.<br>Na região centro-leste do estado de Santa Fé, Argentina, para a expansão dos frutais é preciso introduzir variedades de baixo requerimento de frio. O objetivo deste estudo foi caracterizar o comportamento durante as fases de crescimento e frutificação de variedades de pêssego (Prunus persica L. Batsch) e nectarina com requerimentos de frio que variam entre 150-650 horas de frio (CH). As variedades de pêssego de baixa necessidade de frio (< 450 CH) mostraram maior densidade de flores (22.0-56.5 flores m-1), de estabelecimento de frutos (26.0-56.7%), e rendimento de fruta (9.3-36.6 kg por planta) comparado com variedades de pêssego com necessidade de frio maior (>500 CH). As variedades de maior necessidade de frio tiveram a vantagem da floração, e o estabelecimento dos frutos aconteceu depois do período de risco de geadas. Porém, essas variedades não têm satisfeita sua necessidade de frio, apresentando comportamento vegetativo e reprodutivo inadequado. As variedades de baixa necessidade de frio brotaram entre 4 a 31 de julho e o período de plena floração aconteceu entre 14 de julho a 4 de agosto. A colheita de fruta começou em 19 de outubro com o cv. 'Flordastar', e sua duração foi de 58 dias. Para as variedades de baixa necessidade de frio o período de colheita foi dez dias mais curto

Basal temperature and thermal sum in phenological phases of nectarine and peach cultivars

The objective of this work was to evaluate basal temperature, thermal sum at different phenological stages, phenological phase duration, yield and seasonality of one nectarine and 14 peach cultivars, between 2006 and 2009. The considered phenological phases were: pruning-sprouting; sprouting-flowering, from swollen bud to open flower; flowering-fruiting, from petal fall to medium-sized fruit; and ripening. Minimum basal temperatures (Tb) obtained were: pruning-sprouting, 8°C, irrespective of the cultivars; sprouting-flowering, 10°C, except for 'Cascata 968', which required 8°C Tb; flowering-fruiting, 12°C, except for 'Oro Azteca', which required 14°C Tb; ripening, 14°C, except for 'Sunblaze', 'Diamante Mejorado' and 'Precocinho' with 12°C Tb. For most cultivars, the maximum basal temperatures were 30, 34, 34 and 28ºC for phases pruning-sprouting, sprouting-flowering, flowering-fruiting and ripening, respectively. 'Turmalina', 'Marli' and 'Tropic Beauty' showed average yields of 3,945.0, 3,969.3 and 3,954.0 kg ha-1, respectively, in 2009, while the nectarine 'Sunblaze' showed around 3,900 kg ha-1 in 2008 and 2009. The cultivars differed for their total cycle and for the accumulated thermal sums which varied, respectively, from 245 days and 1,881.4 degree-days for 'Oro Azteca', to144 days and 1,455.7 degree-days for 'Precocinho'